Reference Guide

156 | Bidirectional Forwarding Detection (BFD)
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Configuring Protocol Liveness
Protocol Liveness is a feature that notifies the BFD Manager when a client protocol is disabled. When a
client is disabled, all BFD sessions for that protocol are torn down. Neighbors on the remote system
receive an Admin Down control packet and are placed in the Down state (Message 3).
To enable Protocol Liveness:
Troubleshooting BFD
Examine control packet field values using the command debug bfd detail. The following example shows a
three-way handshake using this command.
Figure 7-29. debug bfd detail Command Output
Examine control packets in hexadecimal format using the command debug bfd packet.
Figure 7-30. debug bfd packet Command Output
The output for the command debug bfd event is the same as the log messages that appear on the console by
default.
Step Task Command Syntax Command Mode
1 Enable Protocol Liveness bfd protocol-liveness CONFIGURATION
R1(conf-if-gi-4/24)#00:54:38: %RPM0-P:RP2 %BFDMGR-1-BFD_STATE_CHANGE: Changed session state
to Down for neighbor 2.2.2.2 on interface Gi 4/24 (diag: 0)
00:54:38 : Sent packet for session with neighbor 2.2.2.2 on Gi 4/24
TX packet dump:
Version:1, Diag code:0, State:Down, Poll bit:0, Final bit:0, Demand bit:0
myDiscrim:4, yourDiscrim:0, minTx:1000000, minRx:1000000, multiplier:3, minEchoRx:0
00:54:38 : Received packet for session with neighbor 2.2.2.2 on Gi 4/24
RX packet dump:
Version:1, Diag code:0, State:Init, Poll bit:0, Final bit:0, Demand bit:0
myDiscrim:6, yourDiscrim:4, minTx:1000000, minRx:1000000, multiplier:3, minEchoRx:0
00:54:38: %RPM0-P:RP2 %BFDMGR-1-BFD_STATE_CHANGE: Changed session state to Up for neighbor
2.2.2.2 on interface Gi 4/24 (diag: 0)
RX packet dump:
20 c0 03 18 00 00 00 05 00 00 00 04 00 01 86 a0
00 01 86 a0 00 00 00 00
00:34:13 : Sent packet for session with neighbor 2.2.2.2 on Gi 4/24
TX packet dump:
20 c0 03 18 00 00 00 04 00 00 00 05 00 01 86 a0
00 01 86 a0 00 00 00 00
00:34:14 : Received packet for session with neighbor 2.2.2.2 on Gi 4/24
RX packet dump:
20 c0 03 18 00 00 00 05 00 00 00 04 00 01 86 a0
00 01 86 a0 00 00 00 00
00:34:14 : Sent packet for session with neighbor 2.2.2.2 on Gi 4/24
TX packet dump: