Patent ID: 8316106

Claim:
A system comprising: a plurality of edge routers configured to direct requests from a client system to one of a plurality of cache servers, each of the cache servers configured to provide content to the client system in response to the requests; and a route controller comprising a processor configured to: receive demand information from the edge routers; estimate an optimal request distribution based on the demand information using a bicriteria approximation algorithm, wherein initial programming states for the estimation are specified by (u, F, D, F S , D S , F exp , Fimp), where u is a current node, F is a vector representing an available facility for large capacity, D is a vector representing an outsourced large client, F S is an amount of cache server capacity offered to small clients, D S is a total demand of outsourced small clients, F exp is an index of a cache server being exported from a subtree, and F imp is an index of another cache server of another subtree that is being utilized; and provide each of the edge routers with anycast route information for the cache servers.