Cisco 1941 Router Interface Troubleshooting

JP D
JP D used Ask the Experts™
on
Hi Experts,

I have a troubleshooting issue of which I require a little help with.

At our main office, I have a Cisco 1941 router as our primary router.  It performs our base routing between multiple internal networks, as well as NAT & Inspection for WAN traffic, and VPN terminations.  For our WAN, we have a wireless point to point connection with one static public IP.  The WAN connection on the 1941 (int ge0/0) physically connects directly to our ISP's wireless radio, of which i do not have access to any management interface.

For the most part, the 1941 router has been running great.  Im still trying to figure out the whole traffic monitoring/top n flows thing, but that is me, not the router.

Ive been noticing in the 1941 logs, that the WAN interface, int ge0/0 has been changing states from up to down, and then down to up.  The downtime averages 2 - 5 seconds every time.  The occurance rate is about 2-3 times a day (average), at random times between days but during the same hour for a given day.  This also only appears to occur during business days and during business hours.

I have checked and re-checked the physical connection from int ge0/0 to the ISP radio, and the power for the ISP radio.  I have also submitted a trouble ticket with our ISP, to see if there is a way I or they could access any kind of log on their radio, to see if it indicates any kind of source to this problem.  Our ISP sadly informed that their radio does not record such logs, however, they are now monitoring our connection for negotiation updates.

My question is, where do I go from here?  How do I determine the source of this problem? Is there a way to have the 1941 log any more information as to why the interface changes state?  What else could cause this?

I've attached my current running config for the 1941 router in question.  Any passwords and public IP's have been "xx"'ed out.

Any help would be greatly appreciated, as I am not sure what to do from here.
Sept-30-Langstaff-1941-config.txt
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Top Expert 2014
Commented:
What's in the log on the 1941?
Top Expert 2014

Commented:
Just looked at the config... there's nothing really wrong there, but I don't know why you're using ip helpers on the interfaces if the helpers are all in the same subnet?  That's not required so it might be worth removing those commands to keep your config tidy.
JP DI.T.

Author

Commented:
I have attached the output of the log.  One is the entire log, which includes some access-list logs I have, and the other file I have removed all the access-list log entries.  

Usernames and certain IP's have been replaced with x's

As to the ip helpers, I had them in there because I thought that it aided with routing between interfaces.  However, i am by no means an expert at Cisco, I've learnt mostly by example or my own studying.  So if they aren't required, then I would deffinetly remove them, to make things a little cleaner.
sept-30-1941-log.txt
sept-30-1941-log-state-changes-o.txt
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Top Expert 2014

Commented:
To be honest, it doesn't look like there's anything wrong from the 1941 side.  If it was doing anything to cause the drops I'd expect to see things which would go toward explaining the drops in the log.
JP DI.T.

Author

Commented:
That is kind of what my gut was telling me.  I am thinking that I am going to enforce that our ISP replaces the radio, and in the mean time I'll just keep my eye on the connectivity state and make a mad dash for the server room when I see it go down (so I can physically see the activity state on the ISP radio and the 1941).

I am going to leave this open for a couple of days, while I wait to hear back from our ISP, in case they find something different that may add to the mystery.

Thanks!
JP DI.T.
Commented:
I just realized that I had this question still open.

To close, it turned out that the isp did have to apply some firmware updates to their radio.  That solved the problem.

I wish that service providers and manufacturers in this industry would stop trying to "pass the buck"! LOL

Even though there wasn't really any additional direction to go in, and the problem was with the ISP and not our hardware, I am still going to award craigbeck with partial points for the assistance.

Thank you!
JP DI.T.

Author

Commented:
Sorry.....i wasn't sure how to reduce the points.
JP DI.T.

Author

Commented:
Please see my last post.

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