C-SPEC CORPORATION
WIRELESS PRODUCTS
Contents
CLARION MERLAN M10
INTRODUCTION..................................................................................................1
PRODUCT OVERVIEW .......................................................................................1
DATA TRANSFERS..............................................................................................1
M10 CONTRASTED WITH WIRED MEDIUMS ................................................3
Buffer Delay ....................................................................................................3
RF Re-transmission Protocol .........................................................................4
Flow Control....................................................................................................5
SECURITY ............................................................................................................5
ANTENNA RECOGNITION ................................................................................6
SPECIFICATIONS................................................................................................7
CONNECTIVITY ..................................................................................................7
Personal Computers .......................................................................................7
Routers ............................................................................................................7
Bridges and Hubs ...........................................................................................8
MANAGER/CONFIGURATION UTILITY........................................................10
Installation....................................................................................................10
M10 Manager ................................................................................................10
Adding a new M10 .................................................................................11
Modifying the description of an M10 ....................................................11
Removing an M10 ..................................................................................12
Configuring an M10 ...............................................................................12
Configuration Parameters ...........................................................................12
Spreading Code selection.......................................................................12
Channel Access protocol ........................................................................13
Retransmission protocol ........................................................................13
AUI parameters......................................................................................14
CLARION MERLAN M10
i
CHAPTER 8.6
SUPPORTED NETWORK CONFIGURATIONS..............................................15
M10 USE OF 802 ADDRESSES.........................................................................16
FIRMWARE UPGRADE.....................................................................................17
Installation....................................................................................................18
Upgrade Procedure.......................................................................................19
LIST OF FIGURES
MerLAN M10 Specifications ..........................................................................7
MerLAN M10 Front and Rear Panel.............................................................9
ii
C-SPEC CORPORATION
WIRELESS PRODUCTS
CLARION MERLAN M10
INTRODUCTION
The Clarion MerLAN M10 is a wireless transceiver providing 10 Megabits/sec
burst data rate to support wireless connections in IEEE 802.3 and Ethernet II
LANs. The MerLAN M10 functions as an Ethernet Medium Attachment Unit
(MAU).
The Medium Access Control (MAC) frame from a standard
Attachment Unit Interface (AUI) port is encapsulated to form a Radio
Frequency (RF) MAC frame. It uses the state-of-the-art spread spectrum
technology to implement robust 10Mbps burst transmission. It also manages
the efficient utilization of frame buffers and coordination of the RF and wired
interface traffic to maintain this high throughput. In addition, the unit offers
true “Plug and Play” installation; no additional driver software is required for
its operation. That is, the MerLAN M10 can be connected to not only a
computer, but also to router. In certain configurations and topologies, the
unit can also be connected directly to a bridge or hub. Accordingly, you can
create various kinds of innovative LANs combining existing wired devices
and the Clarion MerLAN M10 units.
PRODUCT OVERVIEW
The Clarion MerLAN M10 is a combination of hardware and firmware
providing 10 Mbps data rate over a wirless medium using state of the art
direct sequence spread spectrum radio technology in the 2.4 GHz radio
frequency band. Utilizing forward error correction, re-transmission protocol,
flow control, and continuously changing spreading codes, the MerLAN M10
provides a fast, safe, secure, and robust wireless transmission. A Windows 3.1
based configuration utility program enables the MerLAN M10 to be fine
tuned to integrate seamlessly into your existing network environment
preserving your current resource investment. The configuration options
provide network connectivity directly to personal computers, routers, bridges,
and hubs.
DATA TRANSFERS
A data transfer is called an Upload when the ethernet device conveys a
frame from itself to the MerLAN M10’s buffered memory through the MAU
port. The buffered memory is organized as 16 2K byte FIFOs with each
CLARION MerLAN M10
1 of 19
C-SPEC CORPORATION
WIRELESS PRODUCTS
FIFO being independently employed and capable of storing a maximum
length ethernet frame of 1518 bytes. Eight buffers are used to hold ethernet
frames received via the wireless medium and eight buffers are used to hold
ethernet frames received from the wired medium. On an Upload when all
eight buffers are used, a collision signal is generated to force the ethernet
card into its exponential back-off algorithm for flow control. If generation of
the collision is not selected via the configuration process, then no collision is
generated and the Upload is ignored.
