Broadening the IPv6 discussion

Fri Aug 30 08:28:09 UTC 2002

itojun at iijlab.net wrote:
> 
>         you can go hybrid, like
>         - client connects to server for game playing info (like location on the
>           map, inventory and stuff)
>         - client will talk with each other directly for video/voice-chat
>         even with this, server load/traffic will be decreased.

This is exactly what I also had in mind. This would get 1:10 benefit 
in bandwidth and actually enable this kind of activity. 
> 
>         i still don't understand why you say multicast is mandatory.
> 
Most consumer connetions (where this is feasible anyway) are asymmetric,
having 256k-1.5Mbps downstream and 128k-512k upstream. A decent video stream
represents 128k to 384k of bandwidth. If you have a small number, say eight
players in a game, you'll end up sending the stream seven times unless
you do multicast. You probably don't have the upstream bandwidth to accommodate
that unless you're lucky to sit on top of a new housing development with 
fiber in the basement.

The next logical step to this discussion is what happens to multicast routing
when one million gamers setup half a million *,G and a few million S,G pairs.
Add a zero if it makes the excersise more interesting. Keep in mind that 
one million gamers playing is less than what the network currently has at any given
moment.

Pete