Hi Yiu, Thanks for your message. In this sense, any methods except fragmentation and assembly are optimization and up to implementation. But it is not a bad idea to introduce some suggestion for implementation in the draft, so keeping the text for TSS option and others is also reasonable.
Best regards, Zhen On Mon, Aug 17, 2009 at 10:29 AM, Lee, Yiu<[email protected]> wrote: > This is *not* recommended because it will require the v4 host to know about > ds-lite. This won’t work for home router model where the hosts behind the > ds-lite home router won’t know about ds-lite. Besides, the v4 packet isn’t > over-sized, it is the v6 encapsulation caused the oversized issue. So the > tunnel points are responsible to handle the fragmentation. > > In the hosted model, the host is aware of ds-lite. The host can in fact > reduce the v4 packet size to avoid fragmentation. This optimization is up to > the implementation rather than mandated in the draft. > > > On 8/16/09 9:42 PM, "Zhen Cao" <[email protected]> wrote: > > Hi Yiu, > > Thanks for your clarification. > > Do you consider another method that let the IPv4 packet inside the > tunnel do fragmentation at a lower MTU (link-MTU - 40), so that the > packet won't exceed the MTU after IPv6 header encapsulation. Then > there is no need of IPv6 encapsulation and assembly. I believe this > is more cost efficient than IPv6 fragmentation and assembly. > > Thanks and regards, > Zhen > > On Mon, Aug 17, 2009 at 12:34 AM, Lee, Yiu<[email protected]> wrote: >> Hi Zhen, >> >> In general, the Tunnel-Entry Point and Tunnel-Exist Point should fragment >> and reassemble the oversize datagram. This mechanism is transport protocol >> agnostic and work for both UDP and TCP. >> >> For TCP, we “could” potentially avoid fragmentation by modify MSS option. >> However, we were required by the Chairs to remove this optimization from >> the >> draft in next update. >> >> Thanks, >> Yiu >> >> >> On 8/16/09 3:56 AM, "Zhen Cao" <[email protected]> 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. >> >> Thanks and regards, >> Zhen >> _______________________________________________ >> Softwires mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/softwires >> >> > > > _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
