Hi Jerry -- thanks for this work - I have not been able to digest it completely. I am working to try to make some distinctions so that your work can be incorporated in recommendation in a way that is distinct from other parts. I hope to have this in the next few days. Meanwhile we can talk about this on the call tomorrow - John On Feb 7, 2010, at 8:31 PM, Jerry Sobieski wrote:
I wish to pose two questions for discussion regarding Connection Service request handling:
1st: Can we reserve resources backwards?
2nd: How should third party requests be handled?
Backward Reservations-
This is simply doing a path finding process backwards - from destination to source. This does not (must not) change the direction of the connection that is established in the transport plane, it simply constructs the viable path tree from the destination towards the source. THis should still develop a valid connection path, but it may not be the same path selected by a forward pathfinding process...
My recommendation: It should not matter whether a path is discovered from Source to Destination or vice versa. And it is up to the local domain as to decide how to decompose a connection request and perform the path finding/resource allocation within its domain. Any intermediate hops specified in a PO must be honored.
3rd Party Requests
A "3rd Party Request" is a request receive by a local NSA that specifies end-points that are not located within the local NSA's domain. I.e. there is no basis for assuming that the [shortest/best] connection path will transit the local domain. So the question is: should the local NSA simply forward the request towards the Source (or Destination) ? or can the local NSA insert a local intermediate STP (a loose hop) in the path object, thus forcing the connection to transit the local domain?
Since this has to do with how we handle a request - not particularly pathfinding per se, I think we need to think about this to decide if we need to make some firm declaration about this.
One potentially questionable result of this issue is that an intermediate NSA who handles a request could insert a local hop into the Path Object, thus forcng the connection thru their domain. If this sounds ominous, it is. So we should consider what the desired action should be and how to be certain it is followed.
Thoughts? Jerry _______________________________________________ nsi-wg mailing list nsi-wg@ogf.org http://www.ogf.org/mailman/listinfo/nsi-wg