Which two RSTP port roles include the port as part of the active topology? (Choose two.)
A.
root
B.
designated
C.
alternate
D.
backup
E.
forwarding
F.
learning
Explanation:
RSTP defines four port roles:
+ Root port
+ Designated port
+ Alternate port
+ Backup port and three port states:
+ Discarding
+ Learning
+ Forwarding
Only the root ports and designated ports belong to the active STP topology.
Reference:
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml