L3VPN Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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L3VPN Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

Configure Layer 3 route synchronization for EVPN multihoming with all-active redundancy

Updated: September 11, 2026

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Details the process for configuring Layer 3 route synchronization with all-active redundancy, supporting load balancing and seamless routing across multiple active links in EVPN multihomed environments.

Enable and verify Layer 3 route synchronization for VRF instances across redundant PE routers using the all-active EVPN multihoming model.

Layer 3 route synchronization for VRF instances across redundant PE routers with all-active multihoming allows multiple PEs to forward traffic for a given Ethernet segment simultaneously, ensuring efficient load balancing and L2/L3 consistency in the EVPN fabric.

Before you begin

  • Ensure you have access to the CLI of the PE router.

  • Identify the VRF instances for which you want to enable Layer 3 route synchronization.

  • Determine the interfaces that will participate in all-active multihoming.

Procedure

  1. Configure the BGP route targets for VRFs.

    Control IPv4/IPv6 route distribution and enable synchronization of Layer 3 routing information with the Layer-2 EVPN fabric.

    Example:

    Router# configure
Router(config)#vrf PA1
Router(config-vrf)#address-family ipv4 Unicast
Router(config-vrf-af)#import route-target 64600:10000
Router(config-vrf-af)#export route-target 64600:10000
Router(config-vrf-af)#evpn-route-sync 10000
Router(config-vrf)#vrf PA1
Router(config-vrf)#address-family ipv6 Unicast
Router(config-vrf-af)#import route-target 64600:10000
Router(config-vrf-af)#export route-target 64600:10000
Router(config-vrf)#vrf PA2
Router(config-vrf)#address-family ipv4 Unicast
Router(config-vrf-af)#import route-target 64600:10001
Router(config-vrf-af)#export route-target 64600:10001
Router(config-vrf-af)#evpn-route-sync 10001
Router(config-vrf)#vrf PA2
Router(config-vrf)#address-family ipv6 Unicast
Router(config-vrf-af)#import route-target 64600:10001
Router(config-vrf-af)#export route-target 64600:10001
Router(config-vrf-af)#commit
Router(config-vrf-af)#exit
Router(config-vrf)#exit

  2. Configure VRF, encapsulation, and Layer 3 addresses for subinterfaces.

    Example:

    Router(config)#interface Bundle-Ether200.2307
Router(config-subif)#vrf PA1
Router(config-subif)#ipv4 address 172.16.1.1/24
Router(config-subif)#ipv6 address 155:1:1:7::1/64
Router(config-subif)#encapsulation dot1q 2307

  3. Configure Ethernet segment for all-active redundancy.

    Example:

    Router(config)# evpn
Router(config-evpn)# interface Bundle-Ether200
Router(config-evpn-ac)# ethernet-segment
Router(config-evpn-ac-es)# identifier type 0 11.11.11.11.11.11.11.11.11
Router(config-evpn-ac-es)# root
Router(config)# commit

    All-active is the default mode.

    Repeat the configuration for other relevant interfaces.

  4. Use the show arp vrf PA1 detail command to verify the ARP entries and their synchronization status for VRF PA1.

    Example:

    Router#show arp vrf PA1 detail

-------------------------------------------------------------------------------
0/RP0/CPU0
-------------------------------------------------------------------------------
Address         Age        Hardware Addr   State      Flag       Type  Interface
192.0.2.11       -          0000.0000.0200  Interface  Unknown    ARPA  Bundle-Ether200.2301
192.0.2.12      -          0010.9400.2f8e  EVPN_SYNC  EVPN-SYNC  ARPA  Bundle-Ether200.2301
192.0.2.13       -          0000.0000.0200  Interface  Unknown    ARPA  Bundle-Ether200.2303
192.0.2.14      00:00:36   0010.9400.2f90  Dynamic    Dynamic    ARPA  Bundle-Ether200.2303
192.0.2.15       -          0000.0000.0200  Interface  Unknown    ARPA  Bundle-Ether200.2305
192.0.2.16      00:00:36   0010.9400.2f92  Dynamic    Dynamic    ARPA  Bundle-Ether200.2305
192.0.2.17       -          0000.0000.0200  Interface  Unknown    ARPA  Bundle-Ether200.2307
192.0.2.18      -          0010.9400.2f94  EVPN_SYNC  EVPN-SYNC  ARPA  Bundle-Ether200.2307

  5. Verify route synchronization status for the bridge-domain.

    Example:

