keepalive (Tunnel interface view)

Function

The keepalive command enables the Keepalive function for a GRE tunnel.

The undo keepalive command disables the Keepalive function for a GRE tunnel.

By default, the Keepalive function of a GRE tunnel is disabled.

Format

keepalive [ period period [ retry-times retry-times ] ]

undo keepalive [ period period [ retry-times retry-times ] ]

Parameters

Parameter	Description	Value
period period	Specifies the interval for sending Keepalive messages.	The value is an integer ranging from 1 to 32767, in seconds. The default value is 5.
retry-times retry-times	Specifies the count of the unreachable counter.	The value is an integer ranging from 1 to 255. The default value is 3.

Parameter

Description

Value

period period

Specifies the interval for sending Keepalive messages.

The value is an integer ranging from 1 to 32767, in seconds. The default value is 5.

retry-times retry-times

Specifies the count of the unreachable counter.

The value is an integer ranging from 1 to 255. The default value is 3.

Views

Tunnel interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
gre	write

Usage Guidelines

Usage Scenario

To prevent an unavailable GRE tunnel from being selected to transmit packets, enable the Keepalive function for GRE tunnels. Before the Keepalive function is enabled, the local tunnel interface may be Up even if the peer tunnel interface is unreachable. After the Keepalive function is enabled, the local tunnel interface goes Down if the peer tunnel interface is unreachable.

After the Keepalive function is enabled on a GRE tunnel, the tunnel periodically sends Keepalive messages. The unreachable counter increases by one each time a message is sent. If no Keepalive response message is received when the value of the counter reaches the configured retry-times, the peer is considered unreachable.

The Keepalive function immediately takes effect after the keepalive command is run on a GRE tunnel interface. The undo keepalive command disables this function.

Prerequisites

A tunnel interface has been created using the interface tunnel command.

The tunnel encapsulation type has been set to GRE using the tunnel-protocol gre command.

Configuration Impact

If the keepalive command is run more than once, the latest configuration overrides the previous one.

Follow-up Procedure

After configuring the Keepalive function, you can run the display keepalive packets count command to check the numbers of Keepalive messages and Keepalive response messages sent and received by a GRE tunnel interface.

Precautions

The Keepalive function is unidirectional. If you want a GRE tunnel to have the Keepalive function in both directions, enable the Keepalive function on both ends of the GRE tunnel. The Keepalive functions on the local and remote ends of a GRE tunnel do not interfere with each other. It is recommended that you configure the Keepalive function on both ends of a GRE tunnel.

Example

# Enable the Keepalive function for the GRE tunnel. Specify the interval for sending Keepalive messages as 12 seconds and set the retry-times to 4.

<HUAWEI> system-view
[~HUAWEI] interface tunnel 100
[*HUAWEI-Tunnel100] tunnel-protocol gre
[*HUAWEI-Tunnel100] keepalive period 12 retry-times 4

# Enable the Keepalive function for the GRE tunnel. Specify the interval for sending Keepalive messages as 12 seconds and configure the unreachable counter to use default parameters.

<HUAWEI> system-view
[~HUAWEI] interface tunnel 100
[*HUAWEI-Tunnel100] tunnel-protocol gre
[*HUAWEI-Tunnel100] keepalive period 12

# Enable the Keepalive function for the GRE tunnel using default parameters.

<HUAWEI> system-view
[~HUAWEI] interface tunnel 100
[*HUAWEI-Tunnel100] tunnel-protocol gre
[*HUAWEI-Tunnel100] keepalive