A.CDP must be disabled on the switch port to prevent interference between CDP messages and  voice traffic.
B.Port security cannot be configured on a port that is configured for a voice vlan.
C.Static secure MAC addresses should be configured on voice vlan ports to prevent access by  devices other than IP phones.
D.CDP must be enabled on the switch port to allow configuration information to be passed to the  IP phone.
E.Portfast must be enabled on the switch port.
F.802.1x authentication cannot be configured on a port configured for a voice vlan.

A. Trust boundaries are points in the network where Layer 2 CoS markings are converted to Layer  3 DSCP or IP precedence markings.
B. Trust boundaries are a point in the network where QoS functionality begins and ends.
C. Trust boundaries determine whether certain types of traffic can pass.
D. Trust boundaries are a point in the network where decisions about CoS markings on incoming  packets are made.
E. None of the other alternatives apply