Just to add to Vishwas' reply, Pekka's draft can be summarized (for the purposes of this discussion) as follows:
1) For any tunneling technology, either the tunnel head-end has to be prepared to correctly respond to path MTU discovery as if the tunnel is itself a link, or the tunnel head-end and tail-end are going to have to fragment and re-assemble packets. This applies recursively. 2) For a number of well-known reasons, it is not desirable to do IP packet fragmentation inside the network (it is suboptimal to do it anywhere, but inside the network is worse than anywhere else). -- Eric --> -----Original Message----- --> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] --> On Behalf Of Vishwas Manral --> Sent: Sunday, November 20, 2005 11:30 PM --> To: Syed Obaid Amin; [email protected] --> Subject: RE: PMTU dicovery --> --> Hi, --> --> A few more minor things to add: - --> --> 1. If the packet is to be sent over the tunnel and needs to --> be fragmented we could send the Type=2, Code=0 to the source. --> 2. One of the documents I found was --> http://www.ietf.org/internet-drafts/draft-savola-mtufrag-net --> work-tunneling-05.txt . You could look at it. --> --> Thanks, --> Vishwas --> ________________________________________ --> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] --> On Behalf Of Vishwas Manral --> Sent: Monday, November 21, 2005 9:32 AM --> To: Syed Obaid Amin; [email protected] --> Subject: RE: PMTU dicovery --> --> Hi Obaid, --> --> I think we do not require sending the PATH MTU to the --> original source at all. The original source when doing a --> Path MTU would use the tunnel and the PMTU would correctly --> work (the tunnel would be another link in the path). --> --> Thanks, --> Vishwas --> ________________________________________ --> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] --> On Behalf Of Syed Obaid Amin --> Sent: Sunday, November 20, 2005 4:38 PM --> To: [email protected] --> Subject: PMTU dicovery --> --> Hi --> --> Can intermediate routers do Path MTU discovery or the --> originator of packet will do it ONLY? --> for e.g. In case of VPN; can router for encapsulation do --> PMTU and send the "PMTU - (size of Data used for --> encaspulation)" to Source so encapsulation wont fragment the packet? --> --> Thanks --> --> Obaid Amin --> --> --> -------------------------------------------------------------------- --> IETF IPv6 working group mailing list --> [email protected] --> Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --> -------------------------------------------------------------------- --> -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
