Re: [Softwires] MTU problem in DS-lite

["Durand, Alain" <Alain_Durand at cable.comcast.com>]

Title: Re: [Softwires] MTU problem in DS-lite

On 8/16/09 3:56 AM, "Zhen Cao" <caozhenpku at gmail.com> wrote:

> Hi Alain and All,
>
> I have a question on MTU issue in ipv4-in-ipv6 softwire. I notice
> Sec.10.2 of DS-Lite draft has discussed the MTU problem. The draft
> introduces one possible way of using TCP MSS option to avoid IP layer
> fragmentation and reassembly. It is a good idea but how about the case
> for UDP sockets? I suppose there should be a general way to handle the
> MTU issue? Thanks for any explanation.


Zhen,

The ‘generic’ way is as described in the draft & RFC2473, ie encapsulate the IPv4 datagram into an IPv6 datagram that happens to be too big to be transmitted and the fragment the IPv6 datagram. Reverse the procedure at the end of the tunnel.

   - Alain.