The MPLS WG Archive

[Rahul Aggarwal <rahul@redback.com>]

George et al.,
I have a few comments on the new version of the RSVP-TE draft:

1. Bandwidth Increase procedure:
The draft talks about doing bandwidth increase in a manner similar to 
make-before-break i.e. using a new LSP_ID to attempt a larger bandwidth
reservation. 

I am wondering why this can not be achieved by 
sending a new path refresh with an increased adspec. This will result in
the receiver sending a resv with an increased flowspec. If there is an 
admission control failure during path msg propagation (or during resource
reservation, while processing the resv message), a path/resv error will be
sent. In that case its up to the sender to revert back to the old adspec or
to try and reroute the tunnel with the higher adspec.

2. To spread a traffic trunk over multiple paths, a sender may create more
than one LSP tunnel (with a different LSP_ID and the same Tunnel id). It
may be desirable to share resources on common links between the LSP tunnels. In
this case the receiver has to send the resv with a SE style flow descriptor.
Shouldn't there be a flag in the session attribute object to indicate this,
just like it is done for rerouting with the 'ingress node may reroute' flag?

3. The label subobject in a RRO has a flag to indicate a global label. Is
the primary purpose of this to enable the upstream router to do fast reroute
with the knowledge that the downstream supports a global label? Currently
there is no other way of signaling this to an upstream router and such 
an indication is useful, though I am not sure if using the label subobject
in a RRO is the best way to do this. 

4. The draft has removed the 'Merging permitted' flag in the session 
attribute object. I am not sure what the purpose of this flag was, to begin
with, and out of curiosity what is the reason for taking it out? 

I will appreciate any comments on the above.

Thanks,
rahul