Re: End System PMTUD behavior question

Here is a link to the list of all of the different hosts that we have  
performed this testing on:

http://www.iol.unh.edu/services/testing/ipv6/equipment.php

Currently we use the ping application to test PTMUD, however, we would  
be interested in performing addition tests  using various applications.

Thanks,
Tom

On Jan 23, 2009, at 9:54 AM, Dunn, Jeffrey H. wrote:

> Tom,
>
> Many thanks for the information. Could you tell me the OS variants  
> on the hosts and router? Also, do you have any tests involving  
> applications?  I will send you an off-line e-mail to discuss  
> possible additional testing.
>
> Best Regards,
>
> Jeffrey Dunn
> Info Systems Eng., Lead
> MITRE Corporation.
> (301) 448-6965 (mobile)
>
>
> -----Original Message-----
> From: Thomas Peterson [mailto:thomasp@iol.unh.edu]
> Sent: Thursday, January 22, 2009 3:38 PM
> To: Dunn, Jeffrey H.
> Cc: Rémi Denis-Courmont; ipv6@ietf.org; Huang, Frank; Sherman, Kurt  
> T.; Liou, Chern; steve_eiserman@uscourts.gov; ipv6-bounces@ietf.org; v6ops@ops.ietf.org 
> ; Grayeli, Parisa
> Subject: Re: End System PMTUD behavior question
>
> Hi Jeffrey,
>
> I have attached a picture which shows one of the topologies we use for
> our PMTUD tests.
>
> In this test case we transmit an Echo Request from REF-Host2 to TAR-
> Host1 with a packet size of 1500 bytes. REF-Host2 fragments the Echo
> Request it transmits. TAR-Host1 replies to this Echo Request with an
> Echo Reply to REF-Host2 with a size of 1500 bytes that is not
> fragmented. TAR-Router1 sends a Packet Too Big message in response as
> this Echo Reply is too large to forward onto Network 2.
>
> In all of the cases we have seen TAR-Host1 does fragment future Echo
> Replies to REF-Host2, however, it does not retransmit any Echo Replies
> for Echo Requests received prior to receiving the Packet Too Big
> message from TAR-Router1.
>
> Additionally from the tests we have performed in our lab if TAR-Host1
> were to send an Echo Request with a packet size of 1500 bytes TAR-
> Router1 would send a Packet Too Big message in response. In all cases
> we have seen TAR-Host1 would not re-transmit this Echo Request and
> this would be counted as packet loss in the ping command results.
>
> If this does not ideally match your test scenario we'd be happy to
> work together off-line to replicate your scenario.
>
> Thanks,
> Tom
>

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