Example for Configuring FRR for IPv4 Static Routes on the Public Network

FRR for IPv4 static routes on the public network can fast detect link failures.

Networking Requirements

On the network shown in Figure 1, it is required that two IPv4 static routes with Device A and Device B as the next hops be configured on Device T and that Link B function as the backup of Link A. If Link A fails, traffic is switched to the Link B immediately.

Figure 1 Networking for configuring FRR for IPv4 static routes on the public network

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



Precautions

When configuring FRR for IPv4 static routes on the public network, ensure that there are at least two IPv4 static routes to the same destination address.

Configuration Roadmap

The configuration roadmap is as follows:

  1. Configure two IPv4 static routes with Device A and Device B as the next hops on Device T.

  2. On Device T, set a higher priority for Link A to ensure that Link A becomes the primary link.

  3. Enable FRR for IPv4 static routes on Device T, and check the backup outbound interface and the backup next hop.

  4. Configure static BFD for IPv4 static routes to speed up fault detection.

    To speed up fault detection, configure dynamic or static BFD for IPv4 static routes. Static BFD for IPv4 static routes is used as an example because it is more common than dynamic BFD for IPv4 static routes on the live network.

  5. Disable FRR for IPv4 static routes, and check the backup outbound interface and the backup next hop.

Data Preparation

To complete the configuration, you need priorities of IPv4 static routes.

Procedure

  1. Configure an IP address for each interface. For configuration details, see Configuration Files in this section.
  2. Configure IPv4 static routes.

    # On Device A, configure IPv4 static routes.

    [~DeviceA] ip route-static 172.16.1.0 24 GigabitEthernet0/1/0 192.168.10.1
[*DeviceA] ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.11.1
[*DeviceA] commit

    # On Device B, configure static routes.

    [~DeviceB] ip route-static 172.16.1.0 24 GigabitEthernet0/1/0 192.168.20.1
[*DeviceB] ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.21.1
[*DeviceB] commit

    # On Device C, configure IPv4 static routes.

    [~DeviceC] ip route-static 172.16.1.0 24 GigabitEthernet0/1/8 192.168.11.2
[*DeviceC] ip route-static 172.16.1.0 24 GigabitEthernet0/1/16 192.168.21.2
[*DeviceC] ip route-static 192.168.10.0 24 GigabitEthernet0/1/8 192.168.11.2
[*DeviceC] ip route-static 192.168.20.0 24 GigabitEthernet0/1/16 192.168.21.2
[*DeviceC] commit

    # On Device T, configure IPv4 static routes.

    [~DeviceT] ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.10.2
[*DeviceT] ip route-static 172.17.1.0 24 GigabitEthernet0/1/16 192.168.20.2
[*DeviceT] ip route-static 192.168.11.0 24 GigabitEthernet0/1/8 192.168.10.2
[*DeviceT] ip route-static 192.168.21.0 24 GigabitEthernet0/1/16 192.168.20.2
[*DeviceT] commit
[*DeviceT] quit

    # Check the IP routing table of Device T. The following command output shows that load balancing is performed between the two IPv4 static routes.

    <DeviceT> display ip routing-table
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table : _public_
         Destinations : 16       Routes : 16

Destination/Mask    Proto   Pre  Cost        Flags NextHop         Interface

      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
     172.16.1.0/24  Direct  0    0             D   172.16.1.1      GigabitEthernet0/1/0
     172.16.1.1/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/0
   172.16.1.255/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/0
   172.17.1.0/24  Static 60  0             D  192.168.10.2    GigabitEthernet0/1/8
                  Static 60  0             D  192.168.20.2    GigabitEthernet0/1/16
   192.168.10.0/24  Direct  0    0             D   192.168.10.1    GigabitEthernet0/1/8
   192.168.10.1/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/8
 192.168.10.255/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/8
   192.168.11.0/24  Static  60   0             D   192.168.10.2    GigabitEthernet0/1/8
   192.168.20.0/24  Direct  0    0             D   192.168.20.1    GigabitEthernet0/1/16
   192.168.20.1/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/16
 192.168.20.255/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/16
   192.168.21.0/24  Static  60   0             D   192.168.20.2    GigabitEthernet0/1/16
255.255.255.255/32  Direct  0    0             D   127.0.0.1       InLoopBack0

  3. Change the priorities of the IPv4 static routes.

    # Change the priorities of static routes on Device T.

    <DeviceT> system-view
[~DeviceT] ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.10.2  preference 40
[*DeviceT] commit
[*DeviceT] quit

    # Check the IP routing table of Device T. The following command output shows that the priorities of IPv4 static routes have been changed.

    <DeviceT> display ip routing-table
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table : _public_
         Destinations : 16       Routes : 16

Destination/Mask    Proto   Pre  Cost        Flags NextHop         Interface

      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
     172.16.1.0/24  Direct  0    0             D   172.16.1.1      GigabitEthernet0/1/0
     172.16.1.1/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/0
   172.16.1.255/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/0
   172.17.1.0/24  Static 40   0             D  192.168.10.2    GigabitEthernet0/1/8
   192.168.10.0/24  Direct  0    0             D   192.168.10.1    GigabitEthernet0/1/8
   192.168.10.1/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/8
 192.168.10.255/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/8
   192.168.11.0/24  Static  60   0             D   192.168.10.2    GigabitEthernet0/1/8
   192.168.20.0/24  Direct  0    0             D   192.168.20.1    GigabitEthernet0/1/16
   192.168.20.1/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/16
 192.168.20.255/32  Direct  0    0             D   127.0.0.1       GigabitEthernet0/1/16
   192.168.21.0/24  Static  60   0             D   192.168.20.2    GigabitEthernet0/1/16
255.255.255.255/32  Direct  0    0             D   127.0.0.1       InLoopBack0

