The MPLS WG Archive

[David Charlap <david.charlap@marconi.com>]

John Wysocki wrote:
> 
> I have very high level generic MPLS TE questions to ask.  If you
> could help me on it, I'll appreciate very much.
> 
> 1) It's my understanding LSPs are usually within an AS and not
>    inter-AS.  Is this correct?

This is how they will typically be used.

There are explicit-route subobjects in RSVP-TE and CR-LDP for specifying
AS numbers as hops along an LSP.

It is theoretically possible for a single LSP to cross AS boundaries. 
But in actual practice, you will probably not see much of this.  Mostly
for political, security and business reasons.

> 2) BGP-TE is really not well defined yet, right?

There are drafts in progress for this.

> 3) Is multicast well defined in MPLS?

There are drafts in progress for this.

> 4) Only GMPLS defineds bi-directional LSPs, but ISIS usu takes
>    links as bi-directional but MPLS tunnel is not.  Does anyone
>    know how to handle this situation?

I don't see what the problem is.  Knowing that a link is bidirectional
doesn't force you to signal bidirectional LSPs on it.  No more than it
would (somehow) force the existance of bidirectional traffic over a link
in a non-MPLS network.

-- David