Linux Wireless LAN Howto 1 Introduction

< Linux Wireless LAN Howto >
Linux Wireless LAN Howto
Jean Tourrilhes
12 December 05
Linux & Wireless LANs : Un*x, with no string attached...
1 Introduction
This document will explore the magical world of Wireless LANs and Linux.
Wireless LAN is not a very widespread and well known technology, even in the
Linux world, so we will try to gather here most of the available information.
Despite the fact that it is very similar to common networking technologies, it is
significantly different to justify this specific document covering the subject.
1.1
What is a Wireless LAN ?
It’s a networking technology allowing the connection of computers without
any wires and cables (apart from the mains), mostly using radio technology (and
sometime infrared). It’s called LAN (Local Area Network) because the range
targeted is small (within an office, a building, a store, a small campus, a house...).
This technology is slowly growing (I should say maturing), and despite a general
lack of interest, Linux is able to take advantage of some of the wireless networks
available.
1.2
Content of this document
My first task is to talk a bit about the different Wireless LANs options under
Linux. What the products on the market are, their compatibility with Linux and
where to find the necessary bits and pieces to make them work. This should help
you to make your mind on the product of your dreams.
Once you’ve picked a Wireless LAN, you will have to live with it. The next
chapter go through the main differences of Wireless LAN compared to other
networking technologies. This includes the main steps of the installation and usage
considerations.
Then, we will have a nice overview of the Wireless Extensions. The Wireless
Extensions is a new standard interface to configure Wireless LAN devices and get
wireless specific statistics from them. Of course, this is a Linux exclusivity !
At this point, you will find a long and dense section, talking mostly of the
different technologies used in Wireless LANs and other boring related stuff. It is
quite safe to skip that one.
1.3
Target and Assumptions
The main goal of this document is to reduce the traffic of unanswered
questions related to wireless in the Linux newsgroups and mailing lists (and in my
1
< Linux Wireless LAN Howto >
mailbox). After that, you should have no more arguments for asking foolish
questions around (but I know you will do anyway).
I hope that this document will help people to make the most of their Wireless
LAN under a competent operating system and understand what is in the box. If I
could convince people to give it a try, it would make me happy.
This document act mostly as a complement to the exhaustive documentation
existing for Linux. Because of that, I might not explain every details of everything
and target already quite knowledgeable people. Don’t worry, there is a section on
how to improve your culture at the beginning of the section 3.
1.4
Legal stuff
Strange world where everybody has to protect himself from sharks, lawyers
and crazy people :
Any information in this document is purely fictious and any resemblance to
real hardware, software or driver is purely coincidental...
I mean, if because you read this document your hardware burn, you get fired
from your job or anything else bad happen, I’m not responsible, it can’t be my fault,
so please use your own brain. Writing this kind of documents is not part of my job
at HP, so I don’t expect them to claim any responsibility for its content.
Any brand mentioned in this document is trademark of its respective owner.
For example Linux is a trademark of Linus Torvalds.
Then, this is my document, written by me (Jean Tourrilhes), therefore I own
its copyright. So don’t remove my name (and copyright notice) and pretend that you
wrote it yourself. In matter of copy, distribution and modification, you should ask
me politely and use common sense.
Having said that, this document is also licensed under the terms of the Linux
Documentation Project Copying License.
1.5
This document
This document is only available in the format that are convenient to me
(acrobat/pdf, html). It might be updated in the future (if I feel like it and if I have
some time). I guess that it is pretty safe to assume that it will still be available for
the time to come at these web addresses :
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Wireless.html
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Wavelan.html
I may be reached at the following e-mail address :
[email protected]
Constructive comments and interesting information are welcomed. I hope
that you will help me to keep this document up to date and improve its content.
Comments about my english and my style will be answered in french (because
I still curse better in french than in italian). Flames and spam will be processed
through a Rayleig Fading channel with a -120 dB attenuation in order to reduce
the noise :-)
2
< Linux Wireless LAN Howto >
2 The devices, the drivers - pre-802.11 and early 802.11
The following four sections describes the most common Wireless LAN
products available on the market and their compatibility with Linux. Except in
a few case, you need a driver to interface you wireless network device to the Linux
kernel. The availability of a driver is as usual your main concern, especially with
wireless devices because fewer people are using such hardware, and the wireless
drivers are complex, so few of them are willing to develop, debug and maintain such
a piece of code.
I will make a short description of each product and will mainly focus on the
drivers. For each driver, I will list its status (stable, buggy...), the maintainer, the
version, how to get it and the main features. If you hear about something new or if
you have developed yourself a driver, please notify me.
Because of the large number of drivers, it has been divided in four sections,
the first cover really old devices, the second 802.11b devices, the third one devices
faster than 802.11b and the fourth one other stuff.
This section list devices predating the IEEE 802.11 standard or based on the
early IEEE 802.11 standards (see section 8), either 802.11 Frequency Hopping or
802.11 Direct Sequence. Those devices are mostly obsolete and discontinued, so
most of you want to skip directly to the next section (see section 3).
2.1
Lucent Wavelan & DEC RoamAbout DS
Driver status :
stable
Driver name :
ISA : wavelan.o
Pcmcia : wavelan_cs.o
Version :
v19 (20/4/99), v20 (29/7/99) or v23 (10/10/00)
Where :
ISA : Linux kernel (2.0.37, 2.2.11 & 2.3.15)
Pcmcia : Pcmcia package (3.0.11)
Creators :
Maintainer :
Web page :
Mailing list :
Documentation :
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Bruce Janson (ISA) and Anthony D. Joseph (Pcmcia)
Jean Tourrilhes <[email protected]>
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Wavelan.html
http://lists.samba.org/pipermail/wireless/
man pages, headers
Wireless Extensions
Wireless Extensions
Ad-Hoc
DES (only for hardware with the DES option)
No
Yes (nwid off + tcpdump)
isa : up to 4
pcmcia : yes
3
< Linux Wireless LAN Howto >
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
proprietary protocol, interoperate with Windows
module, hardware multicast, Wireless Extensions, SMP
roaming
see release notes on web page :-(
GPL & OpenSource
http://www.wavelan.com/
http://www.networks.digital.com/dr/wireless/
http://www.cabletron.com/dnpg/dr/npg/lanfm-mn.html
2.1.1
The device
The Wavelan has been around for quite a while now, and this product is now
discontinued (and replaced by the Wavelan IEEE/Orinoco - see section 3.1). The
Wavelan is a radio LAN, using the 900 MHz or 2.4 GHz ISM band (Direct
Sequence). It is built by Lucent, formerly AT&T, formerly NCR, and there is a few
OEM version (for example the DEC RoamAbout DS). The Wavelan comes in two
flavours, an ISA card and a PCMCIA card (plus the access point).
The Wavelan appears to the PC as a standard network card and interfaces
naturally with the networking stack. The configuration includes setting the
frequency (10 different channels), Network ID (16 bits). Hardware encryption is
optional (DES or AES - 64 bits key).
This product is built around a standard Ethernet controller (that may be
found in some 3Com and Intel Ethernet cards), and the Ethernet physical layer is
replaced by a radio modem. The ISA and Pcmcia cards share the same basic
architecture, have the same modem, but have different Ethernet Controllers and
bus interfaces (the pcmcia has only one transmit buffer). Because the Wavelan
doesn’t use a specific radio MAC (no MAC level retransmissions for example), it
uses very efficiently the bandwidth, but is more sensitive to packet loss and
collisions.
There is two versions of the modem, a 900 MHz and a 2.4 GHz version.
Revision 2 of the 2.4 GHz modem allows the user to set the frequency (from a set
of predefined channels - the availability of each channel depend on the regulation).
The Wavelan is Direct Sequence Spread Spectrum (11 chips encoding), using a
2 Mb/s signalling rate (using effectively 22 MHz of bandwidth) and diversity
antennas.
2.1.2
The driver
The ISA driver has also been around for quite a while now in the kernel and
is pretty stable. The last set of modifications were to solve a few remaining small
problems and add Wireless Extensions and some other features, so the driver is
fairly complete now. The only things remaining to do is the implementation of the
roaming protocol (but it might come, if I’m not too lazy...).
The Pcmcia driver has caught up with the ISA one to offer the same level of
functionality and reliability. The only difference are the pcmcia specific functions
(auto loading, auto unloading, crude power saving).
4
< Linux Wireless LAN Howto >
The latest releases of both drivers (v23) adds SMP support.
The drivers use the card EEprom to save the configuration changes for
subsequent reboots. Wireless Extensions let you configure the NWID, the
frequency, the sensitivity and the encryption key (optional). Statistics include the
signal quality, signal level, noise level and the count of packet received with an
invalid NWID (see Wavelan documentation). Private Wireless Extensions include
the setting of the quality threshold.
2.2
Netwave AirSurfer & Xircom Netwave
Driver status :
fairly stable
Driver name :
netwave_cs.o
Version :
v 0.4.1
Where :
Linux kernel (2.4.0)
Pcmcia package (2.9.12)
Maintainers :
John Markus Bjørndalen <[email protected]>
Dag Brattli <[email protected]>
Web pages :
http://www.cs.uit.no/~johnm/
http://www.cs.uit.no/~dagb/
Documentation :
man page
Configuration :
Module parameters & Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
8 bit scrambling
Scanning :
No
Monitor :
No
Multi-devices :
yes (except for module parameters setting)
Interoperability :
proprietary protocol, interoperate with Windows
Other features :
Non implemented : hardware multicast, multiple transmit buffers
Bugs :
License :
OpenSource
Vendor web page : http://www.netwave-wireless.com/
2.2.1
The device
The Netwave was also a quite common product, but nowadays this product is
discontinued. This is a radio LAN operating in the 2.4 GHz ISM band. It was
built by Netwave Technologies, formerly part of Xircom. The Netwave is Pcmcia
only, and comes in a small form factor (everything is included on the Pcmcia card !).
The Netwave use a specific MAC protocol designed for radio (a pre 802.11
protocol, with fancy stuff such as RTS/CTS, virtual carrier sense and
5
< Linux Wireless LAN Howto >
fragmentation). It uses a 9 bits domain (Network ID), the highest bit of it used for
the type of network (set for access point operation and unset for ad-hoc operation).
The Netwave uses also a 16 bits scrambling key (encryption). The Modem offers a
1 Mb/s signalling rate and frequency hopping (100 ms hop period). On the bad side,
the Netwave has no antenna diversity and a high overhead.
Note that the Netwave AirSurfer plus is a very different beast (see below).
2.2.2
The driver
The original author of the driver (John) has made a very good job for
debugging it, and his good friend (Dag) has joined the project, and is fixing the
remaining bugs and adding new features. The driver is quite simple and don’t
implement yet the full Wireless Extensions. The driver uses only one transmit
buffer, which lower slightly the performance. The device configuration includes the
domain and the scrambling key which can be set through Wireless Extensions or
as module parameters (need to be set in /etc/pcmcia/config.opts - don’t forget to
restart cardmgr after a change).
It seems that the Netwave is quite picky with some pcmcia sockets and you
might need to choose carefully the interrupt (try different ones) and set the
memory speed correctly. In some cases, under high load (big ftp), the transmission
sometime get stuck (I guess that some interrupt are lost) and the driver has to reset
the card (you won’t notice it, it just decreases the performance).
2.3
Netwave AirSurfer plus
Driver status :
fairly stable
Driver name :
asplus_cs.o
Version :
1.0.2
Where :
http://ipoint.vlsi.uiuc.edu/wireless/asplus.html
ftp://projects.sourceforge.net/pub/pcmcia-cs/contrib/
Maintainer :
Jay Moorman <[email protected]>
Documentation :
Readme, man page
Configuration :
Module parameters, Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
8 bit scrambling
Scanning :
No
Monitor :
No
Multi-devices :
yes (except for module parameters setting)
Interoperability :
proprietary protocol (same as Netwave), interoperate with
Windows
Other features :
Non implemented : 802.11 mode, hardware multicast, multiple transmit buffers
Bugs :
-
6
< Linux Wireless LAN Howto >
License :
OpenSource
Vendor web page : http://www.netwave-wireless.com/
2.3.1
The device
The Netwave AirSurfer plus is the second generation of Netwave card (this
product is now also discontinued), still operate in the 2.4 GHz ISM band and is
as well a small Pcmcia card. Netwave Technologies has now been acquired by
BayNetwork, now a part of Nortel. The BayStack 650 is the new name of the
hardware.
The AirSurfer plus has two modes of operation, compatible with the old
generation of Netwave, or 802.11 compliant. The hardware is based on an AMD
core, and a 1 Mb/s frequency hopping modem.
2.3.2
The driver
Jay took the code of the original Netwave driver and modified it to support the
new AirSurfer plus, keeping most of the features with it. So, you still have the
Wireless Extensions, and modules parameters (in /etc/pcmcia/config.opts).
The current driver support the AirSurfer plus only in Netwave compatible
mode, and doesn’t support the AirSurfer plus with the 802.11 firmware.
2.4
Harris Prism based cards : BayStack 660, ZoomAir, YDI and other...
Driver status :
stable
Driver name :
wlan_cs.o
Version :
0.2.7, 0.2.7a, 0.3.1.1 (beta version) and 0.3.4 (beta version)
Where :
http://www.linux-wlan.com/linux-wlan/
http://www.astro.umd.edu/~teuben/linux/wireless.html
http://www.cs.berkeley.edu/~jhill/linuxwlan/
http://www.spesh.com/danny/wlan
Maintainers :
Mark S. Mathews <[email protected]>
Peter Teuben <[email protected]>
Jason Hill <[email protected]>
Danny O’Brien <[email protected]>
Mailing list :
http://www.linux-wlan.com/linux-wlan/
Documentation :
Readme, man page
FAQ :
http://linux.grmbl.be/wlan/
Configuration :
Module parameters & configuration tool
Statistics :
Statistic tool
Modes :
Managed, Ad-Hoc
Security :
?
Scanning :
?
Monitor :
Yes
7
< Linux Wireless LAN Howto >
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
yes
802.11-DS, interoperate with Windows
Quite exhaustive 802.11 support
WEP
MPL
http://www.netwave-wireless.com/
http://www.zoomtel.com/zoomair/
http://www.ydi.com
http://www.intalk.com/
http://www.dbtel.com.tw/english.html
http://www.gemtek.com.tw/
http://www.sem.samsung.co.kr/
http://www.intersil.com/prism/
http://www.amd.com/products/npd/npd.html
2.4.1
The device
The Harris Prism chipset and the AMD AM930 controller are some highly
integrated parts designed to ease the process of building 802.11 products. Harris
has done a Pcmcia reference design based on their chipset and the AMD core,
which explain the high number of vendors building variants of this card (the Harris
website has a longer list than mine ;-). A special mention for YDI (Young Design
Inc) which openly support Linux (see below). Note that all those products are now
discontinued (and replaced with PrismII design - see section 3.6)...
The AMD core integrates a generic microcontroller and the hardware
baseband (ASIC) to do the time critical functions of 802.11. AMD has developed the
802.11 firmware with all the usual basic 802.11 features (MAC level ACK, RTS/
CTS, Fragmentation...). The Prism chipset is a 2.4 GHz Direct Sequence modem
offering 1 and 2 Mb/s. The Prism chipset can also be extended to supports the new
802.11 HR standard, with 5.5 and 11 Mb/s bit-rate (either MBOK or CCK
modulation).
The Pcmcia cards are mostly similar from vendor to vendor. Some vendors
offer ISA cards, and the Access Points are where vendors are making their
difference (ZoomTelephonics uses a software AP on a PC, others have hardware
AP). Each vendor also has to provide the high level 802.11 in their drivers
(authentication, WEP, Roaming...), so those might be different (not that it does
matter much under Linux).
The BayStack 650 and Netwave AirSurfer plus use the same AMD controller,
but a different physical layer (Frequency Hopping), so are not compatible with this
driver.
Harris has just become Intersil and released the Prism II chipset, successor
of the PrismI chipset, this time including the MAC controller (so they won’t use any
8
< Linux Wireless LAN Howto >
more the AMD part in their reference design). I’ll detail it in the next section (see
section 3.6).
2.4.2
The driver
Mark and the people at AVS have developed a full 802.11 driver for the Prism
reference design card (AMD controller + Prism chipset), and this driver work for
the many other implementations as well (see web page).
The driver is well written and very complete : it’s currently the only driver
where most of the higher layer 802.11 functionality is implemented. There is also
many initialisation parameters and a tool to configure the card. Because the 802.11
standard is very complex, not everything is totally finished and a few features like
WEP (RC4 40 bits encryption) are missing.
There is currently two branches maintained by Mark, 0.2.X which is stable
and 0.3.X which is experimental.
Peter (with help from YDI) has created a alternative version of Mark’s
package to add ISA support, fix a few bugs and with explicit support of cards from
YDI. In the long run, those changes should find their way in Mark’s package...
Jason has created a version of the 0.3.1 beta driver with support for the
BayStack 660, by porting bits from 0.2.6 (this allow support for both the BayStack
660 and infrastructure).
Danny has a patch to make the driver compile and work with kernel 2.4.X.
I believe that this driver doesn’t support the BayStack 650 and Netwave
AirSurfer plus cards (which don’t use the Prism chipset but Frequency Hopping),
but the changes for that might not be that hard to implement.
2.5
Z-Com LANEscape, ELSA MC2, Siemens I-Gate
Driver status :
?
Driver name :
wl24_cs.o
Version :
1.3 (stable), 2.03 (unstable) and 1.53beta2 (Elsa full source)
Where :
http://mc2drv.berlios.de/
Linux kernel (2.6.0-test2)
http://www.boerde.de/~matthias/airnet/zcom/
http://www.boerde.de/~tobias/
http://www.elsa.de
http://pcmcia-cs.sourceforge.net/ftp/contrib/
Maintainers :
Jörg Albert <joerg dot albert at gmx dot de>
Arnaldo Carvalho de Melo <[email protected]>
Gustavo Niemeyer <[email protected]>
Matthias Weingart <[email protected]>
Alfred Arnold <[email protected]>
Heiko Kirschke <[email protected]>
9
< Linux Wireless LAN Howto >
Tobias Hintze <[email protected]>
Documentation :
README file
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
?
Scanning :
No
Monitor :
No
Multi-devices :
unknown
Interoperability :
802.11-DS (with firmware 2.0), interoperate with Windows
Other features :
Non implemented : Bugs :
Must have the correct firmware revision (or driver version).
License :
Binary only (1.3, 2.03) or Open source (1.20), no license info
Vendor web page : http://www.zcom.com.tw/
http://www.elsa.de
2.5.1
The device
Z-Com is based in Taiwan, and the WL2400 family is based on the classic
AMD+Prism design. The family includes the usual ISA and Pcmcia cards, the
Access Point, and also a PC104 version (that’s interesting)...
Z-Com claims that the WL2400 is firmware upgradable to 802.11, but I’ve
been told that some old cards have an hardware bug preventing it. Anyway, the
card has all the usual 802.11 features, and the modem is classsical Direct Sequence
at 2.4 GHz, supporting 1 and 2 Mb/s. Those cards are based on the classical Prism
design (AMD controller + Prism chipset - see section 2.4), but use a firmware
written by Z-Com which is very different from the regular AMD firmware. This
firmware has more features, is more performant, but has more bugs.
Z-Com also offers the XI family, which support 5.5. and 11 Mb/s (probably
using a Prism II chipset). Those are not supported by this driver.
Elsa is a German company selling various hardware component and started
to sell Z-Com cards as Elsa AirLancer MC2. Those cards were quite popular in
Germany.
Elsa also sell a new AirLancer MC11 which has nothing to do with Z-Com and
is the Wavelan-IEEE (see section 3.1).
2.5.2
The driver
The driver has been written by the manufacturer, and Matthias put it on its
web site. The driver only contains the object files (no source) and seem to have been
designed for kernel 1.3.X and working in 2.0.X kernels (but, as the driver interfaces
in the kernel have changed since, this driver might not work in 2.2.X). The driver
10
< Linux Wireless LAN Howto >
only work with old firmware revisions (1.2/1.3), and doesn’t work with the 802.11
compliant firmware (2.0).
Matthias seems to now have access to the driver source code and is
investigating compatibility with 2.2.X and new firmware revisions.
Then, Elsa has released the full source code of this driver for their card,
including configuration utility. Elsa has made the setup easier and seem to have
also fixed a few bugs, because it is now working with kernel 2.2.X... This version
works with 802.11 compliant firmware (2.0).
More recently, Heiko ported the version of the driver from Elsa to 2.4.X. This
version works with the Pcmcia package (in the Pcmcia contrib directory) and with
firmware 2.0. And then, Tobias has released a full source code version of this
driver for kernel 2.4.X, likely based on the latest version on Matthias web page.
This version is a patch to the kernel (on his web page) and works with firmware
1.2/1.3.
Jörg took over the maintenance of Elsa driver (for firmware 2.0) and did a
partial rewrite of it. He fixed many bugs preventing interoperability with more
modern 802.11b hardware, improved compatibility with kernel 2.2.X and 2.4.X,
implemented Wireless Extensions and many other fixes and polishing.
Arnaldo and Gustavo took over the maintenance of the driver from Matthias
(for firmware 1.2/1.3) and did a partial rewrite of it. They updated the driver to
kernel 2.6.X, added full support for Wireless Extensions, and this driver is now
included in Kernel 2.6.0-test2. This driver requires Wireless Extension v16 and
will be soon ported to 2.4.23.
2.6
Proxim RangeLan2, Proxim Symphony, DEC RoamAbout FH, AMP
Wireless, Intel AnyPoint and Compaq Symphony
Driver status :
stable
Driver name :
rlmod.o
Version :
1.7.1
Where :
http://www.komacke.com/distribution.html
Creator :
Paul Chinn <[email protected]>
Maintainer :
Dave Koberstein <[email protected]>
Mailing list :
http://www.komacke.com/archive/rl2-library/
Documentation :
Readme file
Configuration :
specific tool, partial implementation of Wireless Extensions
Statistics :
none
Modes :
Managed, Ad-Hoc, Master
Security :
No
Scanning :
Yes (specific tool)
Monitor :
No
Multi-devices :
no (“insmod -o” multiple modules)
11
< Linux Wireless LAN Howto >
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
proprietary protocol or HomeRF, interoperate with Windows
Uses Proxim source code
Binary only for the core + OpenSource Linux wrapper
http://www.proxim.com/
http://www.wlif.com/
http://www.homerf.org/
http://www.networks.digital.com/dr/wireless/
http://www.intel.com/anypoint/
2.6.1
The device
The RangeLan2 is a classical product using the 2.4 GHz band, made by
Proxim, a small californian company. The products are certified and sold in
approximately 50 countries. The RangeLan2 is based on Proxim proprietary
protocol, OpenAir, that Proxim is trying to push as an alternative to 802.11. Of
course, you will find many OEM version (like the DEC and AMP versions). It comes
as ISA cards, Pcmcia cards, design-in modules, and access point.
The RangeLan2 implements a specific MAC protocol designed for radio
(OpenAir, another pre 802.11) implemented on a generic microcontroller. It uses a
4 bits domain, 4 bits channel and 4 bits subchannel, and also a station type
(primary master, secondary, slave - this is used for network synchronisation).
There is no encryption, instead it uses a technique called Security ID (which is a
simple password used to derive the network ID). The OpenAir protocol is heavily
based on RTS/CTS, offer a good robustness but some overhead. It offers as well a
modulable contention window size, contention free access for the master, packet
fragmentation and power saving.
The Modem uses frequency hopping, and 2 levels of modulations (2FSK/
4FSK) : it runs a 1.6 Mb/s signalling rate for good channel condition (short to
medium distances) and falls back to 0.8 Mb/s otherwise.
The Symphony line of product (home networking) offered by Proxim uses the
MAC protocol of the RangeLan2 (OpenAir) with a lower cost radio, and the main
difference is the software bundle and the price. On the other hand, the Proxim
RangeLan802 line is very different from OpenAir products, using the 802.11-FH
protocol and a different interface, so the Linux driver won’t work with it.
