Appendix B Quality Of Service (Qos) Examples; Overview - Motorola nvg589 Administrator's Hanbook

Appendix B Quality of Service (QoS) Examples
This section contains information about the Motorola Gateway QoS implementation.

Overview

When packets arrive on a high speed interface and are forwarded to a low speed interface, there is
contention for bandwidth. This is the use case for QoS: to make effective use of bandwidth.
The basic steps for Quality of Service are to match and identify packets as belonging to a class of traf-
fic, and to give each class of traffic a certain behavior such as priority queuing or bandwidth shaping
across critical networking bottlenecks.
Packets forwarded through the system are classified using sets of filter rules to match various criteria,
for example p-bit, DSCP, IP address, port, etc. The matching rule can set the classification, which is
the name of the queue that is to be used.
Figure 1. Illustration of upstream congestion, all traffic is consistently delayed.
Figure 2. Illustration of classification and transmit queue in a simple high/low priority scheme. Low priority may transmit
only when high priority is completely empty.
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