Allied Telesis management software layer 2+ fast ethernet switches Example 2 Video Application

AT-S62 Command Line User’s Guide

of a policy concerning packets coming from the application. The classifier for Policy 11 specifies the address as a destination address since this classifier is part of a policy concerning packets going to the application.

❑Flow Groups - Specify the new priority level of 7 for the packets. It should be noted that in this example the packets leave the switch with the same priority level they had when they entered. The new priority level is relevant only as the packets traverse the switch. To alter the packets so that they leave containing the new level, you would use the REMARKPRIORITY option in the CREATE QOS FLOWGROUP command.

❑Traffic Classes - No action is taken by the traffic classes, other than to specify the flow groups. Traffic class has a priority setting that can be used to override the priority level of packets, just as in a flow group. If you enter a priority value both in the flow group and the traffic class, the value in the flow group overrides the value in the traffic class.

❑Policies - Specify the traffic class and the port to which the policy is to be assigned. Policy 6 is applied to port 1 since this is where the application is located. Policy 11 is applied to port 8 since this is where traffic going to the application will be received on the switch.

Example 2: Video Application

Video applications typically require a larger bandwidth than voice applications. Video applications can be set up to have a high priority and buffering, depending on the application.

This example creates policies with low latency and jitter for video streams (for example, net conference calls). The policies assign the packets a priority level of 4 and limit the bandwidth to 5 Mbps. The node containing the application has the IP address 149.44.44.44. Policy 17 is assigned to port 1, where the application is located, and Policy 32 is assigned to port 8 where packets destined to the application enter the switch.

Policy 17 Commands:

create classifier=16 description=”video flow” ipsadddr=149.44.44.44

create qos flowgroup=41 description=”video flow” priority=4 classifierlist=16

create qos trafficclass=19 description=”video flow” maxbandwidth=5 flowgrouplist=41

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