Quality of Service Issues in Internet Web Services

WE take great pleasure in introducing this special section on aQuality of Service Issues in Internet Web Serviceso to the readership of the IEEE Transactions on Computers. This special section is comprised of seven papers, spanning caching, prefetching, replication, admission control, and router scheduling. The topics covered include theoretical and implementation aspects of provisioning quality of service (QoS). A large fraction of Internet users access network resources through web clients/browsers. The quality of service (QoS) experienced by their Internet users has gained great importance in recent years. Furthermore, new web applications require the delivery of multimedia data in real time (e.g., streaming stored video and audio) and information transfer through the Internet is becoming one of the principal paradigms for business: electronic sales, banking, finance, collaborative work are a few examples of this. The QoS perceived by its users is thus becoming a dominant factor for the success of an Internet-based Web service. The principal QoS attributes users perceive include those related to the service aresponsiveness,o i.e., the service availability and timeliness. The performance perceived by the users of a web service depends on the protocols that operate between web clients and servers. Solutions currently investigated in the literature range from new protocols to enhance the network QoS (e.g., differentiated services) to mechanisms running into the end systems to enhance the QoS perceived by the users (e.g., caching, prefetching, Web servers' replications, etc.). In the medium-term, it is envisaged that the Internet will evolve to a universal transport service that will be able to provide on demand delivery of multimedia data with QoS guarantees. Currently, the best effort service provided by an IP network has necessitated development of middleware tools to overcome insufficient bandwidth and high latency. The issues that need to be addressed to improve the QoS are: