R1 and R2 are attached to the same Ethernet VLAN, with subnet 192.168.1.0/24, and addresses 192.168.1.1, 192.168.2 respectively. The routers use an FHRP. Host A and host B attach to the same LAN and have correct default router settings per the FHRP configuration. Which of the following statements is true for this LAN?

(A) You can't connect two routers to the same LAN subnet.
(B) If one router fails, hosts can't send packets off-subnet
(C) If one router fails, both hosts will use the one remaining router as a default router
(D) if one router fails, only one of the two hosts will still be able to send packets off-subnet

If one router fails, both hosts will use the one remaining router as a default router is the correct answer.

The use of an FHRP in this design purposefully allows either router to fail and still support off-subnet traffic from all hosts in the subnet. Both routers can attach to the same LAN subnet per IPv4 addressing rules.

FHRPs make this design work better. The two routers appear to be a single default router. The users never have to do anything: their default router setting remains the same, and their ARP table even remains the same. To allow the hosts to remain unchanged, the routers have to do some more work, as defined by one of the FHRP protocols. Generically, each FHRP makes the following happen:

1. All hosts act like they always have, with one default router setting that never has to change
2. The default routers share a virtual IP address in the subnet, defined by the FHRP
3. Hosts use the FHRP virtual IP address as their default router address
4. The routers exchange FHRP protocol messages so that both agree as to which router does what works at any point in time
5. When a router fails or has some other problem, the routers use the FHRP to choose which router takes over responsibilities from the failed router

The three FHRP protocols are:

1. Hot Standby Router Protocol (HSRP)
2. Virtual Router Redundancy Protocol (VRRP)
3. Gateway Load Balancing Protocol (GLBP)