Title: Heterogeneous clock group protocol for causally ordered delivery of messages

Authors: Satoshi Kawanami, Tomoya Enokido, Makoto Takizawa

Addresses: Department of Computers and Systems Engineering, Tokyo Denki University at Ishizaka, Hatoyama-cyo, Hiki-gun, Saitama 350-0394, Japan. ' Faculty of Business Administration, Rissho University, 2-16 Osaki 4 Chome, Shinagawa-ku, Tokyo, 141-8602, Japan. ' Department of Computers and Information Science, Faculty of Science and Technology, Seikei University, 3-3-1 Kichijoji-kitamachi, Musashino-shi, Tokyo 180-8633, Japan

Abstract: The vector clock widely used in group protocols cannot be adopted to a scalable group due to communication and computation overheads. In order to reduce the overheads, we discuss a hierarchical group which is composed of local subgroups. Processes in subgroups are synchronised by using physical and linear clocks while processes in a WAN are synchronised by using a vector clock. We discuss how to causally deliver messages by using the local synchronisation mechanisms. We discuss how to reduce the number of messages to be unnecessarily ordered. We evaluate the protocol in terms of number of messages ordered.

Keywords: group communication; causally ordered message delivery; large-scale groups; hierarchical groups; physical clock; vector clock; group protocols; WANs; wide area networks.

DOI: 10.1504/IJWMC.2009.029344

International Journal of Wireless and Mobile Computing, 2009 Vol.3 No.4, pp.247 - 254

Published online: 22 Nov 2009 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article