A QoS-AWARE MIDDLEWARE FOR ENSURING WEB SERVICES RELIABILITY

摘要

As Web services are widely adopted, the demands for high Quality of Service (QoS) are increasing continuously and remarkably. Reliability, as one of the key components of QoS, needs to be guaranteed first and foremost even in the cases of network/system failures or service unavailability. To address these requirements, we design Reliable Web Services Bus (RBUS), a QoS-aware middleware for ensuring Web services reliability, which adopts different approaches to implement three important QoS features of reliability. These features include: 1) reliable messaging, implemented by incorporating advanced retransmission and persistence store mechanism; 2) service fault tolerance, achieved by providing the Virtual Service (VS) concept and equivalent service selection algorithm for choosing redundant replaceable services; and 3) service priority, ensuring that the services with higher priorities are more reliable than those with lower priorities. This paper discusses RBUS architecture and reports some experimental results to demonstrate its effectiveness.