On Tue, Sep 13, 2011 at 1:49 PM, Sebastian Kiesel <[email protected]> wrote: > On Tue, Sep 13, 2011 at 10:35:13AM -0400, Bill Roome wrote: >> How many PIDs do we expect an ALTO server to handle? >> >> I ask because I've discovered that code that works fine with a few hundred >> pids dies when I go to 5,000 pids. >> >> The biggest problem is the full cost map response message. With 5,000 >> pids, that has 25 million cost entries. > > I'm wondering whether retrieving the full N x N cost map is an > important (or even a realistic?) use case.
Yes I do believe it is important and realistic. If someone is going to be doing post-processing on the map to optimize for a a network as a whole, then this would be the desired interface to use. > > Consider an ALTO client embedded into a (P2P) application running on a > PC connected to ISP A, say in PID 1. It makes sense to ask ISP A's ALTO > server how expensive it is to get from PID 1 to candidate peers located > in PIDs 2 (other access network of ISP A), 3 (ISP B) and 4 (ISP C), > respectively. That is, it would need to know an 1 x N vector. > But why should the application be interested in knowing the cost from > PID 3 to 4? And even if it was interested, how would ISP A know the cost > between ISP B and C's networks? Yes - some of the feedback from IETF81 was to give an ALTO Server a way to say "I don't know" (one of the ways to do this might be to just omit such entries from the cost map, but that's another thread so I won't comment on it more here). > > If, on the other hand, we consider a big resource directory (e.g. P2P > tracker) it would make sense to know the N x N matrix. Agreed. > But I doubt > that there would be a single ALTO server that can deliver this matrix > with a high level of detail. Why not? I think I would disagree with this, depending on what you mean by "a high level of detail". An ALTO Server does not need to reply based on information from within other ISPs. The semantics of ALTO maps and information in general is that it is from the ALTO service provider's perspective. > Who would be the operator of this > ALTO server? I assume that the resource directory will have to ask > several ALTO servers (of different ISPs) for their 1 x N matrix > from their point of view and it will have to assemble the N x N matrix > from that. Remember that the semantics of ALTO maps and information from its own perspective. See: http://tools.ietf.org/html/draft-ietf-alto-protocol-09#section-2.2 Thanks, Rich > > Just my 2 cents. > > - Sebastian > _______________________________________________ > alto mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/alto > _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
