Abstract: Service-Oriented Architecture(SOA) is emerging as a prevalent technology for software and enterprise information system development. As more and more services with similar functionality, people pay increasingly attention to Quality of Scrvice(QoS). This paper made the state of the art analysis to QoS models, and classified characteristics in existing literature. Their advantages and disadvantages were summarized. This contribution presented a QoS model for SOA which reflects its multi dimensional characteristics, and can be extended and measured dynamically.

Key words: SOA, Quality of service, Characteristics, Model