HSRP Interface Tracking for Uplink Failover
Implement HSRP with interface tracking so the virtual gateway fails over when the active router loses its upstream link. Two routers (R1, R2) share a user LAN via SW with a single virtual default gateway for the PC, and both uplink to a separate CORE switch. The learner adds HSRP group 1 with a virtual IP, priority/preempt on R1, and tracks R1's uplink to drive deterministic failover.