How Does HSRP Provide First Hop Redundancy?

B.

HSRP (Hot Standby Router Protocol) is a Cisco proprietary protocol that provides first hop redundancy for IP networks. It enables multiple routers to participate in a virtual router group, presenting the appearance of a single virtual router to the hosts on a LAN. The protocol works by creating a virtual MAC address and a virtual IP address that are shared among the routers in the group, allowing them to work together to provide redundancy and load balancing.

The correct answer is B, which describes how HSRP provides first hop redundancy. When HSRP is configured on a LAN, the participating routers elect a standby router and a set of active routers. The standby router monitors the active routers and takes over if an active router fails. The virtual IP address is assigned to the active router, which responds to ARP requests for the virtual IP address with the virtual MAC address. The standby router monitors the active router and takes over if it stops responding.

When a host on the LAN sends a packet to a destination outside the local network, the packet is sent to the virtual MAC address of the HSRP group. The active router in the group receives the packet and forwards it to the next hop router in the path to the destination. If the active router fails, the standby router takes over and continues forwarding packets.

Option A is incorrect because HSRP does not load-balance Layer 2 traffic by flooding traffic out all interfaces configured with the same VLAN. It provides redundancy and failover for the default gateway on a LAN.

Option C is incorrect because HSRP does not forward multiple packets to the same destination over different routed links in the data path. It provides redundancy and failover for the default gateway on a LAN.

Option D is incorrect because HSRP does not load-balance traffic by assigning the same metric value to more than one route to the same destination in the IP routing table. It provides redundancy and failover for the default gateway on a LAN.