Recently, Proxim has released its first Symphony products compatible with
the HomeRF SWAP standard. These are also sold as Intel AnyPoint and
Compaq Symphony-HRF. The ISA, PCI and Pcmcia versions are still offered,
and a USB version has been added. Those products use the same physical layer as
the original Symphony, but the MAC protocol can either operate in OpenAir mode
or SWAP mode. The main advantage of SWAP is the support for cordless
telephony.
12
< Linux Wireless LAN Howto >
Proxim has also various 802.11-b products, named Harmony, Skyline or
RangeLan-DS which are PrismII cards (see section 3.6). Proxim has also released
some 802.11-a products which are Atheros cards (see section 4.2).
2.6.2
The driver
Dave uses the Proxim driver source code to build a library (distributed as
object only), so we should expect a good quality code. Paul wrote the part to
interface with the Linux kernel and Dave maintains it. He has written as well a
small utility to set the configuration in the driver (through ioctl). The driver
supports the Proxim Rangelan2, the Proxim Symphony, the DEC RoamAbout FH
and the AMP Wireless products. The driver support both ISA PnP and Pcmcia
cards, both with the RangeLan2 and Symphony labels...
Starting with version 1.7.0, the driver also support the SWAP protocol and
SWAP compliant devices from Proxim, Intel and Compaq (in both OpenAir and
SWAP mode). Both the driver and the configuration tools have been extended for
this support. Also, some primitive support for USB hardware has been added.
What I like about this driver is that after all those years, Dave is still strongly
supporting the driver, fixing bugs, adding new features and adding support for the
newer cards. It’s impressive to see such consistency and dedication...
2.7
Symbol Spectrum24 (FH)
Driver status :
Beta (Pcmcia only)
Driver name :
spectrum24_cs.o
Version :
Beta 4
Where :
http://sourceforge.net/projects/spectrum24
ftp://projects.sourceforge.net/pub/pcmcia-cs/contrib/
Maintainer :
Lee John Keyser-Allen <[email protected]>
Discussion forums : http://sourceforge.net/forum/?group_id=11099
Documentation :
Readme file
Configuration :
module parameters, partial support of Wireless Extensions
Statistics :
None
Modes :
Managed, Ad-Hoc
Security :
No
Scanning :
No
Monitor :
No
Multi-devices :
Interoperability :
802.11-FH, interoperate with Windows
Other features :
Support of micro-AP, multicast, statistics...
Non implemented : Bugs :
License :
GPL
13
< Linux Wireless LAN Howto >
Vendor web page : http://www.symbol.com/products/wireless/wireless.html
2.7.1
The device
Symbol is one of the other major player for Frequency Hopping devices in the
2.4 GHz band and has been selling its Spectrum24 line of products for ages. Symbol
sells mostly to vertical market (in their bar-code readers, in warehouses, in
supermarket), so their products are not usually found in retailers. The Spectrum24
family include an Access Point, a ISA card, a Pcmcia card and a Pcmcia card with
micro-AP functionality. However, the main strength of Symbol is their “all-in-one”
products, including a Palm or a WinCE device with a bar code reader and a 802.11
card, all neatly integrated.
The Spectrum24 products were designed from the start to be compliant with
the 802.11 standard, way before the standard was eventually adopted. The first
generation (1 Mb/s only) was compatible and interoperable with other 802.11
products (but not compliant), and the second generation of Spectrum24 (1 and
2 Mb/s) is officially 802.11 compliant.
Symbol is also very active in developing Voice over IP solutions for their
wireless LANs, and that’s why they are also selling some Spectrum24 phones. They
are using the H.323 codec, compression and call setup (raw 64 kb/s, compressed 10
times) and a 30 ms packet rate (but I fail to see what they have done to overcome
overhead and latency issues at the MAC level).
The MAC has all the usual features of the 802.11 standard, like MAC level
retransmission, RTS/CTS, fragmentation, auto bit-rate selection, power saving
and roaming. A nice feature of the MAC is the support of the micro-AP
functionality, which allows to turn a PC into an Access Point (I would like more
vendors to start doing that). However, their products don’t seem to support ad-hoc
mode.
The physical layer is Frequency Hopping supporting 1 and 2 Mb/s, with
100 mW or 500 mW output power and 100 ms dwell size.
2.7.2
The driver
Lee has written the driver as a student project for Symbol, so with active help
from Symbol. He plans to continue supporting it, and Symbol may get more active
in distributing the driver.
The driver is designed for the Pcmcia card (LA2400 and micro-AP version),
and the new 2 Mb/s version of the card. It is possible to use older cards (1 Mb/s) by
updating the firmware for 802.11 compliance, and to use ISA card by configuring
properly the Pcmcia package (those cards use a regular ISA to Pcmcia bridge).
Despite being beta, the driver is stable, well written and supports most
features of the card (like micro-AP, shared memory access...).
2.8
Aironet ARLAN
Driver status :
stable (ISA only)
Driver name :
arlan.o
Version :
2.0 & 2.1b
14
< Linux Wireless LAN Howto >
Where :
Maintainers :
Linux kernel (2.3.10 & 2.2.7-acX), web-page for 2.0.X version
Elmer Joandi <[email protected]>
Cullen Jennings <[email protected]>
Web pages :
http://www.ylenurme.ee/~elmer/655/
http://www.cs.ubc.ca/spider/jennings/
Documentation :
README file + web page
Configuration :
/proc interface (2.1.X kernels and up only)
Statistics :
?
Modes :
Managed, Ad-Hoc
Security :
?
Scanning :
?
Monitor :
?
Multi-devices :
?
Interoperability :
proprietary protocol, interoperate with Windows
Other features :
Non implemented : Multicast (driver is point to point ?)
Bugs :
License :
GPL
Vendor web page : http://www.aironet.com/products/2200fam/2200fams.html
2.8.1
The device
The Arlan was a radio LAN, built by Aironet, using the 900MHz or 2.4GHz
ISM band (Direct Sequence). This product has been discontinued and replaced by
the 4500 series (see section 3.14). The Arlan comes in 3 flavour, an ISA (655), an
MCA (670) and a pcmcia (690) card (plus the access point). Later, they renamed the
ISA card IC2200 and the Pcmcia card PC2200 (still the same hardware).
The configuration include setting the frequency and Network ID (24 bits ?).
The MAC protocol is implemented on a generic microcontroler. There is two
versions of the modem, a 900 MHz and a 2.4 GHz version. Both use Direct
Sequence Spread Spectrum. The 900 MHz modem allow signalling rate up to
860 kb/s (fall back to 215 kb/s) and 12 channels. The 2.4 GHz version allow
signalling rate up to 2 Mb/s (fall back to 1 Mb/s) and 5 channels.
2.8.2
The driver
Russell Nelson told me a while ago that he was trying to convince Aironet to
release the specifications of the Arlan to develop a Linux driver. Cullen Jennings
started the development of a point to point driver, Elmer Joandi rewrote some
parts and added a lot of features to be compatible with the Access Point, released
the whole under GPL, and here is the result.
The driver support only the ISA version of the card (655 or IC 2200). The
driver have been fully tested and optimised by Elmer Joandi, includes a complete
/proc interface and should be soon included in the kernel.
15
< Linux Wireless LAN Howto >
2.9
Raytheon Raylink, WebGear Aviator2.4 & Aviator Pro and BUSlink
wireless LAN
Driver status :
stable
Driver name :
ray_cs.o
Version :
1.67 (stable) and 1.70 (experimental)
Where :
Pcmcia package (3.1.9)
Linux kernel (2.3.18 & 2.3.24)
Maintainer :
Corey Thomas <[email protected]>
Web page :
http://webpages.charter.net/corey/index.html
http://world.std.com/~corey/raylink.html
Documentation :
README file + headers
Configuration :
modules parameters and Wireless Extensions (init only)
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
No
Scanning :
No
Monitor :
No
Multi-devices :
yes (configuration via Wireless Extensions)
Interoperability :
802.11-FH (need updated firmware), interoperate with
Windows (need to set the correct parameters)
Other features :
hardware multicast, MTU selection
Non implemented : A few high level 802.11 functionalities.
Bugs :
SMP not fully tested, changing parameters through Wireless
Extensions doesn’t work right yet.
License :
GPL
Vendor web page : http://www.raylink.com/micro/raylink/
http://www.webgear.com/
http://www.buslink.com/Net1.htm
2.9.1
The device
The Raylink is a IEEE 802.11 FH device build by Raytheon for the 2.4 GHz
ISM band. Raytheon build only a Pcmcia card and an Access Point. I’ve been told
that some version of the BreezeCom BreezeNet Pro Pcmcia card was an OEM
version of the Raylink.
You are more likely to buy the Raylink as a WebGear product, either as
Aviator2.4 or Aviator2.4 pro (which have nothing in common with their old Aviator
900 MHz line). The Aviator2.4 and Aviator2.4 pro are in fact the same product as
the Raylink, the Aviator2.4 driver comes pre-configured in ad-hoc mode and offer
only the Pcmcia card, whereas the Aviator2.4 pro driver comes preconfigured in
managed mode and offer both the Pcmcia card and the Access Point (translation
16
< Linux Wireless LAN Howto >
seems also to be different in each driver). Of course, it is possible to change the
mode in the driver and all these products are fully interoperable. WebGear also
offers a ISA to Pcmcia bridge to install the Pcmcia card in desktops.
Lately, WebGear has stop selling those cards, but recently BUSlink has
started selling them again (same card, different sticker).
The Raylink delivers all the features expected from a 802.11 compliant device,
with ad-hoc networking, access point operation, authentication and roaming. The
MAC protocol is as defined in 802.11 : CSMA/CA with MAC level retransmissions.
Configuration includes mostly the ESSID (network name).
The modem is 2.4 GHz Frequency Hopping, with 1 Mb/s and 2 Mb/s bit rate,
and includes antenna diversity.
2.9.2
The driver
Corey has implemented a very complete driver supporting most of the feature
of the hardware and some 802.11 functionality (it should be able to talk to some
802.11 nodes). There is an exhaustive list of configuration parameters, a /proc
interface for more parameters, and a tool to dump 802.11 frames. Good work !
The new version of the driver adds Alpha support, authentication, and
compatibility with the Windows driver. SMP is slowly being tested. I’ve added to
the driver quite complete support for Wireless Extension (changing parameters
still doesn’t work right - therefore wireless.opts do not work).
The driver has been developed for the Raytheon Raylink and has also been
successfully tested with the WebGear Aviator2.4 and the BUSlink.
I recently improved the support for Wireless Extensions. It is now possible
to configure the card before the card is brought up (for example in the various
configuration files). However, it is still not possible to change most parameters at
run time (but they can always be read).
2.10
Diamond Multimedia HomeFree
Driver status :
stable
Driver name :
tir2000.o
Version :
06/02/2000
Where :
http://david.poda.cz/homefree
Maintainer :
Pavel Machek <[email protected]>
Documentation :
README file
Configuration :
Module parameters
Statistics :
None
Modes :
Ad-Hoc
Security :
No
Scanning :
No
Monitor :
No
Multi-devices :
yes (except for module parameters setting)
17
< Linux Wireless LAN Howto >
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web page :
proprietary protocol, do not interoperate with Windows
Act as a tty device (not a network driver)
Windows compatibility
May not be legal in all locales...
GPL
http://www.diamondmm.com/
http://www.alation.com/
2.10.1
The device
The HomeFree was one of the first affordable home networking solution. It is
sold by Diamond Multimedia and designed by a small company, Alation. The card
comes in ISA, PCI and Pcmcia form factor.
To reduce the cost, Alation has used the same solution as IrDA : to implement
the MAC protocol in the driver instead of on the card. In fact, they are using a IrDA
chip as the baseband, and instead of connecting it to an Ir transceiver, they use a
classical 1 Mb/s Frequency Hopping modem at 2.4 GHz.
This solution save the cost of an embedded microcontroller on the card and
allow to build a cheaper product (and to develop it faster). The downside is that
building the MAC protocol in the driver tend to increase the protocol overhead (the
MAC need more time to react to events - this reduce throughput and increase
latency) and use more resources on the host (processor cycles and memory). In fact,
this is an effect similar to win-modems and win-printers. Also, because there is a
lot more code (which is more tightly integrated in the OS and performance critical),
the driver is more difficult to port to other OSes (and that’s why the driver below
doesn’t implement the HomeFree MAC protocol).
Personally, I’m not a fan of this design, but it seems to do the job cheaply.
2.10.2
The driver
Pavel has developed a very simple and nice driver for the HomeFree. The
development was sponsored by PODA s.r.o., a Czech company, which allowed Pavel
to release the driver as GPL after some time...
This driver is both very different from a standard network driver (as the other
driver I present on this page) and very different from the HomeFree Windows
driver. This driver is a straight tty interface to the hardware (like a serial port),
and doesn’t implement any MAC protocol. Therefore, it can’t be interfaced directly
to the standard Linux networking stack, and is not compatible with the Windows
driver.
Therefore, to use this driver, a MAC protocol of some sort is needed (to
arbitrate access to the medium, multiplex connection and ensure reliability). Pavel
recommend to use either some Ham protocols such as Scarab, or to use the LinuxIrDA stack. You can also develop you own application directly on top of this half
duplex interface (most serial applications will assume full duplex).
The advantage of that is that those protocols are very lightweight, so usually
perform much better (in term of raw throughput) than the original HomeFree
18
< Linux Wireless LAN Howto >
protocol, and even better than some other WLAN products. However, those
protocol (Scarab, IrDA) are not designed for the specifics of the 2.4 GHz band and
don’t include all the goodies found in 802.11. For example, IrDA allow only two
nodes to be exchanging data at one time (only one IrLAP connection active) and
deal poorly with multi nodes network. I also don’t know how they deal with colocated networks and radio interferences.
However, the most critical missing feature is regulations compliance. The
802.11 protocol include some feature to insure compliance with all the various
regulations in the 802.11 band (such as Frequency Hopping - usage of Radio
Frequency tend to be highly regulated). As the driver of Pavel doesn’t include all
these features, this driver may not be legal in your country (note : this doesn’t
apply to the Windows driver, the Windows driver is legal because Diamond has
certified it with the FCC and ETSI), and usage of this driver may bring you big
troubles (same as setting up a illegal transmitter in the FM band). So, if you care
about legislation, I advise you to check with Pavel about your specific case,
otherwise use at your own risks...
2.11
BreezeCom BreezeNet PRO Pcmcia
Driver status :
stable
Driver name :
brzcom_cs.o
Version :
1.0, 1.1-Beta
http://www.alvarion.com/RunTime/Support_10010.asp?tNodeParam=30
Where :
http://www.breezecom.com/Support_10010.asp?tNodeParam=30
ftp://projects.sourceforge.net/pub/pcmcia-cs/contrib/
Creator :
Christian Olrog
Maintainer :
Alfred Cohen <[email protected]>
Documentation :
Readme file
Configuration :
module parameters
Statistics :
/proc interface
Modes :
Managed, Ad-Hoc
Security :
No
Scanning :
No
Monitor :
No
Multi-devices :
no
Interoperability :
802.11-FH (only pro.11), interoperate with Windows
Other features :
Non implemented : security (WEP), power saving
Bugs :
License :
GPL
Vendor web page : http://www.breezecom.com/
19
< Linux Wireless LAN Howto >
http://www.alvarion.com/
2.11.1
The device
The BreezeNet is a Radio LAN using the 2.4 GHz ISM band (Frequency
Hopping). The earlier versions of the Pcmcia cards were OEM of other vendors, the
old one was an OEM version of the Netwave, then it was an OEM version of the
Raylink, but their latest pro.11 Pcmcia card is 100 % BreezeCom (the one with
two little antenna sticks). BreezeCom has also a 802.11-b line, called DS.11, and
the Pcmcia card is a NWN card.
In term of protocol and modem, the Pcmcia cards are very similar to the other
BreezeCom products (see section 2.12). The first two Pcmcia cards were limited in
term of bit-rate (only 1 Mb/s), and have lower transmit power.
2.11.2
The drivers
The driver presented here apply only to the latest pro.11 Pcmcia card. For the
old Pcmcia card (not pro), you may use the netwave_cs driver (see section 2.2). For
the first pro.11 Pcmcia card, you may use the ray_cs driver (see section 2.9). For
the DS.11 card (802.11-b compliant), you may use the swallow_cs driver (see
section 3.17).
BreezeCom has also release a Linux driver for their latest pro.11 card. I’ve
been informed of the existence of this driver since October 99, and many people
have been using it since by getting it directly from BreezeCom, but BreezeCom did
release this driver to the wide public only 6 months later. Let’s not complain,
because the driver contains the full source and is now GPL, so it was worth the
wait !
The driver was written by Christian Olrog, an employee of Ericsson, based on
the original Windows driver source, and it seems that the maintenance has been
taken over by Alfred Cohen of BreezeCom. The source code looks very nice and
complete, with only a few features missing. One interesting feature is that the
driver can show the signal strength for Access Points in the area. However, the
initial configuration could be simpler...
The driver has been in use by many Linux users since its original
development and there doesn’t seem to have been much complains about it, which
is good ;-)
The original version of the driver, 1.0, is only for Linux kernel 2.2.X. There is
a beta version of the driver for Linux kernel 2.4.X.
2.12
BreezeCom BreezeNet (not Pcmcia)
Driver status :
not needed (for Pcmcia, see above)
Driver name :
Version :
Where :
Maintainer :
none
Documentation :
none
20
< Linux Wireless LAN Howto >
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
none
none
yes
802.11-FH (only pro.11), 802.11-DS and 802.11-b (only
DS.11), interoperate with Windows
Other features :
Non implemented : configuration & statistics
Vendor web page : http://www.breezecom.com/
http://www.alvarion.com/
2.12.1
The device
The BreezeNet is a Radio LAN using the 2.4 GHz ISM band (Frequency
Hopping). It is built by BreezeCom, a small company from Israel, and some OEM
version might be available. The BreezeNet doesn’t connect to any of the usual PC
bus but instead uses an Ethernet network card to interface to the host computer,
and so require no driver to work (they have also some real access points). For the
Pcmcia hardware, see above.
There is three versions of the BreezeNet, the old one, somewhat Netwave
compatible, then the first pro.11 version (flash upgradable to 802.11) and the new
pro.11 version, which is 802.11 compliant, so with all the usual MAC features
expected from 802.11 devices. In all cases the modem includes Frequency Hopping
Spread Spectrum (20 ms hop period), a 3 Mb/s signalling rate (fall back to 2 and
1 Mb/s) and antenna diversity. Note that the 3 Mb/s bit rate is not 802.11
compliant.
BreezeCom now offers a DS.11 series of adapters which is 802.11-b compliant,
with usual 802.11-b features (and up to 11 Mb/s) and still using the Ethernet
interface.
In 2001, BreezeCom and Floware Wireless Systems merged together to form
Alvarion. The new combined company seems to put less emphasis on wireless
LANs and more on point-to-point links and wireless distributions systems, even
though the old BreezeNet product lines are still available.
2.12.2
The drivers
No driver is needed, this product use an Ethernet connection. You need to
have an dedicated Ethernet 10baseT card configured under Linux to plug it into.
For the device configuration and statistics, unless someone write the necessary
tools for Linux, I guess that you must return to DOS/Windows.
21
< Linux Wireless LAN Howto >
3 The devices, the drivers - 802.11b
This section list devices based on the IEEE 802.11b standard (see section 8),
operating in the 2.4 GHz band up to 11 Mb/s.
3.1
Lucent Wavelan IEEE, Lucent Orinoco, Enterasys RoamAbout 802,
Elsa AirLancer 11 and Melco/Buffalo 802.11b
Driver status :
obsolete (see section 3.2)
Driver name :
wvlan_cs.o
Version :
v1.0.7
Where :
Pcmcia package (3.1.25)
Maintainers :
Anton Blanchard <[email protected]>
Andreas Neuhaus <[email protected]>
Harald Roelle <[email protected]>
Moustafa A. Youssef <[email protected]>
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Wavelan-IEEE.html
Web pages :
http://www.fasta.fh-dortmund.de/users/andy/wvlan/
http://www.roelle.com/wvlanPPC/index.html
http://www.cs.umd.edu/~moustafa/mwvlan/mwvlan.html
Mailing list :
http://lists.samba.org/pipermail/wireless/
Documentation :
man page, headers
Configuration :
Wireless Extensions & module parameters
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc and Ad-Hoc-demo
Security :
WEP (based on hardware support)
Scanning :
No
Monitor :
No
Multi-devices :
Yes
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
MTU selection, multicast, promiscuous mode, power
management, WEP hardware encryption, SMP, multifirmware and PPC support.
Non implemented : Some optimisations... Does not support HermesII.
Bugs :
May have some performance issues
License :
GPL
Vendor web page : http://www.wavelan.com/
http://www.proxim.com/
http://www.enterasys.com/wireless/
http://www.elsa.com/
22
< Linux Wireless LAN Howto >
http://www.hp.com/notebooks/us/eng/products/wireless/
http://www.buffalotech.com/
http://www.1stwave.de/
http://www.artem.de/
3.1.1
The device
Even if it uses the same name, the Wavelan IEEE product is completely
different from the old Wavelan (see section 2.1), and totally incompatible in term of
protocol and hardware interface. It is still built by Lucent, and it still operate in
the 2.4 GHz ISM band (Direct Sequence), but the new hardware fully support the
IEEE 802.11 protocol (and 802.11-b for the more recent versions) and is no longer
based on a Ethernet MAC chip. There is only a Pcmcia version (the ISA version
uses a ISA to Pcmcia bridge) and the different access points. Recently, Lucent has
added a USB adapter and mini PCI version of the card for laptop (this one is based
on a PCI-Pcmcia bridge).
To confuse the issue, Lucent has renamed the Wavelan IEEE as Orinoco
(Wavelan was better IMHO), and this division was part of Lucent spin-off into a
new company called Agere. Avaya (another Lucent spin-off) is also selling the
Orinoco. Enterasys is also selling the Wavelan IEEE as RoamAbout 802 (this
company was formerly known as Cabletron, which was the former DEC
networking division). Elsa is selling it in Europe as AirLancer 11 (on the other
hand, the 2 Mb/s version is quite different). In Japan (and maybe also in Europe),
Melco is selling it as Buffalo WLI-PCM-L11. Lately, more vendors have been
joining the club, such as HP (HP 802.11b Wireless LAN), IBM (IBM High Rate
Wireless LAN), Dell (Dell TrueMobile 1150 - on the other hand, the 1100 is an
Aironet card), Compaq (Compaq WL 110, WL 210 and WL 215 - the WL100 and
WL200 are PrismII based), 1stWave (1stWave PC-Card) and ARtem (ARtem
ComCard). The Apple Airport is also derived from the Wavelan IEEE (see section
3.5).
The Wavelan IEEE saga never ends. Proxim bought the card and access
point business of Agere (Agere kept the chipset and radio part), so now the same
Orinoco cards are sold by Proxim under the name Orinoco Classic or Orinoco
World (841X - with the big square antenna and using the same Agere Hermes
chipset). In a bold marketing move, Proxim renamed all it’s other lines of wireless
cards as Orinoco, however those cards are not based on the Agere chipset but on
Atheros chipset (846X, 847X and 848X). The Orinoco 11b (842X - 802.11b only
with a short antenna) are based on the Agere HermesII chipset, which is different
from the old chipset (and therefore not compatible with the usual Orinoco drivers).
So, if the Proxim Orinoco card doesn’t have a big square antenna and do support
802.11a or 802.11g, you can be sure it’s not a true Orinoco.
The Wavelan IEEE appears to the PC as a standard network card and
interfaces naturally with the networking stack. The configuration includes only
setting the network name (ESSID), the rest is automatic (finding the equivalent
BSSID and channel). As usual for Lucent, the documentation and website are rich.
