Subject: RE: End System PMTUD behavior question

From: "Dunn, Jeffrey H." <[email-masked]>
Date: Tue, 17 Feb 2009 14:54:50 -0500

Tom,

We are currently looking at testing with DNS. Do you have any plans to test other applications?

Best Regards, 
  
Jeffrey Dunn 
Info Systems Eng., Lead 
MITRE Corporation.
(301) 448-6965 (mobile)

-----Original Message-----
From: Thomas Peterson [mailto:[email-masked]] 
Sent: Friday, January 23, 2009 11:51 AM
To: Dunn, Jeffrey H.
Cc: Rémi Denis-Courmont; [email-masked]; Huang, Frank; Sherman, Kurt T.; Liou, Chern; [email-masked]; [email-masked]; [email-masked]; Grayeli, Parisa
Subject: Re: End System PMTUD behavior question

Hi Jeffrey,

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:[email-masked]]
> Sent: Thursday, January 22, 2009 3:38 PM
> To: Dunn, Jeffrey H.
> Cc: Rémi Denis-Courmont; [email-masked]; Huang, Frank; Sherman, Kurt  
> T.; Liou, Chern; [email-masked]; [email-masked]; [email-masked] 
> ; 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
>