On an Upload, the MerLAN M10
provides the following:
Detection of the preamble of the ethernet frame followed by the frame
sync pattern
Suppression of the ethernet preamble and frame sync for RF
transmission since these portions are meaningless for wireless
transmission
Generation of a collision signal if an upload commences and there is no
buffer available
Forward Error Correction encoding of the data when that option is
enabled through the configuration process
Generation of the header information for the RF MAC and RF physical
layer
Spread spectrum carrier sense before transmission with preference given
to reception
Data and spread spectrum modulation onto a carrier of 2.4 GHz and RF
transmission
A data transfer is called a Download when the MerLAN M10 conveys a
frame from its buffered memory through the MAU port to the ethernet
device. On a Download, the MerLAN M10 provides the following:
2
Detection of and time alignment to the received radio signal
Demodulation of the physical header and MAC frame
Forward Error Correction decoding when the unit recognizes that the
received frame is FEC encoded by reading the physical header
Checking the 32-bit CRC generated by the ethernet card which uploaded
the frame
conversion of the serial stream to bytes for storing in the buffered
memory FIFO
C-SPEC CORPORATION
WIRELESS PRODUCTS
Regeneration of the ethernet preamble and frame sync
Detection of any collision condition for avoiding collision of the download
to the upload and signaling of such to the AUI interface and to the CPU.
M10 CONTRASTED WITH WIRED-MEDIUM
The industry way of transmitting and receiving data over Clarion’s MerLAN
M10 (and many other) networks cause data packets to be frequently lost or
links to be limited to only point-to-point (i.e., only 2 radios per cell). This is
due to the fact that a wireless network does not have the ability to properly
detect collisions like an Ethernet network has. In an Ethernet network
collisions can be detected by the hardware (Ethernet chip) and are
immediately re-transmitted. Ethernet is referred to as CSMA/CD (Carrier
Sense Multiple Access with Collision Detect). Wireless networks are referred
to as CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance).
The reason that collisions cannot be detected is because with a radio cannot
receive and transmit at the same time, hence collisions cannot be detected.
While the M10 has been designed to appear electrically as a standard
MAU, it is executing a medium-access protocol appropriate for the wireless
medium. As a result, certain of its behaviors are not reflected in a wiredmedium MAU, and the transparency to the wired-medium MAC in the
attached computer or bridging device cannot be absolute. MAUs for wired
networks have no internal storage; they operate with negligible delay relative
to the signals at the AUI/MAU interface. Because the MAC software in the
attached computer is executing a protocol appropriate for the wired medium,
and the M10 must employ a protocol appropriate for the wireless medium,
the M10 stores frames in buffers in order to isolate the (wired and wireless)
media. This results in important differences from conventional 802.3 MAUs;
these include buffer delay as well as the need for RF retransmissions and for
flow control.
BUFFER DELAY
The protocol operating over a MerLAN M10 link has an inherent delay of two
frames in each direction. When a frame is offered from the AUI port, it is
first saved in a buffer. Subsequently, the frame is transferred over the RF
channel to a receive buffer in the destination MerLAN M10. Only then is the
frame downloaded to the destination AUI port. This need not limit
throughput if the transport protocol properly anticipates the delay. If the
protocol waits for each frame to be acknowledged, then the throughput
achieved will be very low due to the excess delay inherent in the buffering
process. However, if a burst mode is used, then the effect of the delay can be
made negligible.
CLARION MerLAN M10
3
C-SPEC CORPORATION
WIRELESS PRODUCTS
RF RE-TRANSMISSION PROTOCOL
RF signals transmitted from the M10 are not simultaneous with the
corresponding AUI activity. Although there are MAC-level retransmissions
in wired networks when a collision is sensed, the buffering of frames in the
M10, added to the fact that failure of an RF transmission cannot be sensed at
the transmitter, means that the wired-side MAC cannot provide
retransmissions. Thus, in order to avoid long delays for retransmission by
the level-four Transport protocol, e.g., TCP or IPX, the use of RF-MAC-level
retransmissions is important for high throughput.
The re-transmission protocol at the RF MAC layer provides enhanced
reliability. The 32 bit CRC, checked by the 802.3 MAC layer to provide the
final data reliability, is also used to support re-transmission protocol. The
use of the RF MAC level re-transmission protocol, recommended by the
802.11 draft standard, is important for high throughput. Re-transmission via
the level four transport protocol must be avoided, if at all possible, because of
the long time-out typically employed. Prior to the re-transmission, the
MerLAN M10 recognizes and memorizes the source MAC address of an
ethernet device connected to the unit through the MAU port. The download
occurs only when the MerLAN M10 recognizes complete matching of the
memorized source MAC address and destination MAC address written in a
received radio frame. Once the MerLAN M10 memorizes the source MAC
address, no update of the source MAC address is performed in the unit unless
power is turned off. This means that applications that lead to frequent
change of the source MAC address of the ethernet frame coming from
multiple ethernet devices through the MAU interface are not suitable for
making the re-transmission protocol effective.
In the case of such
applications, it is recommended that the MerLAN M10 be configured without
the re-transmission option.
