BGP Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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BGP labeled unicast MPLS IP POP

Updated: February 28, 2026

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Overview

Describes BGP labeled unicast MPLS IP POP support and provides instructions to configure this feature on relevant PE devices for efficient label operations in MPLS deployments.

BGP Labeled Unicast MPLS IP POP is a routing feature that

  • enables efficient forwarding of IPv4 unicast traffic using labeled routes

  • uses BGP to distribute labeled prefixes with implicit NULL labels, and

  • applies only the transport LDP label on packets before forwarding them into the MPLS core.

This mechanism optimizes label stacking and improves forwarding efficiency in MPLS networks.

BGP labeled unicast with implicit NULL label and transport LDP label forwarding in MPLS core networks

Table 1. Feature History Table

Feature Name

Release Information

Feature Description

BGP Labeled Unicast MPLS IP POP Support

Release 25.4.1

Introduced in this release on: Fixed Systems (8700 [ASIC: K100])(select variants only*)

*This feature is supported on Cisco 8711-48Z-M routers.

BGP Labeled Unicast MPLS IP POP Support

Release 7.3.1

This feature is based on the BGP labeled Unicast feature. This feature enables a router to send unicast traffic to the destination from BGP labeled unicast using implicit NULL label. Implicit null label avoids adding or removing rewrites for neighbor flaps.

  • IP POP Support allows you to forward IP packets with minimal label stacking, improving network efficiency.

  • For example, in a topology where client A sends IPv4 unicast traffic to client B, IP POP Support enables the Provider Edge (PE) router to add only the transport LDP label on top of the IP packet before forwarding it into the MPLS core.

  • This reduces complexity compared to traditional MPLS forwarding, which may use multiple stacked labels.

  • Understanding IP POP Support helps you design and troubleshoot MPLS networks that optimize label usage and forwarding performance.

Configure BGP labeled unicast on MPLS IP pop Support

Enable and configure BGP labeled unicast on PE1 and PE3 to optimize IPv4 labeled-unicast forwarding by reducing label overhead and simplifying MPLS label stacking.

This configuration allows PE1 to learn destination prefixes from PE3 via BGP labeled unicast using implicit NULL labels. PE1 then applies only the transport LDP label on IPv4 packets before forwarding them into the MPLS core, enhancing forwarding efficiency.

Before you begin

  • Ensure hardware modules on PE1 and PE3 support BGP labeled unicast and the hardware module profile can be enabled.

  • Confirm PE1 and PE3 have proper connectivity and reachability, including configured loopback interfaces for BGP update sources.

  • Make sure BGP is operational on both routers with correct autonomous system numbers.

Configure PE1:

Procedure

1.

Enable BGP labeled unicast on the hardware module:

Example:

Router(config)# hw-module profile bgplu enable
2.

Configure BGP router and enable features

Example:

Router(config)# router bgp 200
Router(config-bgp)# nsr
Router(config-bgp)# bgp router-id 192.168.70.24
Router(config-bgp)# bgp graceful-restart
Router(config-bgp)# ibgp policy out enforce-modifications
3.

Configure IPv4 unicast address family with maximum paths and label allocation:

Example:

Router(config-bgp)# address-family ipv4 unicast
Router(config-bgp-af)# maximum-paths ibgp 8
Router(config-bgp-af)# network 101.101.1.0/24
Router(config-bgp-af)# network 101.101.2.0/24
Router(config-bgp-af)# allocate-label all
Router(config-bgp-af)# exit
4.

Configure BGP neighbor and session parameters:

Example:

Router(config-bgp)# neighbor 10.3.3.3
Router(config-bgp)# remote-as 200
Router(config-bgp)# update-source Loopback0
5.

Configure IPv4 labeled unicast address family and set the next-hop:

Example:

Router(config-bgp)# address-family ipv4 labeled-unicast
Router(config-bgp)# next-hop self
6.

Verify the configuration on the PE1 router. The output should show the bgplu profile enabled and correct BGP labeled unicast settings.

Example:

Router# show running-config
hw-module profile bgplu enable
router bgp 200
 nsr
 bgp router-id 192.168.70.24
 bgp graceful-restart
 ibgp policy out enforce-modifications
 address-family ipv4 unicast
  maximum-paths ibgp 8
  network 101.101.1.0/24
  network 101.101.2.0/24
  allocate-label all
!
 neighbor 10.3.3.3
 remote-as 200
 update-source Loopback0
 address-family ipv4 labeled-unicast
 next-hop self
7.

Verify the configuration on the PE2 router. The output should show the bgplu profile enabled and correct BGP labeled unicast settings.

Example:

Router# show running-config
hw-module profile bgplu enable
router bgp 200
 nsr
 bgp router-id 192.168.70.25
 bgp graceful-restart
 ibgp policy out enforce-modifications
 address-family ipv4 unicast
  maximum-paths ibgp 8
  network 103.101.1.0/24
  network 103.101.2.0/24
  allocate-label all
!
neighbor 10.1.1.1
remote-as 1
update-source Loopback0
address-family ipv4 labeled-unicast
next-hop self
8.

Verify if the feature has been configured.

Example:



Router# show bgp ipv4 unicast labels
  Network           Next Hop    Rcvd Label      Local Label
*>i103.101.1.0/24   10.3.3.3        3            24006
9.

Restart the router so hardware module configuration takes effect.

PE routers use BGP labeled unicast with implicit NULL labels and apply only the transport LDP label before forwarding IPv4 packets into the MPLS core, resulting in improved forwarding efficiency.

What to do next

Monitor BGP and MPLS operations to ensure stable label distribution and end-to-end forwarding.