Example for Associating the BFD Session Status with the Interface Status

Networking Requirements

As shown in Figure 1, SwitchA is directly connected to SwitchB and Layer 2 transmission devices, SwitchC and SwitchD, are deployed between them. It is required that SwitchA and SwitchB fast detect link faults of the Layer 2 transmission devices to trigger fast route convergence.

Figure 1 Associating the BFD session status with the interface status

Configuration Roadmap

The configuration roadmap is as follows:

Configure BFD sessions on SwitchA and SwitchB to detect faults on the link between SwitchA and SwitchB.
Configure association between the BFD session status and interface status on SwitchA and SwitchB after the BFD session becomes Up.

Procedure

Set IP addresses of the directly connected interfaces on SwitchA and SwitchB.

# Assign an IP address to the interface of SwitchA.

<HUAWEI> system-view
[HUAWEI] sysname SwitchA
[SwitchA] vlan 10
[SwitchA-vlan10] quit
[SwitchA] interface gigabitethernet 0/0/1
[SwitchA-GigabitEthernet0/0/1] port link-type hybrid
[SwitchA-GigabitEthernet0/0/1] port hybrid pvid vlan 10
[SwitchA-GigabitEthernet0/0/1] port hybrid untagged vlan 10
[SwitchA-GigabitEthernet0/0/1] quit
[SwitchA] interface vlanif 10
[SwitchA-Vlanif10] ip address 10.1.1.1 24
[SwitchA-Vlanif10] quit

# Assign an IP address to the interface of SwitchB.

<HUAWEI> system-view
[HUAWEI] sysname SwitchB
[SwitchB] vlan 10
[SwitchB-vlan10] quit
[SwitchB] interface gigabitethernet 0/0/1
[SwitchB-GigabitEthernet0/0/1] port link-type hybrid
[SwitchB-GigabitEthernet0/0/1] port hybrid pvid vlan 10
[SwitchB-GigabitEthernet0/0/1] port hybrid untagged vlan 10
[SwitchB-GigabitEthernet0/0/1] quit
[SwitchB] interface vlanif 10
[SwitchB-Vlanif10] ip address 10.1.1.2 24
[SwitchB-Vlanif10] quit

Configure single-hop BFD.

# Enable BFD on SwitchA and set up the BFD session between SwitchA and SwitchB.

[SwitchA] bfd
[SwitchA-bfd] quit
[SwitchA] bfd atob bind peer-ip default-ip interface gigabitethernet 0/0/1
[SwitchA-bfd-session-atob] discriminator local 10
[SwitchA-bfd-session-atob] discriminator remote 20
[SwitchA-bfd-session-atob] commit
[SwitchA-bfd-session-atob] quit

# Enable BFD on SwitchB and set up the BFD session between SwitchA and SwitchB.

[SwitchB] bfd
[SwitchB-bfd] quit
[SwitchB] bfd btoa bind peer-ip default-ip interface gigabitethernet 0/0/1
[SwitchB-bfd-session-btoa] discriminator local 20
[SwitchB-bfd-session-btoa] discriminator remote 10
[SwitchB-bfd-session-btoa] commit
[SwitchB-bfd-session-btoa] quit

# After the configuration is complete, run the display bfd session all verbose command on SwitchA and SwitchB. You can see that a single-hop BFD session is set up and its status is Up. The command output on SwitchA is used as an example.

[SwitchA] display bfd session all verbose
--------------------------------------------------------------------------------
Session MIndex : 16384     (One Hop) State : Up        Name : atob
--------------------------------------------------------------------------------
  Local Discriminator    : 10               Remote Discriminator   : 20
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Interface(GigabitEthernet0/0/1)
  Bind Session Type      : Static
  Bind Peer IP Address   : 224.0.0.184
  NextHop Ip Address     : 224.0.0.184
  Bind Interface         : GigabitEthernet0/0/1
  FSM Board Id           : 0                TOS-EXP                : 7
  Min Tx Interval (ms)   : 1000             Min Rx Interval (ms)   : 1000
  Actual Tx Interval (ms): 1000             Actual Rx Interval (ms): 1000
  Local Detect Multi     : 3                Detect Interval (ms)   : 3000
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 3784             TTL                    : 255
  Proc Interface Status  : Disable          Process PST            : Disable
  WTR Interval (ms)      : -                 
  Active Multi           : 3                DSCP                   : - 
  Last Local Diagnostic  : No Diagnostic
  Bind Application       : No Application Bind
  Session TX TmrID       : -               Session Detect TmrID   : -
  Session Init TmrID     : -               Session WTR TmrID      : -
  Session Echo Tx TmrID  : - 
  PDT Index              : FSM-0 | RCV-0 | IF-0 | TOKEN-0 
  Session Description    : -
--------------------------------------------------------------------------------

     Total UP/DOWN Session Number : 1/0

Configuring association between BFD session status and interface status.
# Configure association between the BFD session status and the interface status on SwitchA.
```
[SwitchA] bfd atob 
[SwitchA-bfd-session-atob] process-interface-status
[SwitchA-bfd-session-atob] quit
```
# Configure association between the BFD session status and the interface status on SwitchB.
```
[SwitchB] bfd btoa
[SwitchB-bfd-session-btoa] process-interface-status
[SwitchB-bfd-session-btoa] quit
```

Verify the configuration.

