10-18-2010 03:33 PM - edited 03-04-2019 10:09 AM
Hello. Our service provider 'accidentily' changed their LAN facing interface to auto-negotiate, but our switch is hard set to 100 full duplex. We didn't notice at first, except for a couple of missed pings when the change was made. Ou Internet access went down 4 hours after they made they change, and they couldn't figure out why. They rebooted the CE router, and everything was fine. This happened over 8 hours increments all weekend until they noticed the problem. They admitted that the when the WIC card see's a duplex mismatch for an extended period of time, it can become unresponsive. This actually caused all 4 ports on the WIC to become unresponsive.
Has anyone ever heard of this? It's a 3825 with a 4 port ethernet WIC. Traffic out the built-in port was working fine while the WIC ports were dead.
Solved! Go to Solution.
10-19-2010 05:03 AM
We would need a little more information in order to fully answer this question. Which WIC and IOS version are being used? Do you have a show interface from the WIC when the "hang" is occuring? It's possible that you are running into CSCsi03915 which reports a problem with the hiwc-4esw. On that card, if a duplex mismatch is present the receive ring can become hung. The only way to clear the problem is to reboot the router.
Tim
10-19-2010 12:27 AM
Hello,
That 4 hours timer looks like the default ARP 4 hours timeout.
- Is the default ARP timer the one you are using?
- Do you have default route towards the CE using the exit-interface instead of a next-hop? ip route 0.0.0.0 0.0.0.0
Did you try setting your switchport to AUTO/AUTO to see if that solved the problem?
Regards.
10-19-2010 05:03 AM
We would need a little more information in order to fully answer this question. Which WIC and IOS version are being used? Do you have a show interface from the WIC when the "hang" is occuring? It's possible that you are running into CSCsi03915 which reports a problem with the hiwc-4esw. On that card, if a duplex mismatch is present the receive ring can become hung. The only way to clear the problem is to reboot the router.
Tim
10-19-2010 05:48 AM
Thanks Tim, that really sounds like it could be the problem. Even though the article says 'several weeks', we were only several hours. I guess it depends on how much traffic the intefrcae see's. Thanks again.
10-19-2010 05:08 AM
The problem went away when the vendor changed their interface back to 100 full duplex, like it should have been. The only symptom I've ever experienced during a duplex mismatch is poor performance. This time, after between 4-6 hours, the WIC card simply stopped passing traffic. The WIC is an HWIC-4ESW, but I'm not sure what the IOS is, since we don't have access to it.
10-19-2010 05:46 AM
My guess is it was CSCsi03915, which effects the esw hwics. The corrective action is to ensure there is no duplex mistmatch.
Tim
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