graphicHomeAdvance ProgramAward Anniversary EventCall for PapersConference CommitteeLocal InformationPaper SubmissionProgram committeeRegistrationStudent Travel AwardsTutorialgraphic Sigcomm logoSigcomm'99

Proportional Differentiated Services: Delay Differentiation and Packet Scheduling

Constantinos Dovrolis
University of Wisconsin

Dimitrios Stiliadis
Bell Laboratories

Parameswaran Ramanathan
University of Wisconsin

Internet applications and users have very diverse service expectations, making the current same-service-to-all model inadequate and limiting. In the relative differentiated services approach, the network traffic is grouped in a small number of service classes which are ordered based on their packet forwarding quality, in terms of per-hop metrics for the queueing delays and packet losses. The users and applications, in this context, can adaptively choose the class that best meets their quality and pricing constraints, based on the assurance that higher classes will be better, or at least no worse, than lower classes. In this work, we propose the proportional differentiation model as a way to refine and quantify this basic premise of relative differentiated services. The proportional differentiation model aims to provide the network operator with the `tuning knobs' for adjusting the quality spacing between classes, independent of the class loads; this cannot be achieved with other relative differentiation models, such as strict prioritization or capacity differentiation. We apply the proportional model on queueing-delay differentiation only, leaving the problem of coupled delay and loss differentiation for future work. We discuss the dynamics of the proportional delay differentiation model and state the conditions under which it is feasible. Then, we identify and evaluate (using simulations) two packet schedulers that approximate the proportional differentiation model in heavy-load conditions, even in short timescales. Finally, we demonstrate that such per-hop and class-based mechanisms can provide consistent end-to-end differentiation to individual flows from different classes, independently of the network path and flow characteristics.

Papers are provided as a service to all by the members of ACM SIGCOMM. Please check this box if you are a SIGCOMM member so we can get an idea of how the service is used.

This paper is available in and .

For information about joining SIGCOMM, follow this link


The referenced paper appears in Computer Communication Review, a publication of ACM SIGCOMM, volume 29, number 4, October 1999.

ACM Copyright Notice: Copyright (c) 1999 by Association for Computing Machinery, Inc. (ACM) Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that the copies are not made or distributed for profit or commercial advantage and that the copies bear this notice and full citation on the first page. Copyright for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permission to publish from: Publications Dept. ACM, Inc. Fax +1 212 869 0481 or email at