Example for Configuring BFD for Static VPN Routes

In CE dual-homing networking, after a static route on a CE is bound to a BFD session, the static route can detect link faults or refresh itself based on the BFD session status. This implementation ensures quick VPN traffic convergence.

Networking Requirements

On the network shown in Figure 1, CE1 and CE2 belong to VPN A. Two default routes with the next hops as PE1 and PE2 respectively are configured on CE1. The two routes work in load-balancing mode. The static routes bound to VPN A are configured on PE1 and PE2 separately and are imported to BGP.

BFD sessions are established between PE1 and CE1, and between PE2 and CE1. It is required that BFD be configured on PE1 and PE2 to detect the link faults of static VPN routes. In normal situations, the traffic from CE1 to the public network can be forwarded through PE1 and PE2 in load balancing mode. If the link between CE1 and PE1 or PE2 fails, CE1 detects the link fault by tracking BFD session status and updates the route. Then, CE1 switches traffic to the other link for transmission.

Figure 1 Configuring BFD for static VPN routes

Interfaces 1 through 3 in this example represent GE 0/1/0, GE 0/1/8, and GE 0/1/16, respectively.


Configuration Notes

When configuring BFD for static VPN routes, ensure that the CE is dual-homed to two PEs configured with VPN instances of different RDs.

Configuration Roadmap

The configuration roadmap is as follows:

  1. Configure OSPF for PEs on the MPLS backbone network to communicate.

  2. Establish MPLS LSPs between PEs.

  3. Configure VPN instances on PEs and bind each interface that connects a PE to a CE to the VPN instance on that PE.

  4. Configure MP-IBGP on the PEs to exchange VPN routing information.

  5. Configure two default routes with the next hops as PE1 and PE2 respectively on CE1 to implement load balancing between PE1 and PE2.

  6. Configure a static route bound to VPN A on PE1 and PE2 and import the static route into BGP.

  7. Configure an MP-EBGP peer relationship between PE3 and CE2.

  8. Configure static BFD sessions with automatically negotiated discriminators between PE1 and CE1, and between PE2 and CE1.

  9. Configure BFD for VPN static routes on PE1 and PE2.

Data Preparation

To complete the configuration, you need the following data:

  • MPLS LSR IDs of the PEs
  • Names, RDs, and VPN targets of the VPN instances on the PEs
  • Local and peer IP addresses of the BFD session

Procedure

  1. Configure an IGP for PEs on the MPLS backbone network to communicate. This example uses OSPF as the IGP.

    # Configure PE1.

    <HUAWEI> system-view
[~HUAWEI] sysname PE1
[*HUAWEI] commit
[~PE1] interface loopback 1
[*PE1-LoopBack1] ip address 2.2.2.2 32
[*PE1-LoopBack1] commit
[*PE1-LoopBack1] quit
[*PE1] interface gigabitethernet 0/1/0
[*PE1-GigabitEthernet0/1/0] ip address 11.11.11.1 24
[*PE1-GigabitEthernet0/1/0] commit
[*PE1-GigabitEthernet0/1/0] quit
[*PE1] interface gigabitethernet 0/1/8
[*PE1-GigabitEthernet0/1/8] ip address 33.33.33.1 24
[*PE1-GigabitEthernet0/1/8] commit
[*PE1-GigabitEthernet0/1/8] quit
[*PE1] ospf
[*PE1-ospf-1] area 0
[*PE1-ospf-1-area-0.0.0.0] network 11.11.11.0 0.0.0.255
[*PE1-ospf-1-area-0.0.0.0] network 33.33.33.0 0.0.0.255
[*PE1-ospf-1-area-0.0.0.0] network 2.2.2.2 0.0.0.0
[*PE1-ospf-1-area-0.0.0.0] commit
[~PE1-ospf-1-area-0.0.0.0] quit
[~PE1-ospf-1] quit

    Configure PE2.

    <HUAWEI> system-view
[~HUAWEI] sysname PE2
[*HUAWEI] commit
[~PE2] interface loopback 1
[*PE2-LoopBack1] ip address 3.3.3.3 32
[*PE2-LoopBack1] commit
[*PE2-LoopBack1] quit
[*PE2] interface gigabitethernet 0/1/0
[*PE2-GigabitEthernet0/1/0] ip address 22.22.22.1 24
[*PE2-GigabitEthernet0/1/0] commit
[*PE2-GigabitEthernet0/1/0] quit
[*PE2] interface gigabitethernet 0/1/8 
[*PE2-GigabitEthernet0/1/8] ip address 33.33.33.2 24
[*PE2-GigabitEthernet0/1/8] commit
[*PE2-GigabitEthernet0/1/8] quit
[*PE2] ospf
[*PE2-ospf-1] area 0
[*PE2-ospf-1-area-0.0.0.0] network 22.22.22.0 0.0.0.255
[*PE2-ospf-1-area-0.0.0.0] network 33.33.33.0 0.0.0.255
[*PE2-ospf-1-area-0.0.0.0] network 3.3.3.3 0.0.0.0
[*PE2-ospf-1-area-0.0.0.0] commit
[~PE2-ospf-1-area-0.0.0.0] quit
[~PE2-ospf-1] quit
    Configure PE3.
    <HUAWEI> system-view
[~HUAWEI] sysname PE3
[*HUAWEI] commit
[~PE3] interface loopback 1
[*PE3-LoopBack1] ip address 4.4.4.4 32
[*PE3-LoopBack1] quit
[*PE3] interface gigabitethernet 0/1/0
[*PE3-GigabitEthernet0/1/0] ip address 11.11.11.2 24
[*PE3-GigabitEthernet0/1/0] commit
[*PE3-GigabitEthernet0/1/0] quit
[*PE3] interface gigabitethernet 0/1/8
[*PE3-GigabitEthernet0/1/8] ip address 22.22.22.2 24
[*PE3-GigabitEthernet0/1/8] commit
[*PE3-GigabitEthernet0/1/8] quit
[*PE3] ospf
[*PE3-ospf-1] area 0
[*PE3-ospf-1-area-0.0.0.0] network 11.11.11.0 0.0.0.255
[*PE3-ospf-1-area-0.0.0.0] network 22.22.22.0 0.0.0.255
[*PE3-ospf-1-area-0.0.0.0] network 4.4.4.4 0.0.0.0
[*PE3-ospf-1-area-0.0.0.0] commit
[~PE3-ospf-1-area-0.0.0.0] quit
[~PE3-ospf-1] quit

