The geometry of mobility

Mobility in networks arises both as mobility of packets and mobility of nodes. In a wireless setting, packets move under network control to meet desiderata of low latency, high throughput, load-balancing, energy conservation, etc. Nodes, though, often move under the influence of forces unrelated to the network state, necessitating the continuous adaptation of supporting network structures. In order to understand how to best design such structures, it is important to study the stability of various network mechanisms under node motion, as well as under other kinds of variability in the network, such as wireless link volatility. Since networks are embedded in the physical world (sometimes in order to monitor this very world, as in sensor networks) and node motion happens under physical laws, geometric and topological methods can be useful in understanding global structures that can affect network performance. In this talk we give a number of examples of such methods, such as the use of kinetic data structures in clustering mobile nodes and the use of topological complexes for capturing the global structure of a static network with the goal of designing efficient routing protocols.