The stringent timing requirements imposed by distributed multimedia applications have raised questions about the adequacy of continuous media support in the current commercial operating systems. The main objective of this research is to study the requirements, also known as Quality of Service (QOS), of multimedia applications and develop a QOS management scheme to support an efficient multimedia networking environment. An integrated QOS management architecture is proposed to maintain synchronization among different continuous media objects.
The primary goal of this research is to present a set of key application QOS parameters and map these requirements through all the layers of our proposed integrated QOS management framework. Emphasis is placed on four performance criteria for continuous media communication: Throughput, transmission delay, delay variations, and error rates.
End-to-end QOS guarantees are ensured by dynamic QOS control that is orchestrated by a protocol entity called the QOS negotiation agent. The QOS negotiation agent expands on the supplier-consumer paradigm, where the consumer requests a service (product) from the supplier and the supplier delivers the service if the consumer agrees on the cost. The QOS negotiation agent is an end-point resource manager that orchestrates the required resources for tasks performed in the application and transport subsystems. Using different negotiation protocols, the consumer side QOS agent negotiates QOS requirements with the network resource management and the supplier side QOS agent.
The QOS negotiation agent was programmed as a Windows NT background process handling all the negotiation threads by monitoring the operating system and network resources while the multimedia application was running in the foreground. To test the effectiveness of the QOS negotiation agent, we developed an AVI video player which could be executed with the QOS negotiation capabilities in either enabled or disabled mode.
The experimental results have demonstrated the effectiveness of the QOS negotiation scheme and confirmed that a comprehensive architectural framework for QOS support is essential for time-critical multimedia applications.