    After the configurations are complete, OSPF neighbor relationships can be set up between PE1, PE2, and PE3. Run the display ip routing-table command. The command output shows that the PEs have learned the routes to each other's Loopback 1 interface.

    The following example uses the command output on PE1.

    <PE1> display ip routing-table
<keyword conref="../commonterms/commonterms.xml#commonterms/route-flags"></keyword>
------------------------------------------------------------------------------
Routing Table: _public_
         Destinations : 14       Routes : 15

Destination/Mask    Proto  Pre  Cost     Flags NextHop         Interface

        2.2.2.2/32  Direct 0    0           D  127.0.0.1       LoopBack1
        3.3.3.3/32  OSPF   10   2           D  33.33.33.2       GigabitEthernet0/1/8
        4.4.4.4/32  OSPF   10   2           D  11.11.11.2       GigabitEthernet0/1/0
      11.11.11.0/24  Direct 0    0           D  11.11.11.1       GigabitEthernet0/1/0
      11.11.11.2/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/0
    11.11.11.255/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/0
      22.22.22.0/24  OSPF   10    2          D  11.11.11.2       GigabitEthernet0/1/0
                    OSPF   10    2          D  33.33.33.2       GigabitEthernet0/1/8
      33.33.33.0/24  Direct 0    0           D  33.33.33.1       GigabitEthernet0/1/8
      33.33.33.1/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/8
    33.33.33.255/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/8
      127.0.0.0/8   Direct 0    0           D  127.0.0.1       InLoopBack0
      127.0.0.1/32  Direct 0    0           D  127.0.0.1       InLoopBack0
127.255.255.255/32  Direct 0    0           D  127.0.0.1       InLoopBack0
255.255.255.255/32  Direct 0    0           D  127.0.0.1       InLoopBack0

  2. Configure MPLS and MPLS LDP both globally and per interface on each node of the backbone network and set up LDP LSPs.

    # Configure PE1.

    [~PE1] mpls lsr-id 2.2.2.2
[*PE1] mpls
[*PE1-mpls] quit
[*PE1] mpls ldp
[*PE1-mpls-ldp] quit
[*PE1] interface gigabitethernet 0/1/0
[*PE1-GigabitEthernet0/1/0] mpls
[*PE1-GigabitEthernet0/1/0] mpls ldp
[*PE1-GigabitEthernet0/1/0] commit
[*PE1-GigabitEthernet0/1/0] quit
[*PE1] interface gigabitethernet 0/1/8
[*PE1-GigabitEthernet0/1/8] mpls 
[*PE1-GigabitEthernet0/1/8] mpls ldp
[*PE1-GigabitEthernet0/1/8] commit
[~PE1-GigabitEthernet0/1/8] quit

    # Configure PE2.

    [~PE2] mpls lsr-id 3.3.3.3
[*PE2] mpls
[*PE2-mpls] quit
[*PE2] mpls ldp
[*PE2-mpls-ldp] quit
[*PE2] interface gigabitethernet 0/1/0
[*PE2-GigabitEthernet0/1/0] mpls
[*PE2-GigabitEthernet0/1/0] mpls ldp
[*PE2-GigabitEthernet0/1/0] commit
[*PE2-GigabitEthernet0/1/0] quit
[*PE2] interface gigabitethernet 0/1/8
[*PE2-GigabitEthernet0/1/8] mpls
[*PE2-GigabitEthernet0/1/8] mpls ldp
[*PE2-GigabitEthernet0/1/8] commit
[~PE2-GigabitEthernet0/1/8] quit

    Configure PE3.

    [~PE3] mpls lsr-id 4.4.4.4
[*PE3] mpls
[*PE3-mpls] quit
[*PE3] mpls ldp
[*PE3-mpls-ldp] quit
[*PE3] interface gigabitethernet 0/1/0
[*PE3-GigabitEthernet0/1/0] mpls
[*PE3-GigabitEthernet0/1/0] mpls ldp
[*PE3-GigabitEthernet0/1/0] commit
[*PE3-GigabitEthernet0/1/0] quit
[*PE3] interfacegigabitethernet 0/1/8
[*PE3-GigabitEthernet0/1/8] mpls
[*PE3-GigabitEthernet0/1/8] mpls ldp
[*PE3-GigabitEthernet0/1/8] commit
[~PE3-GigabitEthernet0/1/8] quit

    After the configurations are complete, LDP sessions can be set up between PEs. Run the display mpls ldp session command. The command output shows that the Status field is Operational.

