Re: Sonet Ring provisioning

["R. Muralidharan" <r.muralidharan@ossi.co.in>]

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Hi All,

My understanding is as follows:

     BLSR or UPSR rings may be already provisioned in the SONET network. The
task using GMPLS is to set up an end to end virtual path, may be
encompassing multiple SONET rings. This virtual path set up is dynamic in
nature and the life of the path may be only for a fixed interval, after
which it would be tore down. When one wants to set up a path through a SONET
ring, one may have to specify whether one wants a 1+1 protection path or a
1:N protection path or just an unprotected path. Based on this specification
the GMPLS can discover and set up an appropriate path in a BLSR or an UPSR
ring as the case may be and hence the cost would be optimum. ( assuming that
a 1+1 path would cost more than an unprotected path). As Greg pointed out, I
also believe that the BLSR and UPSR ring configurations would already have
been set up by associated NMS or EMS and advertised. The granularity of the
path that can be set up using GMPLS could a VT1.5 or multiples of them ( VT
Path) or STS-1s (STS Path).

I have used the words "path" and "virtual path" in generic terms and not in
the SONET or SDH domain definitions.

Does the above make sense ?
regards,
murali
OSS Systems India

----- Original Message -----
From: "Bernstein, Greg" <GregB@ciena.com>
To: "'Manoj Agiwal'" <ManojA@netbrahma.com>; "'Ccamp (E-mail)"
<ccamp@ops.ietf.org>
Cc: "mpls@UU. NET (E-mail)" <mpls@UU.NET>
Sent: Wednesday, May 29, 2002 10:28 PM
Subject: RE: Sonet Ring provisioning


> Hi Manoj, the UPSR and BLSR cases are very different.  I'm assuming that
you
> are setting up SONET paths such as STS-1, STS-3c, ... STS-192c or their
SDH
> equivalent.
> Then
> (1) In the BLSR case the protection is at the SONET line layer, i.e.,
below
> the layer of the connection that you are setting up(SONET/SDH are layered
> networks).  In this case no special action needs to be taken unless of
> course the entity requesting the connection asked for "enhanced"
protection
> in the setup request.
>
> (2) A UPSR works at the path layer, i.e., like a path layer 1+1, with the
> redundant paths taking different routes around the ring.  Hence you are
> actually setting up two connections that have a special relationship with
> each other. This would have to be indicated somehow (tunnel ID or
> something). Some UPSRs may put constraints on the timeslots used too.  One
> meta question is why bother signaling around a UPSR versus talking to a
UPSR
> as a separate "protection domain"?  There is no way mesh restoration could
> come close to a UPSR's restoration speed (it just selects the better of
two
> signals).  Hence I don't understand the benefit signaling around the ring
in
> this case, all vendors have methods for setting up their UPSRs via EMS's
why
> not just interface to those rather than to the individual ring elements...
>
> Greg B.
>
> ***********************************
> Dr. Greg M. Bernstein
> Senior Technology Director, Ciena Corporation
>
>
> -----Original Message-----
> From: Manoj Agiwal [mailto:ManojA@netbrahma.com]
> Sent: Wednesday, May 29, 2002 2:01 AM
> To: 'Ccamp (E-mail)
> Cc: mpls@UU. NET (E-mail)
> Subject: Sonet Ring provisioning
>
>
> Hi ,
>       Do we use GMPLS signaling protocol for configuring Sonet Rings (
UPSR
> / BLSR ( 2 fiber/4
>       fiber ) ?
>
>       I was going  through certain white papers where there was a mention
> that GMPLS is used as
>       a signaling protocol for provisioning mesh topologies only
> .Traditional Sonet rings will be
>       replaced by mesh topologies in future .
>
>       But there is a section 12.( LSP protection and restoration) in GMPLS
> Architecture which says
>       that " Both mesh and ring like topologies are supported "
>
>       How do we provision nodes in Sonet ring using GMPLS ?
>       Or GMPLS has been designed to provision mesh topologies only.
>
> Regards ,
> Manoj
>
>
>
>
>