Configure VPN connectivity with ASBRs exchanging IPv4 routes and MPLS labels

Updated: September 11, 2026

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Details procedures for configuring BGP route reflectors to exchange and reflect VPN-IPv4 routes across autonomous systems, preserving next-hop and label information to ensure seamless MPLS VPN operation.

Enable VPN connectivity across Autonomous Systems by configuring route reflectors to facilitate the exchange and reflection of VPN-IPv4 routes.

This procedure does not apply to Inter-AS VPN connectivity over IP tunnels. It is intended for scenarios where ASBRs exchange IPv4 routes and MPLS labels using route reflectors.

Before you begin

Plan the settings for route reflectors, ASBRs, PEs, VPN-IPv4 or VPNv6, eBGP multihop, and route policies.

Procedure

Configure route reflectors to exchange VPN-IPv4 routes.

For detailed instructions, see Configure route reflectors for VPN-IPv4 route exchange.
Configure the route reflectors to reflect remote routes within an AS.

For detailed instructions, see Configure route reflectors to reflect remote routes within an AS.

VPN connectivity is provided when route reflectors exchange VPN-IPv4 routes and reflect remote routes within the AS.

Configure route reflectors for VPN-IPv4 route exchange

Establish BGP route reflectors that exchange VPN-IPv4 routes between autonomous systems with next-hop and VPN label preservation.

Route reflectors enable the exchange of VPN-IPv4 and VPN-IPv6 routes between BGP peers across different autonomous systems. This setup is essential for multi-AS MPLS VPN deployments, ensuring that routes are properly reflected and next-hop and label information remains intact for seamless forwarding.

Before you begin

Plan the route reflector peer, remote AS, loopback update source, VPNv4 and VPNv6 address families, route policies, and next-hop behavior before you begin.

Procedure

Configure route reflectors to exchange VPN-IPv4 routes.

Example:

Router# configure
Router(config)# router bgp 500
Router(config-bgp)# 
Router(config-bgp-nbr)# remote-as 100
Router(config-bgp-nbr)# ebgp-multihop
Router(config-bgp-nbr)# update-source loopback0
Router(config-bgp-nbr)# address-family vpnv4 unicast
Router(config-bgp-nbr-af)# route-policy pass-all in
Router(config-bgp-nbr-af)# route-policy pass-all out
Router(config-bgp-nbr-af)# next-hop-unchanged
Router(config-bgp-nbr)# address-family vpnv6 unicast
Router(config-bgp-nbr-af)# route-policy pass-all in
Router(config-bgp-nbr-af)# route-policy pass-all out
Router(config-bgp-nbr-af)# next-hop-unchanged

Review the running configuration.

Example:

Router#show run router bgp 500
router bgp 500
bgp router-id 192.0.2.10
address-family ipv4 labeled-unicast
  allocate-label all
!
address-family vpnv4 unicast
!
address-family ipv6 unicast
!
address-family vpnv6 unicast
!
neighbor 10.200.1.1
  remote-as 100
  ebgp-multihop 255
  update-source Loopback0
  address-family vpnv4 unicast
   route-policy PASS-ALL in
   route-policy PASS-ALL out
   next-hop-unchanged
  !
  address-family vpnv6 unicast
   route-policy PASS-ALL in
   route-policy PASS-ALL out
   next-hop-unchanged
  !

Verify the configuration and the state of routes and labels.

Example:

Router#show cef vrf vrf2001 ipv4 172.16.0.1/32 hardware egress location0/0/CPU0
192.0.2.11/32, version 39765, internal 0x5000001 0x0 (ptr 0x9f4d326c) [1], 0x0 (0xa0263058), 0x808 (0x899285b8)
 Updated Oct 27 10:58:39.350
 Prefix Len 32, traffic index 0, precedence n/a, priority 3
   via 10.200.1.1/32, 307 dependencies, recursive, bgp-ext [flags 0x6020]
    path-idx 0 NHID 0x0 [0x89a59100 0x0]
    recursion-via-/32
    next hop VRF - 'default', table - 0xe0000000
    next hop 10.200.1.1/32 via 69263/0/21
     next hop 192.0.2.12/32 Te0/3/0/17/0 labels imposed {24007 64007 64023}


 LEAF - HAL pd context :
 sub-type : IPv4, ecd_marked:0, has_collapsed_ldi:0
 collapse_bwalk_required:0, ecdv2_marked:0
HW Walk:
LEAF:
    PI:0x9f4d326c PD:0x9f4d3304 Rev:3865741 type: 0
    FEC handle: 0x890c0198

    LWLDI:
        PI:0xa0263058 PD:0xa0263098 rev:3865740 p-rev: ldi type:0
        FEC hdl: 0x890c0198 fec index: 0x0(0) num paths:1, bkup: 0

 REC-SHLDI HAL PD context :
ecd_marked:0, collapse_bwalk_required:0, load_shared_lb:0

    RSHLDI:
        PI:0x9f17bfd8 PD:0x9f17c054 rev:0 p-rev:0 flag:0x1
        FEC hdl: 0x890c0198 fec index: 0x20004fa6(20390) num paths: 1
        Path:0 fec index: 0x20004fa6(20390) DSP fec index: 0x2000120e(4622)
               MPLS Encap Id: 0x4001381e

 LEAF - HAL pd context :
 sub-type : MPLS, ecd_marked:0, has_collapsed_ldi:0
 collapse_bwalk_required:0, ecdv2_marked:0
HW Walk:
LEAF:
    PI:0x89a59100 PD:0x89a59198 Rev:3864195 type: 2
    FEC handle: (nil)

