[155943] in North American Network Operators' Group
Re: MTU mismatch on one link
daemon@ATHENA.MIT.EDU (Andrew K.)
Fri Aug 31 10:43:08 2012
Date: Fri, 31 Aug 2012 10:42:28 -0400
From: "Andrew K." <andrew@vianet.ca>
To: nanog@nanog.org
In-Reply-To: <20120831142844.GA4818@dan.olp.net>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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.
>
