Initial configuration of a 881G router Cellular interface
From Internetworkpro
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[edit] Intro
This small configuration provides an example of how to initialize and use the 3G interface in a 881G router.
There is a chapter in the config guide for this router, but it is very brief. I missed some explanations, and it took me a while to gather all the information and steps required to get the interface up and running. Please note that this article may also be helpful if you have a 3G HWIC.
Please note that some of the steps require arguments specific to your mobile service provider.
[edit] Overview
The 3G interface consists of an external modem (looks like a 3G PCI Express card) that you plug into the router. The card provides two logical components from a routers point of view.
First, there is a control channel used by the router to talk to the modem for device setup and call control. It appears as line x in IOS. You use a chat script and AT commands to talk to the modem.
Second, there is the data interface, Cellular X. After a connection has been established, all IP-related information and data flow goes via this interface. Its is designed like a dial on demand interface (BrI, for example), so you can put dial related stuff directly there, or use a Dialer interface that gets bound to the Cellular interface. The latter provides the advantage of an always-on setup through dialer persistent.
The modem itself acts as a ppp server to the router (there is no PPP between the modem and the 3G cloud). It attaches via a profile to the ISP (you have to define it first), and the APN of the ISP assigns you the information required for Internet access. The router will talk to the modem via ppp and the modem supplies the information received from the ISP (IP address, gateway, name servers etc.).
This design has some oddities. I discovered that unless the modem was able to connect successfully to the providers network, it will not do anything useful, but stall the ppp ipcp process between the router and the modem. You will see fake DNS server addresses (10.11.12.13 etc.) and the modem will not hand out/bridge the IP address that it would have received from the ISP when the connection was up.
This happens for example when the modem wasn't able to connect to a network you are allowed to use, or you have weak coverage (verify with sh cell 0 radio and sh cell 0 network).
[edit] Initialization
Place the SIM card into it, then insert the card in the router and power it on.
Before the interface is operational, you need to initialize it. These steps are only required once. All "cellular" commands must be done from privilege exec mode.
[edit] Create a Profile specific to your mobile ISP
- Insert the AP told by your ISP (mine: web.vodafone.de)
- Insert the authentication method (chap or pap) and the credentials, also supplied from your ISP
Please note that my ISP doesnt require authentication, but I had to specify chap user and pwd as dummy variables
Router# cellular 0 gsm profile create 1 web.vodafone.de chap mychapuser mychappass
[edit] Activate Modem
The second step is to activate the SIM/modem combo. Unfortunately, I cannot say much about this, because I used a SIM/modem that was already registered. I even dont know if it applies to gsm networks. Please refer to the command reference of "cellular cdma activate"
[edit] Unlock SIM
If you SIM card is not Unlocked (forces you to enter a PIN), you must unlock it. This will remove the requirement to enter the PIN for SIM usage (Card Holder Verification).
Router# cellular 0 gsm sim unlock <yourpin>
Verify with sh cell 0 security
Router# sh cell 0 security Modem Security Information ========================== Card Holder Verification (CHV1) = Disabled SIM Status = OK SIM User Operation Required = None Number of Retries remaining = 3
Please note that the PIN is not gone, its the request for the PIN you deactivate. If you want to take the SIM out and use it elsewhere later, you can lock the SIM again:
Router# cellular 0 gsm sim lock <yourpin>
[edit] Band selection
The config default, auto-band, should suffice. It prefers high speed networks like HSDPA and UMTS over slower services like GPRS. You can force the switchover to GPRS with
Router# cell 0 gsm band gsm-all-bands
this will prevent the modem from attaching to any 3G network service. It is also possible to use wcdma - this forces 3G only as far as I can tell.
[edit] Provider selection
The modem automatically tries to attach to the provider where the SIM card belongs to, although it is possible to attach to a specific network manually.
To do so, the modem must search through all available networks first:
Router# cell 0 gsm plmn search
This process can take a while; the router will log a message once the search is done. Now do a
Router# sh cell 0 network
The router will output all the networks found, together with their MCC (country) and MNC (network). Locate your provider and the associated MCC and MNC. Now bind the modem to this network manually:
Router# cell 0 gsm plmn select manual <MCC> <MNC>
sh cell 0 netw will tell you if the switchover was successful.
