AN20 - Lock a Digi TransPort Wireless WAN Router

AN20 - Lock a Digi TransPort Wireless WAN Router
Application Note 20
Lock a Digi TransPort wireless WAN router
to a single mobile operator’s network
Sep 2015
Contents
1
2
3
4
Introduction .......................................................................................................................................... 3
1.1
Outline........................................................................................................................................... 3
1.2
Assumptions .................................................................................................................................. 3
1.3
Corrections .................................................................................................................................... 3
1.4
Version .......................................................................................................................................... 3
Configuration ........................................................................................................................................ 4
2.1
Deactivate the PPP interface ........................................................................................................ 4
2.2
Scan for Networks ......................................................................................................................... 5
2.3
Re-Activate the PPP interface ....................................................................................................... 6
2.4
Save the configuration .................................................................................................................. 7
2.5
Extract the configuration change and apply it to other wireless Digi Transport routers. ............ 8
Testing ................................................................................................................................................... 9
3.1
Checking that the Digi Transport is locked to the correct network ............................................ 10
3.2
Checking that the correct command is sent to the module ....................................................... 10
Hardware and firmware details .......................................................................................................... 11
4.1
Digi Transport firmware versions................................................................................................ 11
1 INTRODUCTION
1.1 Outline
Mobile operators allow their users to roam on to the networks of other operators when those users are
away from their home country. This can sometimes cause a problem when a unit is located near a
country border. Here the Digi Transport’s wireless module may attach to a bordering foreign network
and incur expensive GPRS roaming charges.
This application note outlines:
(i) A way of ‘locking’ the Digi Transport to one mobile operator’s network.
(ii) Applying the resulting configuration change to other wireless Digi Transports.
1.2 Assumptions
This application note applies to;
Models shown: Digi Transport WR41
Other Compatible Models: All Digi Transport products.
Firmware versions: All firmware versions.
Configuration: This Application Note assumes the devices are set to their factory default configurations.
Most configuration commands are only shown if they differ from the factory default.
Users have access to the Digi Transport command line interface (via serial port or telnet) and also the
web interface.
1.3 Corrections
Requests for corrections or amendments to this application note are welcome and should be addressed
to: tech.support@digi.com
Requests for new application notes can be sent to the same address.
1.4 Version
1.0
1.1
2.0
2.1
2.2
Status
Published
Revision for new W-WAN usage in the
web GUI post release 5.036.
Updated and rebranded
Completed and published
Updated + Added Dual SIM Lock
Page | 3
2
CONFIGURATION
2.1 Deactivate the PPP interface
In order to perform a successful scan of available networks, it is necessary to have the PPP session
deactivated.
Navigate to: Configuration - Network > Interfaces > Advanced > PPP 1 > Advanced
Remove the tick from the option Enable "Always On" mode of this interface so the PPP interface
remains down whilst the scan takes place.
Click Apply
Navigate to: Management - Network Status > Interfaces > Advanced > PPP > PPP 1
Click on Drop Link
Page | 4
2.2 Scan for Networks
To detect all networks in range, navigate to: Management - Network Status > Interfaces > Mobile
Click the “Scan for networks” button.
After about 30 seconds the router will have scanned all the “visible” networks and populated these
networks into the ‘Networks Detected’ table.
Page | 5
Look for the network that requires locking to and click the
button. This action sends an
AT+COPS modem command to the cellular module (e.g. AT+COPS=1,2,23415), which will only allow
the module to attach to the mobile network with the specified ID number.
2.3 Re-Activate the PPP interface
The PPP deactivation performed in step 2.1 needs to be reversed.
Navigate to: Configuration - Network > Interfaces > Advanced > PPP 1 > Advanced
Insert a tick in the option Enable "Always On" mode of this interface so the PPP interface will
automatically try and connect.
Page | 6
Click Apply
2.4 Save the configuration
The AT+COPS command is not retained by the cellular module, so it is added to the current configuration
of the Digi Transport to be issued every time the router attempts a mobile network connection.
It is therefore now necessary to save the configuration.
Page | 7
2.5 Extract the configuration change and apply it to other wireless Digi
Transport routers.
To avoid the necessity of using the web GUI on every other Digi Transport that needs locking to the
same network, the AT command to lock the network can be extracted from the configuration.
To read the value of the AT command send the following command “modemcc 0 net_str ?”
modemcc 0 net_str ?
+COPS=1,2,23415
OK
Or enter the “config c show” command and look for “modemcc 0 net_str” in the output: config c show
---cut--modemcc 0 net_str "+COPS=1,2,23415"
---cut---
In order to lock other Digi Transports to the same network, simply send the following commands, but
replace the network numerical ID with the one seen in the previous steps output.
