isis circuit-level

Function

The isis circuit-level command sets a link type for an interface on a Level-1-2 router that runs IS-IS.

The undo isis circuit-level command restores the default setting.

This command varies in transport and router modes. For detailed differences, see Differences Between Commands in Transport and Router Modes. This topic describes the command configuration in router mode.

By default, the link type of an interface on a Level-1-2 router that runs IS-IS is Level-1-2, and both Level-1 and Level-2 adjacencies can be established on the interface.

Format

isis circuit-level [ level-1 | level-2 | level-1-2 ]

undo isis circuit-level

Parameters

Parameter	Description	Value
level-1	Indicates the Level-1 link type. After the parameter is configured, the interface can set up only Level-1 adjacencies.	-
level-2	Indicates the Level-2 link type. After the parameter is configured, the interface can set up only Level-2 adjacencies.	-
level-1-2	Indicates the Level-1-2 link type. After the parameter is configured, the interface can set up both Level-1 and Level-2 adjacencies.	-

Parameter

Description

Value

level-1

Indicates the Level-1 link type. After the parameter is configured, the interface can set up only Level-1 adjacencies.

level-2

Indicates the Level-2 link type. After the parameter is configured, the interface can set up only Level-2 adjacencies.

level-1-2

Indicates the Level-1-2 link type. After the parameter is configured, the interface can set up both Level-1 and Level-2 adjacencies.

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, GMPLS-UNI interface view, Global VE sub-interface view, Loopback 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 an adjacency is established between a Level-1-2 router and a remote device, the Level-1-2 router sends and receives both Level-1 and Level-2 Hello packets, wasting bandwidth and memory resources. To solve this problem, run the isis circuit-level command to set a specified link type for an interface on the Level-1-2 router.

Prerequisites

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

Configuration Impact

Network flapping may occur if the link type of an IS-IS interface is changed during network operation. Therefore, setting a link type when configuring IS-IS is recommended.

Precautions

The link type takes effect only when the system type of IS-IS is Level-1-2. Otherwise, the level defined by the is-level command is used.

Example

# Set the link type of GE 0/1/0 that is connected to a non-backbone device in the same area to Level-1 to prevent GE 0/1/0 from receiving and sending Level-2 Hello packets.

<HUAWEI> system-view
[~HUAWEI] isis 1
[*HUAWEI-isis-1] quit
[*HUAWEI] interface GigabitEthernet 0/1/0
[*HUAWEI-GigabitEthernet0/1/0] isis enable
[*HUAWEI-GigabitEthernet0/1/0] isis circuit-level level-1