23
< Linux Wireless LAN Howto >
The Lucent Wavelan IEEE is based on the Lucent Hermes chipset. As with
all IEEE 802.11 products, the Hermes offer a fully featured MAC protocol,
including MAC level acknowledgement (good news for all of us having dealt with
the old Wavelan card), optional RTS/CTS, fragmentation, automatic rate selection,
roaming. This seems exhaustive, but is mandatory for IEEE 802.11 compliance.
Different version of the card include different levels of security (bronze is basic,
silver is with WEP (RC4-40 bits) and gold is with RC4-128 bit encryption).
The MAC support both Managed and Ad-Hoc modes. However, the initial
firmware for those cards did support only a non-compliant Ad-Hoc mode (called AdHoc demo mode - which interoperate with most PrismII cards). In order to gain
WiFi compliance, Lucent added in recent firmware (6.06 and greater) a second AdHoc mode which is fully 802.11 compliant (called Peer to Peer mode or IBSS AdHoc mode - and which interoperate with Aironet cards). Of course, the two Ad-Hoc
modes are not interoperable.
The 2.4 GHz modem is an enhanced version of the previous generation, Direct
Sequence Spread Spectrum (11 chips encoding), using both 1 and 2 Mb/s signalling
rate (using effectively 22 MHz of bandwidth) and 5.5 and 11 Mb/s in second
generation cards, diversity antennas and with 13 different frequencies (depending
on the regulations).
Initially, the Wavelan was only offering 1 and 2 Mb/s bit rates (basic IEEE
802.11 DS standard). For a while, Lucent was also selling a “turbo” version of the
card, which was adding 5 and 10 Mb/s bit-rates for shorter range using Lucent
proprietary modulations (so, not compatible with 802.11-b).
Later, Lucent introduced the second generation of the Wavelan IEEE, still
based on the same Hermes chipset, which is much cheaper and fully compliant
with the new 802.11-b standard, supporting 1, 2, 5.5 and 11 Mb/s bit-rate
(compatible with other 11 Mb/s products).
All Wavelan IEEE cards do not offer the exact same set of features, because
Lucent keep changing the firmware. From firmware 1.00 to 4.52, Lucent was
mostly adding features (encryption, power saving) and keeping it backward
compatible, but firmware 6.04 and later created a major incompatibility. Firmware
6.06 and later implement a fully 802.11 compliant IBSS Ad-Hoc mode (on top of the
Ad-Hoc demo mode). Firmware 6.04 dropped Fragmentation Threshold setting in
favor of microwave oven robustness (an automatic fragmentation scheme).
Firmware 6.16 did fix a few bugs with the IBSS Ad-Hoc mode (security,
ESSID=”any”).
Agere has recently released a new HermesII chipset, derived from the
venerable Hermes chipset. The most notable improvements are a higher
integration (smaller & cheaper), a PCI interface with DMA support and a USB
interface. The chip interface and firmware is not compatible with the old Hermes
chipset, requiring specific driver support for HermesII. To my knowledge, this
chipset is only used in the Proxim 842X cards.
24
< Linux Wireless LAN Howto >
3.1.2
The driver
Andreas Neuhaus is no longer working to improve this driver, therefore it’s
now discontinued in favor of the new Orinoco driver (see section 3.2). The driver is
based on Lucent source code, which is a cut down version of their full driver. So, it
lacks all the part about handling natively 802.11 frames and Lucent proprietary
API, and initially it lacked some of the more fancy features of Lucent’s driver, but
Andreas is adding them slowly. Of course, the driver support all version of the card
(bronze, silver, gold - basic, turbo, turbo 11 Mb/s) and is fully interoperable with
Access Points and Windows nodes.
Andreas has done a very good job into providing features like Wireless
Extensions (I must admit that I did help him quite a bit ;-) and many configuration
parameters (station name, channel, mtu size). The new version adds Power
management and encryption setting, change of the operating mode via Wireless
Extensions, promiscuous and multicast support...
Andreas has done a lot of debugging of the driver and it seems now much more
stable. Lastly, the ISA to Pcmcia and PCI to Pcmcia bridges may be a source
troubles under Linux. The latest version of the driver fixes SMP support, multicards configuration, improve wireless.opts support, add IBSS Ad-Hoc mode
support and support properly and sanely the various firmware releases.
Harald Roelle has developped a patch for this driver in order to fully support
the PPC architecture. This patch mostly contain some bit order fixes. This patch
should help other architecture with endianess issues. His patch was eventually
integrated (with major changes) by David Hinds in version 1.0.6 of the driver. I
added firmware detection support in 1.0.6 to properly handle all the various
firmware releases and their variations (in particular the two Ad-Hoc modes), and
fixed the remaining SMP bugs.
The driver does not support the USB and Mini-PCI version of the Wavelan.
Nowadays, Anton Blanchard is the official maintainer of the driver, with the
help of David Gibson. David has done a complete rewrite of the driver (see section
3.2), so this driver won’t be maintained anymore...
Moustafa has released a version of this driver with scanning support.
Note that Lucent has also released a binary library driver (see section 3.3)
which is maybe more solid and performant than the driver of Andreas, but lack
complete support for Wireless Extensions.
3.2
Wavelan IEEE/Orinoco, PrismII and Symbol cards
Driver status :
stable
Driver name :
Pcmcia : orinoco_cs.o
PLX : orinoco_plx.o
PCI : orinoco_pci.o
Version :
v0.15rc2, CVS
Where :
Linux kernel (2.4.21 ; 2.6.12)
Pcmcia package (3.1.34)
25
< Linux Wireless LAN Howto >
http://www.ozlabs.org/people/dgibson/dldwd
http://savannah.nongnu.org/projects/orinoco/
Maintainers :
David Gibson <[email protected]>
Pavel Roskin <[email protected]>
Web page :
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Orinoco.html
Mailing list :
http://sourceforge.net/mail/?group_id=44338
Documentation :
man page, headers
Configuration :
Wireless Extensions only
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc and Ad-Hoc-demo
Security :
WEP (based on hardware support), 802.1x
Scanning :
Wireless Extensions (v0.14 and later)
Monitor :
Yes (v0.14 and later)
Multi-devices :
Yes
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
MTU selection, multicast, promiscuous mode, power
management, SMP, multi-firmware, multi vendors, PPC &
ARM support, PLX and PCI support.
Non implemented : Does not support HermesII.
Bugs :
WEP not functional on old Prism2 firmwares, some older
driver versions don’t handle properly some Symbol cards.
License :
MPL and GPL
Vendor web pages : [Too many to list here]
3.2.1
The devices
As explained in various sections, Lucent Wavelan-IEEE/Orinoco devices (see
section 3.1), Intersil PrismII devices (see section 3.6) and Symbol High Rate devices
(see section 3.10) are basically using the same MAC controller. This driver
attempt to support all those devices, which are described in details in their own
sections.
However, even though those devices use the same MAC controller and the
same driver, those devices are not the same. Each vendor has its own firmware,
so the set of features of those cards vary. Some differences are visible to the user
(for example 128 bits key support and multicast), some are more related to
performance and robustness tuning of the MAC.
Moreover, those devices don’t use the same radio modem (mostly Lucent or
Intersil) and same antennas. For PrismII cards, even the actual layout of the radio
components on the card can make a huge difference. This will mostly translate into
difference of coverage between the various cards (range and resistance to
interference). The range between some cards may vary by a factor 2 in some
conditions.
26
< Linux Wireless LAN Howto >
3.2.2
The driver
Anton Blanchard and David Gibson became official maintainers of the
wvlan_cs driver (see section 3.1) in the end of 2000. David was not very happy
about the state of wvlan_cs.
The HCF (the low level library provided by Lucent) hadn’t been maintained
since the initial release of the driver and was quite difficult to read and
understand. While the higher layer of the driver had gone a long way and were
robust and fully featured, the HCF was a mess and the cause of many problems
(TxTimeout, driver corruption/crashes and else).
Rather than put up with that, David looked deeply in the low level of the
wlan-ng driver from Mark (see section 3.6) and the FreeBSD driver and wrote a
totally new driver combining a new low level core and the high level features of
wvlan_cs. The end result was a driver much more readable, robust and well
behaved than wvlan_cs. In the process, David added support for PrismII cards.
Then, I fixed a few Wireless Extensions bugs, added some support for Symbol
cards, and we pushed the driver in the kernel. The driver was initially named
dldwd_cs and was renamed orinoco_cs at this point. Later on, David Hinds
backported this driver to the Pcmcia package for users of earlier kernels.
The main goal of the driver is to support Wavelan IEEE/Orinoco cards and
OEM. The driver support all the firmwares and features of those cards properly
and fully (Ad-Hoc demo mode, IBSS mode, bit-rate, encryption keys...), and support
all the features available in wvlan_cs (except module parameters) with less bugs.
Ben has added Airport support to this driver (see section 3.5), and the
support of those cards is similar to Orinoco cards (i.e. most features supported
properly).
Starting in release v0.6d, the support of Symbol cards and OEM is complete,
at least for firmware 1.5 and 1.7. Bit rate, mode of operation (managed, ad-hoc
IBSS and ad-hoc demo), encryption and power management are fully working. The
release v0.8 added full support for later Symbol firmware 2.00 and 2.20. On
firmware 2.20 and later, Power Management is disabled. Version of the driver from
v0.10 to v0.12b don’t work properly with Symbol cards due to a bug, so avoid
those releases. Symbol CF cards are very different and supported in their own
driver (see section 3.13).
The support of PrismII cards and clones is still in progress. More debugging
and testing need to be done, but the driver can set most features to some degree
(Ad-Hoc demo mode, IBSS mode, bit-rate, encryption keys have been seen to work).
It seems the upgrading firmware fixes problems related to encryption. However,
the wlan-ng and HostAP drivers still have more features and are more tested...
Starting in release v0.8, the orinoco driver collection also support PLX
adapters that are sold with some PrismII cards (via the orinoco_plx driver). Those
adapters are not real Pcmcia adapters and the card looks to the system like a PCI
card. The driver also support Pcmcia cards in regular ISA to Pcmcia or PCI to
Pcmcia adapters, as long the Pcmcia adapter is recognised and configured
properly by the Pcmcia package (which might be tricky).
27
< Linux Wireless LAN Howto >
Starting in release v0.11a, the orinoco driver collection also support PCI
cards (all of them being PrismII cards - via the orinoco_pci driver). The standard
driver does not support the various USB versions of the cards. There is various
kind of MiniPCI implementation of the card, the driver support some of them
(Pcmcia based - Lucent ; PCI based - PrismII) but not most (USB based - PrismII).
The latest version (v0.13b) seems to have fix most of the hardware reset
problems of previous versions and seems to have fixed problems with Symbol
firmwares. Pavel has integrated in v0.14 many previously external patches, such
as support for Wireless Scanning and Wireless Events, support for Monitor
mode and support for 802.1x. Pavel also fixed support for kernel 2.6.X,
dramatically improved Symbol firmware support and fixed a tons of bugs in v0.14.
Version 0.15-rc2 of the driver was merged into kernel 2.6.12. This brought all
the features and bugfix above in the kernel. Since then, Pavel is continuing to fix
and update the driver, pushing those changes into recent kernels, but he is no
longer using version number (so I guess we are still a 0.15-rc2).
3.3
Lucent Wavelan IEEE, Enterasys Roamabout and Proxim Orinoco
8420
Driver status :
stable, beta
Driver name :
wavelan2_cs.o, roamabout_cs.o and wlags49_cs.o
Version :
v6.16, v7.18 and v7.22
Where :
http://greenblaze.com/proxim.html
http://www.agere.com/mobility/wireless_lan_drivers.html
http://www.agere.com/support/drivers/index.html
http://www.cs.umd.edu/~moustafa/mwavelan/mwavelan.html
Contact :
Lucent support <[email protected]>
EnteraSys support <[email protected]>
Maintainers :
Richard van Leeuwen <[email protected]>
Dean W. Gehnert <[email protected]>
Moustafa A. Youssef <[email protected]>
Documentation :
Extensive readme
Configuration :
Module parameters, Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc and Ad-Hoc-demo
Security :
WEP (based on hardware support), WPA
Scanning :
Wireless Extensions
Monitor :
No
Multi-devices :
yes, but the ISA to Pcmcia bridge must be reconfigured
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
28
< Linux Wireless LAN Howto >
Other features :
Power management and microwave oven robustness. Support
HermesII cards (v7.08). WPA support.
Non implemented : Do not support all firmware releases
Bugs :
?
License :
Binary only for the core + OpenSource Linux wrapper (up to
v6.16), GPL (v7.08)
Vendor web page : http://www.wavelan.com/
http://www.enterasys.com/wireless/
3.3.1
The device
This is the same device as the previous entry (section 3.1).
3.3.2
The driver
Lucent has decided to not put all its eggs in the same basket and developed a
bold strategy for the support of the Wavelan IEEE under Linux. Not only they have
released some source code to allow the source driver mentioned above, but they
have as well contracted Dean to release a driver based on a binary library. This
gives Linux users the choice, a GPL full source driver to hack with and a stable full
featured binary driver (the official term from Lucent is “Linux Driver Source/
Library”).
Dean has written the code interfacing between Linux and the library, and had
put together a nice package easy to install and with documentation. As expected,
the binary driver is probably more stable and than the full source driver mentioned
above, with a slightly different set of feature, and offers all the features of Lucent
Window drivers, plus a nice integration with Linux. This driver supports both the
basic version of the card and the “turbo”. The major drawback is the binary core,
preventing the use on other architectures (PPC, Arm...).
Now, the driver is supported by Lucent, and they keep adding in it the same
features they add to the Windows drivers (such as microwave oven robustness).
Their also have added support for the IBSS Ad-Hoc mode (see discussion above).
The latest version adds support for 2.4 kernel and many common Wireless
Extensions. Note that Enterasys/Cabletron is also distributing a slightly modified
version of this driver (usually an older one).
Moustafa has released a version of this driver with scanning support.
Recently, Agere has released a new version of this driver which is fully Open
Source. This new version has support for the HermesII chipset found in the
Proxim Orinoco 842X cards (but it seems it no longer support the old Orinoco cards
- use the older driver version). It has also improved Wireless Extension support.
Agere is still working hard on the driver and has recently added support for
Wireless Scanning and WPA.
3.4
Orinoco USB cards and HP/Compaq multiport
Driver status :
beta
Driver name :
orinoco_usb.o
29
< Linux Wireless LAN Howto >
Version :
Where :
0.1.4
http://www.nongnu.org/orinoco/
http://savannah.nongnu.org/projects/orinoco/
Maintainers :
Manuel Estrada Sainz <[email protected]>
Ramon Rey Vicente <ramon.rey at hispalinux.es>
Mailing list :
http://sourceforge.net/mail/?group_id=44338
Documentation :
headers
Configuration :
Wireless Extensions only
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc and Ad-Hoc-demo
Security :
WEP (based on hardware support)
Scanning :
Wireless Extensions (with optional patch)
Monitor :
With optional patch
Multi-devices :
Yes
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
MTU selection, multicast, promiscuous mode,
management, multi-firmware.
Non implemented : Bugs :
License :
MPL and GPL
Vendor web pages : http://www.wavelan.com/
http://www.proxim.com/
http://www.hp.com/
3.4.1
power
The devices
The Orinoco-USB is of course related to other Wavelan-IEEE/Orinoco
devices (see section 3.1). As most first generation USB designs, it is really a
standard Orinoco Pcmcia card plugged into a Cypress EZ-USB USB-Pcmcia
bridge. Such a setup of course brings some performance degradation due to USB
high latency. The Orinoco card inside the device has the same exact features as
other Orinoco Pcmcia cards and is 802.11b compliant.
Lucent, Agere and Proxim are directly selling this Orinoco device. HP/
Compaq sells it as WL215 (standalone) and W200 (multiport option for Compaq
laptops). Other vendors such as Melco are also selling this hardware. One of the
particularity of this hardware is that the USB-Pcmcia bridge doesn’t contain a
firmware, so the driver need to upload the firmware at power up. On the other
hand, the Pcmcia card behind the USB-Pcmcia bridge already contains its own
firmware.
30
< Linux Wireless LAN Howto >
Note that most USB 802.11b cards are based on either the Intersil PrismII
chipset (see section 3.6) or the Atmel chipset (see section 3.20), and are quite
different from this hardware.
3.4.2
The driver
Manuel has managed to reverse engineer the Orinoco USB hardware and is
providing a modified version of the Orinoco driver for Orinoco USB adapters. This
driver only support Orinoco USB hardware, and not other USB cards. Because it
is based on the Orinoco driver (see section 3.2), this driver offer the same extended
feature set, such as Wireless Extension support.
The big difference with the standard Orinoco driver is firmware uploading.
You will need to extract the firmware for the USB-Pcmcia bridge from the Windows
driver using the tools provided on the driver web page. The firmware uploading
support in Linux needed for this driver is currently being finalised, so check the
latest driver documentation. On the other hand, the driver offer no support for
updating the firmware in the Pcmcia card.
This driver was merged into the CVS of the Orinoco driver (see section 3.2).
However, because the Orinoco maintainers are not happy with the locking strategy
of this driver, this driver was never included in any release of the Orinoco driver
and is not included in the kernel. The latest version of the driver may be found in
the Orinoco CVS (see section 3.2).
3.5
Apple Airport
Driver status :
stable
Driver name :
airport.o
Version :
0.15-rc2
Where :
Linux kernel (2.6.12)
http://www.ozlabs.org/people/dgibson/dldwd
http://ppclinux.apple.com/~benh/
Maintainer :
Benjamin Herrenschmidt <[email protected]>
Documentation :
web page, headers
Configuration :
Wireless Extensions & module parameters
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc and Ad-Hoc-demo
Security :
WEP (based on hardware support)
Scanning :
Wireless Extensions
Monitor :
With optional patch
Multi-devices :
No
Interoperability :
802.11-DS and 802.11-b, interoperate with Mac-OS ;-)
Other features :
MTU selection, multicast, promiscuous mode, power
management, SMP and multi-firmware.
Non implemented : Some optimisations...
31
< Linux Wireless LAN Howto >
Bugs :
License :
GPL
Vendor web page : http://www.apple.com/airport/
3.5.1
The device
The Apple AirPort is in fact the Lucent Wavelan IEEE repackaged, so has
the same characteristic as the Wavelan (see section 3.1). All Airport hardware is
802.11-b compliant (second generation of Wavelan IEEE) and support 11 Mb/s, and
Apple seem to offer only the version with 40 bit encryption.
The AirPort card for the most Apple hardware is the OEM version of the
Wavelan IEEE, but it uses a specific slot in those computers and the antennas are
pre-integrated in the host. Most recent Apple machines offer this interface (iBook,
PowerBook 2000 (aka Pismo), AGP G4s, recent iMacs (DV/SE)...). Note that this
interface is not Pcmcia compatible even is the connector is the same, so this card
can’t be used in the normal PC-Card slot of other laptops. This is why this card
work only in specific Apple hardware slot and only with a specific driver.
The Access Point (the famous flying saucer) is similar in functionality to the
Lucent RG-1000 Residential Gateway, and is fully interoperable with other 802.11b hardware.
3.5.2
The driver
The first version of the Airport driver was done by Benjamin Herrenschmidt
by porting the driver of Andreas Neuhaus (see section 3.1) to support the Apple
Aiport card. He has basically integrated the specific PPC patch of Harald Roelle,
thrown away all the Pcmcia code and replaced it with the specific Apple
initialisation code.
Apart from that, the driver is basically the same, with the same features and
same bug ;-)
The second version of the driver was also done by Benjamin Herrenschmidt
and is just a wrapper on top of the driver of David Gibson (see section 3.2), and was
integrated in version 0.05 (kernel 2.4.5). This is a much cleaner solution, because
both driver share the same source, so the feature set is identical and all
improvements and bug fixes of the Orinoco driver are automatically in the Airport
driver and vice-versa. For example, this driver gained both Scanning and
Monitor mode support in version 0.14 and later.
3.6
Intersil PrismII based cards (the most common 802.11b cards)
Driver status :
stable
Driver name :
Pcmcia : prism2_cs.o
PLX : prism2_plx.o
PCI : prism2_pci.o
USB : prism2_usb.o
Version :
0.2.3
Where :
http://www.linux-wlan.com/linux-wlan
32
< Linux Wireless LAN Howto >
Maintainers :
Mark S. Mathews <[email protected]>
Solomon Peachy <[email protected]>
Mailing list :
http://www.linux-wlan.com/linux-wlan/
http://www.lifix.fi/extarchive/lwlan/
Documentation :
Readme
ftp://ftp.linux-wlan.org/pub/linux-wlan-ng/FAQ
http://www.linux-wlan.org/docs/linux-wlan-FAQ.html
Configuration :
Module parameters & configuration tool
Statistics :
Statistic tool & Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP (based on hardware support)
Scanning :
Specific tool & Wireless Extensions
Monitor :
Yes
Multi-devices :
Yes
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Quite exhaustive 802.11 support, Encryption, PPC support,
PLX, PCI and USB support.
Non implemented : ?
Bugs :
?
License :
MPL
Vendor web pages : http://www.compaq.com/products/wlan/index.html
http://www.magiclan.com/
http://www.dlink.com/products/
http://www.linksys.com/products/
http://www.zoomtel.com/zoomair/za11index.html
http://www.nokia.com/corporate/wlan/card_c110.html
http://www.addtron.com/
http://www.gemtek.com.tw/
http://www.smc.com/
http://www.netgear.com/
http://www.ambicom.com/
http://www.teletronics.com/
http://www.intersil.com/design/prism/
http://www.conexant.com/
3.6.1
The device
The PrismII chipset is the successor of the PrismI chipset, described in the
previous section (see section 2.4), and is build by Intersil (formerly Harris). Intersil
33
< Linux Wireless LAN Howto >
offer this chipset and some reference design to various OEM, allowing them to
build various 802.11-b products (cards or integrated in their own products). I
expect that all the people that were formerly using the PrismI chipset will switch
sooner or later to the PrismII.
The first manufacturers to offer PrismII cards were Samsung and Compaq
(WL100, WL200, rumored to be a rebadged Samsung card), with a Pcmcia card, a
PCI card and an Access Point. Other Prism vendors like ZoomAir, Nokia and
GemTek did release later their own version of the PrismII cards, as well as
Proxim (RangeLAN DS, Harmony 802.11b...). Some big networking vendors like
D-Link, LinkSys, NetGear and SMC were also quick to jump on this new
opportunity for them, as well as many smaller vendors like AddTron, Ambicom,
Teletronics, Ampwave and many other that I can’t list... The rule of thumb is
that if your card is not listed in another section of the Howto, it could be a PrismII
card (or not, see below).
Some notable exceptions which are not PrismII cards : the Compaq WL 110,
WL 210 and WL 215 cards (which are Orinoco cards), the D-Link 650H (which is
a Symbol card), most D-Link/LinkSys/SMC USB cards (which are Atmel cards),
the SMC 2632W-v2 (which is an Atmel card), all 22 Mb/s cards such as the DLink 650+/520+ (based on the TI chipset), all CardBus cards such as the new DLink 650 (which is an ADMtek card), all 802.11a cards (which are Atheros or
Intersil PrismDuette cards) and all 802.11g cards (which are Broadcom, Atheros or
Intersil PrismGT cards). In fact, so many vendors seem to be moving away from the
PrismII chipset (usually without warning and without changing the model name)
and there is so many changes happening that it’s impossible to keep track of who
is using what.
Please note that everything that looks like a PrismII card may not be a
PrismII card, and many people are quite confused about that. The cards described
in this section use both a Intersil PrismII chipset and an Intersil firmware. Other
vendors, such as Lucent (see section 3.1), Aironet (see section 3.14), Symbol (see
section 3.10) and Atmel (see section 3.20) use part of the PrismII chipset but with
their own firmware and therefore are not compatible (even if they sometime use
the same device identification as PrismII cards and sort of work with PrismII
drivers).
