Proxy location problems and their generalizations

In this paper we suggest a new angle to look on proxy location problems. We view the proxy as a service and generalize the problem of optimally placing proxies to optimally placing any service in the network. We differentiate between two cases: transparent services, such as transparent caches (TERCs), and non-transparent services where the end stations, such as hosts using a cache, need to be configured with respect to the service locations. This formulation enables us to study in a unified framework the location problems related to active networks, overlay peer-to-peer networks, as well as, CDNs and caching. For both cases we formalize the problem of optimally placing network servers and introduce approximation algorithms. We present simulation results of approximations and heuristics. We also present an optimal solution for the location problem for a special topology. We show, through a series of examples, that our approach can be applied to a variety of different services.