ospf cost-fallback

Function

The ospf cost-fallback multi-area command configures cost-fallback parameters for an Eth-Trunk multi-area adjacency interface.

The undo ospf cost-fallback multi-area command deletes the cost-fallback parameters configured for an Eth-Trunk multi-area adjacency interface.

The ospf cost-fallback command configures cost-fallback parameters for an Eth-Trunk interface.

The undo ospf cost-fallback command deletes cost-fallback parameter configurations of an Eth-Trunk interface.

By default, no cost-fallback parameters are configured for Eth-Trunk interfaces.

Format

ospf cost-fallback fallbackcost threshold fallbackbw [ multi-area { area-id | area-id } ]

undo ospf cost-fallback [ fallbackcost threshold fallbackbw ] [ multi-area { area-id | area-id } ]

Parameters

Parameter	Description	Value
fallbackcost	Specifies a fallback cost.	The value is an integer ranging from 1 to 65535.
threshold fallbackbw	Specifies a fallback bandwidth threshold.	The value is an integer ranging from 1 to 4294967295, in Mbit/s.
area-id	Specifies the ID of an OSPF area.	The value can be a decimal integer ranging from 0 to 4294967295 or in the format of an IP address.

Parameter

Description

Value

fallbackcost

Specifies a fallback cost.

The value is an integer ranging from 1 to 65535.

threshold fallbackbw

Specifies a fallback bandwidth threshold.

The value is an integer ranging from 1 to 4294967295, in Mbit/s.

area-id

Specifies the ID of an OSPF area.

The value can be a decimal integer ranging from 0 to 4294967295 or in the format of an IP address.

Views

Eth-Trunk interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ospf	write

Usage Guidelines

Usage Scenario

If a member interface of an Eth-Trunk multi-area adjacency interface goes down, the remaining bandwidth of the Eth-Trunk multi-area adjacency interface may fail to meet user requirements. As a result, user services are affected. To address this problem, run the ospf cost-fallback multi-area command to configure cost-fallback parameters (fallback cost and bandwidth threshold) for the Eth-Trunk multi-area adjacency interface; if the remaining bandwidth of the interface goes below the bandwidth threshold, the cost of the interface is changed to the fallback cost which is higher than the normal cost, and traffic is then switched to an alternative path; when the remaining bandwidth of the interface reaches or exceeds the bandwidth threshold, the original cost is restored.

Prerequisites

The ospf enable multi-area area-id command has been run.

Example

# Set the fallback cost and bandwidth threshold to 500 and 260, respectively, for an Eth-Trunk multi-area adjacency interface.

<HUAWEI> system-view
[~HUAWEI] ospf 1
[*HUAWEI-ospf-1] area 0
[*HUAWEI-ospf-1-area-0.0.0.0] quit
[*HUAWEI-ospf-1] area 1
[*HUAWEI-ospf-1-area-0.0.0.1] quit
[*HUAWEI-ospf-1] quit
[*HUAWEI] interface Eth-Trunk 1
[*HUAWEI-Eth-Trunk1] ospf enable 1 area 0
[*HUAWEI-Eth-Trunk1] ospf enable multi-area 1
[*HUAWEI-Eth-Trunk1] ospf cost-fallback 500 threshold 260 multi-area 1

# Set the fallback cost and bandwidth threshold to 500 and 260, respectively, for an Eth-Trunk interface.

<HUAWEI> system-view
[~HUAWEI] interface Eth-Trunk 1
[~HUAWEI-Eth-Trunk1] ospf cost-fallback 500 threshold 260