Example for Configuring BFD for BGP4+

Procedure

1. Configure IPv6 addresses for interfaces of all switches. The configuration details are not provided here.
2. Configure basic BGP4+ functions, establish EBGP connections between SwitchA and SwitchB and between SwitchA and SwitchC, and establish an IBGP connection between SwitchB and SwitchC.

   # Configure SwitchA.

   [~SwitchA] bgp 100

   [*SwitchA-bgp] router-id 10.1.1.1

   [*SwitchA-bgp] peer fc00:0:0:8::2 as-number 200

   [*SwitchA-bgp] peer fc00:0:0:10::2 as-number 200

   [*SwitchA-bgp] ipv6-family unicast

   [*SwitchA-bgp-af-ipv6] peer fc00:0:0:8::2 enable

   [*SwitchA-bgp-af-ipv6] peer fc00:0:0:10::2 enable

   [*SwitchA-bgp-af-ipv6] commit

   [~SwitchA-bgp-af-ipv6] quit

   [~SwitchA-bgp] quit

   # Configure SwitchB.

   [~SwitchB] bgp 200

   [*SwitchB-bgp] router-id 10.2.2.2

   [*SwitchB-bgp] peer fc00:0:0:8::1 as-number 100

   [*SwitchB-bgp] peer fc00:0:0:9::1:2 as-number 200

   [*SwitchB-bgp] ipv6-family unicast

   [*SwitchB-bgp-af-ipv6] peer fc00:0:0:8::1 enable

   [*SwitchB-bgp-af-ipv6] peer fc00:0:0:9::1:2 enable

   [*SwitchB-bgp-af-ipv6] network fc00:0:0:7:: 64

   [*SwitchB-bgp-af-ipv6] commit

   [~SwitchB-bgp-af-ipv6] quit

   [~SwitchB-bgp] quit

   # Configure SwitchC.

   [~SwitchC] bgp 200

   [*SwitchC-bgp] router-id 10.3.3.3

   [*SwitchC-bgp] peer fc00:0:0:10::1 as-number 100

   [*SwitchC-bgp] peer fc00:0:0:9::1:1 as-number 200

   [*SwitchC-bgp] ipv6-family unicast

   [*SwitchC-bgp-af-ipv6] peer fc00:0:0:10::1 enable

   [*SwitchC-bgp-af-ipv6] peer fc00:0:0:9::1:1 enable

   [*SwitchC-bgp-af-ipv6] commit

   [~SwitchC-bgp-af-ipv6] quit

   [~SwitchC-bgp] quit

   # Run the display bgp ipv6 peer command on SwitchA. The command output shows that BGP peer relationships have been established.

   [SwitchA] display bgp ipv6 peer

    BGP local router ID        : 10.1.1.1
    Local AS number            : 100
    Total number of peers      : 2
    Peers in established state : 2
   
     Peer            V          AS  MsgRcvd  MsgSent  OutQ  Up/Down       State  PrefRcv
     FC00:0:0:8::2   4         200        5        6     0 00:01:28 Established        1
     FC00:0:0:10::2  4         200        4        5     0 00:00:04 Established        1

3. Configure the MED attribute.

   Set the MED values of routes sent from SwitchB and SwitchC to SwitchA through routing policies.

   # Configure SwitchB.

   [~SwitchB] route-policy 10 permit node 10

   [*SwitchB-route-policy] apply cost 100

   [*SwitchB-route-policy] quit

   [*SwitchB] bgp 200

   [*SwitchB-bgp] ipv6-family unicast

   [*SwitchB-bgp-af-ipv6] peer fc00:0:0:8::1 route-policy 10 export

   [*SwitchB-bgp-af-ipv6] quit

   [*SwitchB-bgp] quit

   [*SwitchB] commit

   # Configure SwitchC.

   [~SwitchC] route-policy 10 permit node 10

   [*SwitchC-route-policy] apply cost 150

   [*SwitchC-route-policy] quit

   [*SwitchC] bgp 200

   [*SwitchC-bgp] ipv6-family unicast

   [*SwitchC-bgp-af-ipv6] peer fc00:0:0:10::1 route-policy 10 export

   [*SwitchC-bgp-af-ipv6] quit

   [*SwitchC-bgp] quit

   [*SwitchC] commit

   # Check the BGP routing table on SwitchA.

   [SwitchA] display bgp ipv6 routing-table

    BGP Local router ID is 10.1.1.1
    Status codes: * - valid, > - best, d - damped, h - history,
                  i - internal, s - suppressed, S - Stale
    Origin      : i - IGP, e - EGP, ? - incomplete
   