    The following example uses the command output on PE1.

    <PE1> display mpls ldp session

               LDP Session(s) in Public Network
 Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDD:HH:MM)
 An asterisk (*) before a session means the session is being deleted.

 ------------------------------------------------------------------------------
 Peer-ID            Status      LAM  SsnRole  SsnAge      KA-Sent/Rcv
 ------------------------------------------------------------------------------
 3.3.3.3:0          Operational DU   Passive  000:02:22   572/572
 4.4.4.4:0          Operational DU   Passive  000:02:21   566/566
 ------------------------------------------------------------------------------
 TOTAL: 2 session(s) Found.
 LAM : Label Advertisement Mode      SsnAge Unit : DDD:HH:MM

  3. Configure VPN instances on PEs and bind each interface that connects a PE to a CE to the VPN instance on that PE.

    # Configure PE1.

    [~PE1] ip vpn-instance VPNA
[*PE1-vpn-instance-VPNA] ipv4-family
[*PE1-vpn-instance-VPNA-af-ipv4] route-distinguisher 100:1
[*PE1-vpn-instance-VPNA-af-ipv4] vpn-target 111:1 both
[*PE1-vpn-instance-VPNA-af-ipv4] quit
[*PE1-vpn-instance-VPNA] quit
[*PE1] interface gigabitethernet 0/1/16
[*PE1-GigabitEthernet0/1/16] ip binding vpn-instance VPNA
[*PE1-GigabitEthernet0/1/16] ip address 10.1.1.2 24
[*PE1-GigabitEthernet0/1/16] commit
[~PE1-GigabitEthernet0/1/16] quit

    # Configure PE2.

    [~PE2] ip vpn-instance VPNA
[*PE2-vpn-instance-VPNA] ipv4-family
[*PE2-vpn-instance-VPNA-af-ipv4] route-distinguisher 100:2
[*PE2-vpn-instance-VPNA-af-ipv4] vpn-target 111:1 both
[*PE2-vpn-instance-VPNA-af-ipv4] quit
[*PE2-vpn-instance-VPNA] quit
[*PE2] interface gigabitethernet 0/1/16
[*PE2-GigabitEthernet0/1/16] ip binding vpn-instance VPNA
[*PE2-GigabitEthernet0/1/16] ip address 10.2.1.2 24
[*PE2-GigabitEthernet0/1/16] commit
[~PE2-GigabitEthernet0/1/16] quit

    # Configure PE3.

    [~PE3] ip vpn-instance VPNA
[*PE3-vpn-instance-VPNA] ipv4-family
[*PE3-vpn-instance-VPNA-af-ipv4] route-distinguisher 100:3
[*PE3-vpn-instance-VPNA-af-ipv4] vpn-target 111:1 both
[*PE3-vpn-instance-VPNA-af-ipv4] quit
[*PE3-vpn-instance-VPNA] quit
[*PE3] interface gigabitethernet 0/1/16
[*PE3-GigabitEthernet0/1/16] ip binding vpn-instance VPNA
[*PE3-GigabitEthernet0/1/16] ip address 10.3.1.1 24
[*PE3-GigabitEthernet0/1/16] commit
[~PE3-GigabitEthernet0/1/16] quit

    Configure CE1.

    [~CE1] interface gigabitethernet 0/1/0
[~CE1-GigabitEthernet0/1/0] ip address 10.1.1.1 24
[*CE1-GigabitEthernet0/1/0] commit
[*CE1-GigabitEthernet0/1/0] quit 
[*CE1] interface gigabitethernet 0/1/8
[*CE1-GigabitEthernet0/1/8] ip address 10.2.1.1 24
[*CE1-GigabitEthernet0/1/8] commit
[~CE1-GigabitEthernet0/1/8] quit

    # Configure CE2.

    [*CE2] interface gigabitethernet 0/1/0
[*CE2-GigabitEthernet0/1/0] ip address 10.3.1.2 24
[*CE2-GigabitEthernet0/1/0] commit
[~CE2-GigabitEthernet0/1/0] quit

    After completing the configurations, run the display ip vpn-instance verbose command on PEs to view the configurations of VPN instances. Each PE can ping its connected CE.

    The following example uses the command output on PE1.

