Configuring MPLS L3VPN inter-AS option A

Network requirements

CE 1 and CE 2 belong to the same VPN. CE 1 accesses the network through PE 1 in AS 100, and CE 2 accesses the network through PE 2 in AS 200.

Configure MPLS L3VPN inter-AS option A, and use the VRF-to-VRF method to manage VPN routes.

Run OSPF on the MPLS backbone in each AS.

Figure 52: Network diagram

Table 9: Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

CE 1

Vlan-int12

10.1.1.1/24

CE 2

Vlan-int12

10.2.1.1/24

PE 1

Loop0

1.1.1.9/32

PE 2

Loop0

4.4.4.9/32

Vlan-int12

10.1.1.2/24

Vlan-int12

10.2.1.2/24

Vlan-int11

172.1.1.2/24

Vlan-int11

162.1.1.2/24

ASBR-PE 1

Loop0

2.2.2.9/32

ASBR-PE 2

Loop0

3.3.3.9/32

Vlan-int11

172.1.1.1/24

Vlan-int11

162.1.1.1/24

Vlan-int12

192.1.1.1/24

Vlan-int12

192.1.1.2/24

Configuration procedure

  1. Configure IGP on the MPLS backbone to implement the connectivity in the backbone:

    This example uses OSPF. (Details not shown.)

    # Execute the display ospf peer command to verify that each ASBR-PE has established an OSPF adjacency in Full state with the PE in the same AS, and that PEs and ASBR-PEs in the same AS have learned the routes to the loopback interfaces of each other. Verify that each ASBR-PE and the PE in the same AS can ping each other. (Details not shown.)

  2. Configure basic MPLS and MPLS LDP on the MPLS backbone to establish LDP LSPs:

    # Configure basic MPLS on PE 1, and enable MPLS LDP on the interface connected to ASBR-PE 1.

    <PE1> system-view
    [PE1] mpls lsr-id 1.1.1.9
    [PE1] mpls ldp
    [PE1-ldp] quit
    [PE1] interface vlan-interface 11
    [PE1-Vlan-interface11] mpls enable
    [PE1-Vlan-interface11] mpls ldp enable
    [PE1-Vlan-interface11] quit
    

    # Configure basic MPLS on ASBR-PE 1, and enable MPLS LDP on the interface connected to PE 1.

    <ASBR-PE1> system-view
    [ASBR-PE1] mpls lsr-id 2.2.2.9
    [ASBR-PE1] mpls ldp
    [ASBR-PE1-ldp] quit
    [ASBR-PE1] interface vlan-interface 11
    [ASBR-PE1-Vlan-interface11] mpls enable
    [ASBR-PE1-Vlan-interface11] mpls ldp enable
    [ASBR-PE1-Vlan-interface11] quit
    

    # Configure basic MPLS on ASBR-PE 2, and enable MPLS LDP on the interface connected to PE 2.

    <ASBR-PE2> system-view
    [ASBR-PE2] mpls lsr-id 3.3.3.9
    [ASBR-PE2] mpls ldp
    [ASBR-PE2-ldp] quit
    [ASBR-PE2] interface vlan-interface 11
    [ASBR-PE2-Vlan-interface11] mpls enable
    [ASBR-PE2-Vlan-interface11] mpls ldp enable
    [ASBR-PE2-Vlan-interface11] quit
    

    # Configure basic MPLS on PE 2, and enable MPLS LDP on the interface connected to ASBR-PE 2.

    <PE2> system-view
    [PE2] mpls lsr-id 4.4.4.9
    [PE2] mpls ldp
    [PE2-ldp] quit
    [PE2] interface vlan-interface 11
    [PE2-Vlan-interface11] mpls enable
    [PE2-Vlan-interface11] mpls ldp enable
    [PE2-Vlan-interface11] quit
    

    # Execute the display mpls ldp peer command on the devices to verify that the session status is Operational, and that each PE and the ASBR-PE in the same AS have established a neighbor relationship. (Details not shown.)

  3. Configure VPN instances on PEs:

    For the same VPN, the route targets for the VPN instance on the PE must match those for the VPN instance on the ASBR-PE in the same AS. This is not required for PEs in different ASs.

