Fair flow control for ATM-ABR multipoint connections

Multipoint-to-multipoint communication can be implemented by combining the point-to-multipoint and multipoint-to-point connection algorithms. In an ATM multipoint-to-point connection, multiple sources send data to the same destination on a shared tree. Traffic from multiple branches is merged into a single stream after every merge point. It is sometimes impossible for the network to determine any source-specific characteristics since all sources in the multipoint connection may use the same connection identifiers. The challenge is to develop a fair rate allocation algorithm without per-source accounting as this is inequivalent to per-connection or per-flow accounting in this case. We define fairness objectives for multipoint connections, and we design and simulate an O(1) fair ATM-ABR rate allocation scheme for point-to-point and multipoint connections sharing the same links. Simulation results show that the algorithm performs well and exhibits many desirable properties. We list key modifications necessary for any ATM-ABR rate allocation scheme to fairly accommodate multiple sources.