ipv6 nd nud reachable-time

Function

The ipv6 nd nud reachable-time command configures the neighbor reachable time.

The undo ipv6 nd nud reachable-time command restores the default neighbor reachable time.

By default, the IPv6 neighbor reachable time is 1200000 milliseconds.

Format

ipv6 nd nud reachable-time value

undo ipv6 nd nud reachable-time

Parameters

Parameter	Description	Value
value	Specifies the neighbor reachable time.	The value is an integer ranging from 1 to 3600000, in milliseconds.

Parameter

Description

Value

value

Specifies the neighbor reachable time.

The value is an integer ranging from 1 to 3600000, in milliseconds.

Views

100ge sub-interface view, 100GE interface view, 10GE sub-interface view, 10GE interface view, 200GE sub-interface view, 25GE sub-interface view, 25GE interface view, 400GE sub-interface view, 400GE interface view, 40GE sub-interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk sub-interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE sub-interface view, GE interface view, GE electrical interface view, Global VE sub-interface view, PW-VE sub-interface view, PW-VE interface view, VBDIF interface view, VE sub-interface view, VLANIF interface view, Management interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
nd	write

Usage Guidelines

Usage Scenario

The IPv6 neighbor reachable time provides the following functions:

Controlling the aging time of ND entries on a local device
Being a parameter in an RA message to help a host to generate the neighbor reachable time
Each RA message sent by a device carries the neighbor reachable time so that all the nodes along the same link can use the same time.

Prerequisites

IPv6 has been enabled on the involved interface using the ipv6 enable command.

Configuration Impact

A smaller neighbor reachable time set on a device indicates that the device can probe the neighbor reachability more quickly but more network bandwidth and CPU resources are occupied. Therefore, on a normal IPv6 network, you are not recommended to set the neighbor reachable time to a smaller value. The default value, 1200000 milliseconds, is recommended.

The ipv6 nd nud reachable-time command is circular in nature. That is, if the neighbor reachable times set two times are different, the latest setting takes effect.

Precautions

Commonly, the neighbor reachable time set on a device is the same as that carried in an RA message. In the following cases, however, the neighbor reachable time set on a device is of the default value 1200000 milliseconds whereas the neighbor reachable time carried in the RA message is 0 milliseconds:

The neighbor reachable time is not set on the device, that is, the default value is used.
The undo ipv6 nd nud reachable-time command is run to restore the default setting.
After a host receives an RA message with the neighbor reachable time being 0 milliseconds, it uses the default neighbor reachable time 1200000 milliseconds.

Example

# Set the neighbor reachable time on GE 0/1/1.

<HUAWEI> system-view
[~HUAWEI] interface GigabitEthernet 0/1/1
[~HUAWEI-GigabitEthernet0/1/1] ipv6 enable
[*HUAWEI-GigabitEthernet0/1/1] ipv6 nd nud reachable-time 10000