    LWLDI:
        EOS0/1 LDI:
        PI:0xb9a51838 PD:0xb9a51878 rev:3864192 p-rev: ldi type:0
        FEC hdl: 0x890c0818 fec index: 0x20004fa2(20386) num paths:1, bkup: 0
        DSP fec index:0x2000120e(4622)
        Path:0  fec index: 0x20004fa2(20386) DSP fec index:0x2000120e(4622)
                MPLS encap hdl: 0x400145ed MPLS encap id: 0x400145ed Remote: 0
        IMP LDI:
        PI:0xb9a51838 PD:0xb9a51878 rev:3864192 p-rev:
        FEC hdl: 0x890c0b58 fec index: 0x20004fa0(20384) num paths:1
        Path:0  fec index: 0x20004fa0(20384) DSP fec index: 0x2000120e(4622)
                MPLS encap hdl: 0x400145ec MPLS encap id: 0x400145ec Remote: 0

 REC-SHLDI HAL PD context :
ecd_marked:0, collapse_bwalk_required:0, load_shared_lb:0

    RSHLDI:
        PI:0xb7e387f8 PD:0xb7e38874 rev:0 p-rev:0 flag:0x1
        FEC hdl: 0x890c0e98 fec index: 0x20004f9e(20382) num paths: 1
        Path:0 fec index: 0x20004f9e(20382) DSP fec index: 0x2000120e(4622)

 LEAF - HAL pd context :
 sub-type : MPLS, ecd_marked:0, has_collapsed_ldi:0
 collapse_bwalk_required:0, ecdv2_marked:0
HW Walk:
LEAF:
    PI:0x89a59028 PD:0x89a590c0 Rev:31654 type: 2
    FEC handle: (nil)

    LWLDI:
        PI:0x8c69c1c8 PD:0x8c69c208 rev:31653 p-rev:31652  ldi type:5
        FEC hdl: 0x8903a718 fec index: 0x0(0) num paths:1, bkup: 0
        Path:0  fec index: 0x0(0) DSP:0x0
        IMP LDI:
        PI:0x8c69c1c8 PD:0x8c69c208 rev:31653 p-rev:31652
        FEC hdl: 0x8903aa58 fec index: 0x2000120e(4622) num paths:1
        Path:0  fec index: 0x2000120e(4622) DSP:0x518
                MPLS encap hdl: 0x40013808 MPLS encap id: 0x40013808 Remote: 0

        SHLDI:
            PI:0x8af02580 PD:0x8af02600 rev:31652 dpa-rev:66291 flag:0x0
            FEC hdl: 0x8903a718 fec index: 0x2000120d(4621) num paths: 1 bkup paths: 0
            p-rev:2373
            Path:0 fec index: 0x2000120d(4621) DSP:0x518 Dest fec index: 0x0(0)

        TX-NHINFO:
            PD: 0x89bf94f0 rev: 2373 dpa-rev: 9794 Encap hdl: 0x8a897628
            Encap id: 0x40010002 Remote: 0 L3 int: 1043 npu_mask: 4

Route reflectors exchange VPN-IPv4 routes across autonomous systems, maintaining next-hop and VPN label information. Verification commands confirm the expected state of route and label propagation.

Configure route reflectors to reflect remote routes within an AS

Configure a route reflector so it can reflect IPv4 routes and labels learned from an ASBR to PE routers in the same autonomous system.

Use this task to enable a route reflector (RR) to pass along IPv4 routes and labels, learned by the autonomous system boundary router (ASBR), to provider edge (PE) routers in the autonomous system. This is accomplished by configuring the ASBR and PE routers as route reflector clients of the RR.

Before you begin

Plan the ASBR and PE route reflector clients, labeled-unicast address families, VPNv4 address family, and BGP router ID before starting this task.

Procedure

Configure route reflectors to reflect remote routes within an AS.

Example:

Router#configure
Router(config)#router bgp 500
Router(config-bgp)#address-family ipv4 unicast
Router(config-bgp-af)#allocate-label all
Router(config-bgp-af)#neighbor 192.0.2.13
Router(config-bgp-nbr)#remote-as 500
Router(config-bgp-nbr)#update-source loopback0
Router(config-bgp-nbr)#address-family ipv4 labeled-unicast
Router(config-bgp-nbr-af)#route-reflector-client
Router(config-bgp-nbr-af)#neighbor 192.0.2.14
Router(config-bgp-nbr)#remote-as 500
Router(config-bgp-nbr)#update-source loopback0
Router(config-bgp-nbr)#address-family ipv4 labeled-unicast
Router(config-bgp-nbr-af)#route-reflector-client
Router(config-bgp-nbr)#address-family vpnv4 unicast
Router(config-bgp-nbr-af)#route-reflector-client

Review the running configuration.

Example:

Router#show run router bgp 500
router bgp 500
 bgp router-id 192.0.2.10
 address-family ipv4 unicast
  allocate-label all
 !
 address-family vpnv4 unicast
 !
 neighbor 192.0.2.13
  remote-as 500
  update-source Loopback0
  !
  address-family ipv6 labeled-unicast
   route-reflector-client
  !
  address-family vpnv6 unicast
  !
 !
 neighbor 192.0.2.14
  remote-as 500
  update-source Loopback0
  address-family ipv4 labeled-unicast
   route-reflector-client
  !
  address-family vpnv4 unicast
   route-reflector-client
  !

Remote routes are reflected within the autonomous system when the route reflector client configuration appears in the running configuration.

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