timer ldp-sync hold-max-cost (OSPF area view)

Function

The timer ldp-sync hold-max-cost command sets a period for an IGP process or instance to advertise the maximum cost.

The undo timer ldp-sync hold-max-cost command restores the default period.

By default, the IGP keeps advertising the maximum cost on a device before an LDP session and an LDP adjacency are reestablished.

Format

timer ldp-sync hold-max-cost { interval | infinite }

undo timer ldp-sync hold-max-cost

Parameters

Parameter	Description	Value
interval	Specifies the period during which the IGP keeps the maximum cost on a device.	The value is an integer that ranges from 0 to 65535, in seconds.
infinite	Specifies the maximum cost that an IGP permanently advertises on the local device.	The IGP permanently advertises the maximum cost on the local device before an LDP session and LDP adjacency are reestablished.

Parameter

Description

Value

interval

Specifies the period during which the IGP keeps the maximum cost on a device.

The value is an integer that ranges from 0 to 65535, in seconds.

infinite

Specifies the maximum cost that an IGP permanently advertises on the local device.

The IGP permanently advertises the maximum cost on the local device before an LDP session and LDP adjacency are reestablished.

Views

OSPF area view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ospf	write

Usage Guidelines

Usage Scenario

After LDP and IGP synchronization is enabled on a network with primary and backup links, if the primary link fails, LDP and IGP switch traffic to the backup link.

When the primary link recovers from a fault, LDP and IGP synchronization notifies the local node of the maximum cost of the primary link. To enable traffic to be forwarded through the backup link before an LSP is established on the primary link within a specified interval, run this command.
After the primary and backup links are normal, if the LDP session or LDP adjacency of the primary link is faulty, the IGP is still normal. In this case, LDP and IGP synchronization notifies the local node of the maximum cost of the primary link. In this way, IGP and LDP both switch traffic to the backup link within a certain period of time.
The timer ldp-sync hold-max-cost command sets the interval for advertising the maximum cost.
If the IGP carries only LDP services, you need to set the infinite parameter to ensure that the IGP route selection is consistent with the LDP LSP.

Configuration Impact

If an LDP session or LDP adjacency is unable to go Up, configuring infinite affects OSPF route selection because the interface keeps advertising the maximum cost.

Example

# Allow OSPF to keep advertising the maximum cost by sending link state PDUs until the LDP session and an LDP adjacency are reestablished.

<HUAWEI> system-view
[~HUAWEI] ospf 1
[*HUAWEI-ospf-1] area 0
[*HUAWEI-ospf-1-area-0.0.0.0] timer ldp-sync hold-max-cost infinite