� 1.3 QoS in ATM Network and Telephone Network

This is a survey paper on Quality-of-Service(QoS) based routing. In this paper, we first introduce the concept of Quality-of-Service and its background. Second, we discuss the concepts of QoS-based routing, its objectives and main issues. After that, several types of QoS based routing algorithms are compared, and the advantages and disadvantages of each type discussed. Then, the relations between QoS based routing and some relevant techniques are studied, including traffic engineering, high level admission control, resource reservation protocols(e.g. RSVP), differential services(DiffServ) and MPL