Re: Suggested Label Doubt

[Eric Gray <eric.gray@sandburst.com>]

Suresh,

    I suspect that you're hitting close to the heart of the issue.
It is arguable that suggested label is redundant in the TDM case -
simply because it is intended to be the same.  Clearly this is not
going to be the case in other technologies within the GMPLS scope.
A major objective of GMPLS is to develop common signaling for a
number of technologies.  There is no reason not to include a
suggested label in a label request, even if it is redundant and it
may be needed when it is not redundant.

    The suggested label is optional in all cases.

--
Eric Gray

You wrote:

> Please see my response in line.
> >
> > > > In my understanding, the purpose of "suggested label" is to speed up circuit
> > > > connection procedure by letting the upstream node to specify a label rather than
> > > > following the conventional MPLS signaling procedure that receiving the label in
> > > > the response.
> > > >
> > > > My questions are:
> > > >
> > > > (1) From a protocol design perspective, what's the benefit to suggest something
> > > > that could be declined?
> > >
> > > The benefit is in optimizing the likely.  As you point out below, it is likely
> > > that the suggestion will be accepted, therefore - for the optimization reason
> > > that you mention above (connection speedup) - it makes sense to allow the
> > > 'suggestion'.
> > >
> >
> > The key is that the likely is not likely in optical network.
> >
> > Basically, "suggested label" adds the local negotiation capability.
> > Therotically, it's a good idea. But it's not necessary in the optical network.
>
> It is completely waste for bidirectional LSPs in TDM networks. In TDM networks,
> the label must be same and current draft (OIF) specifies that the upstream
> lable should be same as Suggested label. It should be really made optional
> so that if an upstream node wants to suggest, then it has freedom to do so.
>
> Thanks,
> Suresh