3com MSR 20-20 참조 매뉴얼

MPLS view

explicit-null: Specifies that the egress does not support PHP and distributes to the 
penultimate hop an explicit null label, whose value is 0.

implicit-null: Specifies that the egress supports PHP and distributes to the 
penultimate hop an implicit null label, whose value is 3.

non-null: Specifies that the egress distributes the label to the penultimate hop 
normally and does not support PHP. The value of the distributed label will be equal 
to or greater than 1024.

Use the label advertise command to specify whether the egress supports PHP 
and what type of label the egress should distribute to the penultimate hop.

Use the undo label advertise command to restore the default.

By default, an egress supports PHP and distributes to the penultimate hop an 
implicit null label.

n

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# Specify the egress to distribute an explicit null label to the penultimate hop.

<Sysname> system-view

[Sysname] mpls

[Sysname-mpls] label advertise explicit-null 

label-distribution { independent | ordered }

MPLS LDP view/MPLS LDP VPN instance view

independent: Works in independent mode, advertising label bindings anytime.

ordered: Works in ordered mode, advertising to its upstream a label binding only 
when it receives a specific label binding message from the next hop for a FEC or 
the LSR itself is the egress node of the FEC.

Use the label-distribution command to configure the label distribution control 
mode.

Use the undo label-distribution command to restore the default.