34.1.7 Notes on using BFD

(1) Conditions for use in channel groups

When using BFD with VLAN interfaces on a channel group, make sure that BFD failure detection time is longer than the failure detection time in the channel group. If BFD fault-detection time is shorter, some line downtime might be detected as faulty by BFD.

(2) Deleting BFD and Changing Monitoring Routes in the Configuration

Before deleting BFD name (configuration command bfd name) or changing the monitoring route (configuration command multihop), delete the settings of the linked BFD name from the routing protocol configuration. If you remove a BFD or change a monitored route first, you may not be able to continue monitoring with the associated BFD.

(3) Configuring BFD for the Same Device

The networking should be designed so that BFD sessions for the same device are one session.

If a device on the same network and the address set for the loopback interface are used for peering, the failure can be detected faster if BGP4 peer that resolves the loopback interface address is configured to work with BFD.

(4) CPU overload

If CPU becomes overloaded, a failure may be detected on the Switch or neighboring devices by discarding or delaying BFD controlpackets sent and received by the Switch. If overloading occurs frequently, increase the sending and receiving intervals for BFD controlpackets.

(5) If no BFD session-session is established

If BFD session is not established or the session status is unstable even after it is established, check that the settings of the Switch and the partner switch are correct. If the settings are correct, re-establish BFD session.. To re-establish, specify BFD session number in the operation command clear bfd session.