The MPLS WG Archive

["James R. Leu" <jleu@mindspring.com>]

On Wed, Jun 07, 2000 at 11:33:26AM -0400, Bob Thomas wrote:

<snip>

> I think you are making this more complicated that it need be.
>
> The purpose of the Address Message is to make it possible for an LSR
> to establish a mapping between the first 4 octets of a peer's LDP Id
> and addresses bound to the peer.
> 
> This mapping is useful in determining whether the peer is the next
> hop for a particular prefix.

I understand your second statement (the first about me making it more
complicated then it need be is always true :-).  With respect to the third
statement, are you saying that this mapping is or is not the ONLY way to
figure out if a peer is the next hop for a particular prefix?

My goal is to get an answer about "non-Directly Connected LSRs" and
how they guarantee that they are distributing labels and installing them
on the correct interfaces.

The way to get the above answer may involve or mimic the way we deal with
mappings over parallel links between two directly connected LDP peers.

If I have LDP sessions over parallel links and a particular prefix is
preferred over only one link, the peer closer to egress may provide mappings for
this prefix via both sessions.  If I use the address list as my definitive
source for which session is the next hop, both sessions will match.

What other information do we use in this case to decide whether or not
a particular session is ACTUALLY the next hop for a particular prefix?

Jim
-- 
James R. Leu