The Cost of Technical Illiteracy
Comcast's challenge is to make their residential network stable and responsive for the majority of its users despite the desire of a few users of such peer-to-peer file-sharing software such as BitTorrent to consume unlimited bandwidth.
BitTorrent's basic approach to bandwidth consumption actually conflicts quite strongly with a key assumption of the internet's architects, that the relationship between users and traffic flows is essentially a constant. On networks where people browsing the web use four connections in short bursts while BitTorrent users consume 40 or 50 constantly, this is no longer the case.
In contrast to the EFF, serious network people are exploring ways to extend the internet's traditional traffic management methods - packet dropping and slow-start - into the new reality where fairness and congestion have to be managed together.
Bob Briscoe of BT and UCL presented a paper to the IETF (the Internet's technical advisory body) in March. Flow Rate Fairness: Dismantling a Religion [PDF] attacking the problem head-on. In Briscoe's abstract we see that the problem afflicting the EFF has its roots in the internet design community's received wisdom:
Resource allocation and accountability keep reappearing on every list of requirements for the Internet architecture. The reason we never resolve these issues is a broken idea of what the problem is. The applied research and standards communities are using completely unrealistic and impractical fairness criteria. The resulting mechanisms don't even allocate the right thing and they don’t allocate it between the right entities. We explain as bluntly as we can that thinking about fairness mechanisms like TCP in terms of sharing out flow rates has no intellectual heritage from any concept of fairness in philosophy or social science, or indeed real life. Comparing flow rates should never again be used for claims of fairness in production networks. Instead, we should judge fairness mechanisms on how they share out the ‘cost’ of each user’s actions on others.
In other words, the internet's traditional method of ensuring fairness doesn't work any more - not for Comcast, not for BT, not for any network that hosts peer-to-peer file-sharing applications designed to grab all the bandwidth they can get. Internet routers can randomly drop packets all the way to the Restaurant at the End of the Universe, and peer-to-peer users will still consume most of the bandwidth on the internet's first and last hops.
The EFF's quibble with Comcast is therefore bankrupt. Home network providers have to provide some measure of fair access to each user they serve, and they can only do so with mechanisms that actually produce a result. The internet's traffic toolkit is nearly barren, so it's no wonder that Comcast and its peers would use mechanisms such as Reset Spoofing to accomplish an end that all rational people agree is worthwhile.
Truth or dare?
So why does the EFF complain? They're aware that file-sharing is troublesome for cable networks, but remain fully committed to the religious view that the internet's protocols were born fully-formed and inviolate in the mind of a virgin engineer in Bethlehem some 40 years ago, IETF discussions to the contrary notwithstanding.
Like many advocacy groups dealing with technical subjects, the EFF represents the view that technologies are meant to liberate the human spirit from the chains of exploitation, hence it's bewildered by the sight of people using the internet for such mundane purposes as downloading porn, bullying, and stealing music.
So it manufactures a fake crisis of network management to avoid the truth about the inanities of the internet. Problem solved. ®
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.