Link flap issues

Unanswered Question
Oct 16th, 2007

I have a few servers that after a reboot link flap. I have the port set to recover at the default time interval. However this causes a problem with some of the servers. Ex- One of the servers is a SQL server. The services start up on this server before network connectivity is established and SQL doesn't function properly. We end up rebooting the server until it doesn't flap. It's a fiber connection to the switch (I have no idea why it's fiber) and I can't adjust the duplex speed on the card. Any suggestions? Can I disable this error detection without causing other problems? Thanks.

I have this problem too.
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saro Wed, 10/17/2007 - 07:13


I assume you are talking about errordisable and errordisable recovery. Which of the errordisable mechanisms is being triggered? UDLD I suspect? Let me know and I have some ideas for you.


saro Fri, 10/19/2007 - 14:06

Hi Mike,

The reason link-flapping is generally enabled in as an errordisable option is that link flaps, generally, indicate some network device is not behaving properly. In your case, that doesn't seem to be the case. It would be interesting to see why it's flapping, but that said, to make your network function better you can disable that errordisable function for linkflap on that switch without really effecting anything else. It will expose you to a link flapping causing other network problems, but that may be a more acceptable risk considering the issue at hand. At the end of the day, you'd need to figure out why that interface is flapping upon insertion.


songshiyou Thu, 11/22/2007 - 04:32

in udld protocol ,what is contain information of echo packet in TLV.


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