I tend to agree. P2P content caches are not going to save on the download from a client perspective because you have to download your file one way or another.
They will save on interconnection costs but I would suggest on a large network, with multiple peering points, over time more savings would be found on the upload from clients or intra-network (metro/regional) transfer of data (which indirectly save on interconnection costs). BTW, there has been efforts to put P2P clients in caches so that caches are seen just as a very high speed peer. Caches then integrate seamlessly into the P2P network. There has also been many interesting studies on P2P caches from (long vs. short tail perspective) vs. (micro caches vs. huge caches). Thanks, Reaindlo On 3/10/09 10:22 AM, "Nicholas Weaver" <[email protected]> wrote: > > On Mar 10, 2009, at 10:16 AM, Arnaud Legout wrote: > >> Hi, >> >> I believe that using caches (using regular clients on dedicated well >> placed machine) makes sense to >> reduce last miles traffic. >> >> However, I do not see a scenario in which caches are useful (here I >> mean that they cannot be replaced by >> a real P2P client with an appropriate locality definition used by >> the P2P protocol because the ISP architecture >> prevent real P2P clients to be located at an appropriate location) >> without requiring a large number of such caches. >> >> In particular, deploying such caches can be much more expensive that >> what you present. >> If you take for instance the case of a DSL provider, you need to >> place one dedicated cache per DSLAM. >> As there is a lot of DSLAM for a single ISP (hundreds to thousands) >> the cost is not negligible. >> One may argue that even a few millions of dollars is not significant >> for an ISP, but if it is to reduce a cost shift >> from content providers to network providers, it might be hard to >> convince ISPs that it is up to them to invest >> in a new infrastructure. >> >> Do you have in mind specific scenarios in which few caches can save >> a lot >> of last mile traffic, or did I misunderstood your proposition. > > The caches don't need to be at the DSLAM, but can be "one up" from the > DSLAM/CMTS. > > THe cache savings is not on the last mile download, but the last mile > UPLOAD which P2P requires, and it is this last-mile upload which make > P2P especially unattractive on cable networks. > > The "Second to last mile" cost of bandwidth (from the central point > within the ISP to the DSLAM) is the only part that would be saved by > locating the caches at the DSLAM rather than slightly more centrally > in the ISP. > > _______________________________________________ > alto mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/alto _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
