The second generation of Web sites provides more complex services than those related to Web publishing. Many users already rely on the Web for up-to-date personal and business information and transactions. This success motivates the need to design and implement Web architectures being able to guarantee the service level agreement that will rule the relationship between users and Web service providers. As many components of the Web infrastructure are beyond the control of Web system administrators, they should augment satisfaction percentage of the assessed service levels by relying on two mechanisms that can be integrated: differentiated classes of services/users, Web systems with multi-node architectures. The focus of this paper is on this latter approach. It reviews systems where replicated Web services are provided by locally and geographically distributed Web architectures. It considers different categories of Web applications, and evaluates how static dynamic and secure requests affect performance and quality of service of distributed Web sites.
['Valeria Cardellini', 'Emiliano Casalicchio', 'Michele Colajanni']
A performance study of distributed architectures for the quality of Web services