ZyXEL XGS4700-48F User Guide - Page 218

Chapter 22 Queuing Method 2(Weight -1) x 10 KB If the weight setting is 5, the actual quantum guaranteed to the associated queue would be as follows: 24 x 10KB = 160 KB 22.1.3 Weighted Round Robin Scheduling (WRR) Round Robin Scheduling services queues on a rotating basis and is activated only when a port has more traffic than it can handle. A queue is given an amount of bandwidth irrespective of the incoming traffic on that port. This queue then moves to the back of the list. The next queue is given an equal amount of bandwidth, and then moves to the end of the list; and so on, depending on the number of queues being used. This works in a looping fashion until a queue is empty. Weighted Round Robin Scheduling (WRR) uses the same algorithm as round robin scheduling, but services queues based on their priority and queue weight (the number you configure in the queue Weight field) rather than a fixed amount of bandwidth. WRR is activated only when a port has more traffic than it can handle. Queues with larger weights get more service than queues with smaller weights. This queuing mechanism is highly efficient in that it divides any available bandwidth across the different traffic queues and returns to queues that have not yet emptied. 218 XGS4700-48F User's Guide