Re: LCAS and GMPLS

["Adrian Farrel" <adrian@olddog.co.uk>]

Hi Greg,

Let me come in a bit heavy here, please.


> Hi all, thanks for the update Diego and Adrian. Where
> we stand seems to be:
> (1) We've got an agreed method using the Call_ID to
> identify (VC-3/VC-4) component belonging to a VCAT
> group. In particular, the Call_ID along with source
> and destination addresses uniquely identifies the VCAT
> group in the network?

No. We do not have agreement on this.
We have a vague statement of requirements that a group of LSPs need to be
associated. Until we see the requirements fleshed out and written up it
would be wrong to pick one solution. For example, we have an Association
object that is part of mainstream GMPLS that could be used for this
purpose.

So, let's see the requirements written up, please.

> (2) I can use GMPLS to setup/tear down one or more
> VCAT group components at a time. (we've had this for a
> while).
> (3) Once we set up via GMPLS a new component
> (VC-3/VC-4) of a VCAT group we want LCAS to hitlessly
> add the new component to the group.
> (4) To remove (hitlessly) the component from the VCAT
> group we need  LCAS to remove it before we actually
> tear down the component connection via GMPLS.

So it seems to me that you have decided that LCAS is a GMPLS application.
That is, LCAS is an end-to-end protocol that triggers the establishment of
LSPs by making requests to GMPLS.

This sounds reasonable, but please write it up.

> Now the thing that seems a bit tricky to me about (3)
> and (4) is that LCAS does things unidirectionally, in
> the sense of adding/removing components, (not in the
> sense of a protocol which has a handshake mechanism).
> All add or remove commands come from the source end
> and since we generally setup/teardown bi-directional
> connections that would leave us with a bit of
> coordination.  Is this what you are thinking Diego?
> LCAS experts chime in too :-)

Nothing to stop you having unidirectional LSPs if you need to support a
service that controls LSPs in a unidirectional way.

Cheers,
Adrian