dono if this been posted b4...

actually they can block/throttle by protocol, application, port, and IP or any combination of them...

how it works is...

for every application/protocol/port/IP, they set rules, which actually consists or 3 parameters:-

1. guaranteed bandwidth - dedicated
2. maximum bandwidth - can't exceed this
3. burstable bandwidth - only opened if the line is free

however, depending on the way it is set, the setting is usually applied across the network e.g if it's placed just before a router that serves a certain IP range, all they need to do is to set the rule to that router's WAN IP and all corresponding LAN IPs in that router will be throttled, and this figure is usually small... e.g 5% or 10% of entire bandwidth is allocated to P2P, with a maximum bandwidth of say... 15% and a burstable of maybe 20%.

what this means is they guarantee 5% of the entire network capacity to P2P. this means that if u subscribe to 1Mb u will NOT get 5% of 1Mb... cos crappy screamyx bandwidth is shared. i forgot the ratio, but IIRC it's around 20Mbps for every 500 ppl with the assumption that not more than 100 will be online concurrently. That's the ISP model being used these days.

guess they just have to do this... WAN bandwidth isn't exactly cheap...

This post has been edited by dckj: Dec 31 2006, 12:35 PM