Supporting real-time IP traffic with enhanced service classes in DiffServ networks

The differentiated services (DiffServ) architecture offers a scalable alternative to provide quality of service (QoS) guarantees for performance-sensitive applications in the Internet. Within the DiffServ framework, however, an efficient traffic scheduling mechanism is a key component to ensure such QoS guarantees. The authors propose a packet scheduling algorithm called enhanced weighted fair queueing (EWFQ). which enables fair bandwidth sharing while supporting tight bounds on end-to-end delay for real-time traffic such as voice over IP (VoIP) in DiffServ networks. EWFQ allows service classes to be created and proportional weights to be assigned to such classes efficiently according to their resource requirements. Results from simulation studies indicate that the mechanism proposed ensures both the required bandwidth fairness and end-to-end network delay bounds according to the specified weight ratios under various traffic and network conditions. The scheme also has lower implementation complexity, along with scalability to accommodate growing traffic flows at the core routers of the high-speed Internet backbone.