13.15. IP BFD Commands

Command Purpose

Use this command to specify the desired transmit interval, receive interval and detect multiplier of IP BFD on the interface.

Use the “no” form of this command to restore the default value.

Prerequisites

Command Syntax

bfd interval {tx MINTX|rx MINRX|multiplier MULTIPLIER}

no bfd interval

Command Mode

Interface Configuration

Default

The default value for minimum TX interval and RX interval is 20 ms.

The default value for detect multiple is 3.

Usage

Use this command to specify the transmit interval, receive interval and detect multiple of IP BFD on the interface.

This configuration should affect all the IP BFD sessions on this interface. The actual transmit interval and receive interval need to negotiate with another end of the session.

Examples

In the following example, the desired transmit interval is set as 3 ms, the desired receive interval is set as 3 ms, the detect multiplier is set as 3 times:

Switch# configure terminal
Switch(config)# interface eth-0-1
Switch(config-if)# bfd interval mintx 3 minrx 3 multiplier 3

Related Commands

None

Command Purpose

Use this command to configure one Single-hop IP BFD session.

Use the “no” form of this command to remove the session

Prerequisites

Command Syntax

bfd NAME peer-ip A.B.C.D (vrf NAME| ) interface (IFPHYSICAL|IFVLAN|IFAGG) (source-ip A.B.C.D| ) (auto|local LDISR remote RDISR)

no bfd NAME

Command Mode

Global Config

Default

By default there is no IP Single BFD session to be created.

Usage

Use this command to specify the IP BFD for static route. BFD session is created, the BFD configurations need meet the following conditions:

• The destination IP address should be subnet with the IP address of the binded interface.

• The specified VRF should be same as that of the binded interface. If users don’t specify the VRF, the BFD VRF would be default.

• The source IP address should be same as that of the binded interface. If users don’t specify the source IP address, the source IP would be got from the binded interface, which is subnet with the destination IP address. If there are many IP addresses of the binded interface subnet the the destination IP address, the primary IP address would be selected firstly, and the smaller values of the IP adderss would be chosen secondly.

If users specify the local and remote discriminator, BFD uses them. Otherwise, the BFD local discriminator would be allocated by system.

Examples

In the following example, the single-hop IP BFD session “test” is created:

Switch# configure terminal
Switch(config)# bfd test peer-ip 9.9.9.2 interface eth-0-9 local 10 remote 20

Related Commands

ip route

Command Purpose

Use this command to configure one Multi-hop IP BFD session.

Use the “no” form of this command to remove this configuration.

Prerequisites

Command Syntax

bfd NAME peer-ip A.B.C.D source-ip A.B.C.D (auto|local LDISR remote RDISR)

no bfd NAME

Command Mode

Global Config

Default

By default there is no IP Multiple BFD session to be created.

Usage

Use this command to specify the IP BFD for static route. BFD session is created, the BFD configurations need meet the following conditions:

1.The source IP address should be same as that of the local L3 interface.

If users specify the local and remote discriminator, BFD uses them. Otherwise, the BFD local discriminator would be allocated by system.

Examples

In the following example, the multi-hop IP BFD session “test” is created:

Switch# configure terminal
Switch(config)# bfd test peer-ip 9.9.9.2 source 10.10.10.1 local 10 remote 20

Related Commands

ip route

Command Purpose

Use this command to specify to bind IP BFD session for static route.

Use the “no” form of this command to remove this configuration.

Prerequisites

Command Syntax

ip route PREFIX NEXTHOP bind bfd NAME

no ip route prefix nexthop bind bfd

Command Mode

Global Config

Default

By default there is no IP BFD session to be binded with one static route.

Usage

Use this command to bind an existent IP BFD session for static route. The session should be create before use this command.

When the IP static route is deleted, the session should be detach from the route, but not destroyed.

