Refer to the exhibit.
How does a switch port that receives marked traffic from a Cisco IP phone use the mls qos trust cos command?
A.
The CoS setting is modified according to the CoS-to-DSCP map.
B.
CoS is used to select the ingress and egress queues.
C.
For non-IP packets, the CoS is set to 7 and DSCP-to-CoS mapping is not applied.
D.
The DSCP-to-CoS map is applied.
Explanation:
http://www.cisco.com/c/en/us/td/docs/ios/qos/command/reference/qos_book/qos_m2.html
All of the CoS-to-DSCP and DSCP-to-CoS maps are globally defined. You apply all maps to all ports.
– If you enter the mls qos trust cos command, the default CoS-to-DSCP map is applied.
– If you enter the mls qos trust dscp command, the default DSCP-to-CoS map is applied.