RE: Sonet Ring provisioning

["Bernstein, Greg" <GregB@ciena.com>]

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