BFD for OSPF configuration example

As shown in Figure 30, run OSPF on Switch A, Switch B, and Switch C so that they are reachable to each other at the network layer. When the link over which Switch A and Switch B communicate through a Layer 2 switch fails, BFD can quickly detect the failure and notify OSPF of the failure. Switch A and Switch B then communicate through Switch C.

1. Configure IP addresses for interfaces. (Details not shown.)

2. Enable OSPF:

   # Configure Switch A.

   <SwitchA> system-view
   [SwitchA] ospf
   [SwitchA-ospf-1] area 0
   [SwitchA-ospf-1-area-0.0.0.0] network 192.168.0.0 0.0.0.255
   [SwitchA-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
   [SwitchA-ospf-1-area-0.0.0.0] network 121.1.1.0 0.0.0.255
   [SwitchA-ospf-1-area-0.0.0.0] quit
   [SwitchA-ospf-1] quit
   [SwitchA] interface vlan 11
   [SwitchA-Vlan-interface11] ospf cost 2
   [SwitchA-Vlan-interface11] quit
   

   # Configure Switch B.

   <SwitchB> system-view
   [SwitchB] ospf
   [SwitchB-ospf-1] area 0
   [SwitchB-ospf-1-area-0.0.0.0] network 192.168.0.0 0.0.0.255
   [SwitchB-ospf-1-area-0.0.0.0] network 13.1.1.0 0.0.0.255
   [SwitchB-ospf-1-area-0.0.0.0] network 120.1.1.0 0.0.0.255
   [SwitchB-ospf-1-area-0.0.0.0] quit
   [SwitchB-ospf-1] quit
   [SwitchB] interface vlan-interface 13
   [SwitchB-Vlan-interface13] ospf cost 2
   [SwitchA-Vlan-interface13] quit
   

   # Configure Switch C.

   <SwitchC> system-view
   [SwitchC] ospf
   [SwitchC-ospf-1] area 0
   [SwitchC-ospf-1-area-0.0.0.0] network 10.1.1.0 0.0.0.255
   [SwitchC-ospf-1-area-0.0.0.0] network 13.1.1.0 0.0.0.255
   [SwitchC-ospf-1-area-0.0.0.0] quit
   [SwitchC-ospf-1] quit
   

3. Configure BFD:

   # Enable BFD on Switch A and configure BFD parameters.

   [SwitchA] bfd session init-mode active
   [SwitchA] interface vlan-interface 10
   [SwitchA-Vlan-interface10] ospf bfd enable
   [SwitchA-Vlan-interface10] bfd min-transmit-interval 500
   [SwitchA-Vlan-interface10] bfd min-receive-interval 500
   [SwitchA-Vlan-interface10] bfd detect-multiplier 7
   [SwitchA-Vlan-interface10] quit
   [SwitchA] quit
   

   # Enable BFD on Switch B and configure BFD parameters.

   [SwitchB] bfd session init-mode active
   [SwitchB] interface vlan-interface 10
   [SwitchB-Vlan-interface10] ospf bfd enable
   [SwitchB-Vlan-interface10] bfd min-transmit-interval 500
   [SwitchB-Vlan-interface10] bfd min-receive-interval 500
   [SwitchB-Vlan-interface10] bfd detect-multiplier 6
   

# Display the BFD information on Switch A.

<SwitchA> display bfd session

 Total Session Num: 1     Up Session Num: 1     Init Mode: Active

 IPv4 Session Working Under Ctrl Mode:

 LD/RD          SourceAddr      DestAddr        State    Holdtime    Interface
 3/1            192.168.0.102   192.168.0.100   Up       1700ms      Vlan10

# Display routes destined for 120.1.1.0/24 on Switch A.

<SwitchA> display ip routing-table 120.1.1.0 verbose

Summary Count : 1

Destination: 120.1.1.0/24
   Protocol: OSPF            Process ID: 1
  SubProtID: 0x1                    Age: 04h20m37s
       Cost: 2               Preference: 10
        Tag: 0                    State: Active Adv
  OrigTblID: 0x0                OrigVrf: default-vrf
    TableID: 0x2                 OrigAs: 0
      NBRID: 0x26000002          LastAs: 0
     AttrID: 0xffffffff        Neighbor: 0.0.0.0
      Flags: 0x1008c        OrigNextHop: 192.168.0.100
      Label: NULL           RealNextHop: 192.168.0.100
    BkLabel: NULL             BkNextHop: N/A
  Tunnel ID: Invalid          Interface: Vlan-interface10
BkTunnel ID: Invalid        BkInterface: N/A

The output shows that Switch A communicates with Switch B through VLAN-interface 10. Then the link over VLAN-interface 10 fails.

# Display routes destined for 120.1.1.0/24 on Switch A.

<SwitchA> display ip routing-table 120.1.1.0 verbose

Summary Count : 1

Destination: 120.1.1.0/24
   Protocol: OSPF            Process ID: 1
  SubProtID: 0x1                    Age: 04h20m37s
       Cost: 4               Preference: 10
        Tag: 0                    State: Active Adv
  OrigTblID: 0x0                OrigVrf: default-vrf
    TableID: 0x2                 OrigAs: 0
      NBRID: 0x26000002          LastAs: 0
     AttrID: 0xffffffff        Neighbor: 0.0.0.0
      Flags: 0x1008c        OrigNextHop: 10.1.1.100
      Label: NULL           RealNextHop: 10.1.1.100
    BkLabel: NULL             BkNextHop: N/A
  Tunnel ID: Invalid          Interface: Vlan-interface11
BkTunnel ID: Invalid        BkInterface: N/A

The output shows that Switch A communicates with Switch B through VLAN-interface 11.