on 10-07-2011 01:03 AM - edited on 03-25-2019 02:26 PM by ciscomoderator
Purpose:
This is a short document to explain about the main configuration changes while migrating from the old 887G
router to the new C887VAG+7-K9.
Summary:
The new C887VAG+7 includes a MC8705 HSPA+ modem which requires some slight configuration changes
compared to all previous 3G modems. Symptoms:
1. It is not possible to configure ¨PPP encapsulation and the following error message is seen.
Router(config)#int cellular 0
Router(config-if)#encapsulation ppp
Cellular0: Only SLIP encapsulation supported
2. It is not possible to connect and get an IP address even when slip encapsulation is configured
Enabling "debug chat" you can see the following messages:
Sep 19 15:42:40: CHAT3: Chat script gsm started Sep 19 15:42:40: CHAT3: Sending string: ATDT*98*1# Sep 19 15:42:40: CHAT3: Expecting string: CONNECT Sep 19 15:43:40: CHAT3: Timeout expecting: CONNECT Sep 19 15:43:40: CHAT3: Chat script gsm finished, status = Connection
timed out; remote host not responding
Solutions:
1. The HSPA+R7 modem requires SLIP encapsulation.
In the new software architecture, on the data link between IOS and the modem itself, it supports IP data frames.
There are no SLIP frames but slip mode config is for legacy reasons only.
This is documented here:
2. You also need a different chat script for this new modem.
chat-script gsm "" "AT!SCACT=1,1" TIMEOUT 60 "OK"
This is documented here:
Verification:
1. To check internet connectivity, you can ping the famous DNS Server which is always up and easy to remember
ping 4.2.2.2
2. Check that the profile is active and that you got an ip address from the mobile wireless provider. The interface
should be up/up.
show cellular 0 all
show ip int brief
show ip route
Contact the TAC:
If there is still some trouble to get a valid IP Address and connectivity through the 3G link, please raise a
new TAC case.
First make sure to enable millisecond (msec) timestamps using the service timestamps command:
Router(config)#service timestamps debug datetime msec
Router(config)#service timestamps log datetime msec
Then disable console logging and increase the logging buffer size to 4MB via
Router(config)#no logging console
Router(config)#logging buffer 4000000
Then enable the following debugs:
debug chat
debug dialer
and generate some traffic to trigger the dialer/cellular connection. If you don't see any debug, check to see
if you have a valid route through either the cellular 0 interface or corresponding dialer interface.
You can also try to reset the modem via:
Router(config)#service internal
Router(config)#exit
Router#test cellular 0 modem-power-cycle
Collect the following information
show tech (includes running-configuration)
show cellular 0 all
show interface cellular 0
show controller cellular 0
show ip int brief
show ip route
show logs (to get the debugs output)
The collected output (show commands and debug) should provide enough information to determine what is
wrong with your configuration.
Hello, I followed the docummentation above, but I need ppp encapsulation and send an unsername/password through the cellular0 interface.
This is exactly my Hw
Cisco 887VAG2 (MPC8300) processor (revision 1.0)
Thank you in advance
Hi Pablo,
The HSPA+R7 modem requires SLIP encapsulation between IOS and the modem firmware. The PPP credentials to be used during the PDP Context establishment need to be configured while provisionning the modem via the 'cellular <> gsm profile create' CLI command.
The following example shows output for this command:
router# cellular 0/0/0 gsm profile create 3 apn.com chap gsm gsmPassword
Profile 3 will be created with the following values:
APN = apn.com
Authentication = CHAP
Username = gsm
Password = gsmPassword
Are you sure? [confirm]y
Profile 3 written to modem
More information on
This is not related to the encapsulation used for the communication between IOS and the modem firmware.
Cheers,
Jean
Hi ,
I am using EHWIC HSPA+R7 module for Cisco 2901 but encountered the following error after configuration.
Can u advise and help?
Thanks
Paul Au
Nov 17 04:54:36.243: %LINK-3-BADENCAP: Interface Cellular0/0/0, Bad encapsulation code (30) -Process= "Exec", ipl= 0, pid= 3
-Traceback= 22B7F5E8z 225F6398z 22B5DE9Cz 22B5F028z 22B5F338z 22B5F3A4z 22EC67F4
z 22BA1EB8z 22BA29A4z 22BA36C0z 22BA3B00z 22BA7420z 2248D858z 2248D9FCz 22B332D8
z 2248C668z
Hi Paul,
This is a software defect, very likely this one which is not yet fixed :
Traceback seen when trying to ping after FW upgrade: EHWIC-A, c3945e
Internally found moderate (Sev3) bug: A-Assigned
You should raise a TAC service request to confirm
Cheers,
Jean
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