isis peer hold-max-cost

Function

The isis peer hold-max-cost command sets the maximum holdtime for the largest IS-IS route cost in local Link State PDUs (LSPs).

The undo isis peer hold-max-cost command restores the default configuration.

By default, no maximum holdtime is set for the largest IS-IS route cost in local LSPs.

Format

isis peer hold-max-cost timer timer-val

isis process-id process-id peer hold-max-cost timer timer-val

undo isis peer hold-max-cost timer [ timer-val ]

undo isis process-id process-id peer hold-max-cost timer [ timer-val ]

Parameters

Parameter	Description	Value
process-id process-id	Specifies the ID of an IS-IS process, which is used in multi-instance process scenarios.	The value is an integer ranging from 1 to 4294967295.
timer timer-val	Sets the maximum holdtime for the largest IS-IS route cost in local LSPs.	The value is an integer ranging from 100 to 1000000, in milliseconds.

Parameter

Description

Value

process-id process-id

Specifies the ID of an IS-IS process, which is used in multi-instance process scenarios.

The value is an integer ranging from 1 to 4294967295.

timer timer-val

Sets the maximum holdtime for the largest IS-IS route cost in local LSPs.

The value is an integer ranging from 100 to 1000000, in milliseconds.

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, VBDIF interface view, VE sub-interface view, VE interface view, VLANIF interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

Usage Scenario

When a Down IS-IS interface goes Up, IS-IS neighbor relationships are re-established on the interface, and traffic is switched back to this Up interface after IGP route convergence. IGP route convergence is fast, but many services that depend on IGP routes may not expect such fast traffic switchback. To delay traffic switchback after IGP route convergence, run the isis peer hold-max-cost command to set the maximum holdtime for the largest IS-IS route cost (16777214 in wide mode and 63 in narrow mode) in local LSPs. In this manner, before the specified maximum holdtime expires, traffic is not switched back to this route due to its large cost. After the specified maximum holdtime expires, the route cost reverts to the original value, and then traffic is switched back to this route.

The effective time of the specified maximum holdtime is different for P2P and broadcast neighbors.

For a P2P neighbor, the maximum holdtime takes effect after the neighbor relationship goes Up.
For a broadcast neighbor, the maximum holdtime takes effect after the neighbor relationship goes Up and then a DIS is elected successfully.

Precautions

This command takes effect both for IPv4 and IPv6. IPv4 and IPv6 use the same hold-max-cost timer on interfaces.

Example

# Set the maximum holdtime to 1000 ms for the largest IS-IS route cost in local LSPs on GE 0/1/0.

<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 peer hold-max-cost timer 1000