Users Guide

Configuring Protocol Liveness
Protocol liveness is a feature that notifies the BFD manager when a client protocol is disabled.
When you disable a client, 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.
To enable protocol liveness, use the following command.
• Enable Protocol Liveness.
CONFIGURATION mode
bfd protocol-liveness
Troubleshooting BFD
To troubleshoot BFD, use the following commands and examples.
To control packet field values or to examine the control packets in hexadecimal format, use the following command.
• Examine control packet field values.
CONFIGURATION mode
debug bfd detail
• Examine the control packets in hexadecimal format.
CONFIGURATION
debug bfd packet
The following example shows a three-way handshake using the debug bfd detail command.
R1(conf-if-te-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 Te 4/24 (diag: 0)
00:54:38 : Sent packet for session with neighbor 2.2.2.2 on Te 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 Te 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 Te 4/24 (diag: 0)
The following example shows hexadecimal output from the debug bfd packet command.
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 Te 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 Te 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 Te 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 Te 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 Te 4/24
L
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Bidirectional Forwarding Detection (BFD)