The Company network administrator has entered the “auto qos voip cisco-phone” command
on switch R1. What does this command do?

A.
It disables the trust boundary feature because the switch knows a Cisco IP phone is
attached.

B.
The switch assigns a CoS value of 5 to incoming packets.

C.
If a Cisco IP phone is attached and removed, the switch continues to trust the CoS
values as long as the switch is not rebooted.

D.
It turns on STP to see if a Cisco IP phone is attached.

E.
If a Cisco IP phone is attached, the switch trusts the CoS.

F.
None of the other alternatives apply.

Explanation:
When the “auto qos voip cisco-phone” interface configuration command is entered, the
trusted boundary feature is enabled. The trusted boundary feature uses CDP to detect the
presence or absence of a Cisco IP Phone. When a Cisco IP Phone is detected, the ingress
classification on the interface is set to trust the QoS label received in the packet. When a
Cisco IP Phone is absent, the ingress classification is set to not trust the QoS label in the
packet. The egress queues on the interface are also reconfigured. This command extends
the trust boundary if an IP Phone is detected.