HSRP vs. VRRP & Interface Tracking Quick Reference

HSRP (Cisco proprietary): active / standby. Virtual MAC in the 0000.0c07.acXX range. Requires a separate, dedicated virtual IP.

VRRP (open standard, RFC 3768/5798): master / backup. Virtual MAC in the 0000.5e00.01XX range. Can use a real physical interface's own IP as the virtual IP.

Without tracking, an FHRP group only reacts to the health of the peer relationship itself — a healthy peer session with a dead WAN uplink behind it produces no failover on its own.

Tracking monitors a separate interface and decrements priority by a configured amount if it goes down. The decrement must be large enough to actually drop the tracking router's priority below its peer's — a too-small decrement means tracking exists in configuration but never triggers a real failover.