The re-transmission protocol is based upon the recognition of
acknowledgments generated by a MerLAN M10 unit that received a radio
data frame from another unit.
A radio frame that carries the
acknowledgment is called an ACK frame which only affects the RF MAC level
protocol. The contents of the ACK frame never appears at the MAU port.
The ACK frame is transmitted immediately after the completion of receiving
the radio frame. The re-transmission protocol is not available for Broadcast
frames (destination ethernet address of all 1 bits) because no ACK frame can
be transmitted for those type of frames.
There are two different causes that will result in the re-transmission of
radio frames. One is the missing of an ACK frame and the other is a missing
data frame. In either case, the sending MerLAN M10 recognizes that there
was no return of the ACK frame from the receiving MerLAN M10 within the
allotted time-out period, therefore, the sending unit initiates the retransmission of the radio frame. In the case of a missing ACK frame, the
radio frame being re-transmitted is recognized by the receiving unit as a
duplicate frame and filters it out, such that the download of the frame does
not occur. This is called the Duplicate Filter function. The Duplicate Filter is
only functional when a single ethernet device is connected to the MerLAN
M10. This function will be updated in the future to make it available for
4
C-SPEC CORPORATION
WIRELESS PRODUCTS
multiple ethernet devices. Duplicate frames that the MerLAN M10 does not
filter out will be removed by a function of the Network Operating System.
The maximum number of re-transmissions is seven (eight transmissions
total) after which the data is dropped and the successful transmission will
depend upon another re-transmission provided by the Network Operating
System protocol. The value of the ACK frame time-out is currently fixed at
300 micro seconds. It will be updated to a user definable time through the
configuration process in the future to support various ranges of wireless link
distances.
FLOW CONTROL
When no buffers are available for an Upload of AUI frames to the MerLAN
M10, the unit will take one of two separate courses depending upon the
option selected during the configuration process. The first course of action,
which is also the default, is for the unit to invoke flow control by using the
collision signal to force the ethernet card into its exponential back-off
algorithm. Because there are eight upload buffers, this flow control can
always maximize the RF throughput even though the attached device may
delay re-offering frames. The second course of action, which is an option that
can be chosen during the configuration process, is to ignore upload frames
when no upload buffer is available. This may be required when the MerLAN
M10 is connected to multiple computers (e.g., via a hub) which might be
disrupted by excessive collision indications. However, ignored frames will
incur a large delay for retransmission by the level-4 transport protocol (TCP,
SPX), or may not be re-offered at all for datagrams (UDP, IPX). Although
using the collision signal for flow control is the default, the user must make
an informed selection between the two possibilities based upon network
topology, acceptable link behavior, and the requirements of the application
software.
SECURITY
Since secure data is a great concern with any wireless transmission system,
the MerLAN M10 offers excellent security without using conventional
cryptography. The security of the data transmissions is achieved by
continuously changing and pseudo-randomly selecting spreading codes. The
16
user may select from 2 (64K) different sequences to determine the order in
which the spreading codes are used. This provides excellent security against
eavesdropping by unintended parties. The actual sequences can be selected
through the configuration process provided by the MerLAN M10
configuration software.
CLARION MerLAN M10
5
C-SPEC CORPORATION
WIRELESS PRODUCTS
ANTENNA RECOGNITION
The FCC prohibits standard types of antenna connectors for systems such as
the MerLAN M10. Although the unit uses a standard SMA female connector
for the external antenna port, the FCC has allowed this standard connection
for the MerLAN M10 because of the special antenna recognition function
provided by the unit. This function is implemented in an electrical manner
instead of a mechanical manner. Accordingly, no antennas or antenna
systems except those that Clarion provides as genuine accessories for the
MerLAN M10 are available. If such antennas or antenna systems are
connected to the MerLAN M10, the unit will never transmit. The external
antenna port outputs a low DC voltage (up to +5 Volts) for this recognition.
The unit is unconditionally safe against any type of passive load connected to
the external antenna port.
WARNING: If any measuring equipment is connected to the external
antenna port, please check that the allowed DC voltage applied to the
input of the equipment can be accommodated without any damage to the
equipment.
NOTE: Transmit signals can not be observed by connecting the external
antenna port to any measuring equipment because of the antenna
recognition function described above. A measuring antenna together with
an approved Clarion antenna can be used for any such requirement.
6
C-SPEC CORPORATION
WIRELESS PRODUCTS
SPECIFICATIONS
The following figure represents the current specifications for the Clarion
MerLAN M10 unit.
