nanog mailing list archives

Re: MTU mismatch on one link


From: "Andrew K." <andrew () vianet ca>
Date: Fri, 31 Aug 2012 10:42:28 -0400

Besides routing protocol convergence is there any service issues with running mismatched MTU? Assuming the packet flow does not exceed the smallest MTU value.


On 8/31/2012 10:28 AM, Dan White wrote:
On 08/31/12 09:30 -0400, Tom Taylor wrote:
Has anyone run into a situation where the MTU at one end of a link was configured differently from the MTU at the other end? How did you catch it?

In general, do you see any need for a debugging tool to be standardized to find such mismatches?

Performing a ping with a large packet size '-s', and/or with packet
fragmentation turned off '-M do' have been our primary tools for finding
MTU (layer 2 and layer 3) mismatches.



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