Label Advertisement Control - Cisco NCS 5500 Series Configuration Manual

Label Advertisement Control

Configuration Example
This example shows how to configure LDP for non-directly connected routers, Router1 and Router 2.
RP/0/RP0/CPU0:Router1(config)#
RP/0/RP0/CPU0:Router1(config-ldp)# router-id 192.168.70.1
RP/0/RP0/CPU0:Router1(config-ldp)# neighbor 172.20.10.10 targeted
RP/0/RP0/CPU0:Router1(config-ldp)# interface HundredGigE 0/0/0/5
RP/0/RP0/CPU0:Router1(config-ldp-if)# commit
RP/0/RP0/CPU0:Router2(config)#
RP/0/RP0/CPU0:Router2(config-ldp)# router-id 172.20.10.10
RP/0/RP0/CPU0:Router2(config-ldp)# neighbor 192.168.70.1 targeted
RP/0/RP0/CPU0:Router2(config-ldp)# address-family ipv4
RP/0/RP0/CPU0:Router2(config-ldp-af)#discoverey targeted-hello accept
RP/0/RP0/CPU0:Router2(config-ldp-af)# commit
Label Advertisement Control
LDP allows you to control the advertising and receiving of labels. You can control the exchange of label
binding information by using label advertisement control (outbound filtering ) or label acceptance control
(inbound filtering).
Label Advertisement Control (Outbound Filtering)
Label Distribution Protocol advertises labels for all the prefixes to all its neighbors. When this is not desirable
(for scalability and security reasons), you can configure LDP to perform outbound filtering for local label
advertisement for one or more prefixes to one more peers. This feature is known as LDP outbound label
filtering, or local label advertisement control. You can control the exchange of label binding information using
the mpls ldp label advertise command. Using the optional keywords, you can advertise selective prefixes
to all neighbors, advertise selective prefixes to defined neighbors, or disable label advertisement to all peers
for all prefixes. Prefixes and peers advertised selectively are defined in the access list.
Configuration Example: Label Advertisement Control
This example shows how to configure outbound label advertisement control. In this example, neighbors are
specified to advertise and receive label advertisements. Also an interface is specified for label advertisement.
RP/0/RP0/CPU0:Router(config)# mpls ldp
RP/0/RP0/CPU0:Router(config-ldp)# address-family ipv4
RP/0/RP0/CPU0:Router(config-ldp-af)# label local advertise to 1.1.1.1:0 for pfx_ac11
RP/0/RP0/CPU0:Router(config-ldp-af)# label local advertise interface TenGigE 0/0/0/5
RP/0/RP0/CPU0:Router(config-ldp-af)# commit
Label Acceptance Control (Inbound Filtering)
LDP accepts labels (as remote bindings) for all prefixes from all peers. LDP operates in liberal label retention
mode, which instructs LDP to keep remote bindings from all peers for a given prefix. For security reasons,
or to conserve memory, you can override this behavior by configuring label binding acceptance for set of
prefixes from a given peer. The ability to filter remote bindings for a defined set of prefixes is also referred
to as LDP inbound label filtering or label acceptance control.
MPLS Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.2.x
6
mpls ldp
mpls ldp
Implementing MPLS Label Distribution Protocol