Note that only the last 5 numbers shown in red should be altered, the “1,2,” should not be altered:
modemcc 0 net_str “+COPS=1,2,23415”
config 0 save
Please wait...
Power Up Profile: 0
OK
reboot
Page | 8
3 APPLY CONFIGURATION CHANGES IN A DUAL SIM SETUP
When using a Dual SIM configuration (failover for instance) it is not recommended to use the net_str
parameter as it will configure the module to lock any SIM card to the specified provider.
To lock each individual SIM cards to a specific and possibly different providers use the following:
init_str2 for SIM 1
init_str2_2 for SIM 2
Using the previous example this would result in:
modemcc 0 init_str2 “+COPS=1,2,23415”
modemcc 0 init_str2_2 “+COPS=1,2,23410”
config 0 save
Please wait...
Power Up Profile: 0
OK
reboot
4 RESET THE MODULE BACK TO DEFAULT
To remove the provider lock set using net_str the following steps are required:
Reset net_str to 0
modemcc 0 net_str “+COPS=0”
config 0 save
Please wait...
Power Up Profile: 0
OK
reboot
Remove completely the locking by restoring the net_str parameter to factory default (using “!”)
modemcc 0 net_str !
config 0 save
Please wait...
Power Up Profile: 0
OK
reboot
Page | 9
5 TESTING
5.1 Checking that the Digi Transport is locked to the correct network
After the changes are complete and the Digi Transport has rebooted and some time has been allowed
for a connection to the GSM network to be established, navigate to –
Management - Network Status > Interfaces > Mobile
Check that the network registration shows the correct network number.
5.2 Checking that the correct command is sent to the module
Each wireless Digi Transport communicates with its wireless module via AT Style “modem” commands.
The AT+COPS command sets the operator selection. This can be captured in the analyser trace by
enabling the GPRS ASY source as seen below.
----08-11-2011 10:45:11.490
ASY 1 DCE to DTE:
------
F9 0F EF 25 41 54 2B 43 4F 50 53 3D 31 2C 32 2C
32 33 34 31 30 0D 4D F9
-------------08-11-2011 10:45:12.630
------
y.o%AT+COPS=1,2,
23415.My
Page | 10
ASY 1 DTE to DCE:
F9 0D EF 25 41 54 2B 43 4F 50 53 3D 31 2C 32 2C
32 33 34 31 30 0D 2C F9 F9 0D EF 0D 0D 0A 4F 4B
0D 0A 1A F9
----------
y.o%AT+COPS=1,2,
23415.,yy.o...OK
...y
6 HARDWARE AND FIRMWARE DETAILS
6.1 Digi Transport firmware versions
This is the firmware & hardware information from the unit used making this application note:
Digi TransPort WR41-HXA1-WE1-XX(WR41v2) Ser#:152211 HW Revision: 3203a
Software Build Ver5140. Oct 14 2011 16:56:23 MW
ARM Bios Ver 6.35 v41 399MHz B256-M256-F80-O140,0 MAC:00042d025293
Power Up Profile: 0
Async Driver
Revision: 1.19 Int clk
Wi-Fi
Revision: 2.0
Ethernet Driver
Revision: 1.11
Firewall
Revision: 1.0
EventEdit
Revision: 1.0
Timer Module
Revision: 1.1
(B)USBHOST
Revision: 1.0
L2TP
Revision: 1.10
PPTP
Revision: 1.00
TACPLUS
Revision: 1.00
MODBUS
Revision: 0.00
RealPort
Revision: 0.00
LAPB
Revision: 1.12
X25 Layer
Revision: 1.19
MACRO
Revision: 1.0
PAD
Revision: 1.4
X25 Switch
Revision: 1.7
V120
Revision: 1.16
TPAD Interface
Revision: 1.12
GPS
Revision: 1.0
SCRIBATSK
Revision: 1.0
BASTSK
Revision: 1.0
PYTHON
Revision: 1.0
ARM Sync Driver
Revision: 1.18
TCP (HASH mode)
Revision: 1.14
TCP Utils
Revision: 1.13
PPP
Revision: 1.19
WEB
Revision: 1.5
SMTP
Revision: 1.1
FTP Client
Revision: 1.5
FTP
Revision: 1.4
IKE
Revision: 1.0
PollANS
Revision: 1.2
PPPOE
Revision: 1.0
BRIDGE
Revision: 1.1
MODEM CC (Option 3G)
Revision: 1.4
Page | 11
FLASH Write
Command Interpreter
SSLCLI
OSPF
BGP
QOS
PWRCTRL
RADIUS Client
SSH Server
SCP
CERT
LowPrio
Tunnel
OVPN
QDL
WiMax
iDigi
OK
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
Revision:
1.2
1.38
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.2
1.2
1.0
1.0
2.0
Page | 12
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