In a network design using carrier Ethernet, which three mechanisms can be used to improve Layer 2 down detection and thereby reduce routing convergence time? (Choose three.)

BFD provides sub-second bidirectional failure detection independent of the routing protocol, allowing the IGP or BGP to immediately begin reconvergence when a forwarding path fails.

Ethernet port debounce timers intentionally delay the reporting of a port-state change to suppress flapping, which increases the time to detect a failure and worsens convergence time.

Link-state tracking propagates uplink failures to downstream interfaces on access switches for redundancy purposes and is not a convergence-acceleration mechanism for routing protocols.

Object tracking monitors interface or reachability state and can trigger immediate routing policy changes when a Layer 2 path goes down, accelerating convergence.

Reducing IGP hello and dead intervals means the routing protocol declares a neighbor down much faster after a link failure, directly shortening overall convergence time.