Hi Wendy, Good discussion. I believe that the previous conclusion is that ECS does not reveal any dependency. Hence, a simple change will be the last sentence:
"...However, to preserve flexibility, there is no need for the ECS resource to declare the network map and/or cost map on which it depends." How does this sound? Richard On Tue, Feb 25, 2014 at 10:06 AM, Wendy Roome <[email protected]>wrote: > I just noticed that draft 25 says that an Endpoint Cost Service MAY be > declared as depending on a network/cost map: > > 11.5.1.5. Uses > It is important to note that although this resource allows an ALTO > Server to reveal costs between individual endpoints, an ALTO Server > is not required to do so. A simple implementation of an ECS resource > may compute the cost between two endpoints as the cost between the > PIDs corresponding to the endpoints, using one of the exposed network > and cost maps defined by the server. However, to preserve > flexibility, the ECS resource MAY omit declaring in the "uses" > attribute the network map and/or cost map on which it depends. > > The ambiguity is whether the ECS uses a Network Map, a Cost Map, or both. > ECS is a post-mode service, and can return one of several different cost > types, as selected by the client. So if an ECS uses a Cost Map, it would > have to use several Cost Maps, one for each cost-type it ca return. > > The IRD example doesn't help, because that ECS resource doesn't have a > "uses" attribute. > > My suggestion: say that if ECS uses anything, it just uses the Network > Map. The client can infer the related Cost Maps -- they're the ones that use > that Network Map. Eg, change the last sentence to: > > > Accordingly, the ECS resource MAY declare a Network Map resource in its > "uses" attribute. If the ECS does so, the ECS costs should be consistent > with those returned by the Cost Map resources associated with that Network > Map. > > and maybe add a "uses" attribute to the ECS IRD example in 9.2.3, as in: > > "endpoint-cost" : { > > "uri" : "http://alto.example.com/endpointcost/lookup";, > > "media-type" : "application/alto-endpointcost+json", > > "accepts" : "application/alto-endpointcostparams+json", > > "capabilities" : { > > "cost-constraints" : true, > > "cost-type-names" : [ "num-routing", "num-hop", > > "ord-routing", "ord-hop"] > > }, > > "uses" : [ "my-default-network-map" ] > > } > > > > If y'all agree, can we get this in the rfc, or does it need to wait for an > errata? > > - Wendy Roome > > _______________________________________________ > alto mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/alto > > -- -- ===================================== | Y. Richard Yang <[email protected]> | | Professor of Computer Science | | http://www.cs.yale.edu/~yry/ | =====================================
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