You need to design router redundancy on the Company network. Which three protocols
could be chosen for IP routing redundancy to protect against first-hop router failure?
(Choose three)

A.
GLBP

B.
ICMP

C.
MSTP

D.
HSRP

E.
VRRP

F.
NHRP

Explanation:
If the gateway router for a subnet or VLAN goes down, packets have no way of being
forwarded off the local subnet. Several protocols (GLBP, HSRP, VRRP) are available that
allow multiple routing devices to share a common gateway address so that if one goes
down, another automatically can pick up the active gateway role.
Cisco Hot-Standby Router Protocol (HSRP):
Created by Cisco, for Cisco in 1994
Uses a default hello timer of 3 seconds with a hold timer of 10 seconds
Virtual Router Redundancy Protocol (VRRP)
Created by the IETF in 1999
Works between multiple vendors
Has faster timers than HSRP by default – hello of 1 second, hold timer of 3 seconds
Gateway Load Balancing Protocol (GLBP)
Created by Cisco, for Cisco in 2005
Identical features to HSRP, but allows an active-active connection that adds load-balancing
features