detect-multiplier

Function

The detect-multiplier command sets the local detection multiplier.

The undo detect-multiplier command restores the default local detection multiplier.

By default, the local detection multiplier is 3.

Format

detect-multiplier multiplier

undo detect-multiplier

Parameters

Parameter	Description	Value
multiplier	Specifies the local detection multiplier of a BFD session.	The value is an integer that ranges from 3 to 50.

Views

BFD session view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

The local detection multiplier determines the detection time of a BFD session.

Detection time = Received Detect Multi of the remote system x Max (Local RMRI/Received DMTI)

where

Detect Multi: local detection multiplier, which is set by using the detect-multiplier command
Required Min Rx Interval (RMRI): minimum interval for receiving BFD packets, which is set by using the min-rx-interval command
Desired Min Tx Interval (DMTI): minimum interval for sending BFD packets, which is set by using the min-tx-interval command

You can increase or reduce the local detection multiplier based on actual networking. On a stable link, there is no need to frequently detect the link status, so you can increase the local detection multiplier.

If no BFD packet is received from the peer device within the detection time, the link is considered as faulty and the BFD session enters the Down state. To reduce the usage of system resources, when the BFD session is detected in Down state, the system adjusts the sending interval to a random value greater than 1000 ms. When the BFD session becomes Up, the configured interval is restored.

Configuration Impact

On an unstable link, if the local detection multiplier is small, the BFD session may flap. It is recommended that a larger local detection multiplier be used.
When other protocols are associated with BFD, if a larger local detection multiplier is used, the BFD session takes a long period of time to detect faults on the link and traffic is switched to the backup link after the specified period. Packets may be lost during this period.

Precautions

Both ends of a BFD session can use different local detection multipliers.

Example

# Set the local detection multiplier of the BFD session atoc to 10.

<HUAWEI> system-view
[HUAWEI] bfd atoc
[HUAWEI-bfd-session-atoc] detect-multiplier 10