Increased bandwidth consumption does not necessarily cost money on most ISP infrastructure. At my home I have a fairly typical ISP service using BT's DSL. If I use a P2P network to download files from other BT DSL users, then it doesn't cost me a penny more than the basic DSL service. It also doesn't cost BT any more
It does cost BT, as I said someone pays even if it's not obvious to the user
The only time that costs increase is when I download data from outside of BT's network because the increased traffic reaquires larger circuits or more circuits, etc.
Incorrect, DSLAM backhaul costs regardless of where the traffic comes from. ISPs pay for that, it costs more than transit
The real problem with P2P networks is that they don't generally make download decisions based on network architecture.
Indeed, that's what I said. Until then ISPs can only fix it with P2P aware caches, if the protocols did it then they wouldn't need the caches though P2P efficiency may go down It'll be interesting to see how Akamai & co. counter this trend. At the moment they can say it's better to use a local Akamai cluster than have P2P taking content from anywhere on the planet. Once it's mostly local traffic then it's pretty much equivalent to Akamai. It's still moving routing/TE up the stack though so will affect the ISPs network ops.
I have to admit that I have no idea how BT charges ISPs for wholesale ADSL.
Hence your first assertion is unfounded
If there is indeed some kind of metered charging then Internet video will be a big problem for the business model.
It is, BT Wholesale don't give it away (usage or capacity based ISPs still have to pay)
The difference with P2P is that caching is built-in to the model, therefore 100% of users participate in caching.
But those caches are in the wrong place, they'd be better at the ISP end of the ADSL
With HTTP, caches are far from universal, especially to non-business users.
Doesn't matter if they're buying P2P caches they could buy HTTP if they don't have one already. The point is they're buying something brandon