Which two statements correctly describe characteristics of the PortFast feature? (Choose two.)
A.
STP is disabled on the port.
B.
PortFast can also be configured on trunk ports.
C.
PortFast is needed to enable port-based BPDU guard.
D.
PortFast is used for STP and RSTP host ports.
E.
PortFast is used for STP-only host ports.
Explanation:
Catalyst switches offer the PortFast feature, which shortens the Listening and Learning
states to a negligible amount of time. When a workstation link comes up, the switch
immediately moves the PortFast port into the Forwarding state. Spanning-tree loop detection
is still in operation, however, and the port moves into the Blocking state if a loop is ever
detected on the port. You can use PortFast to connect a single end station or a switch port to
a switch port. If you enable PortFast on a port that is connected to another Layer 2 device,
such as a switch, you might create network loops. When PortFast is enabled between two
switches, the system will verify that there are no loops in the network before bringing the
blocking trunk to a forwarding state.
Reference:
http://www.cisco.com/en/US/docs/routers/7600/ios/12.1E/configuration/guide/stp_enha.html#wp1042489