Cool Rules for the FCC: In the Lions's Den
Bennett goes to Boston
BitTorrent does this as a direct consequence of its scalability, by running dozens (or even hundreds) of TCP streams concurrently. The proliferation of streams gives BitTorrent immunity, at least partially, from the Internet's packet-drop-triggered congestion management system.
By contrast, most Internet traffic moving upstream on residential broadband networks comes from applications with no more than one stream active at a time. The loss of a single packet slows this application down, and hence the entire PC that runs it. The loss of a single packet by an application with dozens of active connections hardly registers on the host PC's bandwidth consumption scale. That's the loophole in conventional bandwidth management issues, and why Comcast has been hauled before the Star Chamber: when congestion kicks in, the neighbors slow down before BitTorrent does.
So an innovative bandwidth allocator at the client demands an innovative bandwidth allocator on the network, and that's what the Comcast's Sandvine system is. And logic suggests that if we appreciate a break from tradition on the application side we at least have to accept it on the management side, if it's being deployed to benefit the public. No one has suggested that Comcast's management of BitTorrent caused any harm: as a Comcast subscriber and BitTorrent user, the practice kept the application running well, without degrading the rest of the neighborhood.
QED, innovation all around. But how do we define good practice?
This is just what the Commissioners are looking for, too: what several referred to as a "bright line rule". that would allow them to distinguish "good" management from "bad". It's going to take a long trek to the heart of the sacred wood to find one, however. My suggestion, which I developed during my session, is to apply a laundry list of principles:
- Does the practice support a rational goal, such as the fair distribution of bandwidth?
- Is it applied, adapted, or modified by network conditions?
- Does it conform to standard Internet practices, or to national or international standards, and if not, does it improve on them?
- Has it been communicated to customers?
- Has technical information that would allow for independent analysis been made available to the research community and the public at large?
- Does the practice interfere with customer control of traffic priorities or parameters consistent with terms of service?
- Is the practice efficient with respect to both the upstream and downstream data paths?
- Does the practice accomplish its purpose with minimal disruption to the network experience of customers as a whole?
The controversy won't come to an end until the Commission produces a statement of principles and disclosure requirements, so they need to get on with it. I don't want to trudge through the snow in these shabby boating shoes again, even to harangue our federal regulators.®
Richard Bennett is a network architect and occasional activist in Silicon Valley. He wrote the first standard for Ethernet over twisted-pair wiring and contributed to the standards for WiFi and the Ultra-Wideband wireless networks. His eleven-year old blog is at bennett.com.
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