Frequency Range:
Carrier Frequency
Modulation Technique:
Output Power:
Receive Sensitivity
Data Rate:
Media Access Protocol:
Power Consumption (TX):
Power Consumption (RX):
Power Requirements
Power Supply (Input)
Power Supply (Output)
Operating Temperature
FCC Regulations:
2.416 - 2.456 GHz ISM band
2.436 Ghz
Spread Spectrum - BPSK, 32 Mcps
25 mW (14 dBm)
-86 dBm
10 Mbit/sec.
Ethernet Variety (CSMA/CA)
1.6 - 2.0 Amp
1.1 - 2.0 Amp
6.2VDC (min 6.0, max 6.85)
100-125VAC
6.2VDC
2A
0 - 40 C
No site license required
Figure 1 MerLAN M10 Specifications
CONNECTIVITY
The MerLAN M10 can be directly connected to several types of LAN devices
by means of the MAU port on the unit. It can be connected directly to
personal computers, routers, bridges, and hubs by means of the AUI port on
those devices. A standard AUI cable can be connected to the MerLAN M10
and any of these units via their AUI port. A more detailed description of
these connections follows. The main concern is how the MerLAN M10 is
configured when attached to these various devices.
PERSONAL COMPUTERS
The MerLAN M10 can be connected directly to the AUI port of a network
adapter card of a personal computer by using a standard AUI cable. If the
network adapter card in the PC has a 10Base-T connection, that connection
can be used to connect to the MerLAN M10 by means of an AUI to 10Base-T
media converter that also crosses over the send and receive data signals. The
default configuration parameters should be used when the MerLAN M10 is
connected to a personal computer.
CLARION MerLAN M10
7
C-SPEC CORPORATION
WIRELESS PRODUCTS
ROUTERS
All routers normally support an AUI port which can be used to connect the
MerLAN M10 unit via a standard AUI cable. Connecting the MerLAN M10
to routers presents no inherent problems even though many workstations can
be transmitting packets to the routers. A router encapsulates the original
ethernet message with a new ethernet destination (another router) and itself
as the source address and sends the message directly to another router
thereby presenting only a single ethernet source address to the MerLAN M10
which it adopts and can use for acknowledgments for the re-transmission
protocol. The default configuration parameters should be used when the
MerLAN M10 is connected to a router.
BRIDGES AND HUBS
Connecting the MerLAN M10 directly to a bridge or hub can also be done by
means of a standard AUI cable. If there are only 10Base-T connections on the
hub, a 10Base-T to AUI media converter can be used. The physical
connection of a bridge or hub to the MerLAN M10 is not a problem, but this
scenario presents a situation that can impact performance issues based upon
the actual communication topology trying to be supported. Remember that
the MerLAN M10 derives its RF address from the first ethernet message it
receives from the MAU connection and that address is used to generate and
validate acknowledgments.
Since there are several devices generally
connected to a bridge or hub, the source address in the ethernet messages is
constantly changing creating a problem for the MerLAN M10 in the
generation and validation of acknowledgments. In these particular cases,
please read Supported Network Configurations later in this document to
determine how the MerLAN M10 should be configured for your site’s
particular network topology.
8
C-SPEC CORPORATION
WIRELESS PRODUCTS
Figure 2 MerLAN M10 Front and Rear Panel
CLARION MerLAN M10
9
C-SPEC CORPORATION
WIRELESS PRODUCTS
MANAGER/CONFIGURATION UTILITY
The MerLAN M10 Manager/Configuration Utility program is used to manage
any number of M10s and also to set various configuration options if any of the
Merlan M10 default settings are not the ones desired. This utility was
designed to be installed and run as a Microsoft Windows 3.1 application
program.
INSTALLATION
To install the MerLAN M10 Manager/Configuration utility, perform the
following steps:
1.
Insert the Installation disk 1 into Drive A: or B:
2.
Click “FILE” and then “RUN” from the Windows Program Manager
3.
Click “BROWSE”, select Drive A: or B: and click on “SETUP”
4.
Click “OK” to run the Setup program for the Configuration Utility
5.
Follow any instructions indicated by the Setup program
The Installation program will perform the following functions:
1.
Copy the Visual Basic run-time library into the appropriate
directories
2.
Copy the MerLAN M10 configuration software into the directory
C:\M10
3.
Create the MerLAN M10 program group and program icons
To uninstall the MerLAN M10 Configuration Utility
1.
Delete the directory C:\M10 using the Windows File Manager
2.
Delete the M10 Program group or the M10 Icon if it was copied or
moved to another group
3.
