Real-time Data Management with Clock-less Reliable Broadcast Protocols

Distributed applications relying on replication of data objects in several sites are becoming popular. One key to their success is that they rely on reliable broadcast/multicast protocols. There are essentially two classes of approaches to build reliable broadcast services: the clock-driven and the clock-less approach. The former rely on the existence of a global timebase, whereas the latter do not. Clock-driven and clock-less protocols have often been classified as equivalent to `synchronous' and `asynchronous', respectively. The clock as an implementation tool is, however, not mandatory to achieve synchronism. By measuring the quality of synchronism by steadiness and tightness -- a metrics that applies equally to both classes -- we show that the criteria of suitability for real-time and fault-tolerance, can be extended to clock-less protocols. To appear in the Proceedings of the Workshop on the Management of Replicated Data, IEEE, Houston, Texas-USA, November 1990 Partner: INESC Author: P. Ver'issimo Workpackage: Date: August 1990 Reference: Copyright c fl1990 The Delta-4 Project Real-time Data Management with Clock-less Reliable Broadcast Protocols Paulo Ver'issimo Technical University of Lisboa, INESC e-mail:[email protected] or [email protected] Abstract Distributed applications relying on replication of data objects in several sites are becoming popular. One key to their success is that they rely on reliable broadcast/multicast protocols. There are essentially two classes of approaches to build reliable broadcast services: the clock-driven and the clock-less approach. The former rely on the existence of a global timebase, whereas the latter do not. Clock-driven and clock-less protocols have often been classified as equivalent to `synchronou..