Subject: Consensus on compression

From: George Swallow <[email-masked]>
Date: Thu, 20 Jul 2000 14:16:43 -0400

Folks,

Since there clearly is confusion over whether consensus over adopting 

	draft-ietf-mpls-hdr-comp-over-ppp-00.txt
	draft-ietf-mpls-hdr-comp-00.txt	

and since the minutes don't clearly indicate that there was, then we
need to start again.  So, lets discuss see if we can reach consensus
on the list.  If a consensus forms, we'll declare it prior to the
meeting.  If not, we'll allocate a bit of time to discuss it there.

Note that this is not a package deal.  The two drafts should be
considered independently (and on separate threads).

...George

======================================================================
George Swallow       Cisco Systems                   (978) 244-8143
                     250 Apollo Drive
                     Chelmsford, Ma 01824

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From: Lou Berger <[email-masked]>
Date: Thu, 20 Jul 2000 15:04:56 -0400

>considered independently (and on separate threads).

I think the enclosed excerpt from the Adelaide meeting minutes accurately 
summarizes the drafts and presentation (available at 
http://www.labn.net/lberger/docs/cmpls-0003.pdf).  The bit naming issue is 
resolved in the recently posted rev of the draft.

Lou

[Source: http://cell.onecall.net/mhonarc/mpls/2000-May/msg00352.html]

'MPLS/IP Header Compression', <draft-berger-mpls-hdr-comp-00.txt>, Lou Berger

Lou Berger began by enumerating the objectives of the MPLS/IP header 
compression draft. In particular, to enable header compression for MPLS 
encapsulated traffic and to optimize for maximum compression.  He mentioned 
that end-to-end compression was not a requirement and that it was targeted 
at 'lower speed' links, where lower speed was not specified but was 
hardware-specific.

He mentioned that the key consideration was whether MPLS headers are 
compressed.  He went on to cover two options: 1) end-to-end with header 
compression over MPLS, and 2) link-by-link with compression of MPLS/IP 
headers. Subsequently, he discussed the pros and cons of each approach, 
concluding that both are reasonable depending on the application.

He then outlined the basic approach.  That is, it begins with standard IP 
header compression, then support for compression of MPLS packets is added, 
where the first draft preserves the standard compression header (2 bytes, 4 
bytes when UDP checksums are used, and +1 byte per EXP field change). He 
stated that it does not increase with more MPLS headers. And, that the 
second draft, <draft-berger-mpls-hdr-comp-over-ppp-00.txt>, defines PPP 
link layer support, which parallels RFC 2509 (IP header compression over PPP).

He concluded by highlighting two issues. First, the bit naming collision 
with draft-koren-avt-crtp-enhace-01.txt, and second, he remarked that it 
was not clear which IETF working group this work should proceed in.