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Dear Steven and Scott,
Thank you for the LS Reply.
Officially, the LS to SG11 should be sent to SG11 TSB tsbsg11 at itu.int. Then TSB will post it as a TD
document on ITU-T SG11 website.
B. R.
Tina TSOU, ITU-T Q.5/11 Rapporteur
----- Original Message -----
Sent: Friday, September 26, 2008 12:08
AM
Subject: Updated Liaison Statement, "IETF
PCN Working Group Response to Liaison Statement TD 151 (NGN-GSI) (Q.5/11) from
ITU-T Study Group 11"
Title: IETF PCN Working Group Response to Liaison Statement
TD 151 (NGN-GSI) (Q.5/11) from ITU-T Study Group 11
Submission Date:
2008-09-25
URL of the IETF Web page: https://datatracker.ietf.org/public/liaison_detail.cgi?detail_id=474
From: Steven Blake(IETF PCN WG) <slblake at petri-meat.com>
To:
ITU-T/Study Group 11(Tina Tsou <tena at huawei.com>)
Cc: IETF PCN Working
Group <pcn at ietf.org>
Lars Eggert
<lars.eggert at nokia.com>
Magnus
Westerlund <magnus.westerlund at ericsson.com>
Monique
Morrow <mmorrow at cisco.com>
Reponse Contact:
Steven Blake <sblake at extremenetworks.com>
Scott
Bradner <sob at harvard.edu>
Technical Contact:
IETF PCN Working Group <pcn at ietf.org>
Purpose: In response
Body: To: ITU-T Study Group 11
Thank you for your liaison statement
from your Geneva meeting on your intent to incorporate PCN into the RACF
framework.
For your information, the fifth draft of the PCN
Architecture document has completed working group last call, and we expect
that the sixth draft (incorporating edits in response to comments from the
last call) will be submitted for IESG review and IETF last call prior to the
next IETF plenary in November. This draft is available at:
http://tools.ietf.org/html/draft-ietf-pcn-architecture-06.
Subsequent
to our last liaison statement, the PCN working group has achieved consensus to
advance a 2-state PCN encoding proposal for Proposed Standard, although the
specific proposal is still under development. Consensus was also
achieved to allow a 3-state PCN encoding proposal to be advanced for
Experimental status, although again no specific proposal has been
finalized. We note that your attached draft Q.PCNApp "Enhancement of
resource and admission control protocols to use pre-congestion notification
(PCN)" appears to assume that a 3-state PCN encoding mechanism is available,
and we wish to advise you that there is no consensus to standardize a 3-state
PCN encoding mechanism at this time.
In addition, we wish to inform you
that the PCN working group has not made progress in defining a protocol for
conveying pre-congestion information from an egress node to an ingress node
(corresponding to the Rc interface defined in <Draft
Q.PCNApp>).
We note that <Draft Q.PCNApp> discusses the
transport of network topology information from the TRC-PE function to an
egress node, to assist the egress node in associating a received packet with
the ingress node via which that packet entered the network. We believe
that the use of topology information as a means to determine the ingress node
of a particular packet will only work in certain constrained network
topologies. We suggest that one alternative approach would be to define
an interface from the PD-PE function to the egress node, to convey packet
classification state for admitted flows.
We would like to ask for
clarification on the role and operation of the Rp interface in <Draft
Q.PCNApp>. It is not clear from the text whether commands are issued
by the centralized TRC-PE function towards the TRC-FE function, and if so,
what is the defined behavior of these commands.
Thank
you,
Steven Blake and Scott Bradner, PCN working group
co-chairs
Attachment(s):
No document has been
attached
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