ES-4024A User’s Guide
Chapter 22 Queuing Method 145
CHAPTER 22
Queuing Method
This chapter introduces the queuing methods supported.
22.1 Overview
Queuing is used to help solve performance degradation when there is network congestion. Use
the Queuing Method screen to configure queuing algorithms for outgoing traffic. See also
Priority Queue Assignment in Switch Setup and 802.1p Priority in Port Setup for related
information.
Queuing algorithms allow switches to maintain separate queues for packets from each
individual source or flow and prevent a source from monopolizing the bandwidth.
22.1.1 Strict Priority Queuing (SPQ)
Strict Priority Queuing (SPQ) services queues based on priority only. As traffic comes into the
switch, traffic on the highest priority queue, Q3 is transmitted first. When that queue empties,
traffic on the next highest-priority queue, Q2 is transmitted until Q2 empties, and then traffic
is transmitted on Q1 and so on. If higher priority queues never empty, then traffic on lower
priority queues never gets sent. SPQ does not automatically adapt to changing network
requirements.
22.1.2 Weighted Fair Queuing (WFQ)
Weighted Fair Queuing (WFQ) services queues based on their priority and queue weight (the
number you configure in the % field – see Figure 75 on page 146). WFQ 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.
22.2 Configuring Queuing
Click Advanced Application, Queuing Method in the navigation panel.
