Change Changes Things - The Many Facets of Internet Dynamism
The general appeal of abstracting real-world networks to simple static graphs is understandable and has been partly responsible for fueling the new field of "network science." However, as applications to domains like the Internet have demonstrated, such abstractions that ignore much of what engineers consider critical come at a price -- even as toy models, they fail miserably when trying to capture, explain, or predict fundamental aspects real-world network behavior. Fortunately, the Internet application also suggests an alternative and more engineering-based approach to the "art" of abstracting real-world networks. This approach emphasizes the critical role of network dynamism and focuses squarely on understanding the cause-effect relationship between network structure (i.e., connectivity) and network function (i.e., usage). I will use specific Internet-related examples to illustrate this approach and discuss its implications on aspects such as measurement, network inference, and network modeling and model validation.
Walter Willinger, AT&T Labs-Research, USA