The MPLS WG Archive

[Markus Jork <mjork@avici.com>]

Bora,

> When filling in the ERO, there are three options:
> 
> 1) Put in the router ID of the routers. This does not work for cases
> when routers have multiple links and for unnumbered interfaces.
> 
> 2) Put in the egress interface of the routers on the path and finish it
> with the router ID of the final router. So that from router A to router
> B, we represent the hop as the IP address/interface index of the
> interface from A to B on router A.
> 
> 3) Put in the ingress interface of the routers on the path starting with
> the router ID of ingress and finishing with the router ID of the egress
> LSRs. This is kind of opposite of (2).
> 
> I believe that (2) is the only option that works with unnumbered
> interfaces.
> 
> Does anyone think otherwise?

your option (1) will work when you only have a single link (which may
be unnumbered) between the routers. Using router IDs in the
ERO may also be useful in the presence of multiple links when you
don't care which of the multiple links between a pair of routers will
be used.

I'm kind of confused about your option (2). Have you read
draft-kompella-mpls-unnum or are you trying to reinvent it here?

Markus