A mechanism for trading cache capacity among network nodes, or equivalently, Network Service Providers and Internet Service Providers (collectively XSPs). The mechanism includes determining an arbitrage-free path in a network including at least one node having an excess of cache capacity and at least one node having an excess cache demand. The excess cache capacity on the arbitrage-free path is allocated to a node of the at least one node having an excess cache demand. A trading price is established for the excess cache capacity allocated.