- R1 tracks its OSPF metric to R3's loopback interface using a track object, which adjusts R1's HSRP priority when the metric exceeds thresholds. - When R1's link to R3 fails, the track object detects the increased OSPF metric and lowers R1's HSRP priority, making R2 the active router. - R2 also tracks its OSPF metric to R4's loopback, dividing the metric to fit the 1-255 threshold range. This allows R1 to regain active status if its path to R4 improves.