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[AVT] Header Compression over MPLS & Allison's DISCUSS Comment on PWE3 IANA Allocation Draft

"Ash, Gerald R \(Jerry\), ALABS" <gash@att.com> Thu, 20 October 2005 07:47 UTC

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Date: Wed, 19 Oct 2005 09:34:30 -0500
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Thread-Topic: Header Compression over MPLS & Allison's DISCUSS Comment on PWE3 IANA Allocation Draft
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From: "Ash, Gerald R (Jerry), ALABS" <gash@att.com>
To: mankin@psg.com, IETF AVT WG <avt@ietf.org>, pwe3 <pwe3@ietf.org>, rohc@ietf.org
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Cc: "Ash, Gerald R (Jerry), ALABS" <gash@att.com>, "Lars-Erik Jonsson (LU/EAB)" <lars-erik.jonsson@ericsson.com>, "Malis, Andrew G." <Andy.Malis@Tellabs.com>, "Hand, James C, ALABS" <jameshand@att.com>, "Goode, B (Bur), ALABS" <bgoode@att.com>, "raymond.zhang" <raymond.zhang@bt.infonet.com>
Subject: [AVT] Header Compression over MPLS & Allison's DISCUSS Comment on PWE3 IANA Allocation Draft
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Hi Allison, All,

FYI.  Allison made a DISCUSS comment on the PWE3 IANA Allocation draft
http://ietf.org/internet-drafts/draft-ietf-pwe3-iana-allocation-13.txt
that directly affects the Header Compression over MPLS protocol draft
http://ietf.org/internet-drafts/draft-ietf-avt-hc-over-mpls-protocol-01.
txt.

See Allison's comments at
https://datatracker.ietf.org/public/pidtracker.cgi?command=print_ballot&
ballot_id=1697&filename=draft-ietf-pwe3-iana-allocation, which quoted
here again:

<DISCUSS START>
"Separate point:

The initial registrations include the following:

      0x001A  cTCP (RFC1144) Transport Header-compressed Packets
      0x001B  IPHC (RFC2507) Transport Header-compressed Packets
      0x001C  cRTP (RFC2508) Transport Header-compressed Packets
      0x001D  ROHC (RFC3095) Transport Header-compressed Packets
      0x001E  eCRTP (RFC3545) Transport Header-compressed Packets

These are premature registrations, as the mapping of these header
compression
technologies onto the PWE3 architecture hasn't been done, and it's not
clear how it should be done correctly in each case.  There is chartered
work in AVT for a ROHC/eCRTP project that could result in such a spec,
but
it's a fairly complex job.

Two of the protocols, cRTP and RFC1144 have bad flaws for multi-hop and 
should really not be used on a PW (they will break).

I don't know who would work on the IPHC for PW, and how it is controlled

there.  

Carsten Bormann is the right guy to do that work correctly; I've asked
him,
and his ROHC co-chair, Lars-Erik Johnsson, to give further comments for
future reference.

Bottom line / Expert Review:  these registrations must be backed up by
appropriate specs before being made, and so need to be withdrawn now."
<DISCUSS END>

The PW Type values are already contained in Section 4.1 and Section 7 of
the Header Compression over MPLS Protocol I-D.  They were agreed to some
time ago by PWE3, then included in the draft, and discussed at the
IETF-63 AVT meeting.

It looks like we'll also have to focus now on ECRTP and ROHC in the
draft, and remove proposed support for cTCP, IPHC, and cRTP.  Carsten
Bormann made a comment on RFC1144 problems at IETF-63, but I wasn't
aware that cRTP and IPHC were also in the "problem" category.  In
particular, cRTP is widely deployed and IMO should be supported for
Header Compression over MPLS.

Any comments or suggestions?  

Thanks,
Jerry

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