Multicast communication in a distributed system connected by a local area network can increase parallelism, and it can also provide a greater functionality than one-to-one communication. In the authors' multicast protocol, the sender directs a message to a named group of receivers, which can be specified by function without requiring the sender to know the specific members of the group. Each host's kernel in the network can respond to every group message sent, providing various levels of reliability. It was found that the overhead of providing dependable multicast over a single local area network was very small, mainly because the protocol operates at the kernel level rather than the user level. Several forms of this multicast communication, expressed as simple message-passing communication primitives, are described, and the effectiveness of the protocol is evaluated using an example of a distributed algorithm. Performance analyses and actual performance data for the protocol are presented.
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