Transport Layer Network Layer Data Link Layer Physical Layer Application

The OMEGA architecture provides end-to-end quality of service (QoS) guarantees for distributed applications. QoS parameters are translated between application and network requirements by the QoS Broker, thus integrating media and network QoS management into a single entity. Admission control uses a schedulability test derived from application requirements. A novel task priority and precedence based scheme is used to represent complex application requirements and ensure correct feasible schedules. A prototype of OMEGA has been implemented using workstations connected by a 155 Mbps dedicated ATM LAN. To simplify implementation, we assumed a networked multimedia application with periodic media streams, speciically a master/slave telerobotics application. This application employs media with highly diverse QoS requirements (e.g., interarrival times, loss rate, bandwidth) and therefore provides a good platform for testing how closely one can achieve QoS guarantees with workstation hosts and cell-switching. Experience with this implementation has helped to identify new challenges to extending these techniques to a larger domain of applications and systems, and suggests promising new research questions.