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RE: LCAS and draft-mannie-ccamp-gmpls-lbm-tdm-00.txt
Hello Maarten,
> I got the impression that you completely misunderstand the purpose of
LCAS. LCAS is NOT a signalling protocol.
The LCAS specification defines the "LCAS protocol" (annex A), with time
sequence diagrams (Appendix I), control packets (section 6.2) with fields,
etc etc... if this is not a signaling protocol I am not a network scientist
anymore. Anyway, this is not the point.
Kind regards,
Eric
-----Original Message-----
From: Maarten Vissers [mailto:mvissers@lucent.com]
Sent: Friday, November 16, 2001 3:36 PM
To: ccamp; q11/15; t1x1.5
Subject: LCAS and draft-mannie-ccamp-gmpls-lbm-tdm-00.txt
Eric, Dimitri,
I quickly scanned through your draft-mannie-ccamp-gmpls-lbm-tdm-00.txt.
Doing so
I got the impression that you completely misunderstand the purpose of LCAS.
LCAS
is NOT a signalling protocol. It is totally unrelated as such to control
plane
based connection management (GMPLS, ASON) or network management based
connection
management.
LCAS doesn't change the number of VC-n or ODUk trails in the network. If N
trails are set up between the A-end and Z-end, LCAS helps to hitless change
the
number of trails being used for the actual transport of the client signal;
i.e.
if X (X<N) trails are being used, and the operator/user wants to increase
this
number to X+1 or shrink it to X-1, then LCAS coordinates the steps at the
A-end
and Z-end to make sure the increase/reduction is performed hitless.
The steps to perform for the case X=N are:
A) X ==> X+1
1) [Operator or User] request connection management [NMS or ASON/GMPLS]
to setup additional VC-n/ODUk between SNP Pool (SNPP) associated with
virtual concatenated endpoint at A-end and corresponding SNPP at Z-end
2) connection management [NMS or ASON/GMPLS] commands LCAS controllers at
A-end and Z-end to control the "addition" of the (X+1)th trail to the
group of X trails ("Madd" command in G.7042) over which the client
bitstream is transported
3) LCAS at each end generates the ADD command (CTRL=ADD) and sends this
to the receiver at the other end
3) LCAS at A-end [Z-end] waits until connection is setup; the connection
in one direction is setup if the Trail Signal Fail (TSF) condition at
its end has cleared;
4) LCAS communicates the TSF clearing to the other end ("MST=OK")
5) once MST=OK is received, LCAS replaces CTRL=ADD by CTRL=EOS, and
6) at the start of the next VC-n/ODUk frame the client bitstream is
distributed over X+1 (instead of X) VC-n/ODUk trails
7) the receiver at the other end notices the change of CTRL=ADD to
CTRL=EOS, and expects the client signal to be present on X+1 (instead
of X) VC-n/ODUk trails at the begin of the next frame.
Example with X=3
================
The bits in a client bit stream with bits ...,1,2,3,4,... are distributed
over
trails #1..#3 as follows:
trail#1 trail#2 trail#3
...
1-8 9-16 17-24
25-32 33-40 41-48
49-56 57-64 65-72
73-80 ...
When trail #4 is added, no client bits will be transported over it, until
the
source has indicated this via the change of the control word CTRL=ADD =>
CTRL=EOS, and the new VC-n/ODUk frame begins. Assume that client bits
...,1,2,..,48 are transmitted in VC-n/ODUk frame "i", and frame "i+1" begins
at
the moment client bit 49 is to be transmitted, then trail#4 will be used for
the
transport of bits 73-80 and further:
trail#1 trail#2 trail#3 trail#4
...
1-8 9-16 17-24
25-32 33-40 41-48
49-56 57-64 65-72 73-80
81-88 89-96 97-104 105-112
113-120 ...
Regards,
Maarten
Internet-Drafts@ietf.org wrote:
>
> A New Internet-Draft is available from the on-line Internet-Drafts
directories.
>
> Title : GMPLS LSP Bandwidth Modification (LBM) for TDM
> Networks
> Author(s) : E. Mannie, D. Papadimitriou
> Filename : draft-mannie-ccamp-gmpls-lbm-tdm-00.txt
> Pages : 13
> Date : 15-Nov-01
>
> This document defines how GMPLS can be used to dynamically modify
> the bandwidth of a TDM circuit. It focuses first on SONET/SDH and
> will cover G.709 in a next version.
>
> A URL for this Internet-Draft is:
>
http://www.ietf.org/internet-drafts/draft-mannie-ccamp-gmpls-lbm-tdm-00.txt
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