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RE: Moving right along ...
Hi Zhi,
What B does is breaking the label association between A and C by crossing
connect
the time slots.
If the cross connect performed by B is fixed (in your case), what needs to
do is
just to rebuild the label association by configuration or a protocol such as
LMP;
If the cross connect is not fixed but dynamic, the best thing to do is to
make B
a GMPLS speaker.
Yanhe
-----Original Message-----
From: Zhi-Wei Lin [mailto:zwlin@lucent.com]
Sent: Friday, October 19, 2001 6:01 PM
To: Yanhe Fan
Cc: John Drake; Kireeti Kompella; ccamp@ops.ietf.org
Subject: Re: Moving right along ...
Hi Yanhe,
Maybe there is some misunderstanding. Node B is strictly not GMPLS. It
is simply part of the network that made up the "dumb" pipe. And because
the control plane control channel is separate, A and C can be adjacent
without ever knowing who B is or that even B existed. From A and C's
point of view, the network looks like:
A ----- C
Think of the case of how a BGP sees an area. If an area is made up of:
A -- B -- C
and B is internal router, does BGP "see" B?
Zhi
Yanhe Fan wrote:
> Hi, Zhi
>
>
>>For the label value for SONET/SDH or the label description in the
>>generic draft, the label is defined as directly representing the
>>"timeslot". Now if I have a control plane controlled transport network
>>that goes through a ADM that is not control plane controlled, as:
>>
>>
>>+--------+ +--------+ +--------+
>>| | ---1--------- | | ----1-------- | |
>>| | ---2--------- | | ----2-------- | |
>>| A | ---3--------- | B | ----3-------- | C |
>>| | ---4--------- | | ----4-------- | |
>>| | ---5--------- | | ----5-------- | |
>>+--------+ +--------+ +--------+
>>
>>Now imagine A and C is part of GMPLS, but B is just a legacy ADM. So at
>>A you have labels 1,2,3,4,5 (imagine these as in the SUKLM format) and C
>>has labels 1,2,3,4,5 incoming.
>>
>>Now imagine that at B, it actually has a fixed cross-connect that
>>connects A-1 (A's timeslot #1) to C-2 (C's incoming timeslot #2), A-2 to
>>C-3, A-3 to C-4, A-4 to C-5, A-5 to C-1.
>>
>>Now when A GMPLS sends a message to C, the label it uses is "1".
>>However, the connection/LSP associated with timeslot "1" is actually the
>>label of timeslot "2" at C. </z>
>>
>
> In this case, you're trying to use GMPLS to setup an LSP cross a node (B)
> which can't understand GMPLS.
>
> Now imagine A, B and C are all OXCs, can you setup an LSP A-B-C by using
> GMPLS if B can't understand GMPLS?
>
> Now imagine A and B are LSRs, and B is a conventional router (can't
> understand
> MPLS), can you setup an LSP A-B-C?
>
> Now imagine A, B and C are ATM switches, can you setup a svc if B can't
> understand PNNI at all?
>
> My point is that in order to make you case work, some additional work need
> to
> be done besie simply using GMPLS as singnaling protocol, becase some node
on
> the path is not GMPLS speakers. A and C needs the info of time slot
aligment
>
> between them. This can be done by some configurations, some link
management
> protocls (LMP maybe) etc. As long as A and C have this piece of info,
> eveything
> works fine.
>
> Yanhe
>