Which two features describe BFD?

Bidirectional Forwarding Detection (BFD) is a lightweight, low-overhead protocol designed to detect failures in the forwarding path between two routers. It can replace the slower hello mechanisms of routing protocols like OSPF or EIGRP, providing much faster fault detection (sub-second timers are common). This rapid detection allows routing protocols to converge more quickly in the event of a link or node failure, minimizing downtime. BFD is also highly scalable because its sessions are independent of the routing protocol itself and can be applied to many different types of interfaces and protocols without significant overhead. While BFD can be CPU-intensive if timers are set extremely low across many sessions, it's generally considered efficient and not specifically "intensive on CPU for Layer 2 links" compared to its benefits. BFD does not replace routing protocols; it works with them to improve convergence.