Hi Wendy, On Tue, Jul 19, 2016 at 03:18:24PM -0400, Wendy Roome wrote: > draft-kiesel-alto-xdom-disc-02 has this (Sect 3.2, Endpoint Cost Service): > > If an ALTO client wants to query the Endpoint Cost Service (see Section > 11.5 of RFC 7285 [RFC7285]) for the costs from source address X to > destination address(es) Y (and Z), it has to invoke the crossdomain ALTO > server discovery procedure with parameter X. The result will be the IRD > URI of the ALTO server to query for the costs from X to Y (and Z). > > My first comment was why do cross-domain ALTO server discover on X, rather > than Y or Z? > > Then I realized there is a good reason. I believe most ECS queries will be > either 1->N or N->1. That is, costs from many sources to one destination > (client selecting server from which to download a file) or one source to > many dests (client selecting server for upload). > > So if the query is 1->N or N->1, do cross-domain discovery on the one > address. That is probably the address of the real client - the one which > needs ALTO guidance. So use the ALTO server which has the best data for > that address.
exactly! This does not only save on the number of transactions with different ALTO servers, it helps also to deal with our (deliberately) not-so-well-defined "routingcost" default metric. Thanks Sebastian _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
