SMC Networks 100BASE-TX manual Mapping CoS Values to Egress Queues, Egress Queue Priority Mapping

3 Configuring the Switch

Mapping CoS Values to Egress Queues

This switch processes Class of Service (CoS) priority tagged traffic by using four priority queues for each port, with service schedules based on strict or Weighted Round Robin (WRR). Up to eight separate traffic priorities are defined in IEEE 802.1p. The default priority levels are assigned according to recommendations in the IEEE 802.1p standard as shown in the following table.

Table 3-10. Egress Queue Priority Mapping

Queue	0	1	2	3
Priority	1,2	0,3	4,5	6,7

1,2	Q0
0,3	Q1
4,5	Q2
6,7	Q3

Serviced by weighted round robin

The priority levels recommended in the IEEE 802.1p standard for various network applications are shown in the following table. However, you can map the priority levels to the switch’s output queues in any way that benefits application traffic for your own network.

	Table 3-11. Priority Level Descriptions
Priority Level		Traffic Type
1		Background
2		(Spare)
0 (default)		Best Effort
3		Excellent Effort
4		Controlled Load
5		Video, less than 100 milliseconds latency and jitter
6		Voice, less than 10 milliseconds latency and jitter
7		Network Control

Command Attributes

•Priority – CoS value. (Range: 0-7, where 7 is the highest priority)

•Traffic Class* – Output queue buffer. (Range: 0-3, where 3 is the highest CoS priority queue)

*CLI shows Queue ID.

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