err-disable state Link shuts down

Unanswered Question
Feb 16th, 2010


Our ISP at a remote site suffered an outage. When the link came backup it brought down our core link. The ISP responsible for the remote site forgot to configure l2pt protocols which resulted in the core link recieveing encapsulated packets on their link which cause it to shut. The remote site ISP have now resolved this problem, but now the core link receives more than 256 mac addresses which shuts the link. We dont know where the problem is and both ISP are saying it is not their problem. The mac addresses are in our network and legitmit, but why all of the sudden is this happening. We have not added any new devices to our network. we have a Layer 2 design would like some pointers if possible.

I have this problem too.
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tdistlists Tue, 02/16/2010 - 13:21


What is the exact err-disable message that gets logged? This should indicate the reason the port went into err-disable. It can help confirm or deny your ISP's claims that it fixed everything on their end.

I don't think err-disable recovery will benefit you if the port is going to constatnly go into err-disable.

Let us know.

Network_Team_2 Fri, 03/12/2010 - 07:39

The Mac address are from my Lan to the datacenter. These are legitement Mac addresses. When searching on the switch we have 1000 mac address, but our isp says we are capped at 256. I have stressed it has been like this for years and nothing has changed. They have said port security has always been in place. Layer 2 works in this fashion and works well for us apart from this problem. Dont know how to fix this issue as we have not changed anything in our network and nor has our isp.

Any ideas would be appricated


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