control-word enable (VSI-LDP view)

Function

The control-word enable command enables the control word function for a VSI.

The undo control-word enable command disables the control word function for a VSI.

By default, the control word function is disabled for VSIs.

Format

control-word enable

undo control-word enable

Parameters

None

Views

VSI-LDP view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
l2vpn	write

Usage Guidelines

Usage Scenario

Virtual circuit connectivity verification (VCCV) is a mechanism to detect and diagnose end-to-end faults on PWs. VCCV is, in its simplest description, a control channel between a PW's ingress and egress over which connectivity verification messages can be sent. VCCV can be performed in either label alert mode or control word mode. By default, the control word function is not enabled. To detect the connectivity of a VPLS PW, run the control-word enable command to enable the control word function.

Configuration Impact

After the control-word enable command is configured on a device, the device sets the control word flag in Label Mapping messages. A PW can be successfully negotiated only if the control word function is enabled on both ends of the PW.

Follow-up Procedure

Perform a ping operation to detect VPLS PW connectivity.

Precautions

If the control-word enable command has been run in the VSI-LDP view to enable the control word function for all PWs in a VSI, but a PW does not need the control word function, run the control-word disable command in the VSI-LDP-PW view to disable the control word function for the PW.

Example

# Enable the control word function for all PWs in the VSI named vsi1.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] vsi vsi1 static
[*HUAWEI-vsi-vsi1] pwsignal ldp
[*HUAWEI-vsi-vsi1-ldp] control-word enable