Which two mechanisms ensure that a network design provides fast path failure detection? (Choose two.)

BFD (Bidirectional Forwarding Detection) is a dedicated, lightweight protocol that sends rapid control packets between two forwarding engines to detect path failures in milliseconds, independent of the routing protocol in use.

Fast hello packets reduce the hello or dead interval of routing protocols such as OSPF or EIGRP to sub-second values, enabling the routing protocol itself to detect neighbor loss much faster than default timers allow.

UDLD (Unidirectional Link Detection) detects one-way traffic flows on fiber or copper links to prevent loops, but it is not a general fast path failure detection mechanism for routing convergence.

IP Cisco Express Forwarding (CEF) is a Layer 3 switching mechanism that optimizes packet forwarding performance; it does not detect or signal path failures.