Toward a Theory of Differentiated Services.pdf

Toward a Theory of Differentiated Services Huan Ren Kihong Park Network Systems Lab Department of Computer Sciences Purdue University West Lafayette, IN 47907 f renh,parkg @cs.purdue.edu Abstract— Architecting networks capable of providing scalable, effi- QoS-sensitive services but not guarantees, it would be overkill cient, and fair services to users with diverse QoS requirements is a chal- to provision QoS using the mechanisms of per-flow reserva- lenging problem. The differentiated services framework has advanced a tion and admission control. In addition to the service mis- set of building blocks comprised of per-hop and access point behaviors with the aim of facilitating scalable services through aggregate-flow con- match, overhead associated with administering resource reser- trol inside the network and per-flow traffic control at the edge. In spite vation and admission control which require per-flow state at of recent efforts, little is known about how to select “good” per-hop and routers impedes scalability. On the other hand, relying on ho- edge controls, in part, due to a lack of cohesive criteria with respect to which the choices can be effectively reasoned, evaluated, and justified. mogenous best-effort service, characteristic of today’s Inter- In this paper, we provide a theoretical framework for reasoning about net, would be equally unsatisfactory. differentiated services networks, constrained to be implementable in