Exact Admission Control for Networks with a Bounded Delay Service
Jorg Liebeherr
Dallas E. Wrege
Department of Computer Science
University of Virginia
Charlottesville, VA 22903
Domenico Ferrari
CRATOS
Universita Cattolica
Via Emilia Parmense, 84
I-29100 Piacenza, Italy
Abstract
To support the requirements for the transmission of continuous media,
such as audio and video, multiservice packet-switching networks must provide
service guarantees to connections, including guarantees
on throughput, network delays, and network delay variations.
For the most demanding applications, the network must offer a service
which provides deterministically bounded delay guarantees,
referred to as `bounded delay service'.
The admission control functions in a network with a bounded delay
service require `schedulability conditions' that detect violations
of delay guarantees in a network switch.
In this paper, exact schedulability conditions are
presented
for three packet scheduling methods:
Earliest-Deadline-First (EDF), Static-Priority (SP), and a
novel scheduling method, referred to as Rotating-Priority-Queues (RPQ).
By characterizing the worst-case traffic with general subadditive functions,
the presented schedulability conditions can be applied to a large class
of traffic models.
Examples, which include actual MPEG video traces, are presented to
demonstrate the trade-offs involved in selecting a packet scheduling method
for a bounded delay service.