Examples

In the following example, the IP BFD session “test” is bound to the static router 1.1.1.0/24 via 9.9.9.2:

Switch# configure terminal
Switch(config)# ip route 1.1.1.0/24 9.9.9.2 bind bfd test

Related Commands

ip route

Command Purpose

Use this command to configure the interval of sending and receiving BFD packets for BFD session.

Use the “no” form of this command to remove this configuration.

Prerequisites

Command Syntax

bfd set interval mintx MINTX minrx MINRX multiplier MULTIPLIER

no bfd set interval

Command Mode

BFD Configuration

Default

By default, the minimum time of sending and receiving packets are respectively 20ms and 20ms, the times of timeout is 3.

Usage

Use this command to specify the mintx, minrx and timeout of BFD session.

Examples

In the following example, set the interval of sending and receiving BFD packets for BFD session “test”:

Switch# configure terminal
Switch(config)# bfd test
Switch(config-ip-bfd)#bfd set interval mintx 30 minrx 30 multiplier 5

Related Commands

show bfd session detail

Command Purpose

Use this command to configure global DSCP value for all multi-hop BFD sessions.

Use the “no” form of this command to remove this configuration.

Prerequisites

Command Syntax

bfd set dscp DSCP

no bfd global dscp

Command Mode

Global Config

Default

By default, the DSCP value of all the multi-hop BFD sessions is 56.

Usage

Use this command to specify the DSCP for all the multi-hop BFD sessions.

Examples

In the following example, user configures to set the global DSCP value for all the multi-hop for all the BFD sessions:

Switch# configure terminal
Switch(config)# bfd global dscp 63

Related Commands

show bfd session detail

Command Purpose

Use this command to configure global DSCP value for one multi-hop BFD session.

Use the “no” form of this command to remove this configuration.

Prerequisites

Command Syntax

bfd set dscp DSCP

no bfd set dscp

Command Mode

BFD Configuration

Default

By default, the DSCP value of one multi-hop BFD sessions is 56.

Usage

Use this command to specify the DSCP for one multi-hop BFD session.

When removing this configuration, the DSCP of this multiplier BFD session would be the global DSCP value when configuring the global DSCP.

Examples

In the following example, user configures to set the global DSCP value for all the multi-hop for all the BFD sessions:

Switch# configure terminal
Switch(config)# bfd test
Switch(config-ip-bfd)# bfd set dscp 63

Related Commands

show bfd session detail

Command Purpose

Use this command to show the statues of IP BFD module.

Prerequisites

Command Syntax

show bfd

Command Mode

Privileged EXEC

Default

N/A

Usage

Use this command to show the statues of IP BFD module.

Examples

The following example is the result of this command:

Switch# show bfd
BFD ID: 00 Start Time:Thu May 2 03:09:41 2023
Number of Sessions: 2
Slow Timer: 1000 Image type: DISTRIBUTED
Echo Mode: Disabled BFD Notifications disabled
Next Session Discriminator: 10
BFD Clients:
STATIC -\> Client ID: 1
OSPF-\> Client ID: 4

Related Commands

None

Command Purpose

Use this command to show the BFD static configurations.

Prerequisites

Command Syntax

show bfd static configurations (word| )

Command Mode

Privileged EXEC

Default

N/A

Usage

Use this command to show the BFD static configurations.

Examples

The following example is the result of this command:

Switch# show bfd static configurations
==================================================================================================================================
Name Type VRF LocalDiscr RemoteDiscr Src Ip Dst Ip interface Status
test1 single-hop default - - 10.10.10.1 10.10.10.2 vlan10 active
test2 single-hop test - - 9.9.9.1 9.9.9.2 vlan4094 active
test3 single-hop default 8191 4294967295 10.10.10.1 10.10.10.3 vlan10 active

Related Commands

None

Command Purpose

Use this command to show the bfd sessions.

Prerequisites

Command Syntax

show bfd session (detail| )

show bfd session SRC DST interface IFNAME (detail| )

show bfd session SRC DST (detail| )

show bfd session discriminator SESS (detail| )

Command Mode

Privileged EXEC

Default

N/A

Usage

Use this command to show the bfd session.

