Group communication using modular protocol stacks

Today's distributed systems consist of many different components, making th e efficient management of such systems an extremely difficult task Group co mmunication should provide a potential solution to make the management proc ess more flexible. It is possible to build a group communication system bas ed oil traditional distributed technology such as CORBA (Common Object Requ est Broker Architecture), but efficiency is poor due to lack of support for multicast and the overhead of building groups in current commercially avai lable products. Multicast is a key part of a future group communication arc hitecture and although reliability is not yet supported there are workaroun ds which provide a solution. This paper discusses the design and implementa tion of reliable IP multicast protocols for group communication, One import ant aspect of this work is the modularisation of the protocol blocks, and t he design of a modular protocol, which can be used in conjunction with othe r similar protocol blocks to build a communication stack for group communic ations, is described in detail.