explicit-null

Use this command to configure the router to send explicit-null labels for directly connected FECs instead of implicit-null labels. Implicit-nulls are the default labels.

This command controls the label value advertised on the egress router of an LSP. By default, implicit null label (label 3) is advertised for directly connected FECs. LDP advertises an Implicit Null label that causes the previous hop router to perform penultimate hop popping. Use the explicit null command to avoid the penultimate router from penultimate hop popping, and to force it to replace the incoming label with the explicit null label.

Do not use this command if the LDP is concurrently used for MPLS/BGP VPNs.

Use the no parameter to stop sending explicit-null labels for directly connected FECs and resume sending implicit-null labels for them.

Command Syntax

explicit-null
no explicit-null

Parameters

None

Default

By default, sends implicit-null labels.

Command Mode

Router mode

Applicability

This command was introduced before OcNOS version 1.3.

Examples

#configure terminal
(config)#router ldp
(config-router)#explicit-null