Re: Moving right along ...

[Zhi-Wei Lin <zwlin@lucent.com>]

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
>