The MPLS WG Archive

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

djiang1@lucent.com wrote:
> 
> I have a question regarding CR-LDP and RSVP implementation.
> 
> I guess it is possible that both CR-LDP and RSVP implementations will
> be supported on one LSR.

Definitely possible.  And quite probable in the future.

> However, is there any chance that both the implementations will be
> called for one LSP setup?  Say, at the incoming interface, CR-LDP will
> take the PATH message and pass it to some other MPLS processes.  At
> the out going interface, RSVP will get some message from other MPLS
> processes and does something in the middle and sends out another PATH
> message to its neighbor node.

I don't think so.

The only way I can picture such a setup would require a transit router's
ability to terminate one LSP, then initiate setup of another, and
connect them internally.  Theoretically possible, but difficult to
automate and of questionable utility.

I think you may find MPLS networks where RSVP-TE, LDP and CR-LDP are all
used for LSP setup at once.  And this may well result in multiple
redundant LSPs between edge nodes.  But each individual LSP will almost
certainly be set up through exactly one protocol.

-- David