Bfd Packet Format - H3C LS-3100-52P-OVS-H3 Operation Manual

Dynamic BFD parameter changes
After a BFD session is established, both ends can negotiate the related BFD parameters, such as the
minimum transmit interval, minimum receive interval, initialization mode, and packet authentication
mode. After that, both ends use the negotiated parameters, without affecting the current session state.
Authentication modes
BFD provides the following authentication methods:
Simple: Plain text authentication
MD5: MD5 (Message Digest 5) authentication
SHA1: SHA1 (Secure Hash Algorithm 1) authentication

BFD Packet Format

As illustrated in
Figure 1-3 BFD control packet format
Vers: Protocol version. The protocol version is 1.
Diag: This bit indicates the reason for the last transition of the local protocol from up to some other
state. Table 1-1
Table 1-1 Diag bit values
0
1
2
3
4
5
6
7
8~31
State (Sta): Current BFD session state. Its value can be 0 for AdminDown, 1 for Down, 2 for Init,
and 3 for Up.
Figure 1-3, BFD control packets use UDP and port number 3784.
lists the states.
Diag Description
No Diagnostic
Control Detection Time Expired
Echo Function Failed
Neighbor Signaled Session Down
Forwarding Pane Reset
Path Down
Concatenated Path Down
Administratively Down
Reserved for future use
1-4