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)