A framework to support survivable Web services

Web services have gained high popularity in the development of distributed application systems. Some critical applications also consider using Web services paradigm due to the benefits of interoperability, reusability, and adaptability. To support critical applications, existing Web service model needs to be extended to assure survivability. In this paper, we introduce the design of a novel survivable Web service (SWS) framework that supports continuous operation even in the presence of failures and security attacks. The replication scheme and n-modular redundancy (NMR) concept are used as the basis for achieving survivability. Due to replication, communication among multiple Web services becomes costly. We develop protocols, including the inter-group communication (SWS-IGC) and message ordering (SWS-MO) protocols, to guarantee efficient and correct communication. Preliminary performance studies show that the SWS framework only incurs a moderate overhead due to the incorporation of survivability assurance.