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Controlling LDP Label Distribution
By default, LDP advertises label mappings for all IGP prefixes to all LDP peers. In
this case, mappings are not advertised for interface addresses. You can alternatively
specify that LDP labels be distributed for a particular interface itself, in addition to
the subnet that the interface is on. This behavior enables LSPs to be set up to the
LSR configured with the interface address.
When the LSR learns an IGP route and tries to decide whether to advertise a label
for the destination to a particular LDP neighbor, it attempts to match the destination
against a route access list specified by the
mpls ldp advertise-labels command, in
the order in which the commands were issued. The first match determines the action
taken, and no further matching is attempted for that destination. If the destination
matches, labels are advertised to peers subject to any specified neighbor address
list. If either access list is not matched, the labels are not advertised.
To create a filter that determines whether and where incoming (locally assigned)
labels are distributed:
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Issue the mpls ldp advertise-labels command one or more times:
host1(config)# mpls ldp advertise-labels for net25 to euro3
When you do not specify a toAccessList , the action is taken for all peers.
Consider the following example configuration.
host1(config)# mpls ldp advertise-labels for net25 to euro3
host1(config)# mpls ldp advertise-labels for boston1
In this example, suppose the LSR receives a label for destination 10.10.11.12. If
net25 specifies 10.10.11.12, then the access list action—permit or deny—is taken
with the destination. If the action is permit, the peer that the label is advertised to
is subject to the access list euro3. If net25 does not include 10.10.11.12, the LSR
attempts to match it against boston1. If 10.10.11.12 is present in that access list,
the specified action is taken for all peers. If boston1 does not include the destination,
the label is not advertised to any peer.
Related Topics
Basic MPLS Configuration Tasks on page 264
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Additional LDP Configuration Tasks on page 277
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mpls ldp advertise-labels
Additional RSVP-TE Configuration Tasks
All of the following RSVP-TE configuration tasks are optional, depending on your
network topology and needs.
Tasks to configure RSVP-TE settings based on your network topology include:
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Controlling LDP Label Distribution
JUNOSe 11.0.x BGP and MPLS Configuration Guide