MTU mismatch on one link

Andrew K. andrew at
Fri Aug 31 14:42:28 UTC 2012

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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