    <PE1> display ip vpn-instance verbose
 Total VPN-Instances configured : 1
 Total IPv4 VPN-Instances configured : 1 
 Total IPv6 VPN-Instances configured : 0
 VPN-Instance Name and ID : VPNA, 1
  Interfaces : GigabitEthernet0/1/16
 Address family ipv4
  Create date : 2008/09/21 12:18:46
  Up time : 0 days, 02 hours, 35 minutes and 58 seconds
  Vrf Status : UP
  Route Distinguisher : 100:1
  Export VPN Targets :  111:1
  Import VPN Targets :  111:1
  Label policy : label per route
  The diffserv-mode Information is : uniform
  The ttl-mode Information is : pipe
[*PE1] ping -vpn-instance VPNA 10.1.1.1
PING 10.1.1.1: 56  data bytes, press CTRL_C to break
    Reply from 10.1.1.1: bytes=56 Sequence=1 ttl=255 time=130 ms
    Reply from 10.1.1.1: bytes=56 Sequence=2 ttl=255 time=60 ms
    Reply from 10.1.1.1: bytes=56 Sequence=3 ttl=255 time=40 ms
    Reply from 10.1.1.1: bytes=56 Sequence=4 ttl=255 time=30 ms
    Reply from 10.1.1.1: bytes=56 Sequence=5 ttl=255 time=30 ms

  --- 10.1.1.1 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
round-trip min/avg/max = 30/58/130 ms

  4. Import the VPN routes between PE1, PE2, and CE1.

    Configure two default routes with the next hops as PE1 and PE2 respectively on CE1 to implement load balancing between PE1 and PE2. Configure the static routes to be bound to the VPN instances on PE1 and PE2 and import the static routes into BGP.

    # Configure CE1.

    [~CE1] load-balance packet all
[*CE1] ip route-static 0.0.0.0 0 10.1.1.2 
[*CE1] ip route-static 0.0.0.0 0 10.2.1.2
[*CE1] commit

    # Configure PE1.

    [~PE1] ip route-static vpn-instance VPNA 1.1.1.1 32 10.1.1.1
[*PE1] bgp 100
[*PE1-bgp] ipv4-family vpn-instance VPNA
[*PE1-bgp-VPNA] import-route direct
[*PE1-bgp-VPNA] import-route static
[*PE1-bgp-VPNA] commit
[~PE1-bgp-VPNA] quit

    # Configure PE2.

    [~PE2] ip route-static vpn-instance VPNA 1.1.1.1 32 10.2.1.1
[*PE2] bgp 100
[*PE2-bgp] ipv4-family vpn-instance VPNA
[*PE2-bgp-VPNA] import-route direct
[*PE2-bgp-VPNA] import-route static
[*PE2-bgp-VPNA] commit
[~PE2-bgp-VPNA] quit

  5. Set up an EBGP peer relationship between PE3 and CE2, and import VPN routes to EBGP.

    # Configure CE2.

    [~CE2] bgp 65410
[*CE2-bgp] peer 10.3.1.1 as-number 100
[*CE2-bgp] import-route direct
[*CE2-bgp] commit
[~CE2] quit

    # Configure PE3 and specify the number of routes carrying out load balancing to 2 on PE3.

    [~PE3] bgp 100
[*PE3-bgp] ipv4-family vpn-instance VPNA
[*PE3-bgp-VPNA] peer 10.3.1.2 as-number 65410
[*PE3-bgp-VPNA] import-route direct
[*PE3-bgp-VPNA] maximum load-balancing 2
[*PE3-bgp-VPNA] commit
[~PE3-bgp-VPNA] quit

  6. Set up an MP-IBGP peer relationship between PEs.

    # Configure PE1.

    [~PE1] bgp 100
[~PE1-bgp] peer 3.3.3.3 as-number 100
[*PE1-bgp] peer 3.3.3.3 connect-interface loopback 1
[*PE1-bgp] peer 4.4.4.4 as-number 100
[*PE1-bgp] peer 4.4.4.4 connect-interface loopback 1
[*PE1-bgp] ipv4-family vpnv4
[*PE1-bgp-af-vpnv4] peer 3.3.3.3 enable
[*PE1-bgp-af-vpnv4] peer 4.4.4.4 enable
[*PE1-bgp-af-vpnv4] commit
[~PE1-bgp-af-vpnv4] quit
[~PE1-bgp] quit

    # Configure PE2.

    [*PE2] bgp 100
[*PE2-bgp] peer 2.2.2.2 as-number 100
[*PE2-bgp] peer 2.2.2.2 connect-interface loopback 1
[*PE2-bgp] peer 4.4.4.4 as-number 100
[*PE2-bgp] peer 4.4.4.4 connect-interface loopback 1
[*PE2-bgp] ipv4-family vpnv4
[*PE2-bgp-af-vpnv4] peer 2.2.2.2 enable
[*PE2-bgp-af-vpnv4] peer 4.4.4.4 enable
[*PE2-bgp-af-vpnv4] commit
[~PE2-bgp-af-vpnv4] quit
[~PE2-bgp] quit

    # Configure PE3.

    [~PE3] bgp 100
[*PE3-bgp] peer 2.2.2.2 as-number 100
[*PE3-bgp] peer 2.2.2.2 connect-interface loopback 1
[*PE3-bgp] peer 3.3.3.3 as-number 100
[*PE3-bgp] peer 3.3.3.3 connect-interface loopback 1
[*PE3-bgp] ipv4-family vpnv4
[*PE3-bgp-af-vpnv4] peer 2.2.2.2 enable
[*PE3-bgp-af-vpnv4] peer 3.3.3.3 enable
[*PE3-bgp-af-vpnv4] commit
[~PE3-bgp-af-vpnv4] quit
[~PE3-bgp] quit

    After completing the configurations, run the display bgp vpnv4 all peer command on PEs. The command output shows that BGP peer relationships have been established between PEs.

