Cable ISPs, although they appear to deny these allegations, were found to be blocking peer-to-peer trafic like BitTorrent. The Max Planck Institute for Software Systems report, "Glasnost: Results from tests for BitTorrent traffic blocking" differs from the cable company's press releases. Comcast and Cox, the cable companies, were at the top of their list of blocking ISPs. None of the DSL ISPs were found to be blocking traffic.
Cable ISPs, although they appear to deny these allegations, were found to be blocking peer-to-peer trafic like BitTorrent. The Max Planck Institute for Software Systems report, "Glasnost: Results from tests for BitTorrent traffic blocking" differs from the cable company's press releases. Comcast and Cox, the cable companies, were at the top of their list of blocking ISPs. None of the DSL ISPs were found to be blocking traffic.The Max Planck Institute for Software Systems was established in November 2004. It conducts research in all areas related to the design, analysis, modeling, implementation and evaluation of complex software systems. It is part of 80 other institutes run by the Max Planck Society, which conducts research in medicine, biology, chemistry, physics, technology and the humanities.
8,175 users/nodes from locations around the world have used their software tool, Glasnost, to test whether their BitTorrent traffic is being manipulated. The tests were conducted worldwide between March 18 and May 15, 2008. The test sets up a series of BitTorrent flows between an end user's host and the Glasnost test servers. The packet trace for each flow on the server side was collected. Both end points were monitored for any error conditions that might cause a flow to be aborted. If a flow was aborted by a control (RST) packet that was not sent by either of the end points, the flow was reported as being blocked by some ISP along its path.
The number of measured hosts in the U.S. participating was 2,714. A total of 310 ISPs were measured in the U.S. There were 599 blocked hosts in the U.S. out a worldwide total of 628 blocked hosts. Comcast and Cox had 573 of the 599 blocking hosts in the U.S. Seven other U.S. ISPs blocked traffic as well, with a total of 26 blocking hosts. Surprisingly, Singapore's StarHub service was second after the U.S. blocked hosts with 26 blocked hosts out 45 measured hosts.
There is a map of the world in the report showing the locations of the nodes that ran the test and the blocked host locations. The map shows the heaviest blocked host locations to be in the U.S. Northeast, Mid-Atlantic, lower Florida, Great Lakes area, California to Washington and parts of the Southwest. An important point made in the report is that ISPs may throttle (rate-limit) traffic rather than blocking the traffic. The report did not cover traffic throttling. The Institute is working on methods to detect the throttled traffic.
The traffic charts in the report covering Comcast and Cox demonstrated that BitTorrent traffic was blocked over the entire 24-hour day. Comcast blocked about the same amount of traffic for all seven days of the week. Cox's traffic blocking occurred heaviest Thursday through Monday. Over a 24-hour period, Comcast blocked between 30% and 85% of the traffic. Traffic blocking by Cox was all over the map, from less than 20% to 100% traffic blocking, especially late evening to the early morning. There appears to no good time of day to avoid the traffic blocking.
The report had two other conclusions:
1. All observed blocking hosts did so in the upstream direction (i.e., when the client host attempted to upload data to one of our Glasnost servers). A few hosts observed blocking for downstream BitTorrent transfers.
2. The widespread blocking of BitTorrent transfers only occurred in the U.S. and Singapore.
The report measurements run counter to the Comcast and Cox statements about traffic blocking. Comcast has said it, "does not, has not, and will not block any Web sites or online applications. We have acknowledged that we manage peer-to-peer traffic in a limited manner to minimize network congestion. While we believe our current network management approach was a reasonable choice, we are now working with a variety of companies including BitTorrent [to deliver] a protocol-agnostic network management technique."
The Cox statement included, "Cox's network management practices ensure that bandwidth-intensive applications don't negatively impact our customers' Internet service. Cox allows the use of file-sharing and peer-to-peer services for uploads and downloads, and we allow access to all legal content, but we must manage the traffic impact of peer-to-peer services, as most ISPs do for the benefit of the customer."
These statements remind me of some of the ads I see about cable's better service. In this political year, the cable companies seem to be spinning their own way to the customer. Who do you trust, the cable company or the independent tests?
