Reliable multi-user tree setup with local identifiers

A protocol for setting up a tree connection for the purpose of multicast communication over a high-speed packet switched network is presented. The tree connection is based on the use of local identifiers, which 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 authors consider a high-speed network in which the local label swapping on data messages is performed in hardware by the switching subsystem, while the connection set-up is done in software by the switch control subsystem. A reliable protocol for setting up the tree connection is presented, and its correctness is formally proved. The protocol ensures the integrity of the tree and when failures occur, it is gracefully degraded into a smaller tree.