The primary advantage of Bidirectional Forwarding Detection (BFD) is its ability to provide rapid failure detection in the forwarding path between two adjacent devices. BFD is a lightweight protocol designed specifically for this purpose, capable of detecting path failures in tens or hundreds of milliseconds. This is significantly faster than the default failure detection mechanisms of most routing protocols (e.g., OSPF or EIGRP hellos), which typically operate on a scale of seconds. This rapid detection allows for faster network convergence and minimizes traffic loss upon a link or node failure.

A. BFD detects forwarding path failures, not route flapping. While a flapping link can cause route instability, BFD's function is to signal the path failure, not manage the route advertisements.

C. BFD is not a standalone protocol for routing; it is designed to work with client applications, such as routing protocols (OSPF, BGP, EIGRP), to which it signals detected failures.

D. BFD does not directly maintain the routing table. It provides a fast trigger to routing protocols, which then update and maintain the routing table based on the BFD state information.

1. Cisco Systems

Inc.

"IP Routing: BFD Configuration Guide

Cisco IOS XE Release 3S". BFD Overview. "BFD is a detection protocol designed to provide fast forwarding path failure detection times for all media types

encapsulations

topologies

and routing protocols... BFD provides a low-overhead

short-duration detection of failures in the path between adjacent forwarding engines. It operates in the order of milliseconds."

2. Katz

D.

& Ward

D.

"RFC 5880: Bidirectional Forwarding Detection (BFD)"

Internet Engineering Task Force (IETF)

June 2010. Abstract. "This document describes a protocol that is intended to detect faults in the bidirectional path between two forwarding engines... It provides low-overhead

short-duration detection of failures..."

3. Katz

D.

& Ward

D.

"RFC 5882: Generic Application of Bidirectional Forwarding Detection (BFD)"

Internet Engineering Task Force (IETF)

June 2010. Section 3

Why BFD?. "The primary application for BFD is for any two systems that are connected at any protocol layer to agree to track the liveness of the path between them... The intent of BFD is to provide a low-overhead

ubiquitous

short-latency

protocol- and media-independent failure detection mechanism."