Most PrismII vendors offer regular Pcmcia cards for laptops. For desktop
machines, the situation is a bit more messy, some vendors offer standard PCIPcmcia cards (where you can slot the Pcmcia card), dedicated PLX cards (that look
like a regular PCI-Pcmcia bridge but is not) or some fully integrated PCI cards
(Prism2.5). Some vendors also offer USB adapters (beware, some of them are Amtel
cards, and all of them have performance issues). Lastly, some laptop include
MiniPCI cards that may be either integrated PCI cards or USB adapters.
Like the initial PrismI design, the PrismII is fully compatible with 802.11 and
include a 2.4 GHz Direct Sequence modem, with all the usual features (Roaming,
WEP...).
The main differences between the PrismI and PrismII chipset are a higher
integration, a higher performance modem and the replacement of the AMD
34
< Linux Wireless LAN Howto >
controller with Intersil own design. The higher integration (5 chips instead of 8)
allows to reduce the price and the size of the product, and to simplify the
integration. The new physical layer (modem) has a better performance (but a lower
transmit power), increasing range, speed and battery life, and is fully compliant
with the 802.11-b standard (5.5 and 11 Mb/s). Finally, the new MAC controller
handle most of the 802.11 functionality (instead of leaving it to the driver), which
simplify driver development and help performance on slow devices (palmtop,
embedded design).
The Prism2.5 and Prism3 chipsets are evolution of the PrismII chipset,
offering even higher integration, lower cost and backward compatibility. With
respect to the driver, these 3 chipset look the same, and therefore driver supporting
PrismII hardware will also support Prism2.5 and Prism3 hardware.
Note that the PrismII firmwares are usually not of the highest quality and
quite inconsistent from one release to another, both on the cards and on the Access
Points, and you may have to try a few of them before finding the one that work for
you. For example, encryption and IBSS ad-hoc mode seems to be working only in
the latest firmwares (0.8.3 and later), and multicast is not working at all. It also
usually takes a bit of time to get the workaround for the latest firmwares in the
various Linux drivers. Latest firmware seem to have fixed most problems and have
added the feature missing from earlier firmwares.
A few words about Ad-Hoc modes : like for Orinoco card, the firmware
support two ad-hoc mode, the Ad-Hoc demo mode (not 802.11-b compliant, but
reported to be Orinoco Ad-Hoc demo mode compatible) and the IBSS Ad-Hoc mode
(802.11-b compliant). The IBSS Ad-Hoc mode is only available in firmwares 0.8.3
and later.
3.6.2
The driver
Who was more qualified to write this driver than Mark, from AVS, who
already wrote the driver for the PrimsI cards ? In fact, Intersil did partner with
Mark to get this driver written for us !
As usual with Mark, the driver is really complete and well written. It is
currently only in beta stage, and Mark told me that he needs to add more
documentation and debug some more features. The driver support both Pcmcia and
PCI cards. This driver is compatible with Linux bridging software, includes a
generic 802.11 interface, exposing the full 802.11 MIB to user space, and include
hooks to build an Access Point. The driver also come with a configuration tools, an
utility to dump 802.11 frames and a daemon responding to 802.11 events.
The release 0.1.10 fixes a number of long standing problems and include a
number of patches and features that were floating around on the mailing lists. This
version supports properly WEP encryption and Ad-Hoc mode. Note that the driver
supports only IBSS ad-hoc mode (0.1.10 and later) and only for recent firmwares,
whereas most cards also support the old ad-hoc demo mode.
The driver supports Pcmcia, PLX and PCI cards. The PLX card allow to
add a Pcmcia card in a PCI slot, but does not support any of the Pcmcia
functionality, so is not supported through the Pcmcia package but directly by the
35
< Linux Wireless LAN Howto >
driver. PCI support is for fully integrated PCI cards or MiniPCI cards. Mark has
also added USB support (only for Intersil USB cards, not Atmel cards).
Reyk has developped a patch that adds basic Wireless Extension support to
the driver, and that was included in version 0.1.13. He needs help for testing and
improving it.
Since then, Mark is concentrating on a Intersil 802.11a driver (not Atheros)
and has transferred the maintenance of the driver to Solomon (a new AVS
employee). Solomon is making the driver SMP compliant, cleaning it up and
keeping up with the new firmwares from Intersil, and keeping up with new
kernels. Solomon has also added pretty support for Wireless Extensions in 0.2.1,
including Scanning support.
Mark is also selling a Wireless Development kit and an Access Point, based
on a PPC platform and this driver.
3.7
Intersil PrismII support in the Orinoco driver
The Orinoco driver (see section 3.2) may be used with most PrismII cards.
3.8
Intersil PrismII driver with HostAP mode
Driver status :
stable
Driver name :
Pcmcia : hostap_cs.o
PLX : hostap_plx.o
PCI : hostap_pci.o
Versions :
v0.4.7 (stable), 0.4.7 (development)
Where :
Linux kernel (2.6.14)
http://hostap.epitest.fi/
Maintainer :
Jouni Malinen <[email protected]>
Mailing list :
http://lists.shmoo.com/pipermail/hostap/
Documentation :
Readme, web page
Configuration :
Module parameters and Wireless Extensions
Statistics :
Wireless Extensions and /proc interface
Modes :
Managed, Ad-Hoc, Master (HostAP), Repeater (WDS)
Security :
WEP (hardware or host based), 802.1x, WPA
Scanning :
Wireless Extensions
Monitor :
Yes
Multi-devices :
Yes
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Host AP mode, bridging, access list, WDS, PLX and PCI
support
Non implemented : ?
Bugs :
?
36
< Linux Wireless LAN Howto >
License :
GPL
Vendor web pages : [Same as PrismII driver]
3.8.1
The device
This is the same device as the previous entry (section 3.6).
One of the most interesting feature of the standard PrismII firmware is that
it can allow the host to act as an Access Point (HostAP mode). This allow to turn
a regular PC with a Prism2 cards into an Access Point, allowing other nodes to
connect to it. In HostAP mode, the card does only the critical part of the Access
Point (sending beacons) and simply pass all the 802.11 management frames to the
driver (which does 802.11 management itself).
Note that this HostAP mode doesn’t exist or is not documented for other cards
(non-PrismII firmwares). Also, it is possible to load special firmware in PrismII
card which allows the card to perform the full Access Point functionality by itself
(tertiary firmware).
3.8.2
The driver
Jouni has recently written this totally new driver for PrismII card. It is well
written, it was probably inspired by the various other driver floating around and is
much more simpler than the linux-wlan-ng driver (see section 3.6).
The driver has complete support for the various feature of the PrismII card
(WEP, IBSS Ad-Hoc mode, scanning...), Monitor mode, very complete support for
Wireless Extensions and offer various extra information in a /proc directory,
making already an excellent choice for a standard wireless client.
What set this driver apart from the other driver is its support for HostAP
mode. In this mode, the driver act as an Access Point on the air and does all the
802.11 management necessary. In this mode, the driver also allows bridging
through the regular Ethernet bridge driver of Linux. This explain why this driver
is use by most Linux Access-Point projects.
Jouni continues to refine his driver and has added PLX and PCI cards
support, monitor mode, MAC address based access list and WDS support (to allow
Access Point to communicate with each other). Jouni latest masterpiece is the
addition of WPA support in the HostAP driver, and the associated user space
supplicant.
In other words : impressive work...
This driver was included in kernel 2.6.14.
3.9
Samsung MagicLAN (binary library driver)
Driver status :
beta
Driver name :
swld11_cs.o
Version :
1.22
http://www.magiclan.com/product/magiclan/download/mlist.jsp
Where :
Maintainer :
Jae-Jun Lee <[email protected]>
Documentation :
Readme
37
< Linux Wireless LAN Howto >
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Module parameters, Wireless Extensions and utility
Wireless Extensions
Managed, Ad-Hoc
WEP
No
No
yes
802.11-DS and 802.11-b, interoperate with Windows
Encryption, Proprietary Samsung API
?
?
Binary only for the core + (?)source wrapper
http://www.sem.samsung.co.kr/
http://www.magiclan.com/
3.9.1
The device
The Samsung MagicLAN is one of the various products based on the Intersil
PrismII chipset (see section 3.6 for full details). It’s a fully featured wireless lan
compliant with 802.11-b. The Compaq products are rumored to be the Samsung
one, with a new sticker...
3.9.2
The driver
Samsung has released their own version of a PrismII driver for their card. The
driver seems complete and well written, the new releases fixes more bugs and I had
report of people successfully using it (with Samsung cards and even some LinkSys
and D-Link cards).
The main difference with the PrismII driver of Mark (see section 3.6) is that
the Samsung driver is based on a binary library (so, only available on x86
platforms), offer encryption and Ad-Hoc mode and offer some support for Wireless
Extensions.
3.10
Symbol Spectrum24 High Rate, 3Com AirConnect, Intel PRO/
Wireless and Socket Communication
Driver status :
Beta (Pcmcia only)
Driver name :
spectrum24t_cs.o
Version :
1.03 and 1.03-CF
Where :
http://sourceforge.net/projects/spectrum24
ftp://ftp.symbol.com/pub/SOFTWARE/IEEE/PC_CARD/LINUX/
Contact :
Brad LeFore <[email protected]>
Maintainer :
Lee John Keyser-Allen <[email protected]>
Discussion forums : http://sourceforge.net/forum/?group_id=11099
38
< Linux Wireless LAN Howto >
Documentation :
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web page :
Readme file
module parameters
None
Managed, Ad-Hoc
WEP
No
No
802.11-DS and 802.11-b, interoperate with Windows
Multicast, WEP encryption and support for CF cards
GPL or BSD
http://www.symbol.com/products/wireless/wireless.html
http://support.intel.com/support/network/wireless/
http://www.3Com.com/
http://www.socketcom.com/
3.10.1
The device
Despite being a long time proponent of Frequency Hopping, Symbol couldn’t
ignore the success of 802.11-b. After a strategic agreement with Intel, Symbol is
back with a complete line of 802.11-b products, that are called Spectrum24 High
Rate (to better confuse them with their old FH products). Symbol still sell mostly
to vertical markets through VAR, but both 3Com and Intel are repackaging Symbol
cards, as Intel PRO/Wireless and 3Com AirConnect. The Symbol CF card is
also sold by Socket Communications.
Of course, there are exceptions : the Symbol/Socket CF cards (Compact
Flash) and the Intel 2011B card don’t have a built in firmware and require a
specific version of the driver (called CF). On the other hand, the 3Com/Intel PCI
cards are PrismII cards, and the latest 3Com 802.11b cards include various
chipsets (see section 3.18).
The card is mostly sold in the Pcmcia form factor, along with the Access Point.
There is a PCI version that looks like a Pcmcia card in a regular PCI to Pcmcia slot.
The main originality of Symbol is that it offer those famous “all-in-one” products
(PDA + barcode + wireless) with 802.11-b (beware, they share the same model
numbers as the non-802.11b devices). Recently Symbol released a Compact Flash
(CF) version of their card called Wireless Networker which has an amazing form
factor.
The Symbol product is composed of the Intersil PrismII chipset (see section
3.6) with Symbol own MAC controller (which is originally derived from the same
core as the MAC from Lucent, Aironet and Intersil). From Symbol, we can expect
a design giving good quality and performance.
39
< Linux Wireless LAN Howto >
The MAC has all the usual features of the 802.11 standard, like MAC level
retransmission, RTS/CTS, fragmentation, auto bit-rate selection, power saving,
WEP encryption and roaming, which extensive configurability. The physical layer
has the classic PrismII feature, supporting 1, 2, 5.5 and 11 Mb/s.
3.10.2
The driver
The driver was initially written by TriplePoint, and Lee has taken over the
maintenance. Not surprisingly, the driver is very similar to the Wavelan-IEEE
binary driver (except for being full source), to the point of mentioning “Turbo” cards
(what Symbol calls “High Rate”).
The driver is well written, has an extensive collection of module parameters
and has been tested successfully with Symbol, 3Com and Intel cards. Lee plans to
add Wireless Extensions and fix the few remaining bugs...
The version 1.01 of the driver fixes some bugs related to higher bit rate
(11 Mb/s) and encryption. The version 1.02, adds support for kernel 2.4.X and
disable power management (doesn’t work on latest firmwares).
Symbol has recently release a separate version of this driver to support
Compact Flash cards. Compact Flash cards need a specific driver because they
don’t have the firmware stored on the card and therefore the driver has to
download the firmware to the card after each reset.
3.11
Ericsson WLAN 11 Mb/s
Driver status :
First shot
Driver name :
eriwlan_cs.o
Version :
1.0 (2000-10-11)
Where :
http://www.ericsson.com/wlan/su-downloads11.asp
Maintainer :
Christian Olrog <[email protected]>
Documentation :
Readme file
Configuration :
module parameters and /proc interface
Statistics :
/proc interface
Modes :
Managed, Ad-Hoc
Security :
WEP
Scanning :
No
Monitor :
No
Multi-devices :
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Power management
Non implemented : Bugs :
License :
GPL
Vendor web page : http://www.ericsson.com/wlan/
40
< Linux Wireless LAN Howto >
3.11.1
The device
After their success with wide area communications (GSM and co.), Ericsson
decided to expand in new markets and started looking seriously at local
connectivity. Ericsson is of course the main driving force behind BlueTooth (see
section 8), but they realised pretty quickly the BlueTooth would not fulfil the need
of the Wireless LAN market. Ericsson is also pushing hard HiperLAN II (see
section 8), a high performance system (54 Mb/s) in the 5 GHz band with strong
quality of service support.
The initial Ericsson Wireless LAN products were OEM of BreezeCom
pro.11 products (Frequency Hopping, 3 Mb/s - see section 2.11). Due to the success
of 802.11-b, their second product line are fully 802.11-b compliant, and are in fact
OEM of the Symbol cards (see section 3.10). As such, this product has all the usual
802.11-b features...
3.11.2
The driver
This driver apply only to the 11 Mb/s version of the Ericsson card. This is only
the second driver written by Christian from scratch, after the BreezeCom driver
(see section 2.11 - this other driver applies to Ericsson 3 Mb/s cards). And as usual
for him, the source code is well written, concise and clean. Impressive job !
This driver is very new, so I don’t have yet report of its use. The driver seems
to support only a minimal set of configuration and statistics for now. Christian told
me that it should work with other Symbol cards with minor changes, and that the
driver has been tested with IPsec and MobileIP. I hope to have more info about it
at a later date...
3.12
Symbol High Rate support in the Orinoco driver
The Orinoco driver (see section 3.2) may be used with most Symbol HR cards.
3.13
Symbol CF driver based on the Orinoco driver
Driver status :
Beta
Driver name :
spectrum_cs.o
Version :
v0.15-rc2
Where :
Linux kernel (2.6.14)
http://www.red-bean.com/~proski/symbol/
http://savannah.nongnu.org/projects/orinoco/
Maintainer :
Pavel Roskin <[email protected]>
Mailing list :
http://lists.samba.org/pipermail/wireless/
Documentation :
Readme file
Configuration :
Wireless Extensions only
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc and Ad-Hoc-demo
Security :
WEP (based on hardware support)
Scanning :
Wireless Extensions
41
< Linux Wireless LAN Howto >
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Yes
Yes
802.11-DS and 802.11-b, interoperate with Windows
Similar to Orinoco driver (including ARM support)
MPL and GPL
[Same as Symbol HR driver]
3.13.1
The device
This is the same device as the previous entry (section 3.10).
Note that this driver is specific to the Compact Flash (CF) version of the
card and the Intel 2011B.
3.13.2
The driver
The Orinoco driver (see section 3.2) already includes support for regular
Symbol HR cards. However, the Compact Flash cards don’t work with the standard
Orinoco driver because they lack built in firmware. This is the same reason why
there is two different Spectrum24 drivers (see section 3.10).
Pavel has created a new driver based on the Orinoco driver and Spectrum24CF driver for those cards. It is similar to the regular Orinoco Pcmcia driver, but add
the firmware download at each reset necessary for those cards. As the core of the
driver is common with the Orinoco driver, this driver has the exact same feature
set (which is quite extensive - see section 3.2). This driver is now integrated in the
Orinoco driver collection (v0.14 and later), and no longer distributed separately. It
is now part of the Linux kernel (2.6.14 and later).
Note that for cards that don’t require the firmware download (regular Pcmcia
cards), it is recommended to use the regular Orinoco driver instead of this one.
3.14
Aironet ARLAN 4500, 4800, Cisco 340 and Cisco 350 series
Driver status :
stable
Driver name :
ISA, PCI : airo.o
Pcmcia : airo_cs.o
Version :
1.4
Where :
Linux kernel (2.4.6)
Pcmcia package (3.1.26)
Maintainers :
Benjamin Reed <[email protected]>
Javier Achirica <[email protected]>
Web pages :
http://sourceforge.net/projects/airo-linux/
Mailing list :
http://sourceforge.net/mail/?group_id=24926
Documentation :
README file
42
< Linux Wireless LAN Howto >
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web page :
/proc interface and Wireless Extensions
/proc interface and Wireless Extensions
Managed, Ad-Hoc
WEP (hardware), AES (host), MIC, 802.1x
Wireless Extensions
Yes
N/A
802.11-DS and 802.11-b, interoperate with Windows
Support MPI cards (Mini PCI)
MPL & GPL
http://www.aironet.com/
3.14.1
The device
Aironet has been the producer of some of the most performant wireless LANs
for a long time. Aironet was a division of Telxon, and was spun-off when Symbol,
one of their competitor, did acquire Telxon. After a short independent life, Aironet
was acquired by Cisco.
The previous section was dealing with Aironet old pre-802.11 products (see
section 2.8), this section deals with their more recent 802.11 compliant products.
Their first 802.11 products were the 3500 family, Frequency Hopping (1 and 2 Mb/
s), and 4500, Direct Sequence (1 and 2 Mb/s).
The Arlan 4500 family is 802.11 compliant wireless LANs in the 2.4 GHz ISM
band, and is Direct Sequence. It includes an ISA, PCI, Pcmcia, serial, Ethernet and
multi-Ethernet versions, plus the Access Point.
These cards are based on the Harris Prism chipset, like many other cards
(see section 2.4), but Aironet are using their own MAC controller. The 4500 offer
standard 1 and 2 Mb/s bit rate. The MAC includes all the standard 802.11 features,
with Power Saving, WEP, Ad-Hoc mode and roaming, plus a lot of Aironet
extensions (short headers, variable base rate...). Conform to their reputation, their
MAC is one of the richest in term of features, and one of the most performant.
The 3500 family (Frequency Hopping) eventually died, and I won’t talk about
it here.
The 4500 family was quickly followed by the 4800 family, still based on the
Prism chipset, adding 5.5 and 11 Mb/s bit rate, either in MBOK (proprietary) or
CCK, which is 802.11-b compliant. The 4800 can do encryption only at 1 and 2 Mb/
s (this limitation was removed in the 4800B).
With introduction of the PrismII chipset, Aironet did release the 4800B
family. It is functionally equivalent to the 4800, except that the new PrismII
chipset allows lower price, greater sensitivity but force a lower transmit power
43
< Linux Wireless LAN Howto >
(30 mW). Aironet still use their own MAC controller in the 4800B (and not the new
PrismII MAC - see section 3.6).
After the acquisition by Cisco, the Aironet 4800B was renamed Cisco 340
series (exact same hardware, new name). Dell also sell the same hardware under
its own brand as Dell TrueMobile 1100 (on the other hand, the TrueMobile 1150
is a Wavelan IEEE).
Like Lucent, Cisco offer different cards with different level of encryption. The
cards labelled 340 feature no encryption, the cards labelled 341 feature 40 bits
encryption and the cards labelled 342 feature 128 bits encryption. Moreover, some
versions of the Pcmcia card are sold with antenna but others without antennas.
Cisco has now released the Cisco 350, a new family of 802.11b cards. From
the information I did gather, it seems to be equivalent to the 340 series with a
greater transmit power (100 mW instead of 30 mW). The Cisco 350 also improves
the performance of the AP and introduce greater security (Radius authentication
and co).
Cisco has also released a Mini-PCI (MPI) version of the Aironet 350, to be
added in laptops that support a Mini-PCI slot. For some strange reason, this
hardware is slightly different from the regular Aironet 350 PCI.
3.14.2
The driver
Ben has produced a solid driver for the Aironet card, The driver supports the
ISA, PCI and Pcmcia cards (4500, 4800 & 4800B versions), it looks fairly complete
and debugged, with a nice /proc interface. The driver also has very complete WEP
support.
Ben also told me that the driver was able to recognise the PC3500 cards, but
more work would be needed there to get it fully working.
Recently, I’ve started adding Wireless Extension to this driver. Ben was kind
enough to integrate properly my work in his driver. Then, Javier Achirica did an
amazing job of completing Wireless Extension support (power management, spy
and co), and this driver has one of the most complete Wireless Extension support
of all.
Then, Javier added to the driver the Cisco proprietary API, which allow
communication with Cisco utilities (see section 3.16) and, amongst other things,
flashing new firmware on the card. All this amazing work is in the latest release
from Ben (1.5). He also wrote a couple of open source utilities allowing to dump all
the register of the card and to flash new firmwares through this API.
Lately, the driver has been integrated in the Linux kernel (2.4.6 and later)
and moved to SourceForge. Javier has also added the ability to dump raw 802.11
frames. Then Javier did extensive work to fix locking (SMP support), add monitor
mode and Wireless Scanning support (in version 1.4).
Ben attempted to add support to MPI card and added code for those cards in
the CVS. The work on MPI card was completed and now MPI cards are properly
supported.
44
< Linux Wireless LAN Howto >
3.15
Aironet ARLAN 802.11 (alternate driver)
Driver status :
stable
Driver name :
ISA, PCI : aironet4500_card.o
Pcmcia : aironet4500_cs.o
Version :
0.1
Where :
Linux kernel 2.3.31 to 2.5.X
Maintainer :
Elmer Joandi <[email protected]>
Documentation :
Configure.help file
Configuration :
/proc interface
Statistics :
/proc interface
Modes :
Managed, Ad-Hoc
Security :
WEP
Scanning :
?
Monitor :
No
Multi-devices :
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Non implemented : Pcmcia interface
Bugs :
Buggy SMP support.
License :
GPL
Vendor web page : http://www.aironet.com/
3.15.1
The device
This is the same device as the previous entry (section 3.14).
3.15.2
The driver
To some, it may seem that this is a totally new driver that has just popped up
in the kernel with little warning. In fact, Elmer had developed this driver for a
commercial company (SpectrumWireless) a while back and they agreed to let him
release it in GPL form after some month.
The code is very complete, especially the /proc interface. It comes as four
modules, the generic core, the /proc interface, the PCI/ISA interface and the Pcmcia
interface. The driver support both the 4500 and 4800 families. Unfortunately, the
Pcmcia interface is incompatible with the Linux Pcmcia support and doesn’t work
well.
Elmer told me that compared to Ben driver, his driver was probably more
robust and featured but much less friendly. In essence, the focus was slightly
different, so each driver has it own strength.
This driver was removed from the Linux kernel during 2.5.X, so it is no
longer available in kernel 2.6.X.
45
< Linux Wireless LAN Howto >
3.16
Cisco/Aironet 802.11 (Cisco driver)
Driver status :
stable (rock solid)
Driver name :
ISA, PCI : airo.o
Pcmcia : airo_cs.o
Version :
2.1
Where :
http://www.cisco.com/public/sw-center/sw-wireless.shtml
Maintainer :
Cisco
Documentation :
Text files
Configuration :
Cisco utilities, Wireless Extensions
Statistics :
Cisco utilities, Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP (hardware), AES (host), MIC
Scanning :
No
Monitor :
No
Multi-devices :
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Non implemented : Bugs :
License :
Cisco open source license
Vendor web page : http://www.aironet.com/
3.16.1
The device
This is the same device as the two previous entries (section 3.14).
3.16.2
The driver
Recently, Cisco decided to get more involved with supporting their Wireless
LAN cards under Linux. Rather than developing an entirely new driver, they
decided to base their work on Ben’s driver (section 3.14), which is a good idea. One
of the key person behind this operation was Jim Veneskey.