   
    Total Number of Routes: 2
    *>     Network  : FC00:0:0:7::                             PrefixLen : 64  
           NextHop  : FC00:0:0:8::2                            LocPrf    :   
           MED      : 100                                      PrefVal   : 0
           Label    : 
           Path/Ogn : 200i
    *       
           NextHop  : FC00:0:0:10::2                           LocPrf    :   
           MED      : 150                                      PrefVal   : 0
           Label    : 
           Path/Ogn : 200i

   In the BGP routing table, you can view that the next-hop address of the route to FC00:0:0:7::1/64 is FC00:0:0:8::2, and traffic is transmitted on the primary link SwitchA→SwitchB.

4. Configure BFD, and set the intervals at which BFD packets are sent and received and the local detection multiplier.

   # Configure BFD on SwitchA, and set the minimum intervals for sending and receiving BFD packets to both 300 ms and the local detection multiplier to 5.

   [~SwitchA] bfd

   [*SwitchA-bfd] quit

   [*SwitchA] bgp 100

   [*SwitchA-bgp] peer fc00:0:0:8::2 bfd enable

   [*SwitchA-bgp] peer fc00:0:0:8::2 bfd min-tx-interval 300 min-rx-interval 300 detect-multiplier 5

   [*SwitchA-bgp] quit

   [*SwitchA] commit

   # Configure BFD on SwitchB, and set the minimum intervals for sending and receiving BFD packets to both 300 ms and the local detection multiplier to 5.

   [~SwitchB] bfd

   [*SwitchB-bfd] quit

   [*SwitchB] bgp 200

   [*SwitchB-bgp] peer fc00:0:0:8::1 bfd enable

   [*SwitchB-bgp] peer fc00:0:0:8::1 bfd min-tx-interval 300 min-rx-interval 300 detect-multiplier 5

   [*SwitchB-bgp] commit

   [~SwitchB-bgp] quit

   # Check all BFD sessions on SwitchA.

   [SwitchA] display bgp ipv6 bfd session all

   --------------------------------------------------------------------------------
     Local_Address  : FC00:0:0:8::1                           
     Peer_Address   : FC00:0:0:8::2                           
     Tx-interval(ms): 300         Rx-interval(ms): 300 
     Multiplier     : 5           Interface      : 10GE1/0/1 
     Session-State  : Up
     Wtr-interval(m): 0                  
   
   --------------------------------------------------------------------------------

5. Verify the configuration.

   # Run the shutdown command on 10GE1/0/2 of SwitchB to simulate a primary link fault.

   [~SwitchB] interface 10ge 1/0/2

   [~SwitchB-10GE1/0/2] shutdown

   [*SwitchB-10GE1/0/2] commit

   # Check the BGP routing table on SwitchA.

   [SwitchA] display bgp ipv6 routing-table

    BGP Local router ID is 10.1.1.1
    Status codes: * - valid, > - best, d - damped, h - history,
                  i - internal, s - suppressed, S - Stale
    Origin      : i - IGP, e - EGP, ? - incomplete
   
   
    Total Number of Routes: 1
    *>     Network  : FC00:0:0:7::                             PrefixLen : 64  
           NextHop  : FC00:0:0:10::2                           LocPrf    :   
           MED      : 150                                      PrefVal   : 0
           Label    : 
           Path/Ogn : 200i

   In the BGP routing table, you can view that the backup link SwitchA-SwitchC-SwitchB transmits traffic after the primary link fails, and the next-hop address of the route to FC00:0:0:7::1/64 becomes FC00:0:0:10::2.