Mpls Ldp Explicit-Null - Zte ZXR10 8900 Series Command Reference Manual

Purpose
Command Modes
Syntax
Syntax
Description
Defaults
Instructions
Example

mpls ldp explicit-null

Use this command to make the router which is supposed to adver-
tise implicit null labels advertise explicit null labels. To disable this
feature, use the no form of this command.
Global configuration
mpls ldp explicit-null [for <prefix-access-list>][to <peer-acce
ss-list>]
no mpls ldp explicit-null
for <prefix-access-li
st>
to <peer-access-list>
By default, ZXR10 advertises directly connected networks to all
neighbors by means of implicit null labels.
� By default, ZXR10 advertises directly connected networks to
all neighbors by means of implicit null labels. The implicit null
label causes the Penultimate Hop Poping (PHP) router to make
PHP. Sometimes, however, it is prohibited for the PHP router to
make such action so that the explicit null label is used in the
outgoing label forwarding packet.
� The mpls ldp explicit-null command enables the router to
advertise explicit null labels to the neighbors permitted by<pe
er-access-list> and the directly connected networks permitted
by <prefix-access-list>. If the parameter <prefix-access-list>
is not specified in the command, explicit null labels will be ad-
vertised to all the directly connected networks; if the parame-
ter <peer-access-list> is not specified in the command, explicit
null labels will be advertised to all neighbors.
� This command takes effect only to the label advertisement
messages after the configuration. If labels have been adver-
tised before the policy is configured, and the matched networks
and neighbors will not change unless the session is interrupted
and reestablished. Therefore, it is not recommended to con-
figure this command when the system is running to avoid in-
consistency.
1. This example describes how to make LDP advertise all direct
routes by explicit null labels to all neighbors.
ZXR10(config)#mpls ldp explicit-nul
2. This example describes how to advertise explicit null labels to
the directly connected network 137.5.0.0, and advertise im-
plicit null labels to other directly connected networks.
ZXR10(config)#mpls ldp explicit-null for 10
ZXR10(config)#ip access-list standard 10
ZXR10(config-std-nacl)#permit 137.5.0.0 0.0.255.255
ZXR10(config-std-nacl)#deny any
ZXR10(config-ext-nacl)#
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Chapter 2 MPLS LDP Configuration
Specifies the prefix of the explicit null labels
replacing implicit ones, range: 1~99
Specifies which neighbors that the explicit
null labels replaces implicit ones is advertised
to, range: 1~99
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