    <PE1> display bgp vpnv4 all peer

 BGP local router ID : 2.2.2.2
 Local AS number : 100
 Total number of peers : 2                 Peers in established state : 2

Peer            V    AS  MsgRcvd  MsgSent    OutQ  Up/Down  State PrefRcv

4.4.4.4         4   100      205      202       0 03:05:25 Established       0
3.3.3.3         4   100      197      254       0 03:06:54 Established       0

  7. Configure BFD sessions with automatically negotiated discriminators.

    Set up BFD sessions between CE1 and PE1, and between CE1 and PE2.

    # Configure PE1.

    [~PE1] bfd
[*PE1-bfd] quit
[*PE1] bfd pe1_to_ce1 bind peer-ip 10.1.1.1 vpn-instance VPNA interface gigabitethernet 0/1/16 source-ip 10.1.1.2 auto
[*PE1-bfd-session-pe1_to_ce1] commit
[~PE1-bfd-session-pe1_to_ce1] quit

    # Configure PE2.

    [~PE2] bfd
[*PE2-bfd] quit
[*PE2] bfd pe2_to_ce1 bind peer-ip 10.2.1.1 vpn-instance VPNA interface gigabitethernet 0/1/16 source-ip 10.2.1.2 auto
[*PE2-bfd-session-pe2_to_ce1] commit
[~PE2-bfd-session-pe2_to_ce1] quit

    # Configure CE1.

    [~CE1] bfd
[*CE1-bfd] quit
[*CE1] bfd ce1_to_pe1 bind peer-ip 10.1.1.2 interface gigabitethernet 0/1/0 source-ip 10.1.1.1 auto
[*CE1-bfd-session-ce1_to_pe1] commit
[*CE1-bfd-session-ce1_to_pe1] quit
[*CE1] bfd ce1_to_pe2 bind peer-ip 10.2.1.2 interface gigabitethernet 0/1/8 source -ip 10.2.1.1 auto
[*CE1-bfd-session-ce1_to_pe2] commit
[~CE1-bfd-session-ce1_to_pe2] quit

    After completing the configurations, run the display bfd session all verbose command on each PE and CE. The command output shows that a one-hop static auto-negotiation BFD session is established, and the session status is Up. The local and remote IDs of the BFD session are obtained through auto-negotiation. Use PE1 and CE1 as an example.

    The following example uses the command output on PE1 and CE1.

    <PE1> display bfd session all verbose
(w): State in WTR 
(*): State is invalid
--------------------------------------------------------------------------------
  (One Hop) State : Up                      Name : pe1_to_ce1
------------------------------------------------------------------------------
  Local Discriminator    : 8192             Remote Discriminator   : 8192
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Interface(GigabitEthernet0/1/16)
  Bind Session Type      : Static_Auto
  Bind Peer IP Address   : 10.1.1.1
  Bind Interface         : GigabitEthernet0/1/16
  FSM Board Id           : 3                TOS-EXP                : 7
  Min Tx Interval (ms)   : 10               Min Rx Interval (ms)   : 10
  Actual Tx Interval (ms): -                Actual Rx Interval (ms): -
  Local Detect Multi     : 3                Detect Interval (ms)   : -
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 3784             TTL                    : 254  
  Proc Interface Status  : Disable          Process PST            : Disable
  WTR Interval (ms)      : -                Config PST             : Enable
  Active Multi           : 3
  Last Local Diagnostic  : No Diagnostic
  Bind Application       : AUTO
  Session TX TmrID       : -                Session Detect TmrID   : -
  Session Init TmrID     : -                Session WTR TmrID      : -
  Session Echo Tx TmrID  : -
  Session Not Up Reason  : In negotiation 
  Session Description    : - 
------------------------------------------------------------------------------

     Total UP/DOWN Session Number : 1/0
<CE1> display bfd session all verbose
(w): State in WTR 
(*): State is invalid
--------------------------------------------------------------------------------
  (One Hop) State : Up                      Name : ce1_to_pe1
--------------------------------------------------------------------------------
  Local Discriminator    : 8192             Remote Discriminator   : 8192
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Interface(GigabitEthernet0/1/0)
  Bind Session Type      : Static_Auto
  Bind Peer IP Address   : 10.1.1.2
  Bind Interface         : GigabitEthernet0/1/0
  FSM Board Id           : 3                TOS-EXP                : 6
  Min Tx Interval (ms)   : 10               Min Rx Interval (ms)   : 10
  Actual Tx Interval (ms): -                Actual Rx Interval (ms): -
  Local Detect Multi     : 3                Detect Interval (ms)   : -
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 3784             TTL                    : 255
  Proc Interface Status  : Disable          Process PST            : Disable
  WTR Interval (ms)      : -                Config PST             : Enable
  Active Multi           : 3
  Last Local Diagnostic  : No Diagnostic
  Bind Application       : AUTO
  Session TX TmrID       : -                Session Detect TmrID   : -
  Session Init TmrID     : -                Session WTR TmrID      : -
  Session Echo Tx TmrID  : -
  PDT Index              : FSM-5020000 | RCV-0 | IF-5020000 | TOKEN-0
  Session Description    : -
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
  (One Hop) State : Up                         Name : ce1_to_pe2
--------------------------------------------------------------------------------
  Local Discriminator    : 8193             Remote Discriminator   : 8193
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Interface(GigabitEthernet0/1/8)
  Bind Session Type      : Static_Auto
  Bind Peer IP Address   : 10.2.1.2
  Bind Interface         : GigabitEthernet0/1/8
  FSM Board Id           : 3                TOS-EXP                : 6
  Min Tx Interval (ms)   : 10               Min Rx Interval (ms)   : 10
  Actual Tx Interval (ms): -                Actual Rx Interval (ms): -
  Local Detect Multi     : 3                Detect Interval (ms)   : -
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 3784             TTL                    : 255
  Proc Interface Status  : Disable          Process PST            : Disable
  WTR Interval (ms)      : -                Config PST             : Enable
  Active Multi           : 3
  Last Local Diagnostic  : No Diagnostic
  Bind Application       : AUTO
  Session TX TmrID       : -                Session Detect TmrID   : -
  Session Init TmrID     : -                Session WTR TmrID      : -
  Session Echo Tx TmrID  : -
  PDT Index              : FSM-5020000 | RCV-0 | IF-5020000 | TOKEN-0
  Session Description    : -
--------------------------------------------------------------------------------

