Abstract: A method, system and program for transmitting different quality versions of a stream to end-user nodes of a network. The method comprises: for each of a plurality of possible combinations of versions of the stream to different consuming end-user nodes, evaluating a utility function for each of those consuming end-user nodes, the utility function being dependent on the version and defining a quantitative measure of end-user benefit that would be experienced at the respective end-user node by consumption of the respective version; for each of said plurality of possible combinations of versions of the stream over said routes, determining an overall utility value based on the respective evaluation of the utility functions of each of said plurality of consuming end-user nodes; and selecting a preferred combination of versions of the stream over said routes based on the overall utility values of the different possible combinations.

Abstract: A method, system and program for routing a data stream amongst a plurality of network nodes including at least a plurality of end-user nodes. The method comprises: establishing a plurality of routes for the stream to a plurality of consuming end-user nodes, including at least one route via one or more relaying nodes; at each of a plurality of optimizing nodes, executing an optimization algorithm to determine a respective routing modification by evaluating a routing criterion with respect to a collection of end-user nodes which share information with the respective optimizing node and determining a change in the routing criterion that would result from one or more potential routing modifications. The different optimizing nodes' collections of end-user nodes are at least partially coincident such that each optimizing node can determine a different routing modification with respect to at least some of the same end-user nodes.

Abstract: A method of transmitting a data stream to end-user nodes of a network, and a corresponding communication system, program, and distribution system for distributing the program. The method comprises: for each of a plurality of possible combinations of routes of the stream to a plurality of consuming end-user nodes, evaluating a utility function for each of the consuming end-user nodes, the utility function being dependent on route and defining a quantitative measure of end-user benefit that would be experienced at the respective end-user node by consumption of the stream; for each of the plurality of possible combinations of routes, determining an overall utility value based on the respective evaluation of the utility functions of each of the plurality of consuming end-user nodes; and selecting a preferred combination of routes for the stream based on the overall utility values of the different possible combinations.

Abstract: A method, system and program for transmitting different quality versions of a stream to end-user nodes of a network. The method comprises: for each of a plurality of possible combinations of versions of the stream to different consuming end-user nodes, evaluating a utility function for each of those consuming end-user nodes, the utility function being dependent on the version and defining a quantitative measure of end-user benefit that would be experienced at the respective end-user node by consumption of the respective version; for each of said plurality of possible combinations of versions of the stream over said routes, determining an overall utility value based on the respective evaluation of the utility functions of each of said plurality of consuming end-user nodes; and selecting a preferred combination of versions of the stream over said routes based on the overall utility values of the different possible combinations.

Abstract: A method, system and program for routing a data stream amongst a plurality of network nodes including at least a plurality of end-user nodes. The method comprises: establishing a plurality of routes for the stream to a plurality of consuming end-user nodes, including at least one route via one or more relaying nodes; at each of a plurality of optimising nodes, executing an optimisation algorithm to determine a respective routing modification by evaluating a routing criterion with respect to a collection of end-user nodes which share information with the respective optimising node and determining a change in the routing criterion that would result from one or more potential routing modifications. The different optimising nodes' collections of end-user nodes are at least partially coincident such that each optimising node can determine a different routing modification with respect to at least some of the same end-user nodes.