process-interface-status

Function

The process-interface-status command associates the BFD session status with the bound interface status.

The undo process-interface-status command restores the default setting.

By default, the BFD session status is not associated with the interface status. That is, the change of the BFD session status does not affect the interface status.

Format

process-interface-status [ reboot-no-impact ] [ protocol-down ]

undo process-interface-status [ reboot-no-impact ] [ protocol-down ]

Parameters

Parameter	Description	Value
reboot-no-impact	Disables the association between a multicast BFD session and interface during device startup.	-
protocol-down	After protocol-down is configured, when a BFD session detects a fault and enters the Down state, the protocol status of the associated interface becomes Down. In this case, the interface discards Layer 2 and Layer 3 packets but permits BFD packets.	-

Parameter

Description

Value

reboot-no-impact

Disables the association between a multicast BFD session and interface during device startup.

protocol-down

After protocol-down is configured, when

a BFD session detects a fault and enters the Down state, the protocol status of the associated interface becomes Down. In this case, the interface discards Layer 2 and Layer 3 packets but permits BFD packets.

Views

BFD session view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

If a transmission device exists on a direct link, BFD detects a link fault faster than a link protocol on an interface. The link protocol status of a trunk or VLANIF interface depends on the link protocol status of member interfaces.

To help BFD rapidly report the detection result to the application, a BFD status attribute is added to the interface management module of each interface. This attribute indicates the status of the BFD session that is bound to the interface. The system obtains the interface status based on the link status, protocol status, and BFD status on the interface, and then reports the interface status to the application.

Precautions

When configuring the process-interface-status command, pay attention to the following points:

The process-interface-status command takes effect for only the single-hop BFD session that uses the default multicast address. The BFD session can be associated to an interface status.
After the trigger if-down delay and commit commands are run in sequence, if BFD negotiation fails, the Down state is reported to the interface.
If multiple BFD sessions are bound to an interface, you can use the process-interface-status command for only one BFD session. The change of only one BFD session changes the status of the bound interface.
The BFD session does not report the BFD status to the bound interface immediately after the commit command is executed because the BFD session may not be set up or not Up. This prevents the BFD session from reporting an incorrect state to the interface. When the BFD status changes, the BFD session reports the BFD status to the interface to trigger the interface status change.
If the process-interface-status command is saved in the configuration file, the BFD session for which the process-interface-status command is run notifies an interface that the BFD session becomes Down when the device is restarted. This is because the initial status of the interface is Down.
Before the BFD session status is associated with the interface status, the BFD configurations on two ends must be correct and matched. If the BFD session status on the local interface is Down, check whether the BFD configuration on the peer end is correct or whether the BFD session is shut down.
If the BFD session must be synchronized to an interface immediately, ensure that the BFD configurations on the two ends are the same and run the shutdown (BFD session view) and undo shutdown (BFD session view) commands on the BFD session. When the undo shutdown (BFD session view) command is executed for a BFD session, a BFD session detection timer is started. If the BFD session becomes Up through negotiation before the timer times out, the BFD session notifies an interface of the Up state. Otherwise, the BFD session considers the link faulty and notifies the interface of the Down state. The status of a BFD session and the status of an interface can be synchronized in real time.
After a master/slave main control board switchover is performed, BFD notifies the associated interface to update the interface status during data smoothing based on the post-switchover BFD session status and diagnostic information. Specifically:
1. If the BFD session is up, BFD notifies the interface to go up.
2. If the BFD session is down, BFD differentiates between authentication and non-authentication scenarios.
  - BFD notifies the interface to go down in an authentication scenario.
  - In a non-authentication scenario, if the diagnostic word is "Receive AdminDown" and the receiving-admindown trigger if-down command is run before the switchover is performed, BFD notifies the interface to go down. If the diagnostic word is not "Receive AdminDown", BFD notifies the interface to go down.

Example

# Associate the BFD session with an interface to which the BFD session is bound.

<HUAWEI> system-view
[HUAWEI] bfd test
[HUAWEI-bfd-session-test] process-interface-status