No.8（2005）13.A Data Replication Technique for Portable Wireless Terminals

Mamoru OHARA, Hiroshi OKANO and Hiroshi KAWAMURA

Providing information services via wireless networks is a promising way for helping outdoor activities for elderly and physically challenged persons. However, wireless network infrastructures, such as mobile cellar phone networks are still not as dependable as they could be. As an example of this, Internet access services on a mobile cellar phone network often suffer from service suspension due to failures on central server machines and network equipments. In this paper, we replicate important information into user terminals and network equipments near the users and use the replicas to continue services even in the event of such failures. We introduce a coding scheme using Redundant Residue Number System (RRNS) to replicate information. We implemented a prototype system with a Hypertext Transfer Protocol (HTTP) proxy using the RRNS coding scheme and confirmed that the replica could provide information instead of the servers that have failed.

Keywords

dependable system, data replication, personal digital assistance (PDA), redundant residue number system, HTTP proxy

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