Scalability, Throughput Stability and Efficient Buffering in ReliableMulticast Protocols

This study investigates the issues of scalability, throughput stability and efficient buffering in reliable multicast protocols. The focus is on a new class of scalable reliable multicast protoco, PBcast that is based on an epidemic loss recovery mechanism. The protocol offers scalability, throughput stability and a bimodal delivery guarantee as the key features. A theoretical analysis study for the protocol is already available

The refdbms Distributed Bibliographic Database System

Refdbms is a database system for sharing bibliographic references among many users at sites on a wide-area network such as the Internet. This paper describes our experiences in building and using refdbms for the last two years. It summarizes the collection of facilities that refdbms provides, and gives detailed information on how well refdbms functions as a collaborative, wide-area, distributed information system

Weak-Consistency Group Communication and Membership

Many distributed systems for wide­area networks can be built conveniently, and operate efficiently and correctly, using a weak consistency group communication mechanism. This mechanism organizes a set of principals into a single logical entity, and provides methods to multicast messages to the members. A weak consistency distributed system allows the principals in the group to differ on the value of shared state at any given instant, as long as they will eventually converge to a single, consistent value. A group containing many principals and using weak consistency can provide the reliability, performance, and scalability necessary for wide­area systems. I have developed a framework for constructing group communication systems, for classifying existing distributed system tools, and for constructing and reasoning about a particular group communication model. It has four components: message delivery, message ordering, group membership, and the application. Each component may have a different implementation, so that the group mechanism can be tailored to application requirements. The framework supports a new message delivery protocol, called timestamped anti­entropy, which provides reliable, eventual message delivery; is efficient; and tolerates most transient processor and network failures. It can be combined with message ordering implementations that provide ordering guarantees ranging from unordered to total, causal delivery. A new group membership protocol completes the set, providing temporarily inconsistent membership views resilient to up to k simultaneous principal failures. The Refdbms distributed bibliographic database system, which has been constructed using this framework, is used as an example. Refdbms databases can be replicated on many different sites, using the group communication system described here