michael.dillon@bt.com wrote:
But there is another way. That is for software developers to build a modified client that depends on a topology guru for information on the network topology. This topology guru would be some software that is run
While the current bittorrent implementation is suboptimal for large swarms (where number of adjacent peers is significantly less than the number of total participants) I fail to figure out the necessary mathematics where topology information would bring superior results compared to the usual greedy algorithms where data is requested from the peers where it seems to be flowing at the best rates. If local peers with sufficient upstream bandwidth exist, majority of the data blocks are already retrieved from them. In many locales ISP's tend to limit the available upstream on their consumer connections, usually causing more distant bits to be delivered instead. I think the most important metric to study is the number of times the same piece of data is transmitted in a defined time period and try to figure out how to optimize for that. For a new episode of BSG, there are a few hundred thousand copies in the first hour and a million or so in the first few days. With the headers and overhead, we might already be hitting a petabyte per episode. RSS feeds seem to shorten the distribution ramp-up from release. The p2p world needs more high-upstream "proxies" to make it more effective. I think locality with current torrent implementations would happen automatically. However there are quite a few parties who are happy to have it as bad as they can make it :-) Is there a problem that needs to be solved that is not solved by Akamai's of the world already? Pete _______________________________________________ NANOG mailing list NANOG@nanog.org http://mailman.nanog.org/mailman/listinfo/nanog