Adding Group Communication and Fault-Tolerance to CORBA

Groupware and fault-tolerant distributed systems stimulate the need for structuring activities around object-groups and reliable multicast communication. The object-group abstraction permits to treat a collection of network-objects as if they were a single object; clients can invoke operations on object-groups without needing to know the exact membership of the group. Object-groups mainly serve to increase reliability through replication, performance through parallelism, or to distribute data from one sender to a large number of receivers efficiently. This paper describes how object-groups and reliable multicast communication can be added to a CORBA compliant Object Request Broker. It also presents ELECTRA | a CORBA Object Request Broker whose architecture is pervaded by the group concept.