A network design shows two routers directly connected to an Ethernet switch using optical connections. There is an OSPF adjacency between the routers. In this design, which solution will ensure that…

Optimized OSPF SPF timers reduce the time OSPF recalculates the topology after a failure is already known, but they do not accelerate the initial detection of the interface failure itself.

BFD operates at the forwarding plane using rapid hello packets with configurable intervals as low as milliseconds, detecting link failures and immediately notifying OSPF - this is critical in optical-over-Ethernet designs where the Ethernet switch can mask physical failures and prevent the routers from detecting a link-down condition through native interface signaling alone.

Automatic protection switching (APS) is a mechanism for SDH/SONET or optical transport networks and does not apply to an Ethernet switch environment for IGP failure notification.

Optimized OSPF LSA timers reduce delays in LSA generation and flooding, which aids convergence speed after detection but does not improve the speed of detecting the failure event.

Ethernet OAM CFM monitors Layer 2 connectivity between defined maintenance points but does not integrate directly with IGP protocols to report failures as rapidly or as tightly as BFD does.