Allied Telesis AT-S79, User Manual

Page: 102 / 210

Chapter 8: Quality of Service (QoS)
102 Section I: Using the Menus Interface
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 .