Ying-Dar Lin
National Science Council
Integrated Service, Differentiated Service, Interoperation, Edge Router, Boundary Router
The solution architecture for RSVP-based Internet Integrated Services is maturing. It includes the standardized signaling protocol, i.e. RSVP, parameters for guaranteed and controlled load services, as well as algorithms for admission control, classification, policing, and scheduling. Further researches are meant to develop even better algorithms to enhance service and resource utilization. However, the per-flow state and the per-flow processing required in the Integrated Services networks have hindered the deployment of this whole set of solution to the greater scale. It is difficult to support the RSVP per-flow state and processing for thousands of flows in a single port. This kind of scalability, however, is a must in the backbone networks. Thus, an alternative solution, Differentiated Services, that offers per-class, instead of per-flow, service has been proposed. It does not record and process individual flows. It classifies and marks packets for the internal routers to treat them differently. Differentiated Services have been viewed as the promising solution for backbone networks and can be used to interconnect the stub Integrated Services networks. This model, backbone Differentiated Services and stub Integrated Services, retains the flexibility of RSVP QoS signaling and solves the scalability problem in the backbone networks.
This project investigates the problems and their solutions when interoperating these two different service networks, especially the involved protocols and algorithms in the edge or boundary routers interconnecting them. We hope to achieve seamless, flexible, and efficient integration. Our research issues include (1) granularity of service class allotment and bandwidth allocation in the Differentiated Services networks, (2) mapping of RSVP QoS to per-hop-behavior (PHB) and its realization, (3) behavior of concatenated per-hop-behaviors along the path, (4) implicit and explicit admission control in the Differentiated Services networks, (5) static and dynamic routing in the Differentiated Services networks. In (1) and (2), we plan to analyze various policies and make suggestions accordingly. In (3), we will analyze the end-to-end QoS and efficiency for various Differentiated Services. In (4) and (5), we will develop our own algorithms.
The research results will be realized into pieces of software and integrated into an edge router and a boundary router that can interconnect the Integrated Services networks and the Differentiated Services networks.