The main contribution of Cisco is a proprietary API, which allow
communication with Cisco utilities and, amongst other things, flashing new
firmware on the card, and of course a set of utilities which are mostly identical to
the Windows utilities. They also provided nice installation scripts and did lot’s of
testing of the driver to guarantee its stability (Cisco usually do some pretty
intensive testing of their products).
However, even if Cisco regularly synchronise with Ben’s driver (section 3.14),
this one continues to improve. As they are derived from the same base, it’s easy to
compare the two drivers. In term of features, I guess that Ben’s driver is winning,
because it now has the Cisco API of this driver and more complete Wireless
Extensions support. However, I believe that Cisco has an edge in term of stability.
46
< Linux Wireless LAN Howto >
I hope that the two drivers will merge rather than diverge, and that changes
will be propagated from one to the other, so that we have a driver with both
features and rock solid stability, but only time will tell... Cisco told me that they
were going to try to catch up with Ben’s driver.
Note that Cisco changed their web site and their driver is no longer available
as a public download. I can not check if the driver still exist and what changed has
been made to it.
3.17
No Wires Needed Swallow (and BreezeCom DS11)
Driver status :
stable
Driver name :
swallow_cs.o
Version :
0.7.0 (kernel 2.4.0) and 0.4.0 (kernel 2.2.16 - older version)
Where :
http://www.xs4all.nl/~bvermeul/swallow/
Maintainer :
Bas Vermeulen <[email protected]>
Documentation :
README file
Configuration :
Module parameters, Wireless Extensions, /proc interface
Statistics :
no
Modes :
Managed
Security :
WEP, AES
Scanning :
Wireless Extensions
Monitor :
No
Multi-devices :
unknown
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Security (very complete), roaming table
Non implemented : Multicast
Bugs :
License :
GPL
Vendor web page : http://www.nwn.com/
http://www.breezecom.com/
3.17.1
The device
No Wires Needed is a small company in the Netherlands building a range of
802.11 DS devices, including a Pcmcia card (Swallow), an Access Point and a Hub.
They also offer a ISA version using a ISA to Pcmcia bridge. They have two version,
the 550 (5.5 Mb/s) and the more recent 1100 (11 Mb/s). BreezeCom also EOM this
card for their DS.11 range (the PC-DS.11).
The Swallow delivers all the features expected from a 802.11 compliant
device, with ad-hoc networking, authentication and roaming. The main difference
with other 802.11 devices is that NWN offers some strong link layer encryption and
a key management and distribution system.
47
< Linux Wireless LAN Howto >
The modem is the famous Prism chipset used in many other cards (see section
2.4), which is 2.4 GHz Direct Sequence, with 1 Mb/s, 2 Mb/s, 5.5 Mb/s and 11 Mb/s
bit rate. No Wires Needed use their own MAC design on an embedded ARM
processor, and not the AMD or PrismII MAC controller. This give them more
performance and flexibility. Now that Intersil has acquired No Wires Needed,
Intersil can offer 2 different 802.11 MAC controller !
3.17.2
The driver
Bas has implemented a quite complete driver for the Swallow 550 and 1100
card (Pcmcia). He has patiently debugged the driver to fix races, timeouts and
increase the performance. The driver is working for both the NWN and the
BreezeCom cards.
Bas has also implemented Wireless Extension support for the security
support, and support the full range of security features in the driver. You can also
configure the ESSID on the fly with Wireless Extensions...
Lately, Bas has been doing lot of work on roaming support. The driver export
the roaming tables in a /proc interface, allowing the implementation of a user space
roaming daemon. This interface also contains some other configuration
parameters.
3.18
No Wires Needed 1148, old 3Com Wireless LAN XJack
Driver status :
stable
Driver name :
poldhu_cs.o
Version :
0.2.13 (for kernel 2.4.X), 0.3.1 (for kernel 2.6.X)
Where :
http://www.xs4all.nl/~bvermeul/swallow/
Maintainer :
Bas Vermeulen <[email protected]>
Documentation :
README file
Configuration :
Module parameters, Wireless Extensions, /proc interface
Statistics :
no
Modes :
Managed, Ad-Hoc
Security :
WEP, AES
Scanning :
Wireless Extensions
Monitor :
No
Multi-devices :
unknown
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Security (very complete).
Non implemented : Multicast
Bugs :
License :
GPL
Vendor web page : http://www.nwn.com/
http://www.3Com.com/
48
< Linux Wireless LAN Howto >
3.18.1
The device
Recently, No Wires Needed has replaced the Swallow 550 and 1100 with a
new 802.11-b card, the 1148. The design and the feature of this card seems very
similar to their previous one (see section 3.17) : The MAC is the same ARM core and
they still offer AirLock encryption. The main difference seems that they are now
using a PrismII modem (see section 3.6).
3Com has also released a quite rare old Wireless LAN XJack card
(3CRWE62092A) which is a clone of the NWN 1148 (this card). On the other hand,
the newly released OfficeConnect Wireless LAN cards (3CRSHPW196/696 - with
or without the XJack antenna) and new Wireless LAN XJack card
(3CRWE62092B) are Atmel cards (see section 3.20). The even newer
OfficeConnect CardBus card (3CRSHPW796) is an ADMTek card (see section
3.23). The older AirConnect Pcmcia cards (3CRW737A/B) are clone of the
Symbol HR cards (see section 3.10), and the AirConnect PCI card (3CRW777A)
is a PrismII PLX card (see section 3.6). The OfficeConnect 11g card
(3CRWE154G72) is an Intersil PrismGT card (see section 4.3), and the 11a/b/g
cards (3CRPAG175/3CRDAG675) are Atheros cards (see section 4.2).
Coming back to the NWN 1148, the main difference between the 3Com
3CRWE62092A and NWN 1148 cards is the removal of AirLock encryption (WEP
is still available), the addition of Ad-Hoc mode, and of course the famous pop-up
antenna ;-)
3.18.2
The driver
Because the card is so similar to the Swallow, it was natural that a driver for
this card would be derived from the Swallow driver. In fact, No Wires Needed
contacted Bas to implement a driver for the new card. Bas modified his Swallow
driver and created this driver which offer very similar functionality and feature as
the Swallow driver (see section 3.17).
So, the driver includes complete security support, Wireless Extensions and
roaming support. The driver also include read only support for most low level
commands (SNWNMP).
Bas has also added in the driver the necessary support for the 3Com WLAN
XJack cards, including its specific features. All features of the card (ad-hoc mode,
encryption) are configurable through Wireless Extensions.
3.19
Nokia C110/C111
Driver status :
???
Driver name :
nokia_c110.o
Version :
2.05
Where :
http://www.nokia.com/nokia/0,5184,2718,00.html
Maintainer :
Nokia
Documentation :
Readme
Configuration :
Specific Pcmcia scripts
Statistics :
/proc file
49
< Linux Wireless LAN Howto >
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Managed, Ad-Hoc
WEP
No
No
yes
802.11-DS and 802.11-b, interoperate with Windows
Encryption, multicast, user profiles
?
?
Binary only for the core + Nokia OpenSource Linux wrapper
http://www.nokia.com/corporate/wlan/
3.19.1
The device
In the past years, Nokia has slowly moved into the Wireless LAN market.
They started by buying Intalk, a company producing PrismI clones (see section 2.4),
and Nokia continued selling those cards, renamed Nokia C020 and C021. While
being busy working on BlueTooth and HiperLanII, Nokia didn’t forget 802.11-b
and released a new set of card, the C110 and C111.
As can be expected, the Nokia C110/C111 is another PrismII clone (see section
3.6). On the other hand, it seem that Nokia has changed quite a few things
compared to the original PrismII design, for example they have added a Smart
Card reader on the Pcmcia card (for security settings).
3.19.2
The driver
Nokia initially quietly made this driver available in the registered only part
of their web site and didn’t mention it anywhere, fortunately I have my spies to
inform me ;-). Later on, they moved this driver to their official driver page on their
public web site. This driver supports only the C110/C111 cards, on the other hand
the C020 is supposed to work with the linux-wlan package (see section 2.4).
The driver contains a very thin source wrapper on top of the binary part (one
version for kernel 2.2.X, one for 2.4.X). On the other hand, the package come with
exhaustive set of complex Pcmcia scripts to configure the card and enable profiles.
The driver works in infrastructure and Ad-Hoc mode, and support WEP.
3.20
Atmel AT76C502A/AT76C503A cards (802.11b USB and Pcmcia)
Driver status :
stable
Driver name :
Pcmcia : fastvnet_cs.o
USB : vnetusbX.o
Version :
v3.4.1.0, 2002-12-09
Where :
http://atmelwlandriver.sourceforge.net/
Maintainers :
Stavros Markou <[email protected]>
Titos Mpetsos <[email protected]>
50
< Linux Wireless LAN Howto >
Ron Smith (Wireless Extensions)
Web pages :
http://atmelwlandriver.sourceforge.net/howto/howto.html
http://www.fuw.edu.pl/~pliszka/hints/wireless.html
http://www.gemtek.com.tw/faq_download.htm
http://www.houseofcraig.net/belkin_howto.php
Mailing lists :
http://sourceforge.net/mail/?group_id=59001
http://iprserv.jura.uni-leipzig.de/mailman/listinfo/atmel-wlan-usb
Documentation :
Readme files
Configuration :
Specific tools, Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP, WPA
Scanning :
No
Monitor :
No
Multi-devices :
yes
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Non implemented : Intersil radio support
Bugs :
License :
GPL
Vendor web pages : http://www.atmel.com/atmel/products/prod32a.htm
http://www.3com.com/
http://www.gemtek.com.tw/
http://www.dlink.com/products/
http://www.linksys.com/products/
http://www.smc.com/
3.20.1
The device
Atmel has decided to join the selected club of company selling 802.11b
chipsets. Their design is based on an ARM7 processor, and offer a Pcmcia and a
USB version. The USB version is by far the most popular, because it was one of the
first USB chipset to market and is cheap. Various 802.11b radios can be used with
this chipset (such as the Intersil PrismII radio and Atmel RFMD). Very little public
information is available about those products, but as they are 802.11 compliant we
can expect the usual set of features.
Of course, with any USB cards the main issue is performance. The streaming
abstraction of USB doesn’t work well with register/memory based chipset designs
and slow down operations. Also, USB add a noticeable latency. I currently don’t
have any data on how well those cards performs in the respect.
51
< Linux Wireless LAN Howto >
Linksys and D-Link are selling various USB products based on this chipset,
such as Gemtek WL-280, D-Link DWL-120, Linksys WUSB11... It seems that the
SMC 2632W is a Pcmcia card also based on the Atmel chipset.
The newly released 3Com OfficeConnect Wireless LAN cards
(3CRSHPW196/696 - with or without the XJack antenna) and new 3Com Wireless
LAN XJack (3CRWE62092B) are also Atmel Pcmcia cards.
3.20.2
The driver
Atmel decided to release themselves a Linux driver. This driver is in fact a set
of driver for the different combination of controllers and radios, and was initially
based on a binary library. However, Atmel changed their mind and eventually
released the driver as full source GPL. The USB versions work with both uhci and
ohci USB drivers. The driver support WEP and Ad-Hoc mode.
The package from Atmel include specific configuration tools (command line
and X-Window). Just after the driver was GPL’ed, the support for Wireless
Extensions was fixed and greatly enhanced by Ron (Wireless Tools can now be used
to configure the card). Lately, Atmel has improved and enhanced the USB driver,
but also removed support for Intersil radio, so you will need to use older version of
the driver for products using Intersil radio. On the other hand, the Pcmcia driver
seems to be still based on an older version of the code.
Lately, the driver has gained support for kernel 2.6.X, better support for
Wireless Extensions and support for WPA.
3.21
Atmel USB alternate driver
Driver status :
in development
Driver name :
USB : at76c503.o
Versions :
0.11, 0.12-pre9
Where :
http://at76c503a.berlios.de/
http://innominate.org/kurth/at76c503/
Maintainers :
Jörg Albert <joerg dot albert at gmx dot de>
Oliver Kurth <oku at masqmail dot cx>
Web pages :
http://at76c503a.berlios.de/
http://innominate.org/kurth/at76c503/
http://www.wireless.org.au/~jhecker/atmeldrv/atmeldrv.html
Mailing lists :
http://lists.berlios.de/pipermail/at76c503a-user/
http://iprserv.jura.uni-leipzig.de/mailman/listinfo/atmel-wlan-usb
Documentation :
Readme files
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP
52
< Linux Wireless LAN Howto >
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Wireless Extensions (0.12)
No
?
802.11-DS and 802.11-b, interoperate with Windows
Intersil radio support
GPL
http://www.atmel.com/atmel/products/prod32a.htm
http://www.gemtek.com.tw/
http://www.dlink.com/products/
http://www.linksys.com/products/
3.21.1
The device
This is the same device as the previous entry (section 3.20).
3.21.2
The driver
Oliver and a group of people were not happy about the official Atmel driver
and its development (section 3.20), and therefore he started to write an alternate
driver from scratch, based on the information available in the official driver, and
soon those other people started to help him.
The driver support only USB devices, and it support both Intersil and RFMD
radios. At this time, the new driver is still in development, and therefore still has
some limitations, but it already support both infrastructure and ad-hoc mode, and
has some Wireless Extension support.
As Olivier was no longer active, Jörg took over the driver and is now fixing
many bugs, making it more robust and adding a few missing features. For example,
version 0.12 adds Wireless Scanning support.
3.22
Atmel PCI and Pcmcia alternate driver
Driver status :
in development
Driver name :
PCI : atmel_pci.o
Pcmcia : atmel_cs.o
Version :
0.9
Where :
Kernel 2.6.5
Maintainer :
Simon Kelley <[email protected]>
http://iprserv.jura.uni-leipzig.de/mailman/listinfo/atmel-wlan-usb
Mailing lists :
http://lists.berlios.de/pipermail/at76c503a-user/
Documentation :
Readme files
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
53
< Linux Wireless LAN Howto >
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Managed, Ad-Hoc
WEP
Wireless Extensions
No
?
802.11-DS and 802.11-b, interoperate with Windows
Firmware loading via HotPlug
GPL
http://www.atmel.com/atmel/products/prod32a.htm
http://www.3Com.com/
http://www.smc.com/
3.22.1
The device
This is the same device as the previous entry (section 3.20).
3.22.2
The driver
Simon also was not happy with the original Atmel driver. He decided to
rewrite the Pcmcia/PCI driver based on the original code, with the main target
being integration in kernel 2.6.X (which is now done). Simon did an extensive
amount of work on the driver, for example his driver has very complete Wireless
Extension support including Wireless Scanning. However, this driver is not
compliant with kernel 2.4.X and earlier.
This driver was mostly tested with Pcmcia cards, however Simon also
managed to get a PCI card for testing and added PCI support in the driver. Some
of those cards don’t have firmwares and therefore need to use the new firmware
uploading facility of Linux (via HotPlug).
3.23
ADMtek ADM8211 based cards
Driver status :
beta
Driver name :
PCI & Cardbus : 8211.o
Version :
v1.05
Where :
http://www.admtek.com.tw/index/index/Download.htm
http://www.espina.info/papers/officeconnect/
Contact :
ADMtek support <[email protected]>
Maintainers :
?
Documentation :
Readme files
http://www.houseofcraig.net/belkin_howto.php
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
54
< Linux Wireless LAN Howto >
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Managed, Ad-Hoc
WEP
No
No
?
802.11-DS and 802.11-b, interoperate with Windows
PCI busmaster
?
Binary only for the core + OpenSource Linux wrapper
http://www.admtek.com.tw
http://www.dlink.com/products/
3.23.1
The device
ADMtek is a small taiwanese company that designed a single chip 802.11b
MAC solution. Very little is known about it (for example which radio is used with
the MAC), but we can expect compliance with the 802.11b specification and the
usual feature set. One of the main feature of this chipset is that is uses a PCI
busmaster interface (as opposed to the Intersil PrismII that uses ISA PIO - section
3.6), which result in much lower CPU utilisation (and potentially higher
performance).
Most Cardbus 802.11b cards are based on this chipset. The chipset is
starting to appear in products, such as some D-Link 802.11b Cardbus and PCI
cards, Belkin PCI cards, the SMC 2602W V2 and the 3Com 3CRSHPW796.
ADMtek was bought by Infineon in 2004. Since then, their web site
disappeared, and the Infineon web site has no information on their wireless LAN
products.
3.23.2
The driver
ADMtek has released a Linux driver based on a binary library, that can be
compile for different distributions. The driver has complete support for Wireless
Extensions, and many people have reported success using it.
Eduardo made a patch to add support for the 3Com 3CRSHPW796 to this
driver.
3.24
ADMtek ADM8211 full source driver
Driver status :
pre-release
Driver name :
PCI & Cardbus : adm8211.o
Version :
20051031
Where :
http://aluminum.sourmilk.net/adm8211/
Maintainers :
Michael Wu <[email protected]>
Jouni Malinen <[email protected]>
55
< Linux Wireless LAN Howto >
Documentation :
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Wireless Extensions
Wireless Extensions
Managed, Ad-Hoc
WEP
Wireless Extensions
Yes
?
802.11-DS and 802.11-b, interoperate with Windows
PCI busmaster
?
GPL
http://www.admtek.com.tw
http://www.dlink.com/products/
3.24.1
The device
This is the same device as the previous entry (section 3.23).
3.24.2
The driver
Michael took a driver originally started by Jouni (of HostAp fame - section
3.8), completed it, debugged it and finally released it. The main difference with
ADMtek driver is that this driver is fully OpenSource and support only kernel
2.6.X.
The driver is still young, but its gaining feature and stability with each
release, and is well written. Recently it has gained support for monitor and Ad-Hoc
mode, and many bugfixes and cleanups. You should contact Michael if you want to
help.
3.25
Realtek RTL8180L cards
Driver status :
?
Driver name :
PCI : rtl8180_24x.o
Version :
1.5
Where :
http://www.realtek.com.tw/downloads/downloads13.aspx?Keyword=8180
Maintainers :
ShuChen <[email protected]>
Documentation :
Readme files
http://www.alumni.caltech.edu/~rbell/Realtek8180.html
http://www.linuxquestions.org/questions/
showthread.php?s=&threadid=61832&perpage=15&pagenu
mber=1
56
< Linux Wireless LAN Howto >
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Private Extensions
?
Managed, Ad-Hoc, Master
WEP
No
No
?
802.11-DS and 802.11-b, interoperate with Windows
?
Binary only driver + OpenSource Linux wrapper
http://www.realtek.com.tw/
3.25.1
The device
Realtek is a taiwanese company known for its Ethernet cards, which has
recently released a 802.11 chipset. This chip seems to have all the usual 802.11
features, and offer only a PCI/CardBus interface (for lower CPU utilisation).
3.25.2
The driver
Realtek has released a binary driver for their device, with precompiled version
for Red-Hat and SuSE. The driver doesn’t use Wireless Extension (but some
private extensions), and has a strange setup procedure (manual enable, require
proper commands in the proper sequence).
I didn’t try this driver, but I got some feedback from many users. The driver
version before 1.2 were difficult to install and prone to crash the kernel. The
version 1.2 had many troubles (such as reassociation), but was working. Version
1.3 is more stable, but a little too talkative.
Version 1.4 of the driver also adds support for making the card an Access
Point. Version 1.5 supports newer version of gcc and newer kernels.
3.26
Realtek RTL8180L full source driver
Driver status :
Beta
Driver name :
r8180.o
Version :
0.17
Where :
http://rtl8180-sa2400.sourceforge.net/
Maintainers :
Andrea Merello <andreamrl *at* tiscali.it>
Documentation :
Readme files
Configuration :
Wireless Extensions
Statistics :
?
Modes :
Managed, Ad-Hoc
57
< Linux Wireless LAN Howto >
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
WEP
Wireless Extensions
Yes
?
802.11-DS and 802.11-b, interoperate with Windows
Philips and Maxim radio support
SMP, non-i386
GPL
http://www.realtek.com.tw/
3.26.1
The device
This is the same device as the previous entry (section 3.25).
3.26.2
The driver
The Realtek driver is not the most user friendly, and many people can’t
manage to make it work on their configuration. This lead Andrea to write his own
driver for the Realtek chipset. After much hard work by Andrea, his driver is now
functional, and evolving quickly.
This driver is fully OpenSource and the source is much closer to the standard
of other Linux drivers. It support PCI and Pcmcia card with the Philips radio (the
most common), and has experimental support for the Maxim radio. It reuses the
WEP implementation of the Centrino driver (section 3.28), which is well tested and
featured. It supports the latest kernel 2.6.X and 2.4.X, has complete support for
Wireless Extensions, and support monitor mode, so you can see how much Andrea
has been busy lately...
During mid 2005, Andrea decided to reorganise the driver, and created a new
branch of the driver called rtl818x-newstack. This branch is based on the
ieee802.11 stack from the Centrino driver (see section 3.28). The goal of this branch
is better integration in the kernel, and also support for the newer Realtek 802.11g
cards (see section 4.10). It seems that Realtek is also taking a more active role in
supporting Andrea and this driver.
3.27
Ralink RT2400 cards (Minitar driver)
Driver status :
Stable
Driver name :
stable : rt2400.o
alpha : rt2x00.o
Version :
1.2.2 (stable) and 2.0.0 (pre-alpha)
Where :
http://rt2x00.serialmonkey.com/
http://rt2400.sourceforge.net/
http://minitar.com/index.php?maincat=download
http://flavio.stanchina.net/debian/rt2400.html
58
< Linux Wireless LAN Howto >
Maintainers :
Paul Lin
Mark Wallis <markwallis at users.sourceforge.net>
Flavio Stanchina <flavio_AT_stanchina.net>
Ivo van Doorn <ivd at euronet.nl>
Mailing list :
http://sourceforge.net/mail/?group_id=107832
Documentation :
Text files, Howtos
Configuration :
Wireless Extensions and specific graphical tool
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP
Scanning :
Yes (specific tool)
Monitor :
Yes
Multi-devices :
?
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Promisc/bridge mode support
Non implemented : Bugs :
SMP problems
License :
GPL
Vendor web pages : http://www.ralinktech.com/
http://minitar.com/
http://rt2x00.serialmonkey.com/wiki/index.php/Hardware
3.27.1
The device
Ralink is yet another taiwanese company having recently released a 802.11b
chipset. This chip seems to have all the usual 802.11b features, and offer only a
PCI/CardBus interface (for lower CPU utilisation).
3.27.2
The driver
Ralink created the original Linux driver for this card, and Minitar released it
as fully OpenSource and started helping driver users on their forums. This driver
support the Wireless Extensions, and also comes with a dedicated graphical utility.
Flavio created a Debian package for this driver, and documented how to install and
use this driver.
Then, Mark created a SourceForge project for the driver and started to
maintain it, helped by many users of the driver. Many patches have been
integrated to improve the stability and functionality of the driver.
Ivo has started a rewrite of the driver, called rt2x00, his goal is to have a
source code easier to integrate in the Linux kernel and to maintain. His rewrite
targets both the RT2400 and the new RT2500 (section 4.6). This new driver doesn’t
seem to be fully functional yet (at time of writing), but good progress has been
made.
59
< Linux Wireless LAN Howto >
3.28
Intel PRO/Wireless 2100 802.11b (Centrino)
Driver status :
Beta
Driver name :
ipw2100.o
Version :
1.1.3
Where :
Linux kernel (2.6.14)
http://ipw2100.sourceforge.net/
http://ieee80211.sourceforge.net/
Maintainer :
James P. Ketrenos <[email protected]>
Mailing list :
http://lists.sourceforge.net/lists/listinfo/ipw2100-devel/
Documentation :
Readme
Configuration :
Wireless Extensions
Statistics :
/proc interface and Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP, 802.1x, WPA
Scanning :
Wireless Extensions
Monitor :
Yes
Multi-devices :
?
Interoperability :
802.11-DS and 802.11-b, interoperate with Windows
Other features :
Firmware loading via HotPlug
Non implemented : Bugs :
?
