Paper Review : Integrated Services in the Internet Architecture: an Overview

Reviewer : Seh Leng Lim

This memo proposes an extension to the Internet architecture and protocols to provide integrated services to support real-time as well as the current non-real-time service of IP.

The main contribution of the paper is its discussion about how to enhance existing IP Internet to serve both real-time and non-realtime applications. It also touched on the topic of how to control sharing of bandwidth on a particular link among different traffic classes. The authors coined the term “Integrated Services” (IS) for an Internet service model that includes best-effort service, real-time service and controlled link sharing.

The key main ideas expounded are :

(a) Integrated services model providing guaranteed and predictive service towards real-time traffic. The model integrates the services with controlled-link sharing and supports multi-cast as well as unicast.

(b) reference implementation framework comprising of packet scheduler, admission control routine, classifier and reservation setup protocol to realize the IS model

© the idea that the quantity of primary interest in resource sharing is aggregate bandwidth on individual links

The authors assumed that it is desirable to use the Internet as a common infrastructure to support both non-real-time and real-time communication, as building a parallel architecture just for real-time services would lose the advantages coming from the statistical sharing between real-time and non-real-time traffic. The authors have also noted that additional flow state in routers and explicit setup mechanism is necessary to provide the Integrated Service extension to the Internet.

I think that the paper has a modest contribution (rating of 3) to the study reservation protocols. A lot of work (as quoted in the paper) has previously been done. I see that there is very little implementation or experimental work being done and the paper is just focused on the various possible arguments, as it is just an overview as claimed in its title. The authors have rightly pointed out the direction for future work in the area of how to solve problems in implementing reservation protocols brought about by routing.

Researchers and builders working with real-time applications may have a better appreciation from this paper of the difficulties involved in guaranteeing quality of service over the Internet.