Users Guide

Configure BFD for Physical Ports
Configuring BFD for physical ports is supported on the C-Series and E-Series platforms only.
BFD on physical ports is useful when you do not enable the routing protocol. Without BFD, if the remote system fails, the local system
does not remove the connected route until the first failed attempt to send a packet. When you enable BFD, the local system removes the
route as soon as it stops receiving periodic control packets from the remote system.
Configuring BFD for a physical port is a two-step process:
1. Enable BFD globally.
2. Establish a session with a next-hop neighbor.
Related Configuration Tasks
• Viewing Physical Port Session Parameters.
• Disabling and Re-Enabling BFD.
Enabling BFD Globally
You must enable BFD globally on both routers.
For more information about enabling BFD globally, refer to Establishing a Session on Physical Ports.
To enable the BFD globally, use the following command.
• Enable BFD globally.
CONFIGURATION mode
bfd enable
To verify that BFD is enabled globally, use the show running bfd command.
The bold line shows that BFD is enabled.
R1(conf)#bfd ?
enable Enable BFD protocol
protocol-liveness Enable BFD protocol-liveness
R1(conf)#bfd enable
R1(conf)#do show running-config bfd
!
bfd enable
R1(conf)#
Establishing a Session on Physical Ports
To establish a session, enable BFD at the interface level on both ends of the link, as shown in the following illustration. The configuration
parameters do not need to match.
Figure 12. Establishing a BFD Session on Physical Ports
1. Enter interface mode.
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Bidirectional Forwarding Detection (BFD)