HSRP $($Hot Standby Router Protocol$)$ is the most commonly used First Hop Redundancy protocol in Cisco $10$ S networks It works by ereating a growp of HSRP gateways with only one router being the primary gatway, thus all traffic is forword. through that one router. If the primary goes down the a secondary HSRP router in the group will then become primary. CARP, & VRRP are not Cisco proprietary