DO NOT attempt to delete the run-time modules. They will not
cause any problem and they may be required by some other
application
M10 MANAGER
The M10 Manager is designed to handle any number of M10s, all of which
must be reachable from this computer’s 802 LAN, e.g., via any collection of
10
C-SPEC CORPORATION
WIRELESS PRODUCTS
hubs, repeaters, and bridges. The M10 Manager cannot reach any M10 unit
that is not reachable through a completely wired connection. This means
that M10 units which are only reachable via a wireless connection from this
computer cannot be managed from this computer. The M10 Manager does
not directly read the configurations of M10s under its control. A database is
stored on the disk. This information is accessed by selecting a particular M10
from the dropdown list of the M10 Manager dialog box. The user may add a
new M10, modify the description of an M10, remove an M10 or configure an
M10. Any changes are saved to disk to keep the database current. If
configuration frames are required, the frame data is saved to disk, then a
DOS utility is called to actually send the frame.
Adding a New M10
When the New button is clicked, the Add New M10 dialog box appears. The
text description starts with time/date information, for example, M10 added on
9/30/96 10:08:44 AM. This can be edited, and the description entered can be
up to 1000 characters in length. If many M10s are to be managed, then the
description should be detailed enough to avoid confusion. If more than a
single M10 is to be controlled, then the user is advised to set the M10
Address. The M10 Manager will allow only a single unit to use the Clarion
Null address at any time. Thus, if some M10 is identified as, or configured
via the Clarion Null address, no new units can be added.
An RF Address can be entered; if so, this RF Address is stored in non-volatile
memory. A full 12-hex-digit address must be entered for the RF Address. If,
however, the M10 Address is being copied/pasted to the RF Address, then
selecting the six least-significant digits automatically includes the other six.
Deleting the RF Address text unassigns the RF Address.
If no RF Address is entered, the unit will learn its RF Address upon each
power-up cycle. Click Cancel or Done as appropriate to cancel the entry or to
complete the operation.
Modifying the Description of an M10
When the Modify button is clicked, the Change RF Address & Description
dialog box appears. The text can be edited, and the description can be up to
1000 characters in length. If many M10s are to be managed, then the
description should be detailed enough to avoid confusion.
If more than a single M10 is to be controlled, then the user must set the M10
Address. The M10 Manager will allow only a single unit to use the Clarion
Null address at any time. Thus, if some M10 is identified as, or configured
via the Clarion Null address, no new units can be added.
An RF Address can be entered; if so, this RF Address is stored in non-volatile
memory. A full 12-hex-digit address must be entered for the RF Address. If,
however, the M10 Address is being copied/pasted to the RF Address, then
CLARION MerLAN M10
11
C-SPEC CORPORATION
WIRELESS PRODUCTS
selecting the six least-significant digits automatically includes the other six.
Deleting the RF Address text unassigns the RF Address.
If no RF Address is entered, the unit will learn its RF Address upon each
power-up cycle.
Click Cancel or Done as appropriate to cancel the entry or to complete the
operation.
Removing an M10
When the Remove button is clicked, a message box will display “Are you sure
you want to remove .......”. Click OK to remove the unit, or Cancel to cancel
the operation. Clicking the OK button is final.
Configuring an M10
Clicking the Configure button brings up the M10 Configuration dialog box for
that unit. The parameters and values shown are those reflected in the
current data base for the currently selected unit.
The AUI Parameters, Code Channel, and Search Code are configured
directly from this dialog box, while the Retransmission Protocol and ChannelAccess Protocol may be configured by bringing up the appropriate dialog box
using the corresponding Set button.
The Default button sets all parameters back to the factory default
settings. When the Done button is clicked, the updated information is saved
in the M10 Manager data base, and any required configuration frames are
issued.
CONFIGURATION PARAMETERS
The configuration parameters are explained in this section. Each description
includes the permissible values that can be entered for the parameter
enclosed within braces, the default setting of the parameter, and a brief
explanation of the functionality of the parameter.
Spreading Code Selection
Code Channel {four hex digits} default = 2D1B. This is a four-hex-digit
pattern which specifies the sequence of spreading codes used for the data
portion of the frame transmission. This is a security measure. Any two M10s
must use the same Code Channel in order to exchange data. Enter by editing
as text.
Search Code {0,1,2,3,4,5,6,7} default = 0. There are eight Search Codes
available. These do not provide security, rather they can be selected to
provide isolation between independent M10s operating in close proximity.
Operation of different Search Codes simply avoids the transmissions of one
link from triggering detections on the other link. Select via a dropdown list.
12
C-SPEC CORPORATION
WIRELESS PRODUCTS
Channel Access Protocol
On Ethernet both carrier sensing and collision detection are simple processes.
For any radio channel the ability to detect collisions is lost; in addition, for a
spread-spectrum system with changing codes (for security) the ability to
perform carrier sensing is limited to acquisition of the preamble portion of a
transmission. The channel-access protocol (CAP) employed in the M10 is
called P-persistent CSMA.
