A method includes receiving a request for admission of a new communications session to a data network. The requested admission is such that the new communications session is granted a first set of one or more bandwidth usages of a resource of the network in response to being admitted. Each of one or more admitted communications sessions concurrently has a granted set of one or more bandwidth usages of the resource. The method includes admitting the new communications session to the data network in response to a sum over each set of the largest bandwidth usage of the resource in the each set being larger than an effective input bandwidth of the resource. Each admitted communications session is able to access a bandwidth of the resource up to any of the one or more bandwidth usages in its own one of the sets.