Which three protocols have been developed for IP routing redundancy to protect against first-hop
router failure? (Choose three.)

A.
HSRP

B.
MSTP

C.
ICMP

D.
VRRP

E.
GLBP

Explanation:
A First Hop Redundancy Protocol (FHRP) is a computer networking protocol which is designed to
protect the default gateway used on a subnetwork by allowing two or more routers to provide
backup for that address; in the event of failure of the/an active router, the backup router will take
over the address, usually within a few seconds. In practice, such protocols can also be used to
protect other services operating on a single IP address, not just routers.
Examples of such protocols include (in approximate order of creation):
Hot Standby Router Protocol (HSRP) – Cisco’s initial, proprietary standard
Virtual Router Redundancy Protocol (VRRP) – an open standard protocol
Gateway Load Balancing Protocol (GLBP) – a more recent proprietary standard from Cisco that
permits load balancing as well as redundancy