  4. Enable FRR for IPv4 static routes.

    # Enable FRR for static route on Device T.

    <DeviceT> system-view
[~DeviceT] ip route-static frr
[*DeviceT] commit
[*DeviceT] quit

    # Check the backup outbound interface and the backup next hop on Device T.

    <DeviceT> display ip routing-table 172.17.1.0 verbose
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table : _public_
Summary Count : 1

Destination: 172.17.1.0/24
     Protocol: Static          Process ID: 0
   Preference: 40                    Cost: 0
      NextHop: 192.168.10.2     Neighbour: 0.0.0.0
        State: Active Adv             Age: 00h00m03s
          Tag: 0                 Priority: medium
        Label: NULL               QoSInfo: 0x0
   IndirectID: 0x31000032
 RelayNextHop: 0.0.0.0          Interface: GigabitEthernet0/1/8
     TunnelID: 0x0                  Flags: D
    BkNextHop: 192.168.20.2   BkInterface: GigabitEthernet0/1/16
      BkLabel: NULL           SecTunnelID: 0x0
 BkPETunnelID: 0x0        BkPESecTunnelID: 0x0
 BkIndirectID: 0x32000033

  5. Configure static BFD for IPv4 static routes.

    • Configure a BFD session.

      # On Device T, configure a BFD session between Device T and Device C.

      <DeviceT> system-view
[~DeviceT] bfd
[*DeviceT-bfd] quit
[*DeviceT] bfd aa bind peer-ip 192.168.11.1 source-ip 192.168.10.1
[*DeviceT-bfd-session-aa] discriminator local 10
[*DeviceT-bfd-session-aa] discriminator remote 20
[*DeviceT-bfd-session-aa] commit
[~DeviceT-bfd-session-aa] quit

      # On Device C, configure a BFD session between Device C and Device T.

      <DeviceC> system-view
[~DeviceC] bfd
[*DeviceC-bfd] quit
[*DeviceC] bfd ab bind peer-ip 192.168.10.1 source-ip 192.168.11.1
[*DeviceC-bfd-session-ab] discriminator local 20
[*DeviceC-bfd-session-ab] discriminator remote 10
[*DeviceC-bfd-session-ab] commit
[~DeviceC-bfd-session-ab] quit

    • Configure a static route and bind it to the BFD session.

      # On Device T, configure a static route and bind it to the BFD session named aa.

      [~DeviceT] ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.10.2 preference 40 track bfd-session aa

  6. Simulate a fault on Link A.

    <DeviceT> system-view
[~DeviceT] interface gigabitethernet 0/1/8
[~DeviceT-GigabitEthernet0/1/8] shutdown
[~DeviceT-GigabitEthernet0/1/8] commit
[~DeviceT-GigabitEthernet0/1/8] quit
[~DeviceT] quit

    # Check the routes to 172.17.1.0/24 on Device T.

    <DeviceT> display ip routing-table 172.17.1.0 verbose
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table : _public_
Summary Count : 1

Destination: 172.17.1.0/24
     Protocol: Static          Process ID: 0
   Preference: 60                    Cost: 0
      NextHop: 192.168.20.2     Neighbour: 0.0.0.0
        State: Active Adv             Age: 00h00m07s
          Tag: 0                 Priority: medium
        Label: NULL               QoSInfo: 0x0
   IndirectID: 0x32000033
 RelayNextHop: 0.0.0.0          Interface: GigabitEthernet0/1/16
     TunnelID: 0x0                  Flags: D

Configuration Files

  • Device T configuration file

    #
sysname DeviceT
#
bfd
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 172.16.1.1 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 192.168.10.1 255.255.255.0
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 192.168.20.1 255.255.255.0
#
bfd aa bind peer-ip 192.168.11.1 source-ip 192.168.10.1
 discriminator local 10
 discriminator remote 20
#
ip route-static frr
ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.10.2 preference 40 track bfd-session aa
ip route-static 172.17.1.0 24 GigabitEthernet0/1/16 192.168.20.2
ip route-static 192.168.11.0 24 GigabitEthernet0/1/8 192.168.10.2
ip route-static 192.168.21.0 24 GigabitEthernet0/1/16 192.168.20.2 
#
return

  • Device A configuration file

    #
sysname DeviceA
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 192.168.10.2 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 192.168.11.2 255.255.255.0
#
ip route-static 172.16.1.0 24 GigabitEthernet0/1/0 192.168.10.1
ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.11.1
#
return

  • Device B configuration file

    #
sysname DeviceB
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 192.168.20.2 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 192.168.21.2 255.255.255.0
#
ip route-static 172.16.1.0 24 GigabitEthernet0/1/0 192.168.20.1
ip route-static 172.17.1.0 24 GigabitEthernet0/1/8 192.168.10.1
#
return

  • Device C configuration file

    #
sysname DeviceC
#
bfd
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 172.17.1.0 255.255.255.0
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 192.168.11.1 255.255.255.0
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 192.168.21.1 255.255.255.0
#
bfd ab bind peer-ip 192.168.10.1 source-ip 192.168.11.1
 discriminator local 20
 discriminator remote 10
#
ip route-static 172.16.1.0 24 GigabitEthernet0/1/8 192.168.11.2
ip route-static 172.16.1.0 24 GigabitEthernet0/1/16 192.168.21.2
ip route-static 192.168.10.0 255.255.255.0 GigabitEthernet0/1/8 192.168.11.2
ip route-static 192.168.20.0 255.255.255.0 GigabitEthernet0/1/16 192.168.21.2 
#
return
Parent Topic: Configuration Examples for IPv4 Static Routes
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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