License :
GPL
Vendor web page : http://www.intel.com/
3.28.1
The device
The Intel PRO/Wireless 2100 is the second generation wireless LAN product
from Intel. Intel initially sold various wireless LAN cards and Access Points from
Symbol as Intel PRO/Wireless 2011 (section 3.10). However, Intel has a long
experience with Ethernet MAC controllers, so it was natural for them to create
their own wireless LAN chips. The first MAC controller created by Intel is the PRO/
Wireless 2100, and we can expect many more products to come.
The PRO/Wireless 2100 MAC controller is fully IEEE 802.11b compliant
and has all the usual 802.11b features. It’s a PCI Busmaster design, for low CPU
utilisation. The Radio most likely is done in collaboration with Symbol (Intel and
Symbol have one of those strategical alliances).
The main difference between this chipset and the vast number of other
802.11b chipset is Intel’s marketing. The PRO/Wireless 2100 is not sold as a
standalone product, but only as part of the Centrino package. Centrino is just a
marketing exercise, only laptops equipped with a Intel processor, an Intel chipset
and a Intel PRO/Wireless card can carry the Centrino logo. The PRO/Wireless 2100
60
< Linux Wireless LAN Howto >
is a regular MiniPCI card (it’s not integrated on the motherboard as some rumors
suggests), and you can replace the PRO/Wireless 2100 of Centrino laptops by any
other MiniPCI wireless LAN of your choice.
Intel has been quite successful, and a large number of recent laptops includes
a PRO/Wireless 2100 MiniPCI card. In fact, if you buy a laptop with integrated
802.11b support (without 802.11g or 802.11a support), it most likely has a PRO/
Wireless 2100 card. On the other hand, the PRO/Wireless 2100 is not available as
a separate Pcmcia, Cardbus, PCI or USB card.
3.28.2
The driver
The Linux driver for the PRO/Wireless 2100 was released a long time after
the card themselves. For this reason, Intel did receive a lot of harsh criticism from
people buying laptops with this card and finding that there was no driver or
documentation for it. This was a bit unfair, as Intel has always been supportive of
Linux, for example most drivers for Intel Ethernet chipset are directly maintained
by Intel, and producing good driver takes time. Eventually, Intel released a fully
Open Source driver, which they support directly.
By the time James released the driver, it was already functional, but limited.
Since them, many people have contributed fixes and enhancements, and
development is happening quickly. Wireless Scanning was added. WEP support
was added by borrowing code from HostAP. The driver require firmware loading,
and the firmware loading procedure was converted to use the standard HotPlug
firmware loading support. Support is also being added for the wireless on/off
button of many specific laptops.
The Linux driver require a specific firmware which Intel says is identical
to the Windows firmware but packaged differently. This firmware mostly make
sure that Linux users don’t do things breaking various radio regulations. Intel
must be applauded for taking the effort of releasing this specific Linux firmware
(and their updates), this is what enables the driver to be fully OpenSource and
forced other driver to be binary, such as the Atheros driver (section 4.2).
James and various other contributors have been very hard at work on the
driver and many bugs have been fixed. After that, most of the work has been in the
area of ad-hoc and monitor mode, WPA support and power management.
Around summer 2005, James decided to spin-off the code he had borrowed
from the HostAP driver in a separate 802.11 stack, shared by both drivers (see
section 4.5). This stack only handles 802.11 framing and 802.11 encryption, but not
the SoftMAC function, as those drivers don’t require it. This stack was included in
kernel 2.6.14, alongside this driver.
3.29
ZyDAS ZD1201 driver (USB dongles)
Driver status :
Stable
Driver name :
zd1201.o
Version :
0.15
Where :
Kernel 2.6.12
http://linux-lc100020.sourceforge.net/
61
< Linux Wireless LAN Howto >
Maintainer :
Forums :
Documentation :
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Jeroen Vreeken <[email protected]>
http://sourceforge.net/forum/?group_id=94356
Web page
Wireless Extensions
Wireless Extensions
Managed, Ad-Hoc
WEP
Wireless Extensions
Yes
?
802.11-DS and 802.11-b, interoperate with Windows
GPL
http://www.zydas.com.tw/
http://www.sweex.com/
3.29.1
The device
ZyDAS is yet another taiwanese company having recently released a 802.11b
chipset. This chip seems to have all the usual 802.11b features, and offer a PCI.
Pcmcia and USB interface. For some reasons, it seems to have only been used in
various USB dongles.
3.29.2
The driver
Originally Sweex distributed a Linux driver for their ZyDAS based USB
dongles, but suddenly they retired their Linux drivers from their support site. This
driver was based on the linux-wlan-ng driver (see section 3.6). The driver was then
improved by the Linux users.
Jeroen rewrote the driver to get rid of its dependency on linux-wlan-ng, and
created a much smaller and simpler driver. This driver was further improved and
included in kernel 2.6.12. Despite its very small size, the driver support a large
number of features, such as Wireless Extensions, Scanning and Monitor mode.
4 The devices, the drivers - 802.11b+, 802.11a and 802.11g
This section list devices going beyond the IEEE 802.11b standard, such as
those based on the IEEE 802.11a and 802.11g standards (see section 8), offering
bitrates higher than 11 Mb/s in the 2.4 GHz and 5.2 GHz bands.
4.1
TI ACX100 OpenSource driver (All 802.11b+ cards)
Driver status :
beta
Driver name :
PCI : acx100_pci.o
62
< Linux Wireless LAN Howto >
Version :
Where :
0.2.0pre8, 0.2.0pre8_plus_fixes_57, 0.3.11
http://acx100.sourceforge.net/
http://lisas.de/~andi/acx100/
http://rhlx01.fht-esslingen.de/~andi/acx100/
http://www.cmartin.tk/acx/
Contact :
ACX100 OSS driver project team <[email protected]>
Maintainers :
Denis Vlasenko <vda at port.imtp.ilyichevsk.odessa.ua>
Andreas Mohr <andim2 at users.sourceforge.net>
Jeff Williams <angelbane at users.sourceforge.net>
Benjamin Schrauwen <bschrauw at users.sourceforge.net>
Moritz Angermann <sfoi at users.sourceforge.net>
Frederic Deletang <ziga at users.sourceforge.net>
Mailing list :
http://sourceforge.net/mail/?group_id=75380
Documentation :
Readme file, Wiki
http://www.houseofcraig.net/acx100_howto.php
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP
Scanning :
Wireless Extensions
Monitor :
Yes
Multi-devices :
Yes
Interoperability :
802.11b and PBCC, 802.11g depending on hardware
Other features :
Experimental support for HostAP mode
Non implemented : "4X" mode, USB support (WIP), CF support, packet
fragmentation, AutoRate
Bugs :
some configurations may lockup or loose packets
License :
MPL
Vendor web pages : http://www.ti.com/
http://www.dlink.com/products/
http://www.linksys.com/products/
http://www.gemtek.com.tw/
http://www.smc.com/
http://www.netgear.com/
4.1.1
The device
In 2001, TI (Texas Instruments) decided to make a big push on the 802.11
market. Because there was already many other 802.11 vendors, TI needed to
63
< Linux Wireless LAN Howto >
differentiate themselves. Their solution was to introduce a chip with faster data
rate. TI introduced a new modulation, PBCC (Packet Binary Convolutional) at 5.5,
11 and 22 Mb/s, which offers higher speed and longer range than 802.11b
modulations (CCK).
However, to get the market to accept PBCC, TI needed the stamp of approval
of the IEEE standard group. Other vendors within the IEEE were not keen to give
TI any advantage, and decided to base 802.11g on the OFDM modulation rather
than PBCC. After much political fight, the final 802.11g standard include both
OFDM (mandatory) and PBCC (optional). Because PBCC is only optional and
slower, I don’t expect anybody else than TI to implement it.
The ACX100 was one of the first second generation 802.11b chipset. It is
based on a ARM7 core, and offer both a PCI/Cardbus and USB interface. The use
of PCI busmaster allow to reduce CPU utilisation compared to 16 bit cards. The
MAC includes all the common 802.11 features, the Phy implement the regular
802.11b modulations and PBCC. The design goal seems to have been performance
and features.
As soon as TI released its ACX100 chipset, many usual vendors started selling
PCI, Cardbus and USB cards based on it, for example the D-Link 520+ and 650+
cards based on it. All the cards that support up to 22 Mb/s are based on this chipset.
The ACX100 is known for its requirement for PCI2.2 mainboards (lack thereof
or some other reason may lead to conflicts with other cards such as SB Live! and
crashes). This is not specific to the ACX100, other modern wireless chipsets also
tend to require PCI2.2.
Note that TI has released newer chipsets, the TNETW1100b/1130/1230
chipsets, also called ACX111, which add support for 802.11g and 802.11a, and
don’t seem to be driver compatible with the ACX100. All cards supporting both
22 Mb/s and 802.11g/a are based on those chipsets. Note that for 802.11g, a name
including “plus” does not imply a TI chipset, D-Link has a range of 802.11g “plus”
cards including Atheros chipsets.
4.1.2
The driver
From the start, TI has refused to give any help towards a Linux driver and
have decided to totally ignore the Linux community. Toward the end of 2002, a
binary Linux driver was leaked on the net. Because this binary driver is not
officially released by any vendor, its legal status is unclear (and therefore it is not
listed here). Moreover, this driver was compiled for a very specific kernel and was
overall very problematic to install and use.
A group of people using this driver got fed up with the situation and decided
to reverse engineer the binary driver by disassembling it. This is a huge task, as
this hardware and driver are fairly complex, and most other reverse engineering
project I’ve heard off eventually failed. After a few month of work, they eventually
released their first version of the ACX100 opensource driver.
The current driver is still in experimental stage, but it is evolving fairly
rapidly. Most basic features are now working (Ad-Hoc and Infrastructure mode,
WEP, Wireless Extensions, statistics...), and some advanced features are
64
< Linux Wireless LAN Howto >
implemented (monitor mode, 2.6.X support...). However, there are still lockups or
eventual traffic loss on some machines/networks, power management/hotplug is
experimental and 2.6.x support is experimental.
Andi is still working hard on the driver, and fixing bugs. Preliminary support
for USB and ACX111 devices has been added, but this is not yet complete. Denis
has been fixing support for ACX111 in the very latest release, as well as ton of other
bugs.
Around mid 2005, Denis created a branch of the driver targeted at inclusion
in kernel 2.6.X. He dropped support for 2.4.X and some non standard features such
as the old firmware loader, and fixed many bugs. For example, support for USB
dongles, 64 bits, SMP is now functional. This driver is currently included in
Andrew’s kernels (-mm version), and meanwhile can be made to compile for
standard kernels.
4.2
Atheros MADWiFi driver (most cards with 802.11a or 108 Mb/s)
Driver status :
beta
Driver name :
ath_pci.o
Version :
CVS
Where :
http://madwifi.org/
http://sourceforge.net/projects/madwifi
Maintainers :
Sam Leffler <[email protected]>
Michael Renzmann <[email protected]>
Greg Chesson <[email protected]>
Mailing list :
http://sourceforge.net/mail/?group_id=82936
Documentation :
Readme file
http://www.mattfoster.clara.co.uk/madwifi-faq.htm
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc, Master (HostAP)
Security :
WEP, 802.1x, WPA
Scanning :
Wireless Extensions
Monitor :
Yes
Multi-devices :
?
Interoperability :
802.11b, 802.11g, 802.11a depending on hardware
Other features :
HostAP mode
Non implemented : Ad-Hoc mode
Bugs :
Some (see driver readme)
License :
Binary only for the HAL + BSD driver
Vendor web pages : http://www.atheros.com/
65
< Linux Wireless LAN Howto >
http://actiontec.com.tw/
http://www.proxim.com/
http://www.dlink.com/products/
http://www.linksys.com/products/
http://www.gemtek.com.tw/
http://www.smc.com/
http://www.netgear.com/
4.2.1
The device
Atheros was the first company to release a complete 802.11a solution, and
therefore most existing products are based on it. Proxim was the first company
releasing products based on the Atheros chipset, but other familiar names such as
Linksys, D-Link and SMC did follow quickly.
Most vendor offer a CardBus card (32 bits Pcmcia) and Access Points, and a
few offer PCI solutions.
The first Atheros chipset, ar5210, implement the full 802.11a standard. The
MAC protocol is identical to 802.11b, the Atheros chipset offer both infrastructure
and ad-hoc mode, enhanced WEP with per link keys (for 802.1x) The radio modem
use OFDM in the 5 GHz band (8 separate channels), with speeds from 6 Mb/s to
54 Mb/s (depending on range).
The Atheros chipset has a few proprietary features, such as its X2 mode
(turbo) that allow to double the rate by using two channels in parallel
(unfortunately, it also increases the sensitivity to interferences, decrease the
number of channels and is incompatible with 802.11a).
The Atheros cards offer a busmaster host interface, allowing high
performance and low CPU utilisation (almost all 802.11b cards are limited to PIO,
which keeps the CPU busy). The card deals only with the low level of the MAC
protocol, and the driver has to deal with all the 802.11 management (making driver
development more complicated). The other main characteristics of the Atheros
chipset is that it’s a fully CMOS solution (including the radio), which reduces the
cost.
Atheros has released its second generation chipset, derived from the initial
ar5210, that have better performance and are no longer limited to only 802.11a.
The ar5211 support both 802.11a and 802.11b, whereas the ar5212 support
802.11a, 802.11b and 802.11g. The following chipsets from Atheros (ar5213,
ar5214, ar5413, ar5414, ar5513) kept the basic same design and features and
mostly added a wide range of proposed enhancements to the 802.11g/a standard or
proprietary extensions, such as Turbo mode (bound two channels), QoS, bursting
and MIMO.
There is many products on the market using Atheros chipsets. In fact, the
vast majority of 802.11a cards are based Atheros chipset. Most all the 802.11g
cards that advertise 108 Mb/s are also based on Atheros chipsets.
66
< Linux Wireless LAN Howto >
4.2.2
The driver
Sam, with the help of Atheros, had created a BSD driver for those cards some
time ago. Unfortunately, he was unable to release it because of the FCC
regulations. The Atheros hardware is basic and doesn’t enforce that valid operating
parameters are set (such as frequency and power level), however the FCC mandate
that end user should not be able to set invalid operating parameters. Eventually,
Atheros managed to find a solution that was acceptable : they created a HAL, a
binary layer that would sit between the hardware and the driver and enforce that
FCC regulations are respected. The downside is that the HAL is available only for
selected architectures (i386, PPC, Arm, Mips, SH4, Alpha and Sparc64).
In the mean time, Sam had ported is original BSD driver to Linux, and slowly
integrated it in Linux. For example, the driver support Wireless Extensions and
Wireless Scanning. The driver requires a recent 2.4.X kernel or 2.6.X kernel, and
require Wireless Extensions V14.
As the hardware is basic, a lot of the 802.11 functionality is handled in the
driver (as opposed to firmware). To handle this, Sam ported the generic 802.11
layer from BSD into his driver. This is a lot of code, and for the first release there
is still some bugs and many features and optimisations missing (for example, AdHoc mode is not yet functional). The good news is that over time, the performance
and functionality of this driver should increase. Lately, WPA support has been
added to the driver (which is a lot of work).
In early 2005, the project went into hibernation, no new release was done and
activity slowed down. Then, in mid 2005 the project was re-energised, and Michael
took over the driver maintenance. He is coordinating the work on a new branch of
the driver called madwifi-ng created by Atheros to support more recent cards and
their features. They are planning a new release soon, and they have a new web site.
4.3
Intersil Prism54 FullMac (802.11a/802.11g)
Driver status :
stable
Driver name :
Cardbus : prism54.o
PCI : prism54.o
Version :
1.2
Where :
Linux kernel (2.6.8)
http://prism54.org/fullmac.html
Authors :
W. Termorshuizen
R. Bastings
Maintainers :
Luis R. Rodriguez <[email protected]>
Frederik Kunz <[email protected]>
Sebastian Schoeps <[email protected]>
Aurelien Alleaume <[email protected]>
Herbert Valerio Riedel <[email protected]>
Mailing lists :
http://prism54.org/mailing.html
67
< Linux Wireless LAN Howto >
Documentation :
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Readme, web pages
Wireless Extensions & configuration tool
Wireless Extensions
Managed, Ad-Hoc, Master (FirmwareAP)
WEP, AES
Wireless Extensions
Yes
yes
802.11b, 802.11g, 802.11a depending on hardware
Encryption, Access Point mode, WDS, Firmware loading via
HotPlug.
Non implemented : SoftMAC firmware support
Bugs :
?
License :
GPL
Vendor web pages : http://www.dlink.com/products/
http://www.smc.com/
http://www.netgear.com/
http://www.gemtek.com.tw/
http://www.conexant.com/
4.3.1
The device
The Prism Indigo, Prism GT and Prism Duette are the third generation of
chipsets from Intersil, logical follower of the second generation PrismII and Prism3
chipsets (see section 3.6). The Prism Indigo was released first, and support
802.11a (5 GHz band). The Prism GT support 802.11g (and 802.11b - 2.4 GHz
band). The Prism Duette support both 802.11a and 802.11g (in both the 2.4 GHz
and 5 GHz band).
Because of the limitations of the previous PrismII design, those new chipsets
feature a totally new design, much cleaner and much more efficient, and doesn’t
share much in common with the earlier Prism designs, but is more likely to be
related to the NWN MAC that Intersil acquired (see section 3.17).
The chipset is highly integrated (2 or 3 chip solutions). Like previous Prism
chipsets, most of the 802.11 management is handed in firmware. However, the bus
interface is now PCI DMA only (less CPU overhead, faster). The MAC support the
usual 802.11 features, and hardware WEP and AES encryption, and the firmware
fully act as an Access Point. The Radio implement the OFDM modulation
necessary to support 802.11a and 802.11g.
There doesn’t seem to be any products using the Prism Indigo chipset (most
card offering 802.11a are based on Atheros chipset - see section 4.2), and I don’t
expect to see any in the future. A few of the usual Intersil partners, such as
68
< Linux Wireless LAN Howto >
Netgear and SMC, have started selling 802.11g cards based on the Prism GT and
Prism Duette chipsets.
Note that there are two types of firmware for this card, the FullMAC
firmware, that can handle most of the 802.11 functionality by itself, and the
SoftMAC firmware, that delegates it to the driver. Older revision of the hardware
can handle both types of firmware, whereas newer revisions can only handle the
SoftMAC firmware. Cards that can support the older FullMAC firmware are now
very difficult to find.
After releasing this chipset, the wireless division of Intersil (formerly part of
Harris) was bought by GlobespanVirata, and after a few month,
GlobespanVirata merged with Conexant. Therefore, the Prism chipsets are now
sold by Conexant.
4.3.2
The driver
This driver was written and released as GPL by Intersil themselves ! This is
a much stronger commitment to OpenSource than some other vendors have made.
Luis, Frederik and Sebastian are taking care of this driver after the initial
release from Intersil and helping people with the driver. They are fixing a bugs and
improving compatibility with the various kernels and configurations. Aurelien has
done a tremendous work on Wireless Extensions support.
After an initial frenetic pace of changes and reorganisation, the driver has
stabilised and matured, and is now included in the Linux 2.6.X kernel. The driver
requires firmware download (through the standard HotPlug support) and has full
support for Wireless Extensions (including Wireless Scanning) and monitor mode.
The driver also can act as an Access Point through a FirmwareAP mode (all the AP
management is handled by the firmware). Preliminary WPA support is being
added to the driver.
One of the limitation of the driver is that it does not support the new SoftMAC
devices, which means that it only works with older Prism54 devices. For SoftMAC
devices, you will need the SoftMAC driver (see section 4.4).
4.4
Intersil Prism54 SoftMac (802.11a/802.11g)
Driver status :
beta
Driver name :
?
Version :
0.7
Where :
http://prism54.org/newdrivers.html
http://jbnote.free.fr/
Maintainer :
Jean-Baptiste Note <[email protected]>
Mailing lists :
?
Documentation :
?
Configuration :
?
Statistics :
?
Modes :
?
69
< Linux Wireless LAN Howto >
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
?
?
?
?
802.11b, 802.11g, 802.11a depending on hardware
?
?
?
?
http://www.dlink.com/products/
http://www.smc.com/
http://www.netgear.com/
http://www.gemtek.com.tw/
http://www.conexant.com/
4.4.1
The device
After Conexant acquired the Prism54 family of chipsets (see section 4.3), the
Prism54 chipsets changed their mode of operation from FullMAC, where the
firmware handle all the 802.11 protocol, to SoftMAC, where the driver has to
handle all the 802.11 protocol. This allows to reduce the cost of the cards by
decreasing the on-board memory and flash. However, the chipset is no longer
compatible at the driver level, because the firmware is different. Older devices can
support both types of firmwares, newer card with less memory can not
accommodate the FullMAC firmwares. All the Prism54 USB devices and most
recent PCI/Cardbus cards can only support SoftMAC operation.
Conexant also released the Prism WorldRadio, an enhanced version of the
Prism Duette with 802.11a and 802.11g support with proprietary bit rate
enhancement. Then, they released the CX85510, which adds QoS and more
security features, and the CX3110x, a single chip solution.
4.4.2
The driver
Up to that point, Intersil had a long tradition of being one of the most friendly
vendor towards Linux, and they did help the many Linux drivers and even released
themselves the Prism54 FullMAC driver (see section 4.3). However, with the
release of SoftMAC, they decided to ignore the Linux community. The Prism54
team tried for months to negotiate the release of specs in vain.
Jean-Baptiste has led the effort to reverse engineer the Windows driver and
create a driver for the Prism54 SoftMAC devices. He reversed engineered the
driver by loading it with ndiswrapper and spying on the USB traffic, as opposed to
other effort that actually disassemble a driver.
Jean-Baptiste is mostly concentrating on support for USB devices, however
support for PCI devices was added as well to the Prism54 SoftMAC driver. The
driver is based on the 802.11 stack from the MadWifi project (see section 4.2). The
70
< Linux Wireless LAN Howto >
driver is claimed to work, but at the time of writing not tarball or release seems to
be available.
4.5
Intel PRO/Wireless 2200 802.11g and 2915 802.11ag (Centrino)
Driver status :
Stable
Driver name :
ipw2200.o
Version :
1.0.8
Where :
Linux kernel (2.6.14)
http://ipw2200.sourceforge.net/
http://ieee80211.sourceforge.net/
Maintainer :
James P. Ketrenos <[email protected]>
Mailing list :
http://lists.sourceforge.net/lists/listinfo/ipw2100-devel/
Documentation :
Readme
Configuration :
Wireless Extensions
Statistics :
/proc interface and Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP, 802.1x, WPA
Scanning :
Wireless Extensions
Monitor :
Yes
Multi-devices :
?
Interoperability :
802.11b, 802.11g, 802.11a depending on hardware
Other features :
Firmware loading via HotPlug
Non implemented : Bugs :
?
License :
GPL
Vendor web pages : http://www.intel.com/
http://www.passys.nl/tips/tip40_en.htm
4.5.1
The device
The Intel PRO/Wireless 2200 is the second 802.11 product designed by Intel,
following the previous PRO/Wireless 2100 product (section 3.28). It mostly adds
support for 802.11g (i.e. faster data rates). The PRO/Wireless 2915 is their third
802.11 product, and adds support for 802.11a.
The design of the 2200 and 2915 are based on the original 2100, the main
improvement are the new radio modems and better support for the new security
protocols (WPA). The MAC core still support the same vast array of standard
802.11 features. The radio are obviously different, adding the OFDM bit-rates, up
to 54 Mb/s, and support for 5 GHz frequencies for the 2915.
The marketing program is still the same, and the PRO/Wireless 2200 and
2915 Mini-PCI cards are exclusively sold as part of the Centrino package,
71
< Linux Wireless LAN Howto >
therefore you will mostly find them integrated in various laptops, and not as a
separate add-on card.
