1. A method for maintaining consistency in a cache in a data communication network, the method comprising the steps of: receiving a request for a data resource; determining whether the cache holds the requested data resource; detecting a freshness of the requested data resource if determined to be held by the cache; when said freshness of said requested data resource falls outside a predetermined range, generating a change-status request relating to said requested data resource to a source of that requested data resource; when generating said change-status request, identifying at least one other data resource held by the cache and from said source and generating a change-status request relating to said at least one other data resource to said source.