On Nov 17, 2011, at 8:18 PM, Brian E Carpenter wrote: > Ted, > > On 2011-11-17 17:54, Ted Lemon wrote: >> On Nov 17, 2011, at 11:05 AM, "Brian E Carpenter" >> <[email protected]> wrote: >>> I don't see how we could define a helpful API until the generic problem >>> of scope is solved (see my previous message). We have no general way >>> for an application to know or describe the scope that applies to itself and >>> the peer(s) it wants to talk to. >> >> It seems to me that applications "knowing" what scope they want to talk to >> is a very isolated special case. E.g., perhaps your set-top box knows that >> it needs to go through your cable ISP's provisioning domain to get streaming >> video. But generally speaking, your application wants to connect through >> whatever provisioning domain works best, which is something no provisioning >> domain can claim to know; it is something only the host can determine. > > Ultimately, only the hosts involved in a particular transaction can discover > what works best for them, which is why SCTP, MPTCP and SHIM6/REAP were > invented, as well as happy-eyeballs.
Well, ultimately, only the applications involved in a particular transaction can discover these things, because what's good for one application isn't necessarily good for another. Which is why trying to make e.g. happy eyeballs into a general-purpose mechanism is probably a poor idea. > However these (and any other) host mechanisms need an initial set of address > pairs to try out and, in many cases, an order of preference in which to > try them. In some cases (but not all) DNS may be source of a set of > destination addresses, but it's only the routing system that can provide > a priori information about which address *pairs* are worth trying. That is certainly how it should be. Anything based on heuristics, in the absence of routing information provided by the routing system, is just a hack. Keith _______________________________________________ mif mailing list [email protected] https://www.ietf.org/mailman/listinfo/mif