    Router# show l2vpn bridge-domain bd-name rs#10000 detail

Legend: pp = Partially Programmed.
Bridge group: #ROUTE-SYNC, bridge-domain: rs#10000, id: 140, state: up, ShgId: 0, MSTi: 0
  Coupled state: disabled
  VINE state: EVPN Native
  MAC learning: enabled
  MAC withdraw: enabled
    MAC withdraw for Access PW: enabled
    MAC withdraw sent on: bridge port up
    MAC withdraw relaying (access to access): disabled
  Flooding:
    Broadcast & Multicast: enabled
    Unknown unicast: enabled
  MAC aging time: 300 s, Type: inactivity
  MAC limit: 524287, Action: none, Notification: syslog
  MAC limit reached: no, threshold: 75%
  MAC port down flush: enabled
  MAC Secure: disabled, Logging: disabled
  Split Horizon Group: none
  E-Tree: Root
  Dynamic ARP Inspection: disabled, Logging: disabled
  IP Source Guard: disabled, Logging: disabled
  DHCPv4 Snooping: disabled
  DHCPv4 Snooping profile: none
  IGMP Snooping: disabled
  IGMP Snooping profile: none
  MLD Snooping profile: none
  Storm Control: disabled
  Bridge MTU: 1500
  MIB cvplsConfigIndex: 141
  Filter MAC addresses:
  P2MP PW: disabled
  Multicast Source: Not Set
  Create time: 11/06/2025 03:28:06 (00:05:13 ago)
  No status change since creation
  ACs: 0 (0 up), VFIs: 0, PWs: 0 (0 up), PBBs: 0 (0 up), VNIs: 0 (0 up)
  List of EVPNs:
    EVPN, state: unresolved
      evi: 0 (N/A)
      XC ID 0x0
  List of ACs:
  List of Access PWs:
  List of VFIs:
  List of Access VFIs:

  6. Verify EVPN EVI details, including its association with VRF for route synchronization.

    Example:

    Router# show evpn evi vpn-id 10001 detail 

VPN-ID     Encap      Bridge Domain                Type
---------- ---------- ---------------------------- -------------------
10001      ROUTE-SYNC rs#10001                     EVPN
   Stitching: Regular
   E-Tree: Root
   Forward-class: 0
   Advertise MACs: No
   Advertise BVI MACs: No
   Aliasing: Enabled
   UUF: Enabled
   Re-origination: Enabled
   Multicast:
     IGMP-Snooping Proxy: No
     MLD-Snooping Proxy : No
   BGP Implicit Import: Enabled
   VRF Name: PA2
   Preferred Nexthop Mode: Off
   BVI Coupled Mode: No
   BVI Subnet Withheld: ipv4 No, ipv6 No
   L3VRF Label Mode: Per-VRF
   RD Config: none
   RD Auto  : (auto) 192.168.10.1:10001
   RT Auto  : 64600:10001
   Route Targets in Use           Type
   ------------------------------ ---------------------
   64600:10001                    Import
   64600:10001                    Export

  7. Use the show evpn ethernet-segment interface BE200 command to check the load-balancing mode.

    Example:

    Router#show evpn ethernet-segment interface BE200 carving detail
..
Ethernet Segment Id      Interface                          Originating IP
------------------------ ---------------------------------- --------------------
0011.1111.1111.1111.1111 BE200                              192.168.10.1
                                                            192.168.20.1
  ES to BGP Gates   : Ready
  ES to L2FIB Gates : Ready
  Main port         :
     Interface name : Bundle-Ether200
     Interface MAC  : 0000.0000.0200
     IfHandle       : 0x78000234
     State          : Up
     Redundancy     : Not Defined
  ESI ID            : 1
  ESI type          : 0
     Value          : 0011.1111.1111.1111.1111
  ES Import RT      : 1111.1111.1111 (Local)
  Topology          :
     Operational    : MH, All-active
     Configured     : All-active (AApF) (default)
  Service Carving   : Auto-selection
     Multicast      : Disabled
  Convergence       : Reroute
  Peering Details   : 2 Nexthops
     192.168.10.1 [MOD:P:00:T]
     192.168.20.1 [MOD:P:00:T]

Layer 3 route synchronization is successfully configured and verified. You can confirm consistent routing and L2VPN connectivity across the EVPN fabric for VRFs PA1 and PA2 by reviewing ARP entries, bridge-domain status, and Ethernet segment settings.