I think Evangelos is right -- we are talking about slightly different things. I think there are several differences that might be considered 1) for me the difference between a "path" and a "strict path" I think that what Freek describes is a strict path in my terminology. It contains edgepoints (i.e. links), and contains all the (relevant) links A path is just a way to get between two edge points. It may be described in a number of ways a) just the two endpoints b) endpoints + some intermediate hops - where hops can be links or other topological element (i.e. domain, node, port) note that for me a path does not have to specifically define every link in the topology between end points - it is "potential" 2) Freek seems to assume that adaptations occur only at links. In my model the hops in a path may be domains, for example. The implication is that domains must be able to do adaptations. 3) My potential paths may assume adaptations are possible without knowing for sure that they are. I think the potential path probably needs a name different than the actual path 4) I have taken to using circuit as a path with specific resources assigned to it. It is possible, for example, to have multiple circuits using the same path. Circuits are what DCN creates over paths. Adaptations take place on circuits in my view, not paths. It seems to me paths have adaptation points in them but don't do the adaptation (perhaps this is not right - perhaps adaptations are part of paths and circuits -- ?) John On Jul 1, 2008, at 5:24 PM, Evangelos Chaniotakis wrote:
Hi,
My opinion is that we're talking about slightly different things.
Path in the sense Freek defines it seems to represent a "finalized" object while the way John describes it is closer to an "unfinished" object that we would find in a service request.
I think both approaches have value, and are in fact very close but maybe we would like to to differentiate between them?
On Jul 1, 2008, at 8:44 AM, John Vollbrecht wrote:
On Jul 1, 2008, at 9:09 AM, Freek Dijkstra wrote:
John Vollbrecht wrote:
Attached is a DCN glossary which is part of DCN architecture and DCN reservation documents.
Thanks John!
path - a connection between a source and destination. A path is a sequence of hops.
I would argue that a path is a sequence of edges/links rather than hops. That way I can distinguish between two links between the same hops, and can more easily between different types of relations between hops (link, cross connect, adaptation, de-adaptation)
I think of a path a a sequence of hops because a requested path may contain some but not all intermediate hops, and hops may be domains rather than links. A strict path is a sequence of links.
There may be multiple paths between hops but paths may be "potential" or requested as well as confirmed and strict.
John Vollbrecht, Senior Network Engineer Internet2 office +1-734-352-4960 | mobile +1-734-395-7890