The key lies in identifying “hidden” bits of information that could help routers decide where to send a packet, Boguñá says. The people in Milgram’s experiment used such information to figure out how to forward their letters. Instead of passing them on to a random friend, they identified criteria, such as a person’s profession, that meant that they might be a step closer to the intended recipient. The work of Boguñá and his colleagues focuses on identifying and exploiting hidden information on other kinds of networks. In the case of Internet routing, the physical location of a router or the type of information it last handled could provide useful clues for forwarding information toward a final destination without knowing the complete structure of the network.
Kleinberg says that the work is “a very elegant approach to exploring the underlying structures that make navigability possible in real networks.” He adds that Boguñá’s group’s “techniques have the potential to inform a new class of routing strategies in which global information is replaced by local strategies that follow hidden metrics.”
However, Jon Crowcroft, a professor of communication systems at the University of Cambridge, U.K., warns that, while Boguñá’s group has done good work in applying Kleinberg’s theoretical models, it’s too early to tell if the approach would actually work. “When you look at it in reality,” he says, “there are other additional constraints,” such as the requirements of particular applications. Nonetheless, Crowcroft believes that this direction is “absolutely worth exploring” and says that he would like to see the researchers try some real-world experiments.
Boguñá himself admits that his work is “very preliminary.” The next step, he says, is to identify what “hidden metrics” could be used for Internet routing. But Boguñá expects that this could take several more years to figure out.