Building multicast services from unicast forwarding and ephemeral state

We present an approach to building multicast services using unicast forwarding and two additional building blocks: ephemeral state processing, i.e., extremely lightweight distributed computations based on a time-bounded associative memory; and the ability to enable lightweight packet processing modules at the routers. In our approach, senders and receivers use ephemeral state probes to locate the desired network nodes where packet processing functions, e.g., packet duplication should be activated. Our approach reduces the amount of multicast state in the network, eliminates the need for sophisticated routing mechanisms, allows the end-systems to tailor the service to their needs, and can be deployed incrementally. (C) 2002 Elsevier Science B,V. All rights reserved.