Re: LCAS and GMPLS

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

Hi again Wataru,

> > > >IB>> This is an interesting requirement. Fortunately, it is
possible to
> > > >realize this requirement via GMPLS signaling by including several
> > > >ASSOCIATION objects of the same type into the same Path message.
For
> > > >instance, one of them will indicate that the signalled LSP belongs
to
> > > >the nested VCAT group, while another -to the nesting VCAT group.
> > >
> > > Current ASSOCIATION objects relates only two connections.
> >
> >Can you say why you think this is so?
> >Looking at draft-ietf-ccamp-gmpls-recovery-e2e-signaling-03.txt I do
not
> >see anything that forces this limitation. In fact, it would be hard to
> >offer 1:n protection with such a scheme.
>
> In my understanding, the ASSOCIATION ID of ASSOCIATION Object only
> relates protected LSP and protecting LSPs.

Then I am sorry to say that your understanding is wrong.

The Association object is used to associate LSPs.
Clearly, in its use in a protection ID it describes the association for
the purposes of protection. However, the text is carefully worded to
ensure that the object is more widely applicable.
To quote from section 16...
   The ASSOCIATION object is used to associate LSPs with each other.

You originally said...
> > > Current ASSOCIATION objects relates only two connections.
...but you now seem to accept that the Association object can relate more
than one LSP since you say...
> It's OK adoptation of ASSOCIATION Object and ID for 1:n protection.

Thus, I presume that you accept that the Association object could handle
VCAT groups with more than two LSPs.

>   Now, consider the LCAS.
>   Does the LCAS define or have primary connetion ?
>   I think all of conections in LCAS should be equivalent.

Why is primary conneciton valid? LCAS has nothing to do with protection.
The Association object provides an *arbitrary* association ID that is
common across all LSPs in the same group, and unique within the context of
the association source. There is no concept of a primary connection in the
process of association.

I hope this clarifies that the Association object is suitable for
identifying the LSPs in VCAT groups. (Pending the documentation of the
real requirements.)

Thanks,
Adrian