BFD for BGP

Bidirectional Forwarding Detection (BFD) support for BGP4 and BGP4+ can be configured so that BGP is a registered protocol with BFD and receives forwarding path detection failure messages from BFD.

BFD for BGP is disabled by default. When BFD for BGP is enabled, BFD rapidly detects faults on links between BGP peers and reports faults to BGP. BFD for BGP is supported for single-hop and multihop iBGP and eBGP sessions with IPv4 or IPv6 neighbors in the default VRF and non-default VRF instances. BFD behavior is identical for iBGP and eBGP single-hop and multihop sessions and for IPv4 and IPv6 neighbors.

Consider the following when you configure BFD for BGP:

• Registration is global across all VRFs after BGP sends a registration message to BFD.
• BFD sessions for remote BGP neighbors are not triggered if BFD is not configured on these neighbors. Each neighbor can have its own transmit interval, receive internal, and detect multiplier. If the value is not configured, the configured global value is inherited. For single-hop sessions, the interface-level BFD transmit interval, receive interval, and detect multiplier are used.
• When a BGP session enters the Established state, BGP requests that BFD start a BFD session.
• BFD sessions are maintained across a BGP graceful restart.