Which Cisco FHRP uses a shared virtual IP and a virtual MAC address?

Which Cisco FHRP uses a shared virtual IP and a virtual MAC address?

• A. HSRP
• B. VRRP
• C. GLBP
• D. FHRP

Answer: (A)

Gateway redundancy is achieved by presenting a single virtual gateway to hosts and ensuring the MAC used to reach that gateway remains stable during failover. The key point here is using one virtual IP that clients use as their gateway and one shared virtual MAC that all routers in the group respond with. This setup lets traffic keep flowing to the same MAC address even if the active router changes, so hosts don’t need to update their ARP tables or default gateway. This behavior is characteristic of HSRP. It uses a single virtual IP and a single virtual MAC for the group, so the active router responds to ARP for the virtual IP with that shared MAC, and failover preserves both the IP and MAC. In contrast, GLBP assigns multiple virtual MACs from a pool to distribute traffic (not a single shared MAC), and VRRP uses a virtual MAC that is tied to the VRID, which can complicate the “shared MAC” idea in this context.

Gateway redundancy is achieved by presenting a single virtual gateway to hosts and ensuring the MAC used to reach that gateway remains stable during failover. The key point here is using one virtual IP that clients use as their gateway and one shared virtual MAC that all routers in the group respond with. This setup lets traffic keep flowing to the same MAC address even if the active router changes, so hosts don’t need to update their ARP tables or default gateway.

This behavior is characteristic of HSRP. It uses a single virtual IP and a single virtual MAC for the group, so the active router responds to ARP for the virtual IP with that shared MAC, and failover preserves both the IP and MAC. In contrast, GLBP assigns multiple virtual MACs from a pool to distribute traffic (not a single shared MAC), and VRRP uses a virtual MAC that is tied to the VRID, which can complicate the “shared MAC” idea in this context.