RRR: Recursive Round Robin Scheduler

Scheduling has been an interestig problem since its inception. In the context of real-time networks, a scheduling algorithm is concerned with dispatching streams of packets sharing the same bandwidth such that certain guaranteed performance for each stream like rate and delay bound is provided. This function has a wide range of applications in network elements such as host adaptors, routers and switches. This paper proposes and describes a new scheduling algorithm named as recursive round robin (RRR) scheduler. It is based on the concept of the construction of a scheduling tree in which distinct cell streams are scheduled recursively. Special emphasis is placed on the design and analysis of the scheduler. A delay bound is analytically derived for the scheduler and verified using simulation. The scheduler can work in either a work-conserving mode or non-work-conserving mode. It is shown that the work conserving scheduler is fair. Fairness indexes for the work conserving scheduler are analytically derived. The simple nature of this algorithm makes it possible to implement it at very high speeds, while considerably reducing the implementation cost.