When an M10 has scheduled a transmission, the start time of that
transmission is selected randomly from a grid of P possible start times, these
being separated by the slot time. The slot time is somewhat larger than the
one-way propagation time; this ensures that if only one transmission is
started at a slot boundary, then all other M10s can detect that transmission
and cancel any other pending transmissions. Of course, there remains the
probability 1/P that any two radios might select the same slot boundary on
which to transmit, and then the two transmission will collide. In dense
environments selecting a large value for P keeps the network from collapsing,
while in less-dense environments a small P gives higher throughput. With P
as a configurable parameter (in fact, dynamically configurable) the M10
supports a variety of user-controlled CAP strategies.
The M10 provides for adaptive P-CSMA by using a sequence of P values.
These are loosely tied to the transmission attempts in that the P values in the
sequence correspond to the attempt number, but any successful receive resets
to P0 for the next attempt. If that attempt fails, the sequence of P values is
resumed according to which attempt is in progress. (P is a power of two, up to
256.)
P0,...,P7 Default: 4,8,16,32,64,128,256,256. One of three buttons may be set:
Exponential causes each P to be double the previous in the sequence; this is
modeled after exponential backoff of Ethernet. The user sets only P0.
Constant causes only the P0 value to be used, i.e., non-adaptive. The user
sets only P0.
Custom enables the user to select any arbitrary adaptation strategy.
Retransmission Protocol
The retransmission protocol is key to high throughput in any radio LAN.
Without retransmissions at the MAC layer, any lost frame would incur the
relatively large time-out of the layer-4 (Transport layer) reliability protocol
before a missed frame is sent again. The M10 retransmission protocol has a
window of 1 such that it focuses its effort on the delivery of a single frame for
up to eight (8) transmission attempts, and must either succeed or fail on that
frame before moving to the next available (buffered) frame.
When
retransmissions are enabled, a transmitting M10 marks its transmitted
frame as requiring an ACK, transmits the frame, then after the transmission
is completed waits for an ACK. If after waiting for ACK_timeout time and no
CLARION MerLAN M10
13
C-SPEC CORPORATION
WIRELESS PRODUCTS
ACK has been received, then another transmission is scheduled. If an ACK is
received on any attempt, then the M10 moves to the next available frame
awaiting transmission. On the last transmission attempt, the transmitting
M10 does not ask for the ACK; rather it moves immediately to the next
frame.
Check Address {On/Off} default = Off. RF Address comparison for sending
ACKs and receiving ACKs. Click to toggle. See Supported Network
Configurations later in this document for a further explanation of RF address
checking.
The following retransmission parameters are activated by selecting the Set
button:
Transmission Tries {1,2,3,4,5,6,7,8} default = 8. Retransmission (ReTx)
protocol offers up to 8 total tries (7 retries) for lost frames. Enable each try
(after the first) by changing its dropdown-list selection from "off" to "on" ( in
no-diversity mode), or from "off" to either "same" or "toggle" (in diversity
mode). Note: this also selects the diversity antenna sequence; the first try
option selects either the internal or external antenna, or diversity mode.
FEC {1,2,3,4,5,6,7,8,no FEC} default = 2. Use Forward Error Correction to
overcome channel errors when the probability of a successful frame transfer
is too low to clean up with the retransmission protocol alone. Click the button
next to the attempt on which the FEC should be activated (can not be set to
any Retry that is set to Off), or click No FEC.
Antenna Selection Diversity {Int,Ext,Div} default = Ext. The dropdown
list selections for the first transmission attempt are: Int which uses the
Internal Antenna Only; Ext which uses the External Antenna Only; Div
which turns on the Diversity function meaning that either antenna can be
used depending upon the option selected in the Retry choices. The Retry 1
through Retry 7 drop down choices depend upon the selection chosen for the
first transmission attempt. If Ext or Int is the first transmission attempt
selection, then the Retry choices are only On or Off and once Off is selected
for a Retry, then the following Retry choices are automatically set Off. If Div
is the first transmission attempt selection, then the Retry choices are Off,
Same, or Toggle and once Off is selected for a Retry, then the following Retry
choices are automatically set Off.
AUI Parameters
Send SQE Test {On/Off} default = Off. This is a collision pulse issued after
an UPLOAD for checking the collision cable pair. It is the same SQE test as
is implemented in any Ethernet card. (IEEE 802.3 Standard section
7.2.2.2.4).
Collisions for Busy {On/Off} default = On. When all upload buffers are
full, then no more frames can be accepted from the AUI port. If collisions for
14
C-SPEC CORPORATION
WIRELESS PRODUCTS
busy is Off, then frames offered at the AUI port will be ignored, and the level4 transport protocol is responsible for re-initiating the frame transfer for each
such ignored frame; this will result in large delays due to the level-fourtransport time-out delay. If Collisions for busy is On, then the M10 will send
a collision indication for flow control via the Ethernet back-off algorithm.
