BFD Packet Format
Control packets are encapsulated in user datagram protocol (UDP) packets. The following illustration shows
the complete encapsulation of a BFD control packet inside an IPv4 packet.
Figure 10. BFD in IPv4 Packet Format
Field
Description
Diagnostic Code
The reason that the last session failed.
State
The current local session state. Refer to
Flag
A bit that indicates packet function. If the poll bit is set, the receiving system must
respond as soon as possible, without regard to its transmit interval. The responding
BFD
Sessions.
Bidirectional Forwarding Detection (BFD)
166