Hi I support the proposal of a simple correction to fragmentation:
* new dispatch codes for generic datagrams - fragments may carry compressed or uncompressed; it does not matter. * reject fragments of old type in the transition period * strongly deprecate old dispatch code by 2011 Cheers, Anders > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Daniel Gavelle > Sent: Thursday, February 25, 2010 15:18 > To: [email protected] > Subject: Re: [6lowpan] WGLC for 6lowpan HC draft > > On the subject of forward and backward compatibility, I think > the dispatch codes for fragmentation (FRAG1, FRAGN) should be > changed to values that are currently reserved if we move to > sending the datagram_size and datagram_offset as compressed > and uncompressed values. > This will mean that during the transition period, it will > be much easier to sort out interoperability problems where > some nodes use compressed values and some nodes are running > older code using uncompressed values. > > I don't think the new nodes should support both compressed > and uncompressed offsets / sizes but should simply reject > fragments that don't have the dispatch codes they are expecting. > > The existing dispatch codes would not be lost forever as they > could be strongly deprecated and then recycled in a future RFC. > > Daniel. > > > > Jonathan Hui wrote: > > > > It would be helpful to know what people's expectations are > relative to > > what this specific draft should include relative to an acceptable > > timeline of getting a document out. Few comments: > > > > - The WG currently does not have a proposal for TCP header > > compression, let alone one that we have built some consensus around. > > - The RPL protocol mechanisms and headers are still in flux. It is > > difficult to propose a concrete way of compressing them without > > knowing what they will look like. For example, within > ROLL, we will > > be proposing ways to "pack" lists of addresses such that common > > prefixes are only carried once within the datagram. > > - The general 6lowpan-hc format is generic enough to be > used on top of > > other fragmentation mechanisms and/or frame sizes. Do we > really want > > to limit its capabilities to a particular fragmentation and > frame size? > > > > There always seems to be a tension between splitting functionality > > across different drafts vs. delaying the current draft to > "sneak" in > > new functionality. I'm all for sneaking in fixes to RFC > 4944 (i.e. > > simple changes to fragmentation) or additional functionality for > > expediency if we can realize that expedience. But waiting until we > > design a TCP header compression mechanism that we can build > consensus > > around probably isn't the best approach, in my opinion, and > should be > > left to a separate draft. > > > > So what do others think? > > > > (I will start a new thread specifically on fragmentation + > > forward-compatibility so that we drive towards closure on that > > specific issue). > > > > -- > > Jonathan Hui > > > > On Feb 24, 2010, at 10:55 PM, Robert Cragie wrote: > > > >> Hi Geoff, > >> > >> I concur with Joseph's statements and thus do not support > forwarding > >> the draft to IESG yet. > >> > >> Robert > >> Robert Cragie (Pacific Gas & Electric) > >> > >> Gridmerge Ltd. > >> 89 Greenfield Crescent, > >> Wakefield, WF4 4WA, UK > >> +44 (0) 1924 910888 > >> http://www.gridmerge.com > >> > >> > >> > >> Reddy, Joseph wrote: > >>> > >>> > >>> Hi Geoff, > >>> > >>> I do not support forwarding this doc to IESG yet. I would > like the > >>> following issues addressed > >>> > >>> ** Investigate possible TCP header compression scheme > >>> > >>> ** Explain strategy for compressing RPL headers ( I > understand this > >>> could be done in the ROLL group, but I have not seen a definite > >>> statement either way ) > >>> > >>> ** Resolve the "forward compatability" issue ( ideally, while > >>> maintaining backwards-comptability ) > >>> > >>> > >>> -Regards, Joseph > >>> > >>> > >>> > >>> > -------------------------------------------------------------------- > >>> -- > >>> > >>> Message: 1 > >>> Date: Sat, 13 Feb 2010 00:56:31 -0700 > >>> From: Geoff Mulligan <[email protected]> > >>> Subject: [6lowpan] WGLC for 6lowpan HC draft > >>> To: 6lowpan <[email protected]> > >>> Message-ID: <1266047791.3643.48.ca...@dellx1> > >>> Content-Type: text/plain > >>> > >>> Folks, > >>> I realized that I have made a huge slip-up. The HC draft has > >>> languished for the past few months. > >>> At the meeting in Hiroshima we said that we would last call this > >>> draft, but I failed to send out the actual last call. So... > >>> > >>> This note formally starts the WG Last Call for comments on > >>> draft-ietf-6lowpan-hc-06, "Compression Format for IPv6 > Datagrams in > >>> 6LoWPAN Networks". > >>> > >>> The document can be found at: > >>> http://www.ietf.org/id/draft-ietf-6lowpan-hc-06.txt > >>> > >>> The document is intended to be submitted by this Working Group to > >>> the IESG for publication as a Standards Track document. > >>> > >>> Please review the document carefully (one last time), and > send your > >>> comments to the 6lowpan list. Please also indicate in > your response > >>> whether or not you think this document is ready to go to the IESG. > >>> > >>> Because of my gaffe this Last Call will end Wednesday February 24 > >>> 2010 at 2359 UTC. > >>> > >>> Thanks, > >>> Geoff > >>> > >>> > >>> > >>> > >>> > >>> ************************************** > >>> _______________________________________________ > >>> 6lowpan mailing list > >>> [email protected] > >>> https://www.ietf.org/mailman/listinfo/6lowpan > >>> > >>> > >> _______________________________________________ > >> 6lowpan mailing list > >> [email protected] > >> https://www.ietf.org/mailman/listinfo/6lowpan > > > > _______________________________________________ > > 6lowpan mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/6lowpan > > > > -- > __________________________________________________ > Daniel Gavelle, Software Engineer > Tel: +44 114 281 2655 > Fax: +44 114 281 2951 > Jennic Ltd, Furnival Street, Sheffield, S1 4QT, UK Comp Reg > No: 3191371 Registered In England http://www.jennic.com > __________________________________________________ > _______________________________________________ > 6lowpan mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6lowpan > _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
