Re: PQC and QOSPF

[Masataka Ohta <[e-mail]>]

Yao-Min;

> these messages follow the direction of a flow, 
> only downstream routers receive resource reservation
> info of upstream routers but not the other way
> around.  The problem with this is that upstream

Yes, it makes the QOS routing a little more stable and is not a problem.

> I guess a simple fix would be to also 
> piggyback resource reservation on the 
> RESV messages.  Or maybe it is not 
> necessary because receiving successful 
> RSVP Resv message by a router would 
> imply the resource reservation info 
> on downstream links?

Yes, as the QoS routing is hop-by-hop, which is necessary for multicast
and RESV merge, a router do not have to know the result of
previous routing. The router can not, in case of multicast and RESV merge.

Note that, to assist dynamic rerouting, it reduces rerouting delay, if
upstream, NOT DOWNSTREAM, link state of the current path is carried
back in RESV, which is an extension to PQC I'm thinking about now.

Note also that, with QoS routing, PATH must follow the result of
QoS routing, if any, of RESV, because only RESV has the QoS information
which is necessary for QoS routing.

					Masataka Ohta