Digital Extremes programmer Steve Sinclair has shed some light on the logistics of multiplayer Unreal Championship using Xbox Live in a post to the official Infogrames forum. While Sinclair can't comment on whether big bandwidth hosted servers are a certainty, as that's Microsoft and Atari's (Infogrames) area, he does shed some light on bandwidth and voice comm-sensitive issues.
According to Sinclair, Digital Extremes is working hard to trim bandwidth utilisation. When you host a game, UC determines how many players your bandwidth is capable of supporting and sets an appropriate limit. DE has spared a lot of bandwidth use by removing redundancy (the example provided is bullet impacts - the client side implicitly plays the sound, rather than having to wait for a 'playsound' packet).
Voice comms use a relatively small amount of data too, and is channel based to avoid what Sinclair describes as "the packet storm that would result if everyone could hear everyone else." The voice bandwidth usage is tunable and Digital Extremes are still experimenting with this aspect, but expect to ship with four players to a channel and easy channel-changing, not to mention a "push button to talk" feature, which is being tested as you read this.
The current target for the game is 128-256KBps - a reasonable target for DSL and cable modem systems. "Currently the target is to support eight players nicely on a decent DSL-based listen server (where the host can play also)," he says, adding that "if you have a bad-ass connection this could go higher." Playing with several players to one Xbox is also likely to increase the player limit, and we're assured in time-honoured tradition that "playing split-screen multiplayer rocks!"