    # Configure CE 1.

    <CE1> system-view
    [CE1] interface vlan-interface 12
    [CE1-Vlan-interface12] ip address 10.1.1.1 24
    [CE1-Vlan-interface12] quit
    

    # Configure PE 1.

    [PE1] ip vpn-instance vpn1
    [PE1-vpn-instance-vpn1] route-distinguisher 100:1
    [PE1-vpn-instance-vpn1] vpn-target 100:1 both
    [PE1-vpn-instance-vpn1] quit
    [PE1] interface vlan-interface 12
    [PE1-Vlan-interface12] ip binding vpn-instance vpn1
    [PE1-Vlan-interface12] ip address 10.1.1.2 24
    [PE1-Vlan-interface12] quit
    

    # Configure CE 2.

    <CE2> system-view
    [CE2] interface vlan-interface 12
    [CE2-Vlan-interface12] ip address 10.2.1.1 24
    [CE2-Vlan-interface12] quit
    

    # Configure PE 2.

    [PE2] ip vpn-instance vpn1
    [PE2-vpn-instance] route-distinguisher 200:2
    [PE2-vpn-instance] vpn-target 200:1 both
    [PE2-vpn-instance] quit
    [PE2] interface vlan-interface 12
    [PE2-Vlan-interface12] ip binding vpn-instance vpn1
    [PE2-Vlan-interface12] ip address 10.2.1.2 24
    [PE2-Vlan-interface12] quit
    

    # On ASBR-PE 1, create a VPN instance, and bind the instance to the interface connected to ASBR-PE 2. ASBR-PE 1 considers ASBR-PE 2 to be its CE.

    [ASBR-PE1] ip vpn-instance vpn1
    [ASBR-PE1-vpn-instance-vpn1] route-distinguisher 100:1
    [ASBR-PE1-vpn-instance-vpn1] vpn-target 100:1 both
    [ASBR-PE1-vpn-instance-vpn1] quit
    [ASBR-PE1] interface vlan-interface 12
    [ASBR-PE1-Vlan-interface12] ip binding vpn-instance vpn1
    [ASBR-PE1-Vlan-interface12] ip address 192.1.1.1 24
    [ASBR-PE1-Vlan-interface12] quit
    

    # On ASBR-PE 2, create a VPN instance, and bind the instance to the interface connected to ASBR-PE 1. ASBR-PE 2 considers ASBR-PE 1 to be its CE.

    [ASBR-PE2] ip vpn-instance vpn1
    [ASBR-PE2-vpn-vpn-vpn1] route-distinguisher 200:1
    [ASBR-PE2-vpn-vpn-vpn1] vpn-target 200:1 both
    [ASBR-PE2-vpn-vpn-vpn1] quit
    [ASBR-PE2] interface vlan-interface 12
    [ASBR-PE2-Vlan-interface12] ip binding vpn-instance vpn1
    [ASBR-PE2-Vlan-interface12] ip address 192.1.1.2 24
    [ASBR-PE2-Vlan-interface12] quit
    

    # Execute the display ip vpn-instance command to display VPN instance configurations. Verify that the PEs can ping the CEs, and the ASBR-PEs can ping each other. (Details not shown.)

  4. Establish EBGP peer relationships between PEs and CEs, and redistribute VPN routes into BGP:

    # Configure CE 1.

    [CE1] bgp 65001
    [CE1-bgp] peer 10.1.1.2 as-number 100
    [CE1-bgp] address-family ipv4 unicast 
    [CE1-bgp-ipv4] peer 10.1.1.2 enable
    [CE1-bgp-ipv4] import-route direct
    [CE1-bgp-ipv4] quit
    [CE1-bgp] quit
    

    # Configure PE 1.

    [PE1] bgp 100
    [PE1-bgp] ip vpn-instance vpn1
    [PE1-bgp-vpn1] peer 10.1.1.1 as-number 65001
    [PE1-bgp-vpn1] address-family ipv4 unicast
    [PE1-bgp-ipv4-vpn1] peer 10.1.1.1 enable
    [PE1-bgp-ipv4-vpn1] quit
    [PE1-bgp-vpn1] quit 
    [PE1-bgp] quit
    