When such collisions can be used, the (MAC-level) delay for re-initiating a
frame transfer will be small.
Filter Duplicates {On/Off} default = On. There will always be some nonzero rate of lost frames over any RF link; some of these lost frames inevitably
will be ACKs in response to received frames. When this happens, the
retransmission protocol will cause some duplicated frames at the receiver. If
filter duplicates is enabled, this option will inhibit the download of a frame if
its sequence number matches the most-recently downloaded frame.
Download Error Frames {On/Off} default = Off. Sends frames failing
CRC to the AUI port anyway. This option is for diagnostic use only.
SUPPORTED NETWORK CONFIGURATIONS
The use of the MAC-level retransmission protocol combined with the single
RF Address for an M10 limits the configurations supported. The variations
considered are whether the retransmission protocol is used, and, if so,
whether the RF Address is checked for ACKing. The three possible
combinations, each with an explanation of the network topology supported,
are as follows:
Retransmit Off
Any network configuration can be used, e.g., multiple M10s, each possibly
connected to multiple Ethernet cards via 10baseT hubs, in a peer-to-peer
network.
No RF Address assignment is required, or relevant.
The
importance of MAC-level retranmissions because of the unavoidable loss of
RF frames makes this network less attractive in practice than those
supported by having retransmissions on.
Retransmit On, Address Check Off
Any point-to-point connection of a pair of M10s can be used, e.g.,
interbuilding bridging or routing, wireless connection of two 10baseT hubs,
etc. Because there can be only one receiving M10 at any instance, there is no
need for the RF Address. Care must be taken that the pair of M10s is on a
distinct code channel.
CLARION MerLAN M10
15
C-SPEC CORPORATION
WIRELESS PRODUCTS
Retransmit On, Address Check On
In this case, an RF Address must be assigned to each M10. There are
numerous possibilities, depending upon how the RF Address is selected.
1. Multiple M10s, each connected via a single Ethernet card to a computer,
in a peer-to-peer wireless network. Each M10 should learn or be
configured with the attached Ethernet Card's 802 address to be used for
its RF Address. This network behaves (logically) as though the network
cards are connected by wire.
2. Multiple M10s, each connected via a single Ethernet card to a router, in a
multi-point wireless inter-network configuration. Each M10 should be
configured with the attached Ethernet Card's address used for its RF
Address. M10s should be placed on local router ports, rather than WAN
ports, which are restricted in data rate.
3. Multiple M10s, each connected via a single Ethernet card to a bridge, in a
multi-point wireless bridging configuration.
Each M10 should be
configured with its M10 Address as its RF Address. The bridges must
have address bindings between the various Ethernet cards and M10s, and
the source and destination addresses must correspond to the M10s on
either end; (wired-side) frames would, of course, be encapsulated within
the frame delivered to the M10 by the bridge. The topology appears very
similar to that of #2 (the router configuration), but M10 Addresses must
be used.
4. Multiple M10s each possibly connected to multiple Ethernet cards (e.g.,
via 10baseT hubs), in a peer-to-peer network with RF Addresses assigned
for only selected card addresses (one per M10). For example, by assigning
the address of a server to the M10's RF Address it is possible to operate
the RF-MAC-level retransmission protocol for the server traffic, leaving
only lower-priority peer-to-peer traffic somewhat disadvantaged.
In #2 and #3 above, note that a router is a peer correspondent on each
network to which it is connected, while the bridge is a peer on none of the
networks. That is, a router is a source and destination on a network, using
its Ethernet card's unique 802 address; while the bridge uses its Ethernet
card's 802 address only for network control, but for normal traffic it uses the
original source address and the end destination address.
M10 USE OF 802 ADDRESSES
From the wired side, frames are uploaded to and downloaded from the M10 at
the AUI Port (AUI connector is attached, mating MAU connector is on the
M10). From the RF side, frames are transmitted from and received into the
RF Port. The destination address of each received RF frame is checked, if
16
C-SPEC CORPORATION
WIRELESS PRODUCTS
address checking is enabled, to determine whether an ACK is required (or
was received). The destination address of each uploaded AUI frame is
checked to determine if the frame was intended to be used to configure the
M10.
M10 Address
Each M10 is assigned a unique 48-bit IEEE 802 address at the factory in a
similar manner to any Ethernet card. The number serves the purpose of
uniquely labeling the M10 within network address space, and it also doubles
as a manufacturing serial number.
Config Address
An M10 can be configured to recognize management data as frames
addressed to the Clarion NULL address (00606F000000) if there is only a
single M10; for M10s to which configuration frames can be routed via a wired
network, the M10 must be set to accept only management frames specifically
addressed to the M10 via its specific M10 Address.
