Re: [6lowpan] WGLC for 6lowpan HC draft

[Dario Tedeschi]

Hi Geoff  I have a few questions regarding Extended Header Compression: How does one compress the "type-specific data" field in a IPv6 Routing Header? It's a variable-length field with no predefined format given in RFC 2460. To compress this field effectively, a 6LoWPAN encoder would need to know the formats of all the currently used Routing Types. Is the reserved field in the Fragment Header elided or sent inline as 0? If Ext Header [B] follows compressed header [A] and the options in [B] turn out to be longer than 255 bytes during compression, how would you adjust [A] without having to do a memmove to make space for the inline next-header field. What I understand is that, if header [B] itself can't be compressed, the next-header field in header [A] must be placed in the inline portion for header A and before other inline fields in [A]. This problem also requires one to keep a pointer back to where the inline next-header field should be inserted. One other solution would be to look ahead at the length of [B] before compressing [A], but I think this can get messy. Regard Dario Geoff Mulligan wrote: 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 6lowpan@ietf.org https://www.ietf.org/mailman/listinfo/6lowpan

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