    # Configure CE 2.

    [CE2] bgp 65002
    [CE2-bgp] peer 10.2.1.2 as-number 200
    [CE2-bgp] address-family ipv4 unicast
    [CE2-bgp-ipv4] peer 10.2.1.2 enable
    [CE2-bgp-ipv4] import-route direct
    [CE2-bgp-ipv4] quit
    [CE2-bgp] quit
    

    # Configure PE 2.

    [PE2] bgp 200
    [PE2-bgp] ip vpn-instance vpn1
    [PE2-bgp-vpn1] peer 10.2.1.1 as-number 65002
    [PE2-bgp-vpn1] address-family ipv4 unicast
    [PE2-bgp-ipv4-vpn1] peer 10.2.1.1 enable
    [PE2-bgp-ipv4-vpn1] quit
    [PE2-bgp-vpn1] quit
    [PE2-bgp] quit
    
  5. Establish an MP-IBGP peer relationship between each PE and the ASBR-PE in the same AS, and an EBGP peer relationship between the ASBR-PEs:

    # Configure PE 1.

    [PE1] bgp 100
    [PE1-bgp] peer 2.2.2.9 as-number 100
    [PE1-bgp] peer 2.2.2.9 connect-interface loopback 0
    [PE1-bgp] address-family vpnv4
    [PE1-bgp-vpnv4] peer 2.2.2.9 enable
    [PE1-bgp-vpnv4] peer 2.2.2.9 next-hop-local
    [PE1-bgp-vpnv4] quit
    [PE1-bgp] quit
    

    # Configure ASBR-PE 1.

    [ASBR-PE1] bgp 100
    [ASBR-PE1-bgp] ip vpn-instance vpn1
    [ASBR-PE1-bgp-vpn1] peer 192.1.1.2 as-number 200
    [ASBR-PE1-bgp-vpn1] address-family ipv4 unicast
    [ASBR-PE1-bgp-ipv4-vpn1] peer 192.1.1.2 enable
    [ASBR-PE1-bgp-ipv4-vpn1] quit
    [ASBR-PE1-bgp-vpn1] quit
    [ASBR-PE1-bgp] peer 1.1.1.9 as-number 100
    [ASBR-PE1-bgp] peer 1.1.1.9 connect-interface loopback 0
    [ASBR-PE1-bgp] address-family vpnv4
    [ASBR-PE1-bgp-vpnv4] peer 1.1.1.9 enable
    [ASBR-PE1-bgp-vpnv4] peer 1.1.1.9 next-hop-local
    [ASBR-PE1-bgp-vpnv4] quit
    [ASBR-PE1-bgp] quit
    

    # Configure ASBR-PE 2.

    [ASBR-PE2] bgp 200 
    [ASBR-PE2-bgp] ip vpn-instance vpn1
    [ASBR-PE2-bgp-vpn1] peer 192.1.1.1 as-number 100
    [ASBR-PE2-bgp-vpn1] address-family ipv4 unicast
    [ASBR-PE2-bgp-ipv4-vpn1] peer 192.1.1.1 enable
    [ASBR-PE2-bgp-ipv4-vpn1] quit
    [ASBR-PE2-bgp-vpn1] quit
    [ASBR-PE2-bgp] peer 4.4.4.9 as-number 200
    [ASBR-PE2-bgp] peer 4.4.4.9 connect-interface loopback 0
    [ASBR-PE2-bgp] address-family vpnv4
    [ASBR-PE2-bgp-vpnv4] peer 4.4.4.9 enable
    [ASBR-PE2-bgp-vpnv4] peer 4.4.4.9 next-hop-local
    [ASBR-PE2-bgp-vpnv4] quit
    [ASBR-PE2-bgp] quit
    

    # Configure PE 2.

    [PE2] bgp 200
    [PE2-bgp] peer 3.3.3.9 as-number 200
    [PE2-bgp] peer 3.3.3.9 connect-interface loopback 0
    [PE2-bgp] address-family vpnv4
    [PE2-bgp-vpnv4] peer 3.3.3.9 enable
    [PE2-bgp-vpnv4] peer 3.3.3.9 next-hop-local
    [PE2-bgp-vpnv4] quit
    [PE2-bgp] quit
    

Verifying the configuration

# Verify that the CEs can learn the interface routes from each other and ping each other. (Details not shown.)