LTE on ISR C1113 router

[Ron Reid]

Hi All,

With the 89x routers going end of sale I am trying to setup my 1st ISR-C1113 router using 4G LTE to for internet connectivity. I can only get the cellular interface to to apply for an IP address if I ping 8.8.8.8. Until then the cellular profile remains inactive.

Here are my settings:

interface Cellular0/2/0
ip address negotiated
ip nat outside
dialer in-band
dialer idle-timeout 0
dialer-group 1
pulse-time 1

controller Cellular 0/2/0
lte sim data-profile 1 attach-profile 1 slot 0
lte modem link-recovery rssi onset-threshold -110
lte modem link-recovery monitor-timer 20
lte modem link-recovery wait-timer 10
lte modem link-recovery debounce-count 6

I have set the APN with the following command:

cellular 0/2/0 lte profile create 1 wap.my-isp.co.uk

After powering up and waiting for the router to recognise the SIM it won't bring the profile into an active state. "show cellular 0/2/0 all" gives the following result:

[Ron Reid]

Under "Restrictions for Configuring Cisco 4G LTE Advanced" in the c1100 LTE documentation I found the following line:

"Currently, cellular networks support only user initiated bearer establishment"

I'm still waiting for a response from Cisco but this seems to confirm my suspicion.

This is a backward step over the 89x LTE routers for this model. VPN like DMVPN is a common way to connect to corporate networks and it means you can't use these routers for a quick deploy for offices that don't yet have wired connectivity, or who want to use LTE as a backup connection. This is a serious drawback, and with the 89x routers having reached EOS, it means there's no replacement.

[Georg Pauwen]

Hello,

I guess a workaround would be to configure a simple SLA that keeps the link up permanently:

ip sla 1

icmp-echo 8.8.8.8 source-interface Cellular0/2/0

!

ip sla schedule 1 life forever start-time now

[Ron Reid]

sla looks promising as a workaround. I'll give that a go tomorrow when I have access to the router again.

[Georg Pauwen]

Sure, let us know how that goes.

[Ron Reid · Accepted solution]

I found a solution!

The ip sla never worked and I don't know why.

I had the following config:

ip sla 1
icmp-echo 8.8.8.8 source-interface Cellular0/2/0
frequency 5
ip sla schedule 1 life forever start-time now


Router#sh ip sla statistics
IPSLAs Latest Operation Statistics

IPSLA operation id: 1
Latest RTT: NoConnection/Busy/Timeout
Latest operation start time: 08:39:23 UTC Tue Nov 19 2019
Latest operation return code: Timeout
Number of successes: 0
Number of failures: 14
Operation time to live: Forever

The ip sla won't bring up the interface but a ping from the CLI will. Don't ask me why!

I found the solution in the LTE deployment guide:

https://www.cisco.com/c/dam/en/us/td/docs/routers/access/interfaces/software/deployment/guide/c07-731484-00-ngewan.pdf

There is a section for DMVPN tunnels. There needs to be a watch list on the interface:

interface Cellular0/2/0
ip address negotiated
...
dialer watch-group 1
!

dialer watch-list 1 ip 8.8.8.8 0.0.0.0
dialer watch-list 1 delay route-check initial 60
dialer watch-list 1 delay connect 1

The watch list works! It brings up the interface.

[Georg Pauwen]

Hello,

good one. Glad you found this to work...

Thinking about the IP SLA, the problem might be that the source interface is the cellular, and that is down, so maybe that cannot be the source. You might want to try this:

interface Loopback 100

ip address 100.100.100.100 255.255.255.255

!

ip sla 1
icmp-echo 8.8.8.8 source-interface Loopback 100
frequency 5

!
ip sla schedule 1 life forever start-time now

!

ip route 8.8.8.8 255.255.255.255 Cellular0/2/0

 

[ysellal13]

The Watch List Worked for me also. It brings up the Cellular interface!!!

Thank you Ron for this solution