1. All hosts which observed blocking did so in the upstream direction (i.e., when the client host attempted to upload data to one of our Glasnost servers). Only a handful of hosts observed blocking for downstream BitTorrent transfers.
2. We found widespread blocking of BitTorrent transfers only in the U.S. and Singapore. Interestingly, even within these countries, most of the hosts that observed blocking belonged to a few large ISPs.
3. Both in the U.S. and in Singapore, all hosts that suffered BitTorrent blocking are located in cable ISPs. We did not see any blocking of BitTorrent transfers from DSL hosts in these countries.
Most (4,054 of 4,318) U.S. hosts that observed blocking are located in Comcast and Cox networks. In Singapore, almost all blocked hosts are connected using the StarHub network. While we did observe blocking for hosts in 110 other ISPs (43 of which are in the U.S.), we did not see widespread blocking of BitTorrent traffic for hosts in those ISPs.
