OSPF FRR configuration example

As shown in Figure 31, Switch S, Switch A, and Switch D reside in the same OSPF domain. Configure OSPF FRR so that when the link between Switch S and Switch D fails, traffic is immediately switched to Link B.

1. Configure IP addresses and subnet masks for interfaces on the switches. (Details not shown.)

2. Configure OSPF on the switches to make sure Switch S, Switch A, and Switch D can communicate with each other at the network layer. (Details not shown.)

3. Configure OSPF FRR to automatically calculate the backup next hop:

   You can enable OSPF FRR to either calculate a backup next hop by using the LFA algorithm, or specify a backup next hop by using a routing policy.

   • (Method 1.) Enable OSPF FRR to calculate the backup next hop by using the LFA algorithm:

     # Configure Switch S.

     <SwitchS> system-view
     [SwitchS] bfd echo-source-ip 1.1.1.1
     [SwitchS] ospf 1
     [SwitchS-ospf-1] fast-reroute lfa
     [SwitchS-ospf-1] quit
     

     # Configure Switch D.

     <SwitchD> system-view
     [SwitchD] bfd echo-source-ip 4.4.4.4
     [SwitchD] ospf 1
     [SwitchD-ospf-1] fast-reroute lfa
     [SwitchD-ospf-1] quit
     

   • (Method 2.) Enable OSPF FRR to designate a backup next hop by using a routing policy.

     # Configure Switch S.

     <SwitchS> system-view
     [SwitchS] bfd echo-source-ip 1.1.1.1
     [SwitchS] ip prefix-list abc index 10 permit 4.4.4.4 32
     [SwitchS] route-policy frr permit node 10
     [SwitchS-route-policy-frr-10] if-match ip address prefix-list abc
     [SwitchS-route-policy-frr-10] apply fast-reroute backup-interface vlan-interface 100 backup-nexthop 12.12.12.2
     [SwitchS-route-policy-frr-10] quit
     [SwitchS] ospf 1
     [SwitchS-ospf-1] fast-reroute route-policy frr
     [SwitchS-ospf-1] quit
     

     # Configure Switch D.

     <SwitchD> system-view
     [SwitchD] bfd echo-source-ip 4.4.4.4
     [SwitchD] ip prefix-list abc index 10 permit 1.1.1.1 32
     [SwitchD] route-policy frr permit node 10
     [SwitchD-route-policy-frr-10] if-match ip address prefix-list abc
     [SwitchD-route-policy-frr-10] apply fast-reroute backup-interface vlan-interface 101 backup-nexthop 24.24.24.2
     [SwitchD-route-policy-frr-10] quit
     [SwitchD] ospf 1
     [SwitchD-ospf-1] fast-reroute route-policy frr
     [SwitchD-ospf-1] quit
     

# Display route 4.4.4.4/32 on Switch S to view the backup next hop information.

[SwitchS] display ip routing-table 4.4.4.4 verbose

Summary Count : 1

Destination: 4.4.4.4/32
   Protocol: OSPF            Process ID: 1
  SubProtID: 0x1                    Age: 04h20m37s
       Cost: 1               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: 13.13.13.2
      Label: NULL           RealNextHop: 13.13.13.2
    BkLabel: NULL             BkNextHop: 12.12.12.2
  Tunnel ID: Invalid          Interface: Vlan-interface200
BkTunnel ID: Invalid        BkInterface: Vlan-interface100

# Display route 1.1.1.1/32 on Switch D to view the backup next hop information.

[SwitchD] display ip routing-table 1.1.1.1 verbose

Summary Count : 1

Destination: 1.1.1.1/32
   Protocol: OSPF            Process ID: 1
  SubProtID: 0x1                    Age: 04h20m37s
       Cost: 1               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: 13.13.13.1
      Label: NULL           RealNextHop: 13.13.13.1
    BkLabel: NULL             BkNextHop: 24.24.24.2
  Tunnel ID: Invalid          Interface: Vlan-interface200
BkTunnel ID: Invalid        BkInterface: Vlan-interface101