News: 'Selfish' routers slow the Internet
A packet of data has many ways to reach its destination and relies on the routers it encounters to direct it. Routers today, the computer scientists said, have several means to decide which way to send the information. They might send out test packets and time them. At other times, the routers might exchange information about the condition of networks close to them. More often than not, the router will choose the least congested path until it, too, becomes clogged. At that time, the router will settle on a previously neglected route.

The system will eventually stream to an equilibrium that mathematicians call a Nash flow, which is usually slower than an ideal system. The researchers constructed a mathematical analysis of how routers direct packets and found that the average time of travel increased by up to 1.33 times compared with an ideal system.

Adding more interconnected pathways to the network can also be counterproductive because of an effect called Braess' paradox, the researchers said. According to the paradox, the packets of information would simply hop from one path to another--much like drivers switching lanes in a traffic jam--actually slowing down all the other packets traveling on those pathways.…
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