[edit] Configuration
After one-time initialization, you can prepare your IOS configuration
You need to define a chat script first, which is used for modem setup and call initialization. If you are familiar with IOS dial configurations, you feel at home. Please note that the last number in the dial string (1 in the example below) refers to the modem profile number you hopefully have defined earlier.
! The config: ! your chat script chat-script vodafone "" "ATDT*99*1#" TIMEOUT 30 "CONNECT" ! the bare interface config ! please note that I prefer to use Dialer interfaces ! you can also convert this to a non-Dialer int config, just leave the pool-member line and configure all dialer interface ! subcommands at the Cellular interface interface Cellular0 no ip address ip virtual-reassembly encapsulation ppp dialer in-band dialer pool-member 2 ! this denotes that this is indeed a modem-like interface (see line 3 below) async mode interactive ! interface Dialer2 ip address negotiated encapsulation ppp dialer pool 2 ! always-on dialer idle-timeout 0 ! use the chat script name here dialer string vodafone ! always-on dialer persistent dialer-group 2 ! i have to provide dummy chap credentials ppp chap hostname dummy ppp chap password 0 vdfsucks ppp ipcp dns request ! ip route 0.0.0.0 0.0.0.0 Dialer2 dialer-list 2 protocol ip permit ! ! this is the async line assigned to the 3G modem line 3 ! you need to specify your chat script here script dialer vodafone no exec !
During my tests, the router behaved well - I used the Cellular interface as a backup for tunnels.
Below you can find the show output of a sh cell 0 all for reference purposes:
Router#sh cellular 0 all
Hardware Information
====================
Modem Firmware Version = F1_2_3_15AP C:/WS/F
Modem Firmware built = 07/09/08
Hardware Version = 1.1
International Mobile Subscriber Identity (IMSI) = <obscured>
International Mobile Equipment Identity (IMEI) = <obscured>
Factory Serial Number (FSN) = <obscured>
Modem Status = Online
Current Modem Temperature = 29 deg C, State = Normal
Profile Information
====================
Profile 1 = ACTIVE*
--------
PDP Type = IPv4
PDP address = 77.25.33.47
Access Point Name (APN) = web.vodafone.de
Authentication = CHAP
Username: myuser, Password: mypass
* - Default profile
Data Connection Information
===========================
Data Transmitted = 560 bytes, Received = 820 bytes
Profile 1, Packet Session Status = ACTIVE
IP address = 77.25.33.47
Negotiated QOS Parameters:
Precedence = High Priority, Delay = Class 4
Reliability = Unack GTP, LLC, Ack RLC, Protected data
Peak = 128 kB/sec, Mean = 50000 kB/hr
Traffic Class = Background
Uplink Max = Subscribed, Guaranteed = Subscribed
Downlink Max = 3.6Mbps, Guaranteed = Subscribed
Max SDU size = 1500 bytes
SDU error ratio = 1E-4, BER = 1E-5
Profile 2, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 3, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 4, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 5, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 6, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 7, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 8, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 9, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 10, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 11, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 12, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 13, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 14, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 15, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Profile 16, Packet Session Status = INACTIVE
Inactivity Reason = Normal inactivate state
Network Information
===================
Current Service Status = Normal, Service Error = None
Current Service = Combined
Packet Service = HSDPA (Attached)
Packet Session Status = Active
Current Roaming Status = Home
Network Selection Mode = Automatic
Country = DEU, Network = Voda de
Mobile Country Code (MCC) = 262
Mobile Network Code (MNC) = 2
Location Area Code (LAC) = 983
Routing Area Code (RAC) = 1
Cell ID = 24016
Primary Scrambling Code = 229
PLMN Selection = Automatic
Registered PLMN = Vodafone.de , Abbreviated = Voda de
Service Provider =
Radio Information
=================
Current Band = WCDMA 2100, Channel Number = 10588
Current RSSI = -95 dBm
Band Selected = WCDMA I IMT 2000 (EU)
Number of nearby cells = 1
Cell 1
Primary Scrambling Code = 0xE5
RSCP = -93 dBm, ECIO = -0 dBm
Modem Security Information
==========================
Card Holder Verification (CHV1) = Disabled
SIM Status = OK
SIM User Operation Required = None
Number of Retries remaining = 3
References:
