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Re: Sonet Ring provisioning
Hi all,
Seems we have mixed up a "ring topology" from "ring protection mechanism".
* In a general ring topology, *any* recovery mechanism may be used.
This may be the underlying transport's BLSR/MSSPRING or
UPSR/SNCPRING, or it may be using control plane to set up 1+1 or 1:1.
* In a BLSR/MSSPRING ring, the type of protection has already been
decided (i.e., BLSR *is* the name of the protection mechanism).
Similarly for UPSR/SNCPRING.
Thus if we're talking about BLSR/UPSR rings, then the question is: how
does the control plane protocols interact (do they interact?) with the
underlying BLSR/UPSR, e.g., does the control plane simply treat the
*entire* ring as a single node and thus interfaces to existing EMSs to
ask for a sub-network connection across the "node", or does the control
plane actually see all nodes of the ring and ask individual nodes for an
STS-1/VC-3 connection (but note it only asks for the normal channel i.e.
one connection, since the protection channel comes by default -- the
service is either protected or unprotected but one connection in either
case)...
Zhi
R. Muralidharan wrote:
>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
>>
>>
>>
>>
>>
>>
>>
>
>
>