CoS map
The CoS map defines how the QoS settings for an ingress packet are mapped to the local priority settings on the switch. The default settings for the CoS map are compliant with 802.1Q. To view the default settings, use the command
show cos-map default. For example:
switch# show qos cos-map default code_point local_priority color name ---------- -------------- ------- ---- 0 1 green Best_Effort 1 0 green Background 2 2 green Excellent_Effort 3 3 green Critical_Applications 4 4 green Video 5 5 green Voice 6 6 green Internetwork_Control 7 7 green Network_Control(Color is reserved for future use.)
Ethernet 802.1Q and 802.1D CoS
IEEE 802.1Q is the most current Ethernet standard for class of service. It superseded an earlier standard, 802.1D, in 2005. IEEE 802.1Q slightly changed the ordering of the classes of service from its predecessor IEEE 802.1D for CoS 2 and CoS 0:
| CoS 802.1Q | CoS 802.1D |
|---|---|
| 7 Network Control | 7 Network Control |
| 6 Internetwork Control | 6 Voice (<10ms latency) |
| 5 Voice (<10ms latency) | 5 Video (<100ms latency) |
| 4 Video (<100ms latency) | 4 Controlled Load |
| 3 Critical Applications | 3 Excellent Effort |
| 2 Excellent Effort | 0 Best Effort |
| 0 Best Effort | 2 Spare |
| 1 Background | 1 Background |
Note that in 802.1D, both CoS 2 and CoS 1 are below CoS 0 (Best Effort).
To configure support for 802.1D, edit the default CoS map settings for CoS 0 and 2. For example:
switch# config switch(config)# qos cos-map 0 local-priority 2 color green name Best_Effort switch(config)# qos cos-map 2 local-priority 1 color green name Spare switch(config)# exit switch# show qos cos-map code_point local_priority color name ---------- -------------- ------- ---- 0 2 green Best_Effort 1 0 green Background 2 1 green Spare 3 3 green Critical_Applications 4 4 green Video 5 5 green Voice 6 6 green Internetork_Control 7 7 green Network_Control(Color is reserved for future use.)