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New Member

Cisco 7606 intermittent interface failures

Hi Team,

   I have got a client who purchased a cisco 7600 router. These 7600 were deployed as WAN Edge devices and configured with GRE tunnels to their numerous branch offices. They have complained from time to time that different interfaces on the WS-X6748-GE-TX line card just stop responding i.e

even if you connect a laptop directly to it and ping that interface, the router interface will not respond. Btw there are not access lists or any configs that drop traffic on that interfaces. interestingly after a while the interfaces start responding again.

Its quite an usual behaviour, checks were done on the CPU usage at the time of these anormalies and it was less than 10%.

Diagnostic tests have been run on the appliance and its line cards and they proved fine.

According to my client, he says while the issue persisted , the configuration of the unstable box was moved to another stable box which after a while became unstable.

After a review on the running configs , i notice that some tunnels are sourced from physical interfaces of the router , though a good number are sourced of unique loopbacks as recommended by Cisco.

Could the Tunnel config be the cause of this instability, Has anyone experienced anything of this nature before and how did you get around it.

Please see IOS version below.


sh ver


sh ver
Cisco IOS Software, c7600s72033_rp Software (c7600s72033_rp-ADVENTERPRISEK9-M),
Version 12.2(33)SRC3, RELEASE SOFTWARE (fc2)
Technical Support:
Copyright (c) 1986-2008 by Cisco Systems, Inc.
Compiled Tue 16-Dec-08 07:53 by prod_rel_team

ROM: System Bootstrap, Version 12.2(17r)SX5, RELEASE SOFTWARE (fc1)

Uptime for this control processor is 1 day, 5 minutes
System returned to ROM by reload at 10:01:42 PDT Thu Oct 30 2008 (SP by reload)
System image file is "sup-bootflash:c7600s72033-adventerprisek9-mz.122-33.SRC3.b
Last reload type: Normal Reload
Last reload reason: Reason unspecified

VIP Super Bronze

Re: Cisco 7606 intermittent interface failures


I don't think that is a GRE tunnel issue since when you connect a laptop to a port and it does not respond. Looking at your IOS reversion, (SRC) it is a little old and you may want to look into running a newer version to see if it helps.   I checked the CCO, and there are a few versions i.e. SRD, SRE, SXF and now even a 15 available for download.

Does this happen in multiple chassis with 6748 line card or it is only in one chassis?



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