ZyXEL Communications MES-2110 manual QoS Base Configuration Screen, 157

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QoS

21.1 Overview

Quality of Service (QoS) is used to prioritize source-to-destination traffic flows. All frames in the flow are given the same priority. You can use QoS to give different priorities to different frame types to solve performance degradation when there is network congestion.

21.2 The QoS Base Configuration Screen

Queuing algorithms allow switches to maintain separate queues for frames from each individual source or flow and prevent a source from monopolizing the bandwidth.

All High Before Low Queuing

All high before low services queues based on priority only. As traffic comes into the MES-2110, traffic on the highest priority queue, Q7 is transmitted first. When that queue empties, traffic on the next highest-priority queue, Q6 is transmitted until Q6 empties, and then traffic is transmitted on Q5 and so on. If higher priority queues never empty, then traffic on lower priority queues never gets sent. SP does not automatically adapt to changing network requirements.

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 a 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 rather than a fixed amount of bandwidth. WRR is activated only when a port has more traffic than it can

MES-2110 User’s Guide

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