     Total UP/DOWN Session Number : 2/0

  8. Configure BFD for VPN static routes on the PEs.

    # Configure PE1.

    [~PE1] ip route-static vpn-instance VPNA 1.1.1.1 255.255.255.255 10.1.1.1 track bfd-session pe1_to_ce1
[*PE1] commit

    # Configure PE2.

    [~PE2] ip route-static vpn-instance VPNA 1.1.1.1 255.255.255.255 10.2.1.1 track bfd-session pe2_to_ce1
[*PE2] commit

  9. Verify the configuration.

    # After completing the configurations, run the display ip routing-table command on PE1 to check the VPN routing table information on PE1. The command output shows that a static route exists in the routing table.

    <PE1> display ip routing-table vpn-instance VPNA
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table: VPNA
         Destinations : 7        Routes : 7

Destination/Mask    Proto  Pre  Cost     Flags NextHop         Interface

        1.1.1.1/32 Static 60  0         RD 10.1.1.1       GigabitEthernet0/1/16
       10.1.1.0/24  Direct 0    0           D  10.1.1.2        GigabitEthernet0/1/16
       10.1.1.2/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/16
     10.1.1.255/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/16
       10.2.1.0/24  IBGP   255  0          RD  3.3.3.3         GigabitEthernet0/1/8
       10.3.1.0/24  IBGP   255  0          RD  4.4.4.4         GigabitEthernet0/1/0
255.255.255.255/32  Direct 0    0           D  127.0.0.1       InLoopBack0

    # On CE1, run the tracert command to ping the gateway through which the packets destined for CE2 pass. The command output shows that load balancing is implemented between PE1 and PE2 at the first hop.

    <CE1> tracert 10.3.1.2
 traceroute to  10.3.1.2(10.3.1.2), max hops: 30 ,packet length: 40
 1 10.1.1.2 20 ms 10.2.1.2 1 ms 10.1.1.2 40 ms
 2 10.3.1.1 40 ms  30 ms  50 ms
 3 10.3.1.2 80 ms  80 ms  60 ms

    # Run the display ip routing-table command on PE3 to check the routing table information on PE3. The command output shows that there are two routes to CE1 (1.1.1.1), with the next hops being 3.3.3.3 and 2.2.2.2 respectively. The two routes work in load-balancing mode.

    <PE3> display ip routing-table vpn-instance VPNA
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table: VPNA
         Destinations : 7        Routes : 8

Destination/Mask    Proto  Pre  Cost     Flags NextHop         Interface

        1.1.1.1/32  IBGP   255  0          RD  3.3.3.3         GigabitEthernet0/1/8
                    IBGP   255  0          RD  2.2.2.2         GigabitEthernet0/1/0
       10.1.1.0/24  IBGP   255  0          RD  2.2.2.2         GigabitEthernet0/1/0
       10.2.1.0/24  IBGP   255  0          RD  3.3.3.3         GigabitEthernet0/1/8
       10.3.1.0/24  Direct 0    0           D  10.3.1.1        GigabitEthernet0/1/16
       10.3.1.1/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/16
     10.3.1.255/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/16
255.255.255.255/32  Direct 0    0           D  127.0.0.1       InLoopBack0

    # Run the tracert command on CE2 to check the traffic destined for CE1. The command output shows that load balancing is performed when the traffic leaves PE3.

    [~CE2] tracert 1.1.1.1
 traceroute to  1.1.1.1(1.1.1.1), max hops: 30 ,packet length: 40
 1 10.3.1.1 9 ms  2 ms  2 ms
 2 10.2.1.2 < AS=100 > 6 ms  5 ms  2 ms
 3 10.2.1.1 < AS=100 > 6 ms  6 ms  5 ms

    # Run the shutdown command on GE 0/1/0 of CE1 to simulate a link fault.

    [~CE1-GigabitEthernet0/1/0] shutdown

    # Run the display bfd session all verbose command on PE1. The command output shows that the status of the BFD session is Down.

