A method for performing end-to-end "tree-based ordered multicasting" (TOM) which
ensures collective integrity and consistency of distributed operations, and which
is applicable to distributed multiparty collaboration and other multipoint applications.
The TOM protocol performs cascaded total ordering of messages among on-tree hosts
en route from senders to receivers, and does not require the building of a separate
propagation graph to compute ordering information. TOM elects sequencer nodes dynamically
based on address extensions of the multicast tree. Message ordering is performed
by multicasting a message from each source node to receivers, unicasting a control
message from a source node across a primary node to an ordering node for the designated
multicast group or transmission in the tree, determining a binding sequence number
for the message and a multicast to the receiver group, and delivering messages
at end hosts according to the agreed-upon sequence numbers.