First hop redundancy protocol

Question 1

Gratuitious ARP

Answer 1

ARP reply that is sent by device that is not in response to a ARP request

Question 2

How does FHRC work?

Answer 2

a virtual IP and virtual MAC are generated for two routers (one active and other standby)

end hosts use virtual IP as gateway and ARP is sent via virtual MAC

Question 3

What happens if active router goes down?

Answer 3

standby router becomes active and if old active comes back online, it becomes standby (unless preemption is enabled)

Question 4

HSRP

Answer 4

Hot Standby Router Protocol, cisco protocol where active and standby router is elected

Question 5

VVRP

Answer 5

Virtual Router Redundancy Protocol. Industry standard where master and backup are elected

Question 6

GLBP

Answer 6

Gateway Load Balancing Protocol, Load balances among multiple routers within a subnet. AVG (Active virtual Gateway) is elected with up to four AVFs (Active Virtual Forwarders) and acts as a default gateway for a portion of hosts in subnet