    <PE1> display bfd session all verbose
(w): State in WTR 
(*): State is invalid
--------------------------------------------------------------------------------
  (One Hop) State : Down                   Name : pe1_to_ce1
------------------------------------------------------------------------------
  Local Discriminator    : 8192             Remote Discriminator   : 8192
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Interface(GigabitEthernet0/1/16)
  Bind Session Type      : Static_Auto
  Bind Peer IP Address   : 10.1.1.1
  Bind Interface         : GigabitEthernet0/1/16
  FSM Board Id           : 3                TOS-EXP                : 6
  Min Tx Interval (ms)   : 10               Min Rx Interval (ms)   : 10
  Actual Tx Interval (ms): -                Actual Rx Interval (ms): -
  Local Detect Multi     : 3                Detect Interval (ms)   : -
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 3784             TTL                    : 255  
  Proc Interface Status  : Disable          Process PST            : Disable
  WTR Interval (ms)      : -                Config PST             : Enable
  Active Multi           : 3
  Last Local Diagnostic  : No Diagnostic
  Bind Application       : AUTO
  Session TX TmrID       : -                Session Detect TmrID   : -
  Session Init TmrID     : -                Session WTR TmrID      : -
  Session Echo Tx TmrID  : -
  Session Not Up Reason  : In negotiation 
  Session Description    : - 
------------------------------------------------------------------------------

     Total UP/DOWN Session Number : 1/0

    # Run the display ip routing-table vpn-instance command on PE1 to check the VPN routing table. The command output shows that the next hop of the route destined for CE1 is only PE2.

    <PE1> display ip routing-table vpn-instance VPNA
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table: VPNA
         Destinations : 4        Routes : 4

Destination/Mask    Proto  Pre  Cost     Flags NextHop         Interface

    1.1.1.1/32  EBGP   255  0           RD  3.3.3.3         GigabitEthernet0/1/8
       10.2.1.0/24  IBGP   255  0          RD  3.3.3.3         GigabitEthernet0/1/8
       10.3.1.0/24  IBGP   255  0          RD  4.4.4.4         GigabitEthernet0/1/0
255.255.255.255/32  Direct 0    0           D  127.0.0.1       InLoopBack0

    # On CE1, check the gateway through which the packets destined for CE2 pass. The command output shows that load balancing is not carried out between PE1 and PE2 at the first hop, and the traffic flows only through PE2.

    <CE3> tracert 10.3.1.2
 traceroute to  10.3.1.2(10.3.1.2), max hops: 30 ,packet length: 40
 1 10.2.1.2 50 ms  30 ms  10 ms
 2 10.3.1.1 110 ms  70 ms  90 ms
 3 10.3.1.2 60 ms  70 ms  80 ms

    # Run the display ip routing-table vpn-instance command on PE3 to check the routing table. The command output shows that there is only one route to CE1 (1.1.1.1) with the next hop as PE1 (3.3.3.3).

    <PE3> display ip routing-table vpn-instance VPNA
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table: VPNA
         Destinations : 6        Routes : 6

Destination/Mask    Proto  Pre  Cost     Flags NextHop         Interface

        1.1.1.1/32  IBGP   255  0          RD  3.3.3.3         GigabitEthernet0/1/8
       10.2.1.0/24  IBGP   255  0          RD  3.3.3.3         GigabitEthernet0/1/8
       10.3.1.0/24  Direct 0    0           D  10.3.1.1        GigabitEthernet0/1/16
       10.3.1.1/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/16
     10.3.1.255/32  Direct 0    0           D  127.0.0.1       GigabitEthernet0/1/16
255.255.255.255/32  Direct 0    0           D  127.0.0.1       InLoopBack0

    # On CE2, check the traffic destined for CE1. The command output shows that the traffic is forwarded through GE 0/1/8 (10.2.1.2) after the traffic leaves PE3.

    [~CE2] tracert 1.1.1.1
 traceroute to  1.1.1.1(1.1.1.1), max hops: 30 ,packet length: 40
 1 10.3.1.1 9 ms  2 ms  2 ms
 2 10.2.1.2 < AS=100 > 6 ms  5 ms  5 ms
 3 10.2.1.1 < AS=100 > 6 ms  5 ms  5 ms

    Use a tester to generate traffic, and the traffic is forwarded in load balancing mode. After a link between CE1 and PE1 or a link between CE1 and PE2 fails, you can find that the traffic is switched in less than 50 ms.

Configuration Files

  • PE1 configuration file

    #
 sysname PE1
#
ip vpn-instance VPNA
 ipv4-family
  route-distinguisher 100:1
  apply-label per-instance
  vpn-target 111:1 export-extcommunity
  vpn-target 111:1 import-extcommunity
#
bfd
#
mpls lsr-id 2.2.2.2
#
mpls
#
mpls ldp
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 11.11.11.1 255.255.255.0
 mpls
 mpls ldp
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 33.33.33.1 255.255.255.0
 mpls
 mpls ldp
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip binding vpn-instance VPNA
 ip address 10.1.1.2 255.255.255.0
#
interface LoopBack1
 ip address 2.2.2.2 255.255.255.255
#
bgp 100
 peer 3.3.3.3 as-number 100
 peer 3.3.3.3 connect-interface LoopBack1
 peer 4.4.4.4 as-number 100
 peer 4.4.4.4 connect-interface LoopBack1
 #
 ipv4-family unicast
  undo synchronization
  peer 3.3.3.3 enable
  peer 4.4.4.4 enable
 #
 ipv4-family vpnv4
  policy vpn-target
  peer 3.3.3.3 enable
  peer 4.4.4.4 enable
 #
 ipv4-family vpn-instance VPNA
  import-route direct
  import-route static
#
ospf 1
 area 0.0.0.0
  network 11.11.11.0 0.0.0.255
  network 33.33.33.0 0.0.0.255
  network 2.2.2.2 0.0.0.0
#
ip route-static vpn-instance VPNA 1.1.1.1 255.255.255.255 10.1.1.1 track bfd-session pe1_to_ce1
#
bfd pe1_to_ce1 bind peer-ip 10.1.1.1 vpn-instance VPNA interface GigabitEthernet0/1/16 source-ip 10.1.1.2 auto
#
return

