Force Cellular interface up

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Jul 2nd, 2010
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We have a Cisco 1841 with a cdma cellular card. The router is configured to establish an IPSec tunnel back to our corporate office. This IPSec tunnel only allows GRE from the celluar interface to an Internal router at our corporate office. We then have a tunnel interface configured on this 1841 which establishes a GRE tunnel back to this internal router.

The above works great when the cellular interface is up, but when it goes down standard traffic doesn't bring it back up. Is there anyway to force this cellular interface to stay up no matter what? We have a true unlimited plan from Sprint so we're not worried about excessive data or usage.


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Ahmed Shaheen Tue, 07/06/2010 - 23:37
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hello denny,

did you try to add a idle timeout 0 on the interface?

dennylester Wed, 07/07/2010 - 09:07
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Thank you for the suggestion. I didn't try the idle timer since my problem wasn't keeping the interface up as much as it was forcing a connect or reconnect. If I had shipped this router to a remote site it wouldn't come up until something routed traffic over the cellular interface.

I was able to have the router initiate traffic over this interface by configuring an SLA monitor to send a ping via the cellular interface.


Ahmed Shaheen Wed, 07/07/2010 - 20:47
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hey denny,

how is the router configured?

are you using nat statments?

dennylester Wed, 07/07/2010 - 22:05
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No I'm not using NAT since this is strictly used for connectivity back to the Corporate office. I'm sorry I didn't clarify in the last message, I was able to get the cellular interface to come up using an SLA monitor, so I am okay. I will see about marking this post as resolved.

Thank you,



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