Reliable multiuser tree setup with local identifiers

The authors present a reliable protocol for setting up a tree connection for the purpose of multicast communication over a high-speed packet switched network. The tree connection is based on the use of local identifiers that are swapped at every intermediate node of the tree. Local identifiers are simple to manage, provide fast access to the routing tables, and are very efficient in terms of the size of the resulting routing space. The context of the present work is a high-speed network in which the local label swapping on data messages is performed in hardware by the switching subsystem, while the connection setup is done in software by the switch control subsystem. The correctness of the protocol is formally proved. The protocol ensures the integrity of the tree, and, when failures occur, the tree is gracefully degraded into a smaller tree