Re: Failure definition w.r.t. SONET/SDH and Protection/Restoration

["Diego Caviglia" <Diego.Caviglia@marconi.com>]

Hi Amit,
               actally for link/span protection I don't see any problem
with control plane restoration and data plane protection interworking.

It is sufficient to hide protection resourse to control plane.

I see a lot of problems (there are SPs opened in the ITU-T documents about
that) when you want an MS-SPRing protected ring to interwork with GMPLS
restoration.

Actually I'm not sure if that topic is in the charter of the CCAMP (Adrian
what is your feeling about this?) but in any case it is a problem.

Regards

Diego



Amit 70405 <AmitG@huawei.com> on 25/03/2005 02.41.04

To:    Adrian Farrel <adrian@olddog.co.uk>, Igor Bryskin
       <i_bryskin@yahoo.com>
cc:    Diego Caviglia <Diego.Caviglia@marconi.com>, ccamp@ops.ietf.org,
       Sasha@AXERRA.com

Subject:    Re: Failure definition w.r.t. SONET/SDH and
       Protection/Restoration


Hi Adrian & Igor,
   But there is one issue with this multilayer protection.
   Say in the case if the link gets broken, and the lower layer protection
has succeeded.
   In this case, should the control plane(higher layer) be notified by the
lower layer of link??

   If yes than it has following consequences:
   - As control plane is unaware of any failure, control plane will
continue to setup new connections on the failed.
   - This may not be a good thing to do.
   - Some means may be needed to avoid this link in Path computation.

   If no than following are the consequences:
   - Control plane too will go ahead with its protection mechanism.

   Let me know your view.
Regards,
Amit.


----- Original Message -----
From: Adrian Farrel <adrian@olddog.co.uk>
Date: Thursday, March 24, 2005 7:40 pm
Subject: Re: Failure definition w.r.t. SONET/SDH and Protection/Restoration

> Hi Amit,
>
> >    Do you mean to say that Data plane & Control plane protection
> shouldbe independant of each other??
>
> No, I mean that they MAY be independent.
> In particular, if you are using the control plane *and* the data
> plane to
> manage protection on the same set of resources you are bound to
> get in a
> horrible mess.
>
> Seems more reasonable that you would apply data plane protection
> first and
> then apply control plane protection at a higher level.
>
> >    If so, in case of MSP protection in SDH,
> >     Control plane should not have any control over the resource pool
> >      used for MSP switch.
> >    This may lead to lot of unused resource in the network.
>
> It is certain that each layer of protection that you install MAY
> result in
> unused resources. Building multiple layers of protection will,
> therefore,potentially build up more and more unused resources. It
> is the job of
> CCAMP to produce the tools that allow operators to build the
> protectionschemes that they want. It's not really our business to
> tell them which
> schemes to build and when.
>
> Cheers,
> Adrian
>
>