An article by Vinod Tandon in last month’s Develop magazine (September 2010), discusses bandwidth issues from the perspective of someone working within SCEA’s Online Technology Group. Unfortunately the online version of the article only shows the first two out of three pages. This is a very basic discussion of some techniques to reduce bandwidth, including network topology and message aggregation. The third page has some interesting statistics about the upstream bandwidth profiles of PSNet users. This informs the situation where one of the players hosts the server, rather than using a centralized server. In North America there is a smooth spread of upstream rates, with two peaks at 513-768kbps (17% of connections) and 2049-8192kbps (24%). The European one has two peak also, with 513-768 (19%) 769-1024 (21%) being one peak, and then 49153+ (19%). To compare in North America only 4% had 49153+. Japan and Korea have much better upstream bandwidth. 50% of Japanese users have 49153+ whilst 38% have 8193-49152kbps. In Korea 94% have 49153+kbps.
The implications for peer to peer games are quite significant. In North America a peer-hosted service could suffer on outbound bandwidth, thus limiting the number of players. Relatively few people can host large games. In Europe there is a large group who could host such games, but there may not be such a person within any social group. However, people who select to host games are likely to be able to get the bandwidth to attract players. In Japan and Korea it is much easier as most players have the upstream bandwidth to host large games.