Mpls Ldp Egress - Zte ZXR10 Command Manual

Purpose
Command Modes
Syntax
Syntax
Description
Defaults
Instructions

mpls ldp egress

Use this command to control LDP to allocate popup labels to the
designated indirectly connected destination networks (that is, the
egress control policy). To disable this feature, use the no form of
this command.
Global configuration
mpls ldp egress {for <prefix-access-list>| nexthop <nexthop-
access-list>}
no mpls ldp egress {for | nexthop}
for <prefix-access-li
st>
nexthop <nexthop-a
ccess-list>
By default, LDP allocates popup labels only to the directly con-
nected networks and makes advertisements to the peer LSR.
By default, LDP allocates popup labels only to the directly con-
nected networks and makes advertisements to the peer LSR. For
destination networks not directly connected, LDP acquires the idle
label from the label pool as the incoming label and chooses the
label value in the mapping message sent by the next hop of the
route as the outgoing label.
If local router is an edge LSR and the router of nexthop may be
a non-MPLS router, local LSR cannot bind the outgoing label, and
the received label packet be will discarded at the data layer be-
cause there is no outgoing label according to the MPLS framework
protocol.
In this case, it is necessary to configure the egress control pol-
icy to specify LDP to allocate popup labels to destination networks
flowing out of MPLS network, and make advertises to the upstream
LSR. Thus upstream LSR will forward the traffic from the MPLS net-
work in the form of IP packets (or explicitly popup label packets).
There are two kinds of control policies: based on destination net-
work segment and based on next hop.
1. The egress control policy based on destination networks (mpls
ldp egress for <prefix-access-list>) directly specifies which
destination where local LSR is terminated.
2. The egress control policy based on next hop (mpls ldp egress
nexthop <nexthop-access-list>) specifies which neighbors
are non-MPLS routers so that the traffic of these neighbors
as next hops is the traffic out of MPLS. Local router allocates
popup labels for this traffic.
As long as a route meets either of the two policies, that is, the
destination prefix is permitted by <prefix-access-list> or the next
hop is permitted by <nexthop-access-list> , the LDP will allocate
a popup label to it.
The policy takes effect only on the refreshed FECs after the config-
uration and does not reallocate labels to the existing FECs. There-
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Chapter 2 MPLS LDP Configuration
Specifies which destination networks to which
popup labels are allocated, range: 1~99
Specifies the nexthop of the destination
networks, range: 1~99
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