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.
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.
Follow-up Procedure
Perform a ping operation to detect VPLS PW connectivity.
Precautions
The control-word enable command enables the control word function for all PWs in a VSI. If the control word function is not required for a VSI, run the undo control-word enable command to disable the control word function for the VSI.