I agree with you, Sebastian. We still need to consider the ALTO client in PID1 may need to retrieve the whole network map. Then the size of the network map matters. And the App resource directory may want to get the full network map and cost map from ALTO Server in ISP A, which contains the M (number of PIDs within ISP A) * N (Number of total PIDs from ISP A's perspective) matrix.
BTW, IMO, PID is a local meaningful number within an ISP. Two ISPs can use the same PID to define different things. -Haibin > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of > Sebastian Kiesel > Sent: Wednesday, September 14, 2011 4:49 AM > To: Bill Roome > Cc: [email protected] > Subject: Re: [alto] How many PIDs in an ALTO server? > > 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. > > 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? > > 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. But I doubt > that there would be a single ALTO server that can deliver this matrix > with a high level of detail. 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. > > 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
