Computer programs that run over the Internet are extremely convenient, but they can fail or lead to data-routing problems if they are not properly tested, says Amin Vahdat, a computer scientist at Duke University. He and his colleagues hope to rectify the problem with ModelNet—a mock-Internet proving ground for new applications.
Vahdat's team linked a few dozen PCs to simulate the way computers connect to the Internet. Some individual PCs simulated the functions of 10 to 100 home computers, all with the ability to run different programs; the rest moved around packets of data, delaying them long enough to make it seem as if the data had traveled across the world. If parts of the network became overloaded, some packets got lost, just as on the real Internet. Vahdat could then simulate technical problems or changes in consumer behavior: "We can say, What if certain links fail? or, What if ...
