Weighted Fair Queuing - ZyXEL Communications MS-7206 - EDITION 1 Manual

Chapter 25 Queuing Method
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.

25.1.3 Weighted Fair Queuing

Weighted Fair Queuing (WFQ) is used to guarantee each queue's minimum
bandwidth based on its bandwidth weight (portion) when there is traffic
congestion. WFQ is activated only when a port has more traffic than it can handle.
Queues with larger weights get more guaranteed bandwidth than queues with
smaller weights. This queuing mechanism is highly efficient in that it divides any
available bandwidth across the different traffic queues. By default, the weight for
Q0 is 1, for Q1 is 2, for Q2 is 3, and so on. Guaranteed bandwidth is calculated as
follows:
For example, using the default setting, Q0 on Port 1 gets a guaranteed bandwidth
of:
170
MS-7206 User's Guide