Here’s a little speech I gave to members of the EU Parliament in Brussels on Oct. 14th. The cousins are contemplating a set of Internet access account regulations that would mandate a minimum QoS level and also ban most forms of stream discrimination. This explains why such rules are a bad (and utterly impractical) idea.
The Internet is a global network, and regulating it properly is a matter of global concern. I’d like to share a view of the technical underpinnings of the question, to better inform the legal and political discussion that follows and to point out some of the pitfalls that lie in wait.
Why manage network traffic?
Network management, or more properly network traffic management, is a central focus of the current controversy. The consumer-friendly statements of policy, such as the Four Freedoms crafted by Senator McCain’s technology adviser Mike Powell, represent lofty goals, but they’re constrained by the all-important exception for network management. In fact, you could easily simplify the Four Freedoms as â€œyou can do anything you want except break the law or break the network.â€ Network management prevents you from breaking the network, which you principally do by using up network resources.
Every networking technology has to deal with the fact that the demand for resources often exceeds supply. On the circuit-switched PSTN, resources are allocated when a call is setup, and if they aren’t available your call doesn’t get connected. This is a very inefficient technology that allocates bandwidth in fixed amounts, regardless of the consumer’s need or his usage once the call is connected. A modem connected over the PSTN sends and receives at the same time, but people talking generally take turns. This network doesn’t allow you to save up bandwidth and to use it later, for example. Telecom regulations are based on the PSTN and its unique properties. In network engineering, we call it an â€œisochronous networkâ€ to distinguish it from technologies like the old Ethernet that was the model link layer technology when the DoD protocol suite was designed.
The Internet uses packet switching technology, where users share communications facilities and bandwidth is allocated dynamically. Dynamic bandwidth allocation, wire-sharing, and asynchrony mean that congestion appears and disappears on random, sub-second intervals. Packets don’t always arrive at switching points at the most convenient times, just as cars don’t run on the same rigorous schedules as trains.
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