Chapter 8: Quality of Service (QoS)

Configuring CoS

As explained in “QoS Overview” on page 96, a packet received on a port is placed it into one of four priority queues on the egress port according to the switch’s mapping of 802.1p priority levels to egress priority queues.

The default mappings are shown in Table 2 on page 97.

You can override the mappings at the port level by assigning a different egress queue to a port. Note that this assignment is made on the ingress port and before the frame is forwarded to the egress port. Consequently, you need to configure this feature on the ingress port. For example, you can configure a switch port so that all ingress frames are stored in egress queue 3 of the egress port.

Note

The switch does not alter the original priority level in tagged frames. The frames leave the switch with the same priority level they had when they entered the switch.

To configure CoS for a port, perform the following procedure:

1.From the Main Menu, type A to select Advanced Switch Configuration.

The Advanced Switch Configuration Menu is shown in Figure 14 on page 59.

2.From the Advanced Switch Configuration Menu, type S to select Quality of Service Configuration.

The Quality of Service Configuration Menu is shown in Figure 23 on page 99.

3.From the Quality of Service Configuration Menu, type P to select Port Priority Configuration.

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Section I: Using the Menus Interface

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Allied Telesis AT-S79 manual Configuring CoS