(Optional) Configuring BFD on the Specified Interface
Context
After BFD for OSPF is configured on a specified interface and the interface becomes faulty, the router rapidly detects the fault and instructs OSPF to recalculate routes. This speeds up OSPF convergence. When the OSPF neighbor relationship goes Down, the BFD session between OSPF neighbors is dynamically deleted.
Before configuring BFD for OSPF, enable BFD globally.
Perform the following steps on the router:
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The view of the interface enabled with BFD for OSPF is displayed.
- Run ospf bfd enable
BFD is enabled on the interface to establish the BFD session.
If all the interfaces in a certain process are configured with BFD and their neighbor relationships are in the Full state, OSPF creates BFD sessions with default parameter values on specified interfaces in the process.The priority of BFD for OSPF configured on an interface is higher than that of BFD for OSPF configured for a process.Run the ospf bfd { min-rx-interval receive-interval | min-tx-interval transmit- interval | detect-multiplier multiplier-value } * command to set parameters for BFD sessions.
You can skip this step. The default interval at which BFD packets are transmitted and the default detection multiplier are recommended.
The parameters are configured based on the network status and network reliability requirements. A short interval at which BFD packets are transmitted can be configured if high network reliability is required. A long interval at which BFD packets are transmitted can be configured if high network reliability is not required.
- Actual interval at which BFD packets are transmitted on the local router = Max { configured interval transmit-interval at which BFD packets are transmitted on the local router, configured interval receive-interval at which BFD packets are received on the peer router }
- Actual interval at which BFD packets are received on the local router = Max { configured interval transmit-interval at which BFD packets are transmitted on the peer router, configured interval receive-interval at which BFD packets are received on the local router }
- Actual time for detecting BFD packets = Actual interval at which BFD packets are received on the local router x Configured detection multiplier multiplier-value on the peer router
For example:
- On the local router, the configured interval at which BFD packets are transmitted is 200 ms; the interval at which BFD packets are received is set to 300 ms; the detection multiplier is 4.
- On the peer router, the configured interval at which BFD packets are transmitted is 100 ms; the interval at which BFD packets are received is 600 ms; the detection multiplier is 5.
Then:
- On the local router, the actual interval at which BFD packets are transmitted is 600 ms calculated by using the formula max {200 ms, 600 ms}; the interval at which BFD packets are received is 300 ms calculated by using the formula max {100 ms, 300 ms}; the detection period is 1500 ms calculated by multiplying 300 ms by 5.
- On the peer router, the actual interval at which BFD packets are transmitted is 300 ms calculated by using the formula max {100 ms, 300 ms}, the actual interval at which BFD packets are received is 600 ms calculated by using the formula max {200 ms, 600 ms}, and the detection period is 2400 ms calculated by multiplying 600 ms by 4.
