Differentiated Internet services

With the grown popularity of the Internet and the increasing use of business and multimedia applications the users' demand for higher and more predictable quality of service has risen. A first improvement to offer better than best-effort services was made by the development of the integrated services architecture and the RSVP protocol. But this approach proved only suitable for smaller IP networks and not for Internet backbone networks. In order to solve this problem the concept of differentiated services has been discussed in the IETF, setting up a working group in 1997. The Differentiated Services Working Group of the IETF has developed a new concept which is better scalable than the RSVP-based approach. Differentiated Services are based on service level agreements (SLAs) that are negotiated between users and Internet service providers. With these SLAs users describe the packets which should be transferred over the Internet with higher priority than best-effort packets. The SLAs also define parameters such as the desired bandwidth for these higher priority packets. The implementation of this concept requires additional functionality such as classification, metering, marking, shaping, policing etc. within routers at the domain boundaries. This paper describes the Differentiated Service architecture currently being defined by the IETF DiffServ working group and the required components to implement the DiffServ architecture.