suppress-flapping route-calculate

Function

The suppress-flapping route-calculate command configures a period for the device to delay route calculation when the device receives an LSP during route flapping.

The suppress-flapping route-calculate disable command restores the default configuration.

The undo suppress-flapping route-calculate command restores the default configuration.

By default, if the device receives an LSP during route flapping, it delays route calculation for 10s.

Format

suppress-flapping route-calculate { disable | timer delay-interval [ threshold threshold-value ] }

undo suppress-flapping route-calculate

Parameters

Parameter	Description	Value
timer delay-interval	Specifies a period for the device to delay route calculation when the device receives an LSP during route flapping.	The value is an integer ranging from 1 to 600, in seconds.
threshold threshold-value	Specifies a route flapping threshold. If a route flaps for the specified number of times, route calculation is delayed.	The value is an integer ranging from 3 to 100, in times.

Parameter

Description

Value

timer delay-interval

Specifies a period for the device to delay route calculation when the device receives an LSP during route flapping.

The value is an integer ranging from 1 to 600, in seconds.

threshold threshold-value

Specifies a route flapping threshold. If a route flaps for the specified number of times, route calculation is delayed.

The value is an integer ranging from 3 to 100, in times.

Views

IS-IS view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

Usage Scenario

On an IS-IS network, if the Router receives an LSP with a routing information change, the device needs to calculate routes based on the LSP. If routing information changes frequently and routes are calculated immediately, a lot of system resources will be consumed. To prevent this problem, run the suppress-flapping route-calculate command to configure a period for the device to delay route calculation when the Router receives an LSP during route flapping.

The flapping suppression process is as follows:

If the same LSP with a routing information change is received repeatedly within 3s, IS-IS records a flapping event and increases the flapping_count by 1. If the interval at which the system receives the same LSP with a routing information change is greater than 10s before flapping suppression takes effect, IS-IS clears the flapping_count. If the flapping_count is greater than threshold-value, flapping suppression takes effect.
During the flapping suppression period, IS-IS does not calculate routes in response to the LSP, but the flapping_count may increase during this period. After the delay-interval elapses, IS-IS exits from flapping suppression and clears the flapping_count.

Prerequisites

An IS-IS process has been created and the IS-IS view has been displayed using the isis command.

Example

# Configure the device to delay route calculation for 5s after a route flaps 10 times.

<HUAWEI> system-view
[~HUAWEI] isis
[*HUAWEI-isis-1] suppress-flapping route-calculate timer 5 threshold 10