ECS3510-26P_Management Guide R02

C HAPTER 10 | Class of Service
Layer 2 Queue Settings
– 243 –
Figure 116: Setting the Queue Mode (Strict and WRR)
MAPPING COS VALUES
TO EGRESS QUEUES
Use the Traffic > Priority > PHB to Queue page to specify the hardware
output queues to use based on the internal per-hop behavior value. (For
more information on exact manner in which the ingress priority tags are
mapped to egress queues for internal processing, see "Mapping CoS
Priorities to Internal DSCP Values" on page 249).
The switch processes Class of Service (CoS) priority tagged traffic by using
four priority queues for each port, with service schedules based on strict
priority, Weighted Round-Robin (WRR), or a combination of strict and
weighted queuing. Up to eight separate traffic priorities are defined in IEEE
802.1p. Default priority levels are assigned according to recommendations
in the IEEE 802.1p standard as shown in Table 14. This table indicates the
default mapping of internal per-hop behavior to the hardware queues. The
actual mapping may differ if the CoS priorities to internal DSCP values have
been modified (page 249).
The priority levels recommended in the IEEE 802.1p standard for various
network applications are shown in Table 15. However, priority levels can be
mapped to the switch’s output queues in any way that benefits application
traffic for the network.
Table 14: IEEE 802.1p Egress Queue Priority Mapping
Priority 01234567
Queue 10012233
Table 15: CoS Priority Levels
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