Sent by: owner-ccamp@ops.ietf.org
To: ccamp <ccamp@ops.ietf.org>
cc:
Subject: RE: LCAS and GMPLS
In considering the use of LCAS, it is important to note that there are separate requirements here:
1. Having multiple LSPs participate in a single service. This is not just limited to virtual concatenation but is also useful for 1:1 and other restoration mechanisms.
2. If LSPs can be added/removed from a common service after they have been set up.
3. What effects LSP addition/removal are allowed to have on the common service.
Putting these together, one could envision a requirement to offer a service whose bandwidth requirements are met with a service in a transport network that uses multiple LSPs for bandwidth efficiency. Further this service allows changes to be signalled and the bandwidth change is to be non-disruptive.
Mechanisms to accomplish such a service could consist of VCAT and LCAS. Note that LCAS has its own "in-band" signalling. I think that the service associated with the VCAT adaptation is the one that should be LCAS aware, not the individual LSPs.
Stephen
> -----Original Message-----
> From: owner-ccamp@ops.ietf.org
> [mailto:owner-ccamp@ops.ietf.org] On Behalf Of Adrian Farrel
> Sent: Tuesday, June 14, 2005 14:48
> To: Greg Bernstein <gregbern; Diego Caviglia
> Cc: yhwkim; ccamp
> Subject: Re: LCAS and GMPLS
>
<snip>
> Nevertheless, before completing on the solutions discussion,
> we still have to sort out the issues above. I am most
> concerned about the "layering" issue. That is:
> a) Is the LCAS component on the egress started by management,
> by a trigger in some communication between LCAS components,
> or by a trigger in GMPLS signaling?
> b) Do the LCAS components converse through GMPLS signaling
> or by other (existing?) means?
>
> > [dc] My initial idea was to use Call_ID to identify the LSP that are
> part of the
> > same VCAT/LCAS set and a bit in the profile filed to inform
> the other
> and
> > that LCAS protcol has bo enabled.
>
> Understood. I think we have moved on a little from that
> suggestion. Presumably you will not be unhappy with any
> solution that is functional and not over-complex.
>
> I would suggest that Greg and Diego start an I-D. Call it
> something like "Applicability Statement for Operating LCAS
> and VCAT with GMPLS LSPs".
> Include:
> - Simple overview of VCAT and LCAS (no more than a page, please)
> - Simple statement of how LSPs fit into the picture (about
> half a page)
> - Statement of the requirements on GMPLS signaling (about a page)
> - Mechanisms and procedures (two or three pages)
>
> It may be that we need to define a new bit somewhere in which
> case we will drop "Applicability Statement for" from the name
> of the I-D.
>
> I would be very happy to discuss the solutions component with
> you before publication so that we avoid thrashing.
>
>
> Anyone who is interested in this topic should contact Diego
> and Greg to offer help.