Increasing Web Service Dependability Through Consensus Voting

This paper demonstrates our Web Service based N-Version model, WS-FTM (Web Service-Fault Tolerance Mechanism), which applies this well proven technique to the domain of Web Services to increase system dependability. WS-FTM achieves transparent usage of replicated Web Services by use of a modified stub. The stub is created using tools included in WS-FTM. Our initial implementation includes a simple consensus voter that allows generic result comparison. Finally we show, through the use of a non-trivial example, that WS-FTM can be used to increase the reliability of a Web Service system.