ISP throttling P2P networks is not new. But often, they just control the bandwidth once they identified P2P packets. It is why encrypting the transfer (BitTorrent has an encryption mode) often cures throttling. Comcast uses a new method, deployed by Sandvine, of throttling. When a comcast peer seeds a non-comcast user/peer, after a few seconds Comcast issues a reset (RST) packet to the non-Comcast user. This has two consequences:
- The non comcast-user losses its seed
- The comcast-user losses some upload bandwidth. This may have an impact on the transfer ratio in case of private P2P. In these P2P network, the more you seed, the more and faster you receive
Of course, the community immediately reacted and worked on the problem. The nicest solution is based on the use of Linux Firewall. It is possible to filter the RST packets, thus stopping the throttling. Some sites provide all the information to setup the filtering for different Linux distributions ( For instance Tux training)
But was is more interesting is the reaction of the FCC. It is expected that FCC will order Comcast to cease throttling. According to a majority of members of FCC, they believe it is illegal to throttle without informing customers. Decision to be announced in the coming days.
We may expect some ISPs soon to change their licensing conditions and put in it that they may throttle. If there is an obligation to announce clearly throttling, this will be an argument for choosing his/her ISP (with or without throttling).