The MPLS WG Archive

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

Bin Zhou wrote:
> 
> You ask a good question.
> I think Tunnel ID is local in the daemon of the sender. We can use
> Tunnel ID and Sender address to distinguish a tunnel. If I need to
> identify application in my case, I need host address. The host
> address should be informed to destination and intermediate node in
> my case. So what should I do?

Tunnel ID is not a globally unique identifier in RSVP.  It is not the
same as the tunnel ID that LDP defines.

In RSVP, a _session_ must be defined by the triple {egress-address,
tunnel-id, extended-tunnel-id}.  A session is a _set_ of LSPs that all
share the same session information.  A single LSP is defined by the
combination of its session information and the double {sender-address,
LSP ID}.

If you treat {sender-address, tunnel-id} as a unique identifier (as it
is defined in LDP), then your code will break.

It is perfectly legal in RSVP-TE for one ingress router to use the same
tunnel ID for a thousand different sessions, if they all have different
egress addresses.

-- David