detect-active-link enable

Function

The detect-active-link enable command enables interface status monitoring on a device, so that when the interface is Down, the Eth-Trunk interface that shares the same VLAN with the interface will send a Flush packet to instruct the peer device to update its ARP entries.

The undo detect-active-link enable command restores the default configuration.

By default, interface status monitoring is not configured, and therefore, when the interface is Down, the Eth-Trunk interface that shares the same VLAN with the interface cannot send a Flush packet to instruct the peer device to update its ARP entries.

Format

detect-active-link enable

undo detect-active-link enable

Parameters

None

Views

Layer 2 100GE interface view, Layer 2 10GE interface view, 25GE-L2 view, 400GE-L2 view, Layer 2 40GE interface view, Layer 2 50GE interface view, Eth-Trunk interface view, Layer 2 GE interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
smlk	write

Usage Guidelines

Usage Scenario

To ensure traffic proper transmission, run the detect-active-link enable command on a PE interface connecting to CE1 to enable interface status monitoring on the PE, so that when the interface is Down, the Eth-Trunk interface that shares the same VLAN with the interface will send a Flush packet to instruct the peer device to update its ARP entries.

Prerequisites

The interface on which the detect-active-link enable command is to be run must be a Layer 2 interface. If the interface is a Layer 3 interface, run the portswitch command to switch the Layer 3 interface to a Layer 2 interface.

Precautions

The detect-active-link enable command monitors the status of a Layer 2 interface based on the interface's traffic statistics. To help obtain the real-time traffic statistics, run the set flow-stat interval interval command to set the interval at which traffic statistics are collected to a small value (10s is the lower threshold).

By default, the interval at which traffic statistics are collected is 5 minutes. On the network, if an interface connecting a PE to CE1 alternates between Up and Down, traffic statistics on the interface cannot be updated in time. As a result, the Eth-Trunk interface that shares the same VLAN with the interface cannot promptly be aware of the interface status changes and may incorrectly send or send fewer Flush packets than expected.

Example

# Enable interface status monitoring on a Layer 2 interface, so that when the interface is Down, the Eth-Trunk interface that shares the same VLAN with the interface can send a Flush packet to instruct the peer device to update its ARP entries.

<HUAWEI> system-view
[~HUAWEI] interface GigabitEthernet 0/1/1
[~HUAWEI-GigabitEthernet0/1/1] portswitch
[*HUAWEI-GigabitEthernet0/1/1] detect-active-link enable