Scalable Scheduling Support for Loss and Delay Constrained Media Streams

View/ Open
Date
1998Author
West, Richard
Schwan, Karsten
Poellabauer, Christian
Metadata
Show full item recordAbstract
Real-time media servers need to service hundreds and, possibly, thousands of
clients, each with their own quality of service (QoS) requirements. To
guarantee such diverse QoS requires fast and efficient scheduling support at
the server. This paper describes the practical issues concerned with the
implementation of a scalable real-time packet scheduler resident on a
server, designed to meet service constraints on information transferred
across a network to many clients. Specifically, we describe the
implementation issues and performance achieved by Dynamic Window-Constrained
Scheduling (DWCS), which is designed to meet the delay and loss constraints
on packets from multiple streams with different performance objectives. In fact, DWCS
is designed to limit the number of late packets over finite numbers of
consecutive packets in loss-tolerant and/or delay-constrained, heterogeneous
traffic streams. We show how DWCS can be efficiently implemented to provide
service guarantees to hundreds of streams. We compare the costs of different
implementations, including an approximation algorithm, which trades service
quality for speed of execution.