Also, it probably has to be cheaper than the cost for more links/bandwidth such that increased costs related to this set of devices (knowing that optimally these are deployed at every cable-head-end or DSL subscriber facing interface) is below the other options available. It must also not impact the end-user pricing.

It’s a tough road to hoe…

One question that I’ve been wondering from the out-of-path deployment model, how do you identify what’s a p2p session? Trying to identify via port numbers would seem to cause false positives and miss non-standard/http tunneled traffic (as was reported in this case, with lotus notes users being unable to pass traffic). Blocking any sessions that are long/large in size would seem to cause a lot of collateral damage too (hello Windows service packs!).

There’s also a question - how harmful can resetting one session be - when there doesn’t seem to be any evidence that’s what they were doing. From what I’ve read, rst packets were spoofed/flooded on all sessions. Also - how effective really would a p2p blocking system be that only stopped one out of hundreds of sessions? I’d want my money back if I paid for a solution that that was the best it could do.

Right now I’m downloading, via bittorrent, Ubuntu 8.04. It was released today and all the public mirrors are down. This is pretty much the only way for me to get it, and it’s working very well. I’d be quick to switch providers if I suddenly lost this ability - but many consumers don’t have a choice in high-speed ISPs.

Looking at this example - it seems there’s not a net sum difference between in the total bandwidth used between 100k people all downloading a file via http, and the same number redistributing it between themselves via p2p. One just seems much more fault tolerant and effective at handling these types of sudden large popular files.