Configuring Bidirectional Forwarding Detection This document describes how to enable the Bidirectional Forwarding Detection (BFD) protocol. BFD is a detection protocol that is designed to provide fast forwarding path failure detection times for all media types, encapsulations, topologies, and routing protocols. BFD provides a consistent failure detection method for network administrators, in addition to fast forwarding path failure detection.
Because the network administrator can use BFD to detect forwarding path failures at a uniform rate, rather than the variable rates for different routing protocol hello mechanisms, network profiling and planning will be easier, and reconvergence time will be consistent and predictable.
Prerequisites for Bidirectional Forwarding Detection, on page 1 Restrictions for Bidirectional Forwarding Detection, on page 1 Information About Bidirectional Forwarding Detection, on page 2 How to Configure Bidirectional Forwarding Detection, on page 5 Feature History for Configuring Bidirectional Forwarding Detection , on page 22 Prerequisites for Bidirectional Forwarding Detection • All participating switches must enable Cisco Express Forwarding and IP routing. • Before BFD is deployed on a switch, it is necessary to configure one of the IP routing protocols that are supported by BFD. You should implement fast convergence for the routing protocol that you are using.
See IP routing documentation for your version of Cisco IOS software for information on configuring fast convergence. See the "Restrictions for Bidirectional Forwarding Detection" section for more information on BFD routing protocol support in Cisco IOS software. Restrictions for Bidirectional Forwarding Detection • BFD works only for directly connected neighbors. BFD neighbors must be no more than one IP hop away. BFD does not support Multihop configurations. • BFD support is not available for all platforms and interfaces.
To confirm if a specific platform or interface has BFD support and to obtain the most accurate platform and hardware restrictions, see the Cisco IOS software release notes for your software version. • The QoS policy for self-generated packets does not match BFD packets. Configuring Bidirectional Forwarding Detection 1