In which three HSRP states do routers send hello messages? (Choose three.)
A.
standby
B.
learn
C.
listen
D.
speak
E.
active
Explanation:
When HSRP is configured on an interface, the router progresses through a series of states before
becoming active. This forces a router to listen for others in a group and see where it fits into the
pecking order. The HSRP state sequence is Disabled, Init, Listen, Speak, Standby, and, finally,
Active.
Only the standby (second highest priority) router monitors the hello messages from the active
router. By default, hellos are sent every 3 seconds. If hellos are missed for the duration of the
holdtime timer (default 10 seconds, or 3 times the hello timer), the active router is presumed down.
The standby router is then clear to assume the active role. If other routers are sitting in the Listen
state, the next-highest priority router is allowed to become the new standby router.
Reference: Cisco Hot Standby Router Protocol (HSRP)
(http://tools.ietf.org/html/rfc2281#page-8)