RF Address
The retransmission protocol uses an acknowledgment (ACK) sent from the
receiving M10 to the transmitting M10 to indicate that the frame
transmission was successful. Each M10 uses an RF Address which is
compared to the destination address of a received frame to determine that the
frame was intended for that M10, hence that it should send an ACK if the
frame was received intact. An M10 awaiting an ACK compares the
destination address of the ACK it receives to its RF Address. No filtering of
traffic is performed by the M10; the RF Address is used only to operate the
retransmission protocol. The M10 should use as its RF Address the address
of a device attached to the AUI port. The RF Address can be designated by
user configuration; otherwise it is learned by the M10 from the first frame
offered to the M10 after power-up. Power-up learning of the RF Address is
consistent with M10 attachment to a single Ethernet card. Configuring the
M10 to retain a specific RF Address for traffic purposes is required, for
example, when the M10 is attached to a network traffic source/sink and also
to a network-monitoring device whose address might be unintentionally
learned during power-up. When designated by user configuration, the M10
could have its RF Address set to its unique M10 Address. This supports
bridging, where the attached bridge has binding address information
sufficient to direct frames to specific M10s.
FIRMWARE UPGRADE
In the event that new MerLAN M10 firmware is released and needs to be
installed, you will receive a floppy disc with the necessary programs and files
CLARION MerLAN M10
17
C-SPEC CORPORATION
WIRELESS PRODUCTS
to perform the upgrade. The upgrade software uses Novell’s IPX/SPX
protocol and will run under DOS or as a DOS program under Windows 3.1.
Of course, the PC must have a network interface card (NIC) installed with an
AUI and/or a 10BaseT port. If the NIC does not have an AUI port, then a
10BaseT to AUI converter must be used, such as a hub with both types of
connections or an AUI to 10BaseT media converter. If the MerLAN M10 is to
be directly attached to the NIC with an AUI port, then an AUI transceiver
cable can be used to make the connection. If the MerLAN M10 is to be
directly attached to the NIC with a 10BaseT port, then an AUI to 10BaseT
media converter must be used which can crossover the send and receive
signals. There is no problem if a hub is used as the media converter. Finally,
the standard Clarion Power Supply accessory for the MerLAN M10 must also
be used to power the unit.
INSTALLATION
The following steps should be taken to install the upgrade software:
1. Prepare your PC to execute a DOS program.
2. Insert the floppy disc labelled “M10 UPGRADE” into a floppy disc drive.
3. Type A: or B: to change to the floppy disc drive where the disc was
inserted.
4. Type INSTALL <drive> where <drive> is a letter of a hard disc drive of
the PC (usually C:). The install procedure automatically creates a new
directory called M10UG on the selected hard drive and extracts the
upgrade programs and files into it.
18
C-SPEC CORPORATION
WIRELESS PRODUCTS
UPGRADE PROCEDURE
The upgrade procedure requires that the MerLAN M10 unit be connected
directly to the NIC on the PC via an AUI cable, or 10BaseT cable with an AUI
to 10BaseT media converter which crosses the send and receive data signals,
or thru a hub. Perform the following steps to upgrade the MerLAN M10.
1. Connect the Clarion Power Supply to the M10. Wait for the blinking of
the red TX LED to stop before trying to run the upgrade program.
2. Type UPGRADE <xxxxxx> where <xxxxxx> is the last six digits of the
serial number of the M10 unit which is written on the label attached to
the bottom of the unit or is the Clarion NULL address of six zeroes. The
first six digits are always 00606F. If the unit is configured to use the
Clarion NULL address, then type UPGRADE 000000 . If the unit is not
configured to use the NULL address and if the serial number is
00606F040417, then type UPGRADE 040147. You will see the following
messages displayed:
**********************
*
* M10 Uploader v2.7
*
**********************
Initializing IPX...
Canceling pending events...
Getting network address...
Setting target address...
Getting local node...
Uploading...
Frame: 24/24, 024840 bytes...
NOTE: The frame number begins at 01/24 and increases up to 24/24 during
which the red TX LED begins blinking twice at approximately 2 second
intervals. The completion of the firmware transmission is indicated by the
red TX LED remaining on and the following messages being displayed.
Transfer complete
Wait for boot LED or AUI boot message (apox. 4 mins)
Hit any key to exit.
04:17
At this time, the MerLAN M10 starts burning the EEPROM and the red TX
LED remains on and blinks approximately every 20 seconds. The AUI cable
may be disconnected at this time to be used to connect another M10 for
upgrade purposes but the power cable must remain connected throughout the
burning process which takes approximately 4.5 minutes after which the red
TX LED goes off.
CLARION MerLAN M10
19