Subject: Incoming liaison (2) from ITU-T SG15

From: "Adrian Farrel" <[email-masked]>
Date: Tue, 21 Dec 2004 16:27:20 -0000

Hi,

Here is the text of an incoming liaison just received.
In due course it will be posted at the IETF's liaison web site. Until then
you can see the original at http://www.olddog.co.uk/incoming.htm

Cheers,
Adrian

============
From: ITU-T SG15
To: CCAMP
For: Action
Deadline: 15 March 2005
Subject: Response to IETF CCAMP WG on Comparison of LMP and ASON Discovery

Q14/15 thanks the IETF CCAMP WG for providing us the draft document
<draft-ietf-ccamp-transport-lmp-00.txt>. This I-D was discussed at the
meeting and several of the comments are provided below.  Based upon this
discussion we believe it would be highly beneficial to have some joint
discussions on terminology to ensure an aligned view to facilitate our
future work efforts.

We have several questions of clarification, e.g., in section 3.1
(paragraph 2) of the I-D, "The separation between the two processes and
corresponding two name spaces has the advantage that the discovery of the
transport plane can be performed independent from that of the control
plane (and vice-versa), and independent of the method used in each name
space. This allows assigning link connections in the control plane without
the link connection being physically connected."

What is the intention of the term independent, for example, could it be
indicating at a different time or different approaches?
In the last sentence, is "assign" used in the context of the management
plane, meaning management plane provisioning?  Is it assumed that the
transport plane resources supporting the link connection endpoints exist
or do not exist?
In section 4.2 (paragraph 2) of the I-D, "G.8080 refers to a component
link as a variable adaptation function i.e. a single server layer trail
dynamically supporting different multiplexing structures." This could be
interpreted as indicating G.8080 defines the term "component link".
G.8080 does not use this term.  Some clarification would be beneficial.

Initial reviews of the draft document have raised concerns about the
possible misinterpretation in the usage of the term 'TE link'. As the
draft notes, the definition of a TE link is concise. Some more clarity
would be appreciated.  Our current understanding of this term includes the
following:
A TE link may be composed of resource from multiple (G.805) layers in
parallel.  If so, this is an important distinction as an SNPP link is in a
single layer only.
An SNPP link may contain SNP link connections from various links (e.g.,
different STS-1s from a set of parallel OC -48 trails).  It is not clear
if this is also true for TE links.  We think it may, but it is not stated.
SNPPs exist at different routing levels (not layers) and thus an SNPP link
at a higher level can encompass SNPPs at a lower level (see Section 6.2.2
of G.8080 Amendment 2, which is attached for your convenience).  We think
TE links may do this with bundles and FAs, but the definition is not clear
to us.

Please advise if this is a correct understanding or not.  This may have an
impact on the terminology mapping in the draft.  We think it would be
beneficial to have a TE link definition that enables these distinctions to
be understood.

In the table in section 4.2 "CP" is mapped to "Interface".  A Connection
Point is more closely related to a timeslot, wavelength, etc. rather than
to an entire interface.  Similarly "CP Name" is mapped to "Interface ID"
while it might more closely relate to a "Label".  Joint discussion of the
terminology mapping may be beneficial in reaching alignment on the most
accurate mapping.
As noted above, these represent several of the comments discussed.  In
order to progress our mutual understanding, we would like to invite IETF
participants to attend the January 24-28, 2005 Q14/15 interim meeting, in
New Jersey, USA, where we could devote a session to terminology alignment.
We believe this effort will greatly benefit our future collaboration on
control plane standards development.  We welcome IETF experts'
participation in other sessions of the interim meeting as well. Details of
the meeting agenda will be provided prior to the meeting. For those
interested in further information and/or attending the interim meeting
should contact the Rapporteur for Q.14/15 (H. Kam Lam, [email-masked])
by 10th January 2005.

An electronic copy of this liaison and the attachments can be found at
<ftp://sg15opticalt:[email-masked]/tsg15opticaltransport/COMMUNICAT
IONS/index.html >

Attachment: Editor's draft of G.8080 incorporating Amendment 2
[this can be seen at the CCAMP alternative web site]