After the configuration is completed, run the display bfd session all verbose command on SwitchA and SwitchB. You can see that the Proc interface status field is displayed as Enable.

The command output on SwitchA is used as an example.

[SwitchA] display bfd session all verbose
--------------------------------------------------------------------------------
Session MIndex : 16384     (One Hop) State : Up        Name : atob
--------------------------------------------------------------------------------
  Local Discriminator    : 10               Remote Discriminator   : 20
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Interface(GigabitEthernet0/0/1)
  Bind Session Type      : Static
  Bind Peer IP Address   : 224.0.0.184
  NextHop Ip Address     : 224.0.0.184
  Bind Interface         : GigabitEthernet0/0/1
  FSM Board Id           : 0                TOS-EXP                : 7
  Min Tx Interval (ms)   : 1000             Min Rx Interval (ms)   : 1000
  Actual Tx Interval (ms): 1000             Actual Rx Interval (ms): 1000
  Local Detect Multi     : 3                Detect Interval (ms)   : 3000
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 3784             TTL                    : 255
  Proc Interface Status  : Enable           Process PST            : Disable
  WTR Interval (ms)      : -                
  Active Multi           : 3                DSCP                   : - 
  Last Local Diagnostic  : No Diagnostic
  Bind Application       : IFNET
  Session TX TmrID       : -               Session Detect TmrID   : -
  Session Init TmrID     : -               Session WTR TmrID      : -
  Session Echo Tx TmrID  : -  
  PDT Index              : FSM-0 | RCV-0 | IF-0 | TOKEN-0
  Session Description    : -
--------------------------------------------------------------------------------

     Total UP/DOWN Session Number : 1/0

Run the shutdown command on GE0/0/1 of SwitchC to make the BFD session go Down.

<HUAWEI> system-view
[HUAWEI] sysname SwitchC
[SwitchC] interface gigabitethernet 0/0/1
[SwitchC-GigabitEthernet0/0/1] shutdown
[SwitchC-GigabitEthernet0/0/1] quit

Run the display bfd session all verbose and display interface gigabitethernet 0/0/1 commands on SwitchA. You can see that the BFD session status is Down, and the status of GE0/0/1 is UP (BFD status down).

[SwitchA] display bfd session all verbose
--------------------------------------------------------------------------------
Session MIndex : 16384     (One Hop) State : Down      Name : atob
--------------------------------------------------------------------------------
  Local Discriminator    : 10               Remote Discriminator   : 20
  Session Detect Mode    : Asynchronous Mode Without Echo Function
  BFD Bind Type          : Interface(GigabitEthernet0/0/1)
  Bind Session Type      : Static
  Bind Peer IP Address   : 224.0.0.184
  NextHop Ip Address     : 224.0.0.184
  Bind Interface         : GigabitEthernet0/0/1
  FSM Board Id           : 0                TOS-EXP                : 7
  Min Tx Interval (ms)   : 1000             Min Rx Interval (ms)   : 1000
  Actual Tx Interval (ms): 2900             Actual Rx Interval (ms): 2900
  Local Detect Multi     : 3                Detect Interval (ms)   : -
  Echo Passive           : Disable          Acl Number             : -
  Destination Port       : 3784             TTL                    : 255
  Proc Interface Status  : Enable          Process PST            : Disable
  WTR Interval (ms)      : -                 
  Active Multi           : 3                DSCP                   : - 
  Last Local Diagnostic  : Control Detection Time Expired
  Bind Application       : IFNET
  Session TX TmrID       : 1038               Session Detect TmrID   : -
  Session Init TmrID     : -               Session WTR TmrID      : -
  Session Echo Tx TmrID  : - 
  PDT Index              : FSM-0 | RCV-0 | IF-0 | TOKEN-0
  Session Description    : -
--------------------------------------------------------------------------------

     Total UP/DOWN Session Number : 0/1

[SwitchA] display interface gigabitethernet 0/0/1
GigabitEthernet0/0/1 current state : UP                                         
Line protocol current state : UP(BFD status down)
...

The output of the display interface gigabitethernet 0/0/1 command displays information that you need to concern and "..." indicates that information is omitted.

Configuration Files

SwitchA configuration file

#
sysname SwitchA
#
vlan batch 10
#
bfd
#
interface Vlanif10
 ip address 10.1.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type hybrid
 port hybrid pvid vlan 10
 port hybrid untagged vlan 10
#
bfd atob bind peer-ip default-ip interface GigabitEthernet0/0/1
 discriminator local 10
 discriminator remote 20
 process-interface-status
 commit
#
return

SwitchB configuration file

#
sysname SwitchB
#
vlan batch 10
#
bfd
#
interface Vlanif10
 ip address 10.1.1.2 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type hybrid
 port hybrid pvid vlan 10
 port hybrid untagged vlan 10
#
bfd btoa bind peer-ip default-ip interface GigabitEthernet0/0/1
 discriminator local 20
 discriminator remote 10
 process-interface-status
 commit
#
return