What type of routes will EIGRP perform unequal-cost load-balancing over?

EIGRP (Enhanced Interior Gateway Routing Protocol) is capable of performing unequal-cost load-balancing over routes that are classified as feasible successors. A feasible successor is a route that fulfills the criteria of being a valid alternative to the primary route (the successor) while also having a lower feasible distance compared to the successor's reported distance.

This capability is fundamental to EIGRP's dynamic routing nature, allowing it to effectively distribute traffic across multiple paths of differing costs. Consequently, when an active path fails or becomes unavailable, EIGRP can immediately switch to a feasible successor without needing to recalculate the topology, thereby maintaining network efficiency.

Routes with equal metrics or only successor routes do not apply here because unequal-cost load balancing specifically requires the existence of feasible successors that can handle traffic distribution across varying path metrics. The concept of advertised routes also encompasses routes that might not meet the criteria for feasible successors, and therefore, would not facilitate unequal-cost load balancing as effectively.