If you really want a separate add-on card, Intel also sells the Intel PRO/
Wireless 2225, which is basically the PRO/Wireless 2200 in a half-height PCI card
and sold separately. And obviously, it’s not called Centrino. And this card is very
hard to find and buy, and is not listed on Intel web site.
Some people, such as Passys, have built PCI to Mini-PCI adapters for the
PRO/Wireless 2200. This allows to put a standard Mini-PCI PRO/Wireless 2200 in
any regular desktop, and it is supported by Linux.
4.5.2
The driver
Intel is actively supporting the driver for both the PRO/Wireless 2200 and
2915, like they do for the PRO/Wireless 2100 (section 3.28). James is still leading
the development of this driver. The driver is fully OpenSource, and like for the
2100 require a specific firmware.
Obviously, the driver share a lot of code with the 2100 driver, it supports both
the 2200 and the 2915 and offer a similar rich feature set (WEP, WPA, Scanning).
The development is very active and many bug are being fixed and features added.
The 802.11 code originally taken from the HostAP driver (see section 3.8) was
eventually spin-off into a separate 802.11 stack (see section 3.28). This driver and
the 802.11 stack was included in Linux kernel 2.6.14.
4.6
Ralink RT2500 and 2570 cards
Driver status :
Beta
Driver name :
rt2500.o
rt2x00.o
Version :
1.1.0 (beta) and 2.0.0 (pre-alpha)
Where :
http://rt2x00.serialmonkey.com/
http://rt2400.sourceforge.net/
http://www.ralinktech.com/supp-1.htm
Maintainers :
Paul Lin
Mark Wallis <markwallis at users.sourceforge.net>
Ivo van Doorn <ivd at euronet.nl>
Mailing list :
http://sourceforge.net/mail/?group_id=107832
Documentation :
Text files, Howtos
http://www.bb-zone.com/misc/rt2500/
Configuration :
Wireless Extensions and specific graphical tool
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP, WPA
Scanning :
Yes
72
< Linux Wireless LAN Howto >
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Yes
?
802.11b and 802.11g
GPL
http://www.ralinktech.com/
http://minitar.com/
http://rt2x00.serialmonkey.com/wiki/index.php/Hardware
4.6.1
The device
Ralink may have been late in releasing a 802.11b chipset, the RT2400 (section
3.27), however it was fairly quickly followed by the RT2500, a 802.11g chipset. The
RT2500 is a evolution of the RT2400, and share many characteristics with it.
Like other 802.11g chipsets, it supports standard OFDM bitrates up to 54 Mb/
s and all modern 802.11 features such as WPA and QoS (802.11e). On top of that,
it support a proprietary 72 Mb/s bitrate. The RT2500 is designed for MiniPCI and
CardBus interfaces, and the RT2570 is designed with a USB 2.0 interface.
As usual, this chipset is sold by a wide variety of vendors under different
model names, and some of those use the same model name for different chipsets.
The project pages includes a long list of cards including this chipset. A special
mention to Minitar which has a dedicated Linux support forum.
4.6.2
The driver
Like for the RT2400, Ralink wrote a Linux driver for the RT2500 and RT2750,
but this time they decided to release it themselves as GPL. Moreover, the driver is
functional, full of features and with a graphical utility, so this represent a very
generous contribution to the OpenSource community. The driver supports WEP,
WPA, Scanning and Monitor mode...
Mark integrated this driver in the existing SourceForge project for the
RT2400 driver and started to maintain it. Many patches have been integrated to
improve the stability and functionality of the driver. Ivo is also adding RT2500
support in his rewrite of the RT2400 driver called rt2x00 (section 3.27).
4.7
Ralink ural-linux driver (BSD driver)
Driver status :
Alpha
Driver name :
ural.o
Version :
0.8.2
Where :
http://etudiants.insia.org/~jbobbio/ural-linux/
Maintainers :
Jeremy Bobbio <[email protected]>
Mailing list :
-
73
< Linux Wireless LAN Howto >
Documentation :
Configuration :
Statistics :
Modes :
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
4.7.1
Wireless Extensions
Wireless Extensions
Managed, Ad-Hoc
WEP, WPA
Wireless Extensions
No
?
802.11-b and 802.11g
BSD
http://www.ralinktech.com/
The device
This is the same device as the previous entry (section 4.6).
4.7.2
The driver
Jeremy has ported the BSD driver for the RT2750 to Linux. This port is
based on the 802.11 stack from the MadWifi project (see section 4.2) and support
only USB devices. This driver is fairly new and still experimental.
4.8
Broadcom 43xx cards
Driver status :
Alpha
Driver name :
bcm43xx.o
Version :
?
Where :
http://bcm43xx.berlios.de/
http://linux-bcom4301.sourceforge.net/
Maintainers :
Michael Buesch <[email protected]>
Martin Langer <[email protected]>
Stefano Brivio <[email protected]>
Danny van Dyk <[email protected]>
Andreas Jaggi <[email protected]>
Mailing list :
https://lists.berlios.de/mailman/listinfo/bcm43xx-dev
Documentation :
README files
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
74
< Linux Wireless LAN Howto >
Security :
Scanning :
Monitor :
Multi-devices :
Interoperability :
Other features :
Non implemented :
Bugs :
License :
Vendor web pages :
Wireless Tools
Yes
?
802.11b, 802.11g, 802.11a depending on hardware
Encryption, 802.11a
GPL
http://www.broadcom.com/
http://www.linksys.com/
http://www.usr.com/
4.8.1
The device
Broadcom is a company that is developing all king of networking solutions,
and well known for its Ethernet chipsets. When it decided to enter the Wireless
LAN market, they decided a bold strategy. Instead of releasing a 802.11b product,
which was the only standard at that time, they decided to release a product based
on the upcoming 802.11g specification that was still one year from completion.
Most competitors were taken by surprise, consumer were attracted by the higher
speed and Broadcom quickly gained a good market share. When the 802.11g
standard was eventually released, Broadcom quickly upgraded to it, and for a
while the vast majority of 802.11g card were based on Broadcom chipsets. Many
laptops of that period also included Broadcom chipsets. The Apple Airport
Express is also based on the Broadcom chipset.
Eventually, the competition caught up, started offering more features than
Broadcom or cheaper prices, and a lot of vendor using Broadcom chipsets migrated
to other chipsets. Linksys is still a Broadcom stronghold, and a large portion of
their 802.11g products are based on Broadcom chipsets (but not exclusively).
Like most 802.11g chipsets, the BCM43xx chipsets supports standard OFDM
bitrates up to 54 Mb/s and all modern 802.11 features such as WPA and QoS
(802.11e). Their newer chipsets support 802.11a. Broadcom main extension is
SpeedBooster, Broadcom’s name for Packet Bursting, which is part of the 802.11e
standard. They have few proprietary extension, their newer chipsets include a
proprietary 125 High Speed Mode : this is not a enhanced modulation at 125 Mb/s,
the card still use 54 Mb/s and a combination of protocol enhancement and
compression. In fact, if a card advertise 125 Mb/s (which is misleading), it’s a good
clue that it’s most likely a Broadcom card.
4.8.2
The driver
Like TI (see section 4.1), Broadcom quickly gained a reputation as being very
unfriendly to Linux. It was known that Broadcom internally had a fully functional
Linux driver, but it was unwilling to release it in any form (even binary), and was
not answering call for chipset specifications. However, soon people realised that
75
< Linux Wireless LAN Howto >
the Linksys WRT54G, a router/access point with a Broadcom chipset, was based
on Linux. Linksys was made aware that, because Linux is GPL, they had to release
the full source code of the WRT54G firmware, which they promptly did. This source
code contained a binary Linux driver for the Broadcom chipset.
A team of people led by Brett Wooldridge, Joe Jezak and Johannes Berg
started to reverse engineer this driver by disassembling it, like it was done for the
TI driver (see section 4.1). They did not write directly a driver, they produced a set
of documentation so that the driver development would be legally separate from
the reverse engineering effort.
A second team of people led by Michael started to write a driver based on
those documents. They based their driver on the 802.11 stack from the Centrino
driver (see section 3.28), and added a SoftMAC layer. Their driver has basic
functionality and communicate with Access Points, but many features are still
missing (such as encryption).
4.9
ZyDAS ZD1211 driver (USB dongles)
Driver status :
Beta
Driver name :
zd1211.o
Version :
R42, 2.2.2.0
Where :
http://sourceforge.net/projects/zd1211/
http://zd1211.ath.cx/zd1211
http://www.zydas.com.tw/downloads/download-1211.asp
Maintainers :
Markus Karg <[email protected]>
ZyDAS
Mailing list :
http://sourceforge.net/mail/?group_id=129083
Documentation :
Web pages
Configuration :
Wireless Extensions
Statistics :
Wireless Extensions
Modes :
Managed, Ad-Hoc
Security :
WEP, WEP256, WPA
Scanning :
Wireless Extensions
Monitor :
No (need external patch)
Multi-devices :
?
Interoperability :
802.11b, 802.11g, 802.11a depending on hardware
Other features :
64 bit support
Non implemented : Bugs :
License :
GPL
Vendor web pages : http://www.zydas.com.tw/
76
< Linux Wireless LAN Howto >
4.9.1
The device
After the release of the ZD1201 (see section 3.29), the logical step for ZyDAs
was to release a 802.11g chipset, the ZD1211. This chipset has similar features as
other 802.11g chipset, such as advanced security features, and it seems that some
version also support 802.11a.
The main feature of ZyDAS chipsets is their small size and low power
consumption, making them especially suitable for USB dongles. Actually, it
seems that this chipset is only found in USB dongles, even though it support other
interfaces (PCI and Pcmcia). USB 2.0 is needed for full 802.11g operation.
4.9.2
The driver
Like for the ZD1201 (see section 3.29), ZyDAS themselves released a driver to
support the ZD1211 under the GPL license.
At this point, a community organised around this driver : many people
contributed patches and created branches of the driver. Most of the branches,
which were aiming at simplifying the driver code or integrating it in the kernel,
seems to have died.
Meanwhile, ZyDAS continues to release new version of the driver including
bug fixes and patches from the community. Markus is hosting this driver and many
patches on his web site.
4.10
Realtek RTL8185L & RTL8187L (802.11g)
Driver status :
Experimental
Driver name :
r8180.o
Version :
0.17
Where :
http://rtl8180-sa2400.sourceforge.net/
Maintainers :
Andrea Merello <andreamrl *at* tiscali.it>
Documentation :
Readme files
Configuration :
Wireless Extensions
Statistics :
?
Modes :
Managed, Ad-Hoc
Security :
WEP
Scanning :
Wireless Extensions
Monitor :
Yes
Multi-devices :
?
Interoperability :
802.11b, 802.11g, 802.11a depending on hardware
Other features :
Non implemented : SMP
Bugs :
License :
GPL
Vendor web pages : http://www.realtek.com.tw/
77
< Linux Wireless LAN Howto >
4.10.1
The device
Like all the other 802.11b chipset manufacturer, Realtek introduced a new
802.11g chipset based on their earlier design, the RTL8180L (see section 3.25). It
mostly adds support for the OFDM bit rates (up to 54 Mb/s), and some version also
support 802.11a. The RTL8185L has a PCI/Cardbus interface, whereas the
RTL8187L has a USB 2.0 interface. Realtek offers a proprietary turbo mode with
72 Mb/s, but other chipsets do as well (see section 4.6).
4.10.2
The driver
With those new chipsets, Realtek changed their driver strategy. Instead of
releasing a binary driver (see section 3.25), they decided to team up with Andrea
who produced the GPL driver for their previous chipset (see section 3.26). They sent
him a few reference design cards (prototypes) and specifications to help him.
Andrea has added preliminary support for those cards in the new branch of
the RTL8180L driver. With times, this driver should become more functional and
polished.
5 The devices, the drivers - other
This section contains information about all devices which don’t have a specific
entry in one of the previous three sections.
5.1
Not supported (the hall of shame)
Netwave AirSurfer plus (in 802.11 mode), BayStack 650 : Now that a
driver for the BayStack 660 is available, it should be quite easy to make a driver
for those cards, by reusing the physical layer parts in the AirSurfer plus driver.
FreeBsd seems to have a driver for this device... This product has been
discontinued.
RadioLan has a 10 Mb/s at 5 GHz product, rather very short range and no
Linux drivers. This product has been discontinued.
WebGear Aviator 900 MHz : connect to the parallel port and offer cable
replacement solution. No functional Linux driver. This product has been
discontinued.
The IBM Wireless LAN Entry is a discontinued product that may be
sometime found for a very very low price. Unfortunately, there is no working driver
for those and information on the device is impossible to find. This product has been
discontinued.
Both TI and Broadcom are very unfriendly toward Linux. They don’t release
Linux drivers or any information to help build Linux drivers for their cards despite
using Linux drivers internally and in some products. Open Source drivers for those
cards exist, based on reverse engineering, but because those drivers probably will
never support all features/models of those cards and because of the overall attitude
of those companies, you may want to avoid those cards.
Conexant (formerly Intersil) seems to have reverted their previously proLinux approach to ignoring the Linux community (which did help them so much).
78
< Linux Wireless LAN Howto >
5.2
Win32 drivers
Two packages enable the use of Win32 wireless LAN drivers under Linux :
DriverLoader : http://www.linuxant.com/driverloader/
NdisWrapper : http://ndiswrapper.sourceforge.net/
DriverLoader is commercial, whereas NdisWrapper is GPL. Both seems to
work with a wide range of Win32 drivers and Linux features, for example both
support Broadcom, TI and Intel drivers, and most Wireless Extensions including
Wireless Scanning.
Some people have strong objections to using Win32 drivers under Linux.
Obviously, such a solution is restricted to the i386 architecture, and make use of a
lot of binary code. Also, some less used Wireless Extensions features are not
available in the NDIS specification (such as link quality, noise level, iwspy, master
and monitor mode).
5.3
A note on driver licenses
Donald Becker’s web page alerted me on the license and copyright issues
for networking drivers (see http://www.scyld.com/expert/modules.html#legal for
details). If you just plan to use the driver in your Linux PC, there should be no
problem, but if you plan other use of the drivers you should pay attention to the
exact license the driver come in.
Most drivers are GPL, which prevent their use with non-GPL kernels (so
commercial operating systems can’t reuse the code) and prevent to use portions of
the source in non-GPL drivers, except with the explicit authorisation from the
author.
Some other drivers come with a binary library, which restrict its potential
use (the driver can’t be ported to other architectures).
This may be restrict what you can do with those drivers, but those people have
spend long nights and week ends convincing the hardware manufacturer to release
information, writing and debugging the code, so please respect their copyrights and
decisions.
5.4
More information on the devices, other Wireless LANs
You will notice that I don’t give too much information on the different devices.
The web page of each vendors usually contain the full specification of the products
they sell.
They are many more products available than the ones that I’ve listed (which
are the most common). If your favourite wireless LAN is not listed above, either
there is no driver under Linux that I know of, or it is an OEM version of one of
these (same hardware under a new brand).
To have a good picture of all the devices available and their characteristics,
you should redirect your favourite browser to :
http://hydra.carleton.ca/info/wlan.html
79
< Linux Wireless LAN Howto >
5.5
Other Wireless technologies
5.5.1
Wireless bridges
Wireless bridges allow to connect different networks via radio, their goal is
to replace a dedicated leased line (T1, for example). They usually offer longer
distance through directional antennas, and are peer to peer.
These devices are a totally independent box (like other bridges, routers or
gateways) and not a card to plug in your PC, so have no interactions with Linux.
5.5.2
Radio Amateur and AX25 (HAM)
These devices are quite specific and are described in their own howto.
5.5.3
Infrared
Apart from the remote control stuff, most infrared devices are IrDA
compliant. IrDA defines a full lightweight protocol stack on top of very cheap and
simple hardware, and is optimal for short ad-hoc transactions (using Obex for
example). TCP/IP networking over IrDA can be done using PPP over IrComm,
IrLAN or IrNET (all of them point-to-point solutions).
More information on IrDA for Linux is available at :
http://irda.sourceforge.net/
http://www.tuxmobil.com/howtos.html
http://www.hpl.hp.com/personal/Jean_Tourrilhes/IrDA/IrDA.html
There is also some real Wireless LANs using diffuse infrared (no more peer
to peer), but I don’t have much information on these.
5.5.4
BlueTooth
BlueTooth is a radio standard heavily influenced by IrDA and USB, and
offers the functionality of a wireless USB and serial cable replacement (see section
8 for a more complete description). BlueTooth defines its own protocol stack as well,
and offers the possibility to create long term binding between devices (attach
wirelessly peripherals to a phone or a PDA). TCP/IP networking over BlueTooth
can be done using PPP over RfComm or PAN (BNEP).
More information on BlueTooth for Linux is available at :
http://bluez.sourceforge.net/
http://sourceforge.net/projects/bluetooth/
http://www.holtmann.org/linux/bluetooth/
http://www.hpl.hp.com/personal/Jean_Tourrilhes/bt/
5.5.5
Digital mobile phones and other radio WAN
Again, this is quite different from Wireless LANs. I don’t know much about
those devices, except the usual generalities.
Digital mobile phones (GSM, TDMA, CDMA, PHS) very often allow data
connections (slow and expensive). Most of them offer a standard serial interface
with an extended AT command set, so can be configured like a normal modem : ppp
over the serial port.
80
< Linux Wireless LAN Howto >
Some Nokia GSM phones use a kind of half winmodem interface where the
upper layer handling is done by the host. For these phones you need gnokii (http:/
/gnokii.org). This package also provide tools to play with various extra features of
the phone (SMS, address book...).
Of course, the ultimate geek challenge is to use IrDA (see section 5.5.3) to
connect your mobile phone to your laptop. That’s done with PPP over IrComm or
gnokii.
In most cases, Wireless WANs such as CDPD cards, the Metricom Ricochet
and ARDIS should use modem interface as well.
6 Wireless LANs in use
Installing and using a Wireless LAN is not such a big deal, and is not much
different from other kind of networks. In this chapter, I will give you a few tricks
on how to install those beast and will mostly redirect you to a lot of literature
explaining the things much better than I would do.
Then, I will explain some of the difference of Wireless LANs compared to
wired technology from the user point of view and why it reacts sometime
differently. For more curious people, see the section 5.
6.1
Choice and selection of a Wireless LAN
There is far too many people buying a Wireless LAN and discovering only
after that it is not supported under Linux. So, please, check that a driver is
available for the hardware you plan to use.
Most Wireless LANs are designed to work well in most configurations, but my
experience tells that some Wireless LANs or some environment may be capricious.
Of course, the vendor won’t advertise this, so it’s your responsibility to check that
the Wireless LAN is working with your particular setup. If you intend to cover a
large range, test as many physical locations and combinations as possible to avoid
surprises. Know the limits of your hardware.
The performance of different Wireless LANs may vary widely, depending on
may factors. The throughput of two Wireless LANs advertising the same bit rate
may vary by a factor 5 (I won’t give the names). Range also can have wide
variations, even between similar cards. So, be warned and benchmark your
Wireless LAN...
If you are not happy with your choice of Wireless LAN, don’t hesitate and
return it to where you bough it for a refund.
6.2
Features of the hardware
Obviously, I don’t need to tell you to check the price of the Wireless LAN you
plan to buy, but however consider checking the price in different places, especially
on the Internet. Some hardware are still difficult to find and impossible to get
directly from the manufacturer, and a bit of research always pay off...
Then, the second issue is the form factor, and the interface use to connect
the card to your PC. Most cards nowadays are in Cardbus form factor and USB
81
< Linux Wireless LAN Howto >
form factor, most vendors offer as well PCI or Mini-PCI versions of their cards.
Older cards may come in ISA, Pcmcia (16 bits) and CF form factor. In some cases,
it is possible to plug a Pcmcia or Cardbus card in a desktop using ISA-to-Pcmcia or
PCI-to-Cardbus bridges, but those are not always properly supported. I’ve seen
some old cards in PC104 form factor (for embedded applications).
Often, people do wonder about Access Points and residential gateways
and if they need some for their network. In most cases, the Access Point is a bridge
and allow to connect the wireless network to an Ethernet backbone, whereas the
Residential Gateway connect it to an ISP (via dialup/cable/DSL), and those two
kind of products are usually not fully interchangeable. However, most Wireless
LAN cards work in ad-hoc mode (so without Access Point), and a Linux box can
offer connectivity to other networks (routing+proxy ARP, or masquerading).
For people who plan to establish point to point links, they will likely need the
card to offer a connector for an external antenna. Quite often those connectors
are small and not really standard. Of course, if the card doesn’t offer such a
connector, it’s always possible to butcher it...
Then, you may care about all the usual performance characteristics, such as
speed, range, and power consumption. However, be aware that it’s quite
difficult to compare products, for the speed read my various comments about
overhead and benchmarking, and for range pay mostly attention to the transmit
power and the sensitivity.
Finally, each implementation may offer more or less wireless parameters.
Having those parameters will allow to tune the card for specific environments and
configurations. With that, you probably want some deployment and diagnostic
tools from the vendor...
Personally, I believe that the number one consideration in making your choice
should be the range (coverage), and that raw speed is the least important of the
things mentioned above. If you need speed, you should use Gigabit Ethernet.
Wireless enables mobility, and you want to make sure to retain network connection
wherever you are.
6.3
Interoperability
For people having dealt with Ethernet, it may seem absurd to see all the
interoperability worries that we have to go through for Wireless LANs. But such is
life, and product A may not communicate with product B. To their defense,
Wireless MAC protocols are a few order of magnitude more complex than Ethernet
and have not been around for as long.
For most of the old hardware, and for all the proprietary products,
interoperability is none. In other word, those products communicate only with
products from the same vendor. The risk for you is that you are locked with this
vendor to upgrade your network. That is still OK if the vendor is strong and has
been around in the business for a long time.
The only two standards that have been demonstrated to be interoperable
across different implementations are 802.11-FH and 802.11-DS (other standards
may be interoperable due to a single implementation). I must there applaud the
82
< Linux Wireless LAN Howto >
various vendors which have gone through great pain to make sure that their
hardware was playing nice with others and fixing their interoperability problems.
Note that 802.11-FH products are not interoperable with 802.11-DS products, and
vice versa, so you can only mix products of the same kind of 802.11.
As the 802.11-b specification is just a simple extension of 802.11-DS (adding
5.5 and 11 Mb/s speeds), all products interoperate at least at 2 Mb/s (802.11-DS
mode), and all products I have seen also interoperate at 11 Mb/s.
802.11+ is a semi-proprietary extension of 802.11b, adding the 22 Mb/s speed.
All products are based on the same chipset, and they also interoperate with
802.11b products. In general, all proprietary extensions of 802.11 will
interoperate only if all devices are from the same vendor, but interoperate at
standard speeds.
The 802.11g standard is a non straightforward extension of 802.11b. Products
from different vendors do not always interoperate properly with each other at
higher speeds (but will interoperate at 802.11b speeds), and sometime they do not
interoperate with 802.11b products and may actually disrupt 802.11b networks.
This will get better over time.
Currently, all 802.11a products (5 GHz) are interoperable, because based on
the exact same chipset. They do not interoperate with 802.11b products, because
using a different frequency band, but some products doing both 802.11b and
802.11a are now available.
Other standards (such as HiperLan, HiperLan2 and SWAP) are
interoperable in theory. As there is very few vendors using those standards (or
even none) and the products are often too recent, we can’t say much about
interoperability. Note that compliance doesn’t mean interoperability and vice
versa...
Note that in some cases, the Linux driver of a device doesn’t implement all
the features of the corresponding Windows driver (typically security), limiting the
interoperability.
6.4
Which vendor to select
Buying a Wireless LAN card used to be relatively straightforward, because
there was a limited choice, but has now become very complex and confusing.
The first problems is that there are now lot’s of different vendors and
brands, and most I’ve never heard off (and they tend to be the cheapest, so the
most popular). It’s almost impossible to track down all of them. Fortunately, there
is only a limited number of chipset, so most of those vendors sell the same
hardware (or minor derivation) and there is a good probability that it works with
an existing Linux driver.