Use the key word “detail” to show the detailed information.

To filter the show result, user can specify the session’s source and destination address and interface.

Examples

The following example is the result of this command:

Switch# show bfd session
Abbreviation:
LD: Local Discriminator. RD: Remote Discriminator
S: Single hop session. M: Multi hop session.
SD: Static Discriminator. DD: Dynamic Discriminator
A: Admin down. D:Down. I:Init. U:Up.
============================================================================
LD RD TYPE ST UP-Time Remote-Addr VRF
8191 4294967295 S-SD D 00:00:00 10.10.10.3 default
8192 0 S-DD D 00:00:00 11.11.11.2 yoush
8193 0 S-DD D 00:00:00 10.10.10.2 default
8194 0 S-DD D 00:00:00 9.9.9.2 test
Number of Sessions: 4

Switch# show bfd session detail
======================================================
Session Interface : vlan10 Session Name : test3
Lower Layer : IPv4 Version : 1
Session Type : Single Hop Session State : Down
Discriminator Type : Static DSCP : 0
Local Discriminator : 8191 Local Address : 10.10.10.1
Remote Discriminator: 4294967295 Remote Address: 10.10.10.3
Local Port : 49155 Remote Port : 3784
vrf : default
Diagnostics : None
Timers in Milliseconds :
Min Tx: 20 Min Rx: 20 Multiplier: 3
Neg Tx: 4 Neg Rx: 20 Neg detect mult: 3
Sess up time : 00:00:00
Sess down time : 00:00:00
Bind Application : -
----------------------------------------------------------
Session Interface : vlan11 Session Name : -
Lower Layer : IPv4 Version : 1
Session Type : Single Hop Session State : Down
Discriminator Type : Dynamic DSCP : 0
Local Discriminator : 8192 Local Address : 11.11.11.1
Remote Discriminator: 0 Remote Address: 11.11.11.2
Local Port : 49152 Remote Port : 3784
vrf : yoush
Diagnostics : None
Timers in Milliseconds :
Min Tx: 20 Min Rx: 20 Multiplier: 3
Neg Tx: 4 Neg Rx: 20 Neg detect mult: 3
Sess up time : 00:00:00
Sess down time : 00:00:00
Bind Application : VRRP

Related Commands

None

Command Purpose

Use this command to show the resource of static BFD configurations

Prerequisites

Command Syntax

show resource bfd static configurations

Command Mode

User EXEC

Default

None

Usage

Use this command to show the resource of static BFD configurations

Examples

The following example is the result of this command:

Switch# show resource bfd static configurations
BFD (Static-BFD, Vrrp-BFD)
Resource Used Capability
=============================================================
BFD static configuration

Related Commands

None

Command Purpose

Use this command to show the IP BFD interface statues.

Prerequisites

Command Syntax

show bfd interface (IFNAME|all| )

Command Mode

Privileged EXEC

Default

N/A

Usage

Use this command to show the IP BFD interface statues.

User can show the specified interface or all interfaces.

Examples

The following example is the result of this command:

Switch# show bfd interface eth-0-9
Interface: eth-0-9 ifindex: 9 state: UP
Interface level configuration: NO ECHO, NO SLOW TMR
Timers in Milliseconds
Min Tx: 1 Min Rx: 1 Multiplier: 3
----------------------------------------------------------
Number of Sessions: 2
BFD discriminator: 8193 BFD state: DOWN
BFD discriminator: 8191 BFD state: DOWN

Related Commands

None

Command Purpose

Use this comment to see BFD session added to fail-list

Prerequisites

Command Syntax

show bfd add-fail-session

Command Mode

Privileged EXEC

Default

None

Usage

Use this comment to see VFD session added to fail-list

Examples

The following example is the result of this command:

Switch# show bfd add-fail-session
========================================================
Name Type Src Ip Dst Ip
ccc single-hop 4.4.4.1 4.4.4.2

Related Commands

None