Nomadic Service Assignment

We consider the problem of dynamically assigning application sessions of mobile users or user groups to service points. Such assignments must balance the trade-off between two conflicting goals. On the one hand, we would like to connect a user to the closest server in order to reduce network costs and service latencies. On the other hand, we would like to minimize the number of costly session migrations, or handoffs, between service points. We tackle this problem using two approaches. First, we employ algorithmic online optimization to obtain algorithms whose worst-case performance is within a factor of the optimal. Next, we extend them with opportunistic heuristics that achieve near-optimal practical average performance and scalability. We conduct case studies of two settings where such algorithms are required: wireless mesh networks with mobile users and wide-area groupware applications with or without mobility.