  • PE2 configuration file

    #
 sysname PE2
#
ip vpn-instance VPNA
 ipv4-family
  route-distinguisher 100:2
  apply-label per-instance
  vpn-target 111:1 export-extcommunity
  vpn-target 111:1 import-extcommunity
#
 bfd
#
mpls lsr-id 3.3.3.3
#
mpls
#
mpls ldp
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 22.22.22.1 255.255.255.0
 mpls
 mpls ldp
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 33.33.33.2 255.255.255.0
 mpls
 mpls ldp
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip binding vpn-instance VPNA
 ip address 10.2.1.2 255.255.255.0
#
interface LoopBack1
 ip address 3.3.3.3 255.255.255.255
#
bgp 100
 peer 2.2.2.2 as-number 100
 peer 2.2.2.2 connect-interface LoopBack1
 peer 4.4.4.4 as-number 100
 peer 4.4.4.4 connect-interface LoopBack1
 #
 ipv4-family unicast
  undo synchronization
  peer 2.2.2.2 enable
  peer 4.4.4.4 enable
 #
 ipv4-family vpnv4
  policy vpn-target
  peer 2.2.2.2 enable
  peer 4.4.4.4 enable
 #
 ipv4-family vpn-instance VPNA
  import-route direct
  import-route static
#
ospf 1
 area 0.0.0.0
  network 33.33.33.0 0.0.0.255
  network 22.22.22.0 0.0.0.255
  network 3.3.3.3 0.0.0.0
#
 ip route-static vpn-instance VPNA 1.1.1.1 255.255.255.255 10.2.1.1 track bfd-session pe2_to_ce1
#
bfd pe2_to_ce1 bind peer-ip 10.2.1.1 vpn-instance VPNA interface GigabitEthernet0/1/16 source-ip 10.2.1.2 auto
#
return

  • PE3 configuration file

    #
 sysname PE3
#
ip vpn-instance VPNA
 ipv4-family
  route-distinguisher 100:3
  apply-label per-instance
  vpn-target 111:1 export-extcommunity
  vpn-target 111:1 import-extcommunity
#
mpls lsr-id 4.4.4.4
#
mpls
#
mpls ldp
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 11.11.11.2 255.255.255.0
 mpls
 mpls ldp
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 22.22.22.2 255.255.255.0
 mpls
 mpls ldp
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip binding vpn-instance VPNA
 ip address 10.3.1.1 255.255.255.0
#
interface LoopBack1
 ip address 4.4.4.4 255.255.255.255
#
bgp 100
 peer 2.2.2.2 as-number 100
 peer 2.2.2.2 connect-interface LoopBack1
 peer 3.3.3.3 as-number 100
 peer 3.3.3.3 connect-interface LoopBack1
 #
 ipv4-family unicast
  undo synchronization
  peer 2.2.2.2 enable
  peer 3.3.3.3 enable
 #
 ipv4-family vpnv4
  policy vpn-target
  peer 2.2.2.2 enable
  peer 3.3.3.3 enable
 #
 ipv4-family vpn-instance VPNA
  peer 10.3.1.2 as-number 65410
  import-route direct
  maximum load-balancing 2
#
ospf 1
 area 0.0.0.0
  network 11.11.11.0 0.0.0.255
  network 22.22.22.0 0.0.0.255
  network 4.4.4.4 0.0.0.0
#
return

  • CE1 configuration file

    #
 sysname CE1
#
 bfd
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.1.1.1 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.2.1.1 255.255.255.0
#
interface LoopBack1
 ip address 1.1.1.1 255.255.255.255
#
 load-balance packet all
#
 ip route-static 0.0.0.0 0.0.0.0 10.1.1.2
 ip route-static 0.0.0.0 0.0.0.0 10.2.1.2
#
bfd ce1_to_pe1 bind peer-ip 10.1.1.2 interface GigabitEthernet0/1/0 source-ip 10.1.1.1 auto
#
bfd ce1_to_pe2 bind peer-ip 10.2.1.2 interface GigabitEthernet0/1/8 source-ip 10.2.1.1 auto
#
return

  • CE2 configuration file

    #
 sysname CE2
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.3.1.2 255.255.255.0
#
bgp 65410
 peer 10.3.1.1 as-number 100
 #
 ipv4-family unicast
  undo synchronization
  import-route direct
  peer 10.3.1.1 enable
#
return
Parent Topic: Configuration Examples for BFD
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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