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Egress queue vs packet priority mapping – Allied Telesis AT-GS950/48 User Manual

Page 197

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AT-GS950/48 Web Interface User Guide

197

Egress Queue vs

Packet Priority

Mapping

Each port has four egress queues, labeled Low, Medium, High, Highest.
Low is the lowest priority queue and Highest is the highest. A packet in a
high-priority egress queue is typically transmitted sooner than a packet in
a low-priority queue.Table 2 lists the default mappings between the eight
CoS priority levels and the four egress queues of a switch port.

You can change these mappings. For example, you might decide that
packets with a priority of 6 and 7 need to be handled by egress queue
Highest and packets with a priority of 2 and 3 should be handled in
Medium. The result is shown in Table 3.

Table 2. Default Mappings Priority Levels to Priority Queues

IEEE 802.1p

Priority Level

Port Priority

Queue

0

Low

1

Low

2

Low

3

Low

4

Low

5

Low

6

Low

7

Low

Table 3. Customized Mappings Priority Levels to Priority Queues

IEEE 802.1p

Priority Level

Port Priority

Queue

0

Low

1

Low

2

Medium

3

Medium

4

High

5

High

6

Highest

7

Highest