isis timer ldp-sync hold-down

Function

The isis timer ldp-sync hold-down command sets the interval during which an interface waits for creating an LDP session and an LDP adjacency before establishing an IS-IS neighbor relationship.

The undo isis timer ldp-sync hold-down command restores the default interval.

By default, the interval is 10 seconds.

Format

isis timer ldp-sync hold-down value

undo isis timer ldp-sync hold-down

Parameters

Parameter	Description	Value
value	Specifies the interval during which an interface waits for creating an LDP session and an LDP adjacency before setting up the IS-IS neighbor relationship.	An integer ranging from 0 to 65535, in seconds. The default value (10 seconds) is recommended.

Parameter

Description

Value

value

Specifies the interval during which an interface waits for creating an LDP session and an LDP adjacency before setting up the IS-IS neighbor relationship.

An integer ranging from 0 to 65535, in seconds. The default value (10 seconds) is recommended.

Views

100GE interface view, 10GE interface view, 25GE sub-interface view, 25GE interface view, 400GE interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE electrical interface view, Global VE sub-interface view, Tunnel interface view, VE sub-interface view, VE interface view, XGE interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

Usage Scenario

On a network with both active and standby links, if the active link fails, traffic switches to a standby link. Therefore, the standby IS-IS route and backup LDP LSP along the standby link become reachable. After the active link recovers, its IS-IS route converges more rapidly than the LDP LSP. As a result, the IS-IS neighbor relationship is established earlier than the LDP session or LDP adjacency on the active link. Although traffic is directed over the IS-IS route to the active link, traffic fails to be forwarded because no LDP LSP is established.

To prevent the traffic forwarding failure, LDP and IS-IS synchronization can be configured. After the active link recovers from a physical fault, the IS-IS route for the active link is set to the Hold-down state, and the Hold-down timer starts. After an LDP session and an LDP adjacency are reestablished over the active link or the Hold-down timer expires, the IS-IS neighbor relationship starts to be established. This allows the LDP LSP and IS-IS route to go Up simultaneously. To set the Hold-down timer, run the isis timer ldp-sync hold-down command.

Prerequisites

An IS-IS process has been enabled using the isis enable command in the interface view.

Example

# Set the interval to 15 seconds, during which an interface waits for creating an LDP session and an LDP adjacency before setting up the IS-IS neighbor relationship.

<HUAWEI> system-view
[~HUAWEI] isis 1
[*HUAWEI-isis-1] quit
[*HUAWEI] interface GigabitEthernet 0/1/0
[*HUAWEI-GigabitEthernet0/1/0] isis enable 1
[*HUAWEI-GigabitEthernet0/1/0] isis timer ldp-sync hold-down 15