The other issue is that some vendors use different chipsets in their various
products, so some of their cards might be supported and some might not be. They
can switch their entire product line to a new chipset pretty quickly, so a “brand” is
not a safe bet. Some vendor even sell different chipset under the same model
number (example D-Link and Linksys), making it very difficult to know in
advance if the card is supported or not.
83
< Linux Wireless LAN Howto >
In the past, most of the “generic” brands selling 802.11b cards were using the
Intersil PrismII chipset, which is well supported under Linux (various drivers),
so it was not a problem. A lot of them have recently moved to non-supported
chipset. For now, if it’s faster and better than 802.11b, it’s most likely not
supported.
There are various hardware surveys that attempt to capture the latest list
of compatible cards (see Wireless Howto front page). You can also search the
various mailing list archives and the web for information.
6.5
How to identify a card
Let assume you already have a wireless card plugged in your PC, and want to
know which one it is and which driver you need. Linux has usually a way to display
a card identification, but this depend on the type of card.
If the card is an ISA card, you are usually out of luck.
If the card is a PCI card, you need to use the command “lspci” to display the
card identification strings.
If the hardware is a USB dongle, you need to use the command “lsusb” to
display the dongle identification strings. In some case, “lsusb” doesn’t work (for
example if usbfs is not mounted), and you can get the identification strings from
the kernel log using “dmesg” (or in /var/log/messages).
If the card is a Cardbus card (32 bits Pcmcia), and if you are using kernel
2.6.X or kernel 2.4.X with the kernel Pcmcia subsystem, you need to use the
command “lspci” to display the card identification strings. If the card is a Cardbus
card (32 bits Pcmcia), and if you are using an older kernel with the standalone
Pcmcia subsystem, you need to use the command “cardctl ident” display the card
identification strings. Try both and see what comes out.
If the card is a true Pcmcia card (16 bits), and if you are using kernel 2.6.14
or later, you need to use the command “pccardctl ident” to display the card
identification strings. If the card is a true Pcmcia card (16 bits), and if you are
using an older kernel, you need to use the command “cardctl ident” display the card
identification strings. Note that cardmgr will also write some identification strings
in the message logs (/var/log/daemon.log) that may be different from the real card
identification strings.
The card identification usually helps to identify the chipset inside the
hardware, and in some other cases it does not, because the vendor has changed the
identity. Once you have identified the chipset, it is usually straightforward to
check if the hardware is supported and which driver to use.
Most Linux drivers knows about some of those card identifications, and will
automatically bind to the hardware. It is usually simple to add new identification
to a driver.
Jacek Pliszka recommends to get the FCC-ID written at the back of the
hardware and to run it through the FCC database. He also recommend to check the
Windows driver (both identification and file name) for some clues.
84
< Linux Wireless LAN Howto >
6.6
•
•
•
•
•
Wireless hardware compatibility
Linux Wireless Howto
- Second section, organised by chipset
Linux hardware surveys
- Not always complete
Community wireless web sites - Usually most up-to-date, by vendor
Linux wireless tools web sites - List cards compatible with the specific tool
Mailing list archives
- Use a search engine
6.7
Driver installation
The reader should be familiar with some of the documents listed in the Useful
readings chapter below, because the information here mainly acts as a complement
to them. A good knowledge of your Wireless LAN is also a prerequisite before
switching to Linux.
Most Wireless LAN vendors have tried to make things easy and offer product
with an interface as similar as possible as Ethernet, and which work mostly the
same way. So, a bit of background on Ethernet and the general Linux networking
is welcomed (see below).
The operating system need a piece of software to interface to the hardware.
That is the role of the driver. Basically, when Linux gives to the driver a packet to
send, the driver have to copy the packet to the hardware and toggle the correct bits
in the correct register on the card to send it. It is the same when the card generates
an interrupt, the driver go and read the packet and give it to Linux. Of course, the
driver needs to know about the specific hardware details and the specific operating
system ways.
In conclusion, you must check first if the driver for your Wireless LAN exists
(see previous section), because in many case it proves to be quite useful...
With Linux, you normally have to compile the driver source code, however
most Linux distribution offer precompiled modules for the most popular drivers.
There is usually two compilation options : drivers compiled staticaly in the kernel
and as a module. If the driver is already in the kernel sources, the compilation is
quite simple (you have to enable it in the kernel configuration, static or module). If
it is in the Pcmcia package, you just need to install this package.
Otherwise, see the installation instructions coming with the driver which
should detail the procedure to install it.
Once you’ve got the driver compiled and installed, you must tell your system
about it. This involve getting the driver to load (see section 6.9), wireless
configuration (see section 6.10) and network configuration (see section 6.12).
6.8
•
•
•
•
•
Useful Linux related readings
Ethernet HowTo - How to install and configure most of the network drivers
Net2 HowTo
- The network stack story
Module HowTo - To compile you driver as a module
Pcmcia HowTo - An excellent medicine for pcmcia drivers
AX25 HowTo
- AX25 and Radio Amateur users should enjoy this one
85
< Linux Wireless LAN Howto >
• The Linux Network Administration guide - A lot of background and tips about
networking and Linux
• Your distribution documentation or FAQ (if any)
6.9
Driver loading and driver parameters
If your card is removable (Pcmcia, USB), you usually want the system to
automatically load the driver when the card is plugged or activated. The Pcmcia
subsystem is usually very good at doing this, and has it’s own scripts. The USB
subsystem use the relatively new HotPlug scripts.
For non-removable cards, things are simpler. If the driver is compiled
staticaly, it will be loaded at boot time. If it’s a module, you can load it as needed
using /etc/modules.conf (see below).
Some driver may load only with some required driver parameters. Those
parameters usually allow to specify the base address and interrupt of the hardware
to avoid scanning, but also might be used for multi-device configuration or wireless
specific parameters (see below). Note that for all modern Plug-and-Play cards
(PCI), those extra parameters are no longer necessary, as the system figure things
by itself, so you can omit them (or set them to 0).
A lot of users are confused when it comes to set driver loading and
parameters. As it is explained nowhere correctly, I disgress a bit and give you a few
hints on how to load drivers with and without parameters...
For driver compiled staticaly in the kernel, the parameters are passed on
the kernel command line. The syntax is “ether=irq,base,name” where base is the
base address, irq the interrupt and name the device logical name (ex : eth0). The
kernel command line is passed by lilo (or loadlin) itself, so in fact it means that you
add in /etc/lilo.conf a line which look like this :
append=”reboot=warm ether=0,0,eth1 ether=10,0x3E0,eth2 ether=11,0x390,eth3”
For drivers compiled as modules (but which are not for removable devices),
the parameter interface is much more flexible and each driver may be different, so
you must look in the documentation. Basically, the driver define a set of
parameters by their name and you may set for each keyword an array (one value
for each instance of the hardware). The module configuration is usually done in /
etc/conf.modules like this :
alias eth1 hp100
alias eth2 wavelan
options wavelan io=0x3E0,0x390 name=eth2,eth3 irq=10,11
For Pcmcia modules, the configuration is usually done in the pcmcia scripts
in the directory /etc/pcmcia/, and you should check the Pcmcia Howto for details.
Note that some distributions may use the HotPlug scripts. Usually, you don’t need
extra driver parameters, as Pcmcia is Plug-and-Play, and all driver part of the
Pcmcia package are already preconfigured for proper auto-loading.
86
< Linux Wireless LAN Howto >
However, you need to make sure the Pcmcia subsystem load the driver you
desire, if there are multiple drivers bound to the same device you may end up with
an unexpected driver. In this case, you need to edit the various Pcmcia config files
(in /etc/pcmcia/ - grep is your friend).
For USB modules, you may use the HotPlug scripts. USB usually don’t
require any driver parameters, but again, you need to make sure the proper driver
is loaded.
Before following up with the wireless configuration, you may want to make
sure the driver is properly loaded, recognise the hardware and can initialise it. This
can be done by checking the message logs (with dmesg).
6.10
Wireless configuration (more parameters to configure)
The most obvious difference with Ethernet cards is that there are more
parameters to configure. In order to communicate, all nodes of the network must
have those parameters configured the same. Some examples are : frequency or
hopping pattern, network id, domain or essid, encryption key (for security)...
Under Windows, the installation program usually opens a nice window and
asks the user to enter these parameters, or sets them to a default value. Some
drivers set those parameters in a permanent storage in the device (EEprom), so the
Linux driver is able to reuse them. But, the current tendency is to scrap the
EEprom and to use the Windows registry to save those parameters instead. Of
course, the Linux driver can’t retrieve the parameters in those conditions.
The Wireless Extensions (see next section) has been designed to simplify the
process of setting those parameters under Linux by providing an unified interface
across drivers, but not all drivers support (yet) the Wireless Extensions...
For the majority of drivers that support it, Wireless Extensions allow to
change parameters at run time (using various tools - see my web pages) or be use
at boot time or card insertion time through various initialisation scripts (this is
usually distribution specific). Most Linux distributions nowadays fully integrate
wireless configuration in their network configuration. The Wireless Tools
package contains additional documentation on all this.
http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Tools.html
The Wireless Tools also allow you to diagnose various basic problems
(configuration not applied, not connected to the Access Point, invalid encryption
key) and monitor the link. You need to make sure that the wireless link is
established if you want your network setup to be successful.
Drivers that don’t use Wireless Extensions can use a variety of methods for
configuration. Some have their own dedicated tools, some use a /proc interface and
some use modules parameters, or a combination of these. The previous section of
the Wireless Howto should give you some hints on the subject.
In conclusion, you must read your documentation to know what parameters
need to be set, what they are used for, and look the Linux driver documentation to
know how to set them under Linux. See below for a suggested list of information
sources.
87
< Linux Wireless LAN Howto >
It is usually quite a good idea to install the Wireless Lan first under some
mainstream operating system with the official vendors driver and tools, to have a
feeling of how the beast does work. You might also compare the performance before
and after :-)
Once you’ve got all those new parameters set, your Wireless LAN should be
up and running.
6.11
Where to get information about your Wireless LAN configuration
• The official documentation that come with your product.
• Manufacturer web page and support.
• Linux driver source code, documentation (headers, man pages), maintainer.
• Documentation and man pages in the Wireless Tools package.
• Network configuration documentation for your specific Linux distribution
6.12
Network configuration
After having setup the wireless parameters, you need to configure the regular
network parameters. At the minimum, you need to tell the system to use DHCP or
not. Very often, you may have to configure an IP address, Gateway and a DNS
server. More complex setup (such as a Wireless Router) will require some route and
firewall configuration.
All this is exactly similar to standard Ethernet cards, and often specific to
each distribution, so please check the relevant documentation. Note however that
bridging very often won’t work (see section 6.14).
6.13
Wireless LAN deployment
From the network administrator point of view, the main problem with
Wireless LANs is that the medium is shared. If on a cable you can physically
know who is connected, however anybody and anything can use the radio band.
To try to separate everyone out there, most products define some network
identifier (802.11 it is also called ESSID). This is a number or character string
which is used to identify all the people wanting to be one the same logical
network. Networks using different network identifiers still share the bandwidth,
but are logically separate and ignore each other.
This situation is not totally ideal, so that’s why usually you have some
distinct channels (or frequencies, or hopping patterns). People on distinct
channels use different part of the bandwidth, so don’t interfere at all. If you want
to install multiple independent networks in the same area, this is the way to go.
The Wireless LAN has only a limited range, so you may reach only device
within that range. This is usually why you should define some cells where
everybody is in range. If you want those cells to communicate or a node to move
across cells, you should install an access point in each of those and configure
those with the same network identifier (and add an Ethernet segment between the
access points).
88
< Linux Wireless LAN Howto >
On the other hand, some time you just want to quickly set up a network
between a group of nodes and don’t want to build an infrastructure. Most Wireless
LANs offer ad-hoc networking, allowing you to just do that (apart from TCP
configuration).
Some network administrators are also a bit scared by security problem over
the medium. The only solution is to use encryption.
6.14
Access Points, Home Gateways and Ethernet bridging
Most Access Points act as a MAC level bridge, allowing the Wireless LAN to
be a natural extension of a wired network. They are deployed in a cellular fashion,
and provide extended security, management and roaming.
On the other hand, the Home Gateways allow a single cell to be connected
to a WAN, like a modem, a cable modem or a DSL access. The set of features is
quite different, and they offer NAT/masquerading and PPP configuration.
The conventional Ethernet bridging method (promiscuous sniffing) doesn’t
work with most wireless LAN standard, because of the header encapsulation and
the interactions with link layer retransmissions. In other word, most often, when
you use a software bridge on a wireless LAN (such as the Linux bridge on a 802.11
card), it doesn’t work (moreover, quite often promiscuous is broken as well).
The driver could work around this restriction by creating its own MAC
headers (802.11 headers instead of 802.3, and putting the right bits in the right
place), but in fact most vendors don’t provide the specification on how to this with
their hardware (when they don’t explicitly prevent it in hardware, to force you to
buy their Access Points).
In other words, don’t expect to use your Linux PC as a wireless bridge or
wireless Access Points with most products out there, and forget about turning it
into an Access Point. Of course, there are some exceptions that are listed in the
driver descriptions (section 2).
The workaround is to set the wireless LAN in ad-hoc mode and to use other
methods, such as routing, masquerading, IP bridging, ARP proxying...
6.15
Point to point links (connecting different LANs by wireless)
Most Wireless LANs are designed to be used as a local area network, where
all the nodes can see each other or can see the access point, and they are attached
to other networks through a single access point (or not at all in ad-hoc mode).
Some people have asked me question on how to use Wireless LANs to connect
different LANs together using wireless technology, usually those LANs are in
distant places (across the street). Most of the time, you can’t use a Wireless LAN
because you don’t have a fully connected topology (some node can’t see each other,
it’s more a set of point to point links) and you may need to use directional antennas
to overcome the distance.
I’ve never personally tried this, but I see 2 ways to achieve this.
The first solution is to use Wireless Bridges. Each Wireless Bridge is
connected to one of the LAN section and redirect the traffic over the air to the
89
< Linux Wireless LAN Howto >
correct destination. There is many products on the market, they are a bit expensive
but very flexible, transparent and optimised for the task.
The second is to use normal Wireless LAN cards, and to plug them in a router
(for example a Linux PC). I recommend to use a Wireless LAN supporting RTS/
CTS if you have more than one link, and to set them in ad-hoc mode (no access
point). Each LAN segment must have a different IP subnet, and the wireless link
must have it’s own subnet (it can be a private subnet if you use masquerading).
After much configuration of the routing tables of your network, you should be able
to get it working.
Some people using the Aironet Arlan cards for this kind of application have
made a very nice Arlan Wireless Routing Howto, and I believe it can apply to
most other Wireless LANs as well :
http://www.rage.net/wireless/wireless-howto.html
Note that it is not always possible to use a bridging software on top of a
Wireless LAN card, and that is why I do recommend routing (or proxy-ARP + IP
forwarding). Setting the card in promiscuous mode won’t give the behavior
expected by the bridge, because of the interaction with MAC level retransmissions.
Some drivers are clever enough, and by playing directly with the 802.11 headers (if
the hardware allows it), they can allow bridging to work, but most drivers are not.
6.16
Performance (speed)
Most people want to know how fast it goes, and complain that they can’t get
the speed written on the box, and that the number seems low, even if in real use
they are far away from saturating the network. Even when converting the byte per
seconds to bit per seconds, there is no denying that the TCP throughput is lower
than the signalling rate. This is because the Wireless LANs are slower to start
with and on top of that uses less efficiently the available bandwidth.
Most Wireless LANs have a signalling rate around 1 or 2 Mb/s. The
signalling rate is the speed the bits are send over the air (Ethernet is 10 Mb/s), but
doesn’t account of all the overhead of the protocols.
The Wireless LAN protocols have usually a higher overhead than their wired
counterpart (like Ethernet) because of some technological limitations and to
improve the reliability and the coverage of the Wireless LAN (optimisation tradeoffs). On the other hand, Wireless LANs protocols are also usually less sensitive to
high load (the throughput doesn’t drop when you overload the network - which
could happen more often).
Some protocols also adapt the signalling rate depending on the quality of the
link (for example a 2 level modulation 2FSK/4FSK). When the link is clear and
reception is strong, it will use the fastest rate, but when there start to be noise or
the device is further away, it goes down to the more robust rate. The throughput
that you will get will depend on that as well (for example the high speed might be
only usable in line of sight).
90
< Linux Wireless LAN Howto >
6.17
Reliability
Most Wireless LANs protocols include mechanisms to improve the reliability
of the packet transmissions to be at the same level or even better than Ethernet
(MAC level retransmissions for example). Anyway, if you are using a protocol such
as TCP (the default under Linux), you will be fully protected again any loss or
corruption of data over the air. In other word, when you copy a file across the radio,
it can’t be corrupted (but it might fail completely).
6.18
Coverage
As said earlier, people get excited about speed, and they often don’t realise
that the main measure of performance of a wireless LAN is the coverage, and by
a wide margin. This includes maximum distance between nodes, resistance to
interferences and ability to keep connectivity in a wide range of conditions.
The propagation of radio transmissions is influenced by many factors. Walls
and floors tend to decrease and reflect the signal, and background noise make it
more difficult to extract. The channel quality vary quite a lot over the time (fading).
Depending on the quality of reception, the error rate will change (forcing
packet retransmissions), or the system may switch to a more robust (and slower)
mode (fragmentation or modulation), so the actual throughput will vary from good
to nothing.
Because of the way radio transmission are affected by the environment, it is
quite difficult to predict the comportment of the system and to define a range. You
will have some good, fair and bad area/period, the closer you are the more likely
you are to be in a good one.
6.19
Mobility
One of the main advantage of Wireless LANs is that they offer mobility. It
mean that even when moving around, you retain your connection to the network.
Of course, this mobility is limited by the range of the Wireless LAN. To extend
the range, you must cover the area with access points, which very often include
roaming : you switch transparently to the closer access point which provide you a
connection to the rest of the world and nodes out of range.
Note that most cheap Access Point don’t include roaming (to force you to buy
the more expensive Access Point version), and that Access Points of different
vendors usually don’t fully interoperate (the Access Points don’t talk to each other).
If you want to move across IP subnets, this is time to try Mobile IP :-)
6.20
Security and Privacy
Because they use radio waves, wireless LANs are usually perceived as a
security problem. In fact, it’s much more likely that you will get hacked from the
Internet or that somebody will tap your phone line at the back of your house. It is
also possible to read your screen and your Ethernet cable from across the street,
with the correct equipment, so nothing is bullet proof. But it’s important to assess
the security threat and the possible remedies.
91
< Linux Wireless LAN Howto >
First of all, any attack on a Wireless LAN will be necessary local (physical
proximity), because of the limited range of radio. Most “attacks” will be your
neighbor accidentally connecting to your network due to improper configuration.
Directional antennas will allow the attacker to be further away than regular nodes,
but only with line of sight. But this limit greatly the scope of the risk.
Wireless LAN, because they use digital transmissions, can not be listen to
with a regular radio scanner. The only practical way to attack a Wireless LAN is
to use another Wireless card compatible with it. The attacker may mostly try to do
two things, snoop your communications (for example to read the e-mail you are
sending) or access your resources (for example your access to the Internet).
For most users, the network identifier will be enough protection against
casual users : other people can’t accidentally join your network by mistake, unless
they guess the correct network identifier or really try to attack you. Trying to
discover the network identifier is usually not as easy as it seems, unless you use
social engineering...
Some people are more concerned about those issues or may want to increase
the security of their system. Some Wireless LANs offer MAC level encryption
(sometimes only as an option), which is designed for those concerned users and
target security equivalent to a having a shared Ethernet cable (i.e. not much), and
a few systems offer stronger encryption (but still considered weak by some experts
because of the distributed single key and the lack of per-packet authentication).
With these schemes, each packet transmitted over the network is individually
encrypted, and the card refuses unencrypted data. This encryption is totally
transparent to the higher layer and the user just need to set the same encryption
key in the access point and all nodes of the network. The main advantage of those
scheme is that they are very easy to set up.
Recently, various attacks have been found on WEP, the MAC level encryption
scheme of 802.11, which illustrate that WEP is not more secure than what it was
designed for (and probably less - but WEP is still better than nothing). Other
products may use other security mechanism, but designing a secure AND user
friendly AND cost effective security mechanism at the MAC layer is nearly
impossible, and wireless manufacturers are usually not security expert, so most
people serious about security already use a security solution independent of
the wireless link (like a regular VPN, see below). This separation of wireless and
security has other advantages (independent upgrades for example).
I would still argue that most home users don’t really need security beyond
preventing people accidentally joining your network. Most web site that you will
access over wireless and that handle critical information already use SSL to
encrypt those transactions, which is proven to be very secure, and there exist
secure versions of POP or IMAP (still using SSL). Users that access remote
Intranets most often already uses VPN software. So all critical transactions are
often already protected.
For those who need it, like if you are paranoid, your life depends on it, or if the
wireless link is already behind a firewall, you need to set up a encrypted tunnel
above the wireless link with a VPN protocol. Various VPN protocols can be used
92
< Linux Wireless LAN Howto >
with Linux, such as IPsec, PPTP and SSH (IPsec is the ultimate security solution,
but much more complex to set up and not much more secure). You will need to
setup a VPN gateway on the other side of the Access Points and the VPN software
on every wireless device. That’s usually complicated to setup, but that’s the price
for security.
6.21
Benchmarks
For all the reasons described above, I think it is quite tricky to benchmark
Wireless LANs, and measuring coverage or throughput in isolation is not fair.
Remember that coverage matters much more than raw performance in real life.
This is why I don’t give any performance numbers. Some computer magazine
publish from time to time some extensive review of all those products and try to do
some performance comparison more or less real life.
If you want to test the throughput of your device, you should use a tool called
Netperf. You might want to submit your results in the database...
http://www.netperf.org/netperf/NetperfPage.html
6.22
Tuning
More and more, vendors are delivering products in configuration that look
good in benchmarks and doesn’t perform as well in real life. This is where you need
to tune a few parameters to get better performance.
Some vendors ship products with RTS/CTS disabled. This is the best setting
if you have only two nodes, but when you have a fair number of nodes active at the
same time, RTS/CTS can increase the performance. And of course, if you have
hidden nodes, you can not get away without it...
Some vendors also tend to set the number of MAC retransmissions a bit
low for my taste. If you use TCP, this might improve your performance slightly
under good conditions, because TCP do its own retransmissions. However, all
applications not using TCP (ping, RTP, NFS...) might suffer from the packet losses.
On a related note, you can play with the bit-rate setting of the card. Most
cards nowadays include a rate-adaptation scheme, which adapt the bit-rate to the
range : basically the card try transmitting at the highest rate and decrease the rate
in case of packet losses. However, in configuration with large number of active
nodes, packet losses also come from the contention process, so disabling this rate
adaptation scheme (forcing the highest rate) can increase performance in some
cases.
If you have interferers in the band, you might need to enable fragmentation
(send smaller packet to fit between interferences) and to raise the sensibility (tell
the card to ignore the noise). Of course, the best thing is to eliminate the interferer,
if possible.
If you have different Access Points and have enabled roaming, you should also
set carefully the roaming threshold, which is the point (in signal strength) at
which the card search for a new Access Point. If you set it too low, the card will
spend to much time with a non optimal AP (getting a poorer throughput), and if
you set it too high the card will waste time searching for a new AP too often.
93
< Linux Wireless LAN Howto >
To finish, all this fine tuning and optimisation could/should be done in the
card itself, the card itself has most of the information it needs to optimise those
settings and the algorithms are not that complex (I describe some in my latest
papers). This ensure that users automatically get the best performance in any
condition. Most modern wireless hardware is now getting much better at doing this
automatic tuning, and nowadays you need less and less to do any manual tuning
(and actually tuning may be counter-productive in some cases).
7 Wireless Extensions for Linux
See the document about Wireless Extensions.
8 Wireless LAN technology overview
See the document about the technology overview.
94