5. BFD Echo Packet Format

BFD Echo packets are sent in an encapsulation appropriate to the environment. See the appropriate application documents for the specifics of particular environments.

The payload of a BFD Echo packet is a local matter, since only the sending system ever processes the content. The only requirement is that sufficient information is included to demultiplex the received packet to the correct BFD session after it is looped back to the sender. The contents are otherwise outside the scope of this specification.

Some form of authentication SHOULD be included, since Echo packets may be spoofed.