Contents

BFD commands· 1

Basic BFD commands· 1

bfd authentication-mode· 1

bfd dampening· 2

bfd demand enable· 3

bfd detect-interface first-fail-timer 4

bfd detect-interface source-ip· 4

bfd detect-interface special-processing· 6

bfd detect-multiplier 7

bfd echo enable· 8

bfd echo-source-ip· 9

bfd echo-source-ipv6· 10

bfd min-echo-receive-interval 10

bfd min-receive-interval 11

bfd min-transmit-interval 12

bfd multi-hop authentication-mode· 13

bfd multi-hop destination-port 14

bfd multi-hop detect-multiplier 15

bfd multi-hop min-receive-interval 16

bfd multi-hop min-transmit-interval 16

bfd session init-mode· 17

bfd static· 18

bfd template· 20

discriminator 21

display bfd session· 21

reset bfd session statistics· 27

snmp-agent trap enable bfd· 28

 

BFD commands

Basic BFD commands

bfd authentication-mode

Use bfd authentication-mode to configure the BFD authentication mode for single-hop BFD control packets.

Use undo bfd authentication-mode to restore the default.

Syntax

bfd authentication-mode { hmac-md5 | hmac-mmd5 | hmac-msha1 | hmac-sha1 | m-md5 | m-sha1 | md5 | sha1 | simple } key-id { cipher | plain } string

undo bfd authentication-mode

Default

Single-hop BFD control packets are not authenticated.

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

hmac-md5: Specifies the HMAC MD5 algorithm.

hmac-mmd5: Specifies the HMAC Meticulous MD5 algorithm.

hmac-msha1: Specifies the HMAC Meticulous SHA1 algorithm.

hmac-sha1: Specifies the HMAC SHA1 algorithm.

m-md5: Specifies the Meticulous MD5 algorithm.

m-sha1: Specifies the Meticulous SHA1 algorithm.

md5: Specifies the MD5 algorithm.

sha1: Specifies the SHA1 algorithm.

simple: Specifies the simple authentication mode.

key-id: Sets the authentication key ID in the range of 1 to 255.

cipher: Specifies a key in encrypted form.

plain: Specifies a key in plaintext form. For security purposes, the key specified in plaintext form will be stored in encrypted form.

string: Specifies the key. Its plaintext form is a case-sensitive string of 1 to 16 characters. Its encrypted form is a case-sensitive string of 33 to 53 characters.

Usage guidelines

Use this command to enhance BFD session security.

A static BFD session supports this command only when it is in IPv4 or IPv6 control packet mode used for single-hop detection.

BFD version 0 does not support this command. The configuration does not take effect.

Examples

# Configure VLAN-interface 11 to perform simple authentication for single-hop BFD control packets, setting the authentication key ID to 1 and plaintext key to 123456.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd authentication-mode simple 1 plain 123456

bfd dampening

Use bfd dampening to configure BFD session flapping suppression.

Use undo bfd dampening to disable BFD session flapping suppression.

Syntax

bfd dampening [ maximum maximum-interval initial initial-interval secondary secondary-interval ]

undo bfd dampening

Default

BFD sessions are not suppressed.

Views

System view

Predefined user roles

network-admin

Parameters

maximum-interval: Specifies the maximum amount of time a BFD session is suppressed, in the range of 1 to 3600 seconds. The default is 20 seconds.

initial-interval: Specifies the amount of time a BFD session is suppressed for the first time. The value range for the initial-interval argument is 1 to 3600 seconds. The default is 6 seconds.

secondary-interval: Specifies the amount of time a BFD session is suppressed for the second time. The value range for the secondary-interval argument is 1 to 3600 seconds. The default is 10 seconds.

Usage guidelines

When BFD detects a link failure, it tears down the BFD session and notifies the upper-layer protocol of the failure. When the upper-layer protocol re-establishes a neighbor relationship, the BFD session comes up again. BFD session flaps occur when a link fails and recovers repeatedly, which consumes significant system resources and causes network instability.

This command allows you to suppress BFD session flapping by using the initial-interval, secondary-interval, and maximum-interval arguments.

·     A BFD session is suppressed within the specified interval. The suppression time does not exceed the maximum-interval.

·     After a BFD session goes down for the second time, it cannot be re-established within the initial-interval.

·     After a BFD session goes down for the third time, it cannot be re-established within the secondary-interval.

·     After a BFD session goes down for the fourth time and at any later time, the following rules apply:

¡     If secondary-interval × 2n-3 is smaller than or equal to the maximum-interval, the BFD session cannot be re-established within the secondary-interval × 2n-3.

¡     If secondary-interval × 2n-3 is greater than the maximum-interval, the BFD session cannot be re-established within the maximum-interval.

The letter n, starting from 4, is the number of times the BFD session flaps.

Examples

# Enable BFD session flapping suppression, and set the maximum-interval, initial-interval, and secondary-interval to 12 seconds, 4 seconds, and 8 seconds, respectively.

<Sysname> system-view

[Sysname] bfd dampening maximum 12 initial 4 secondary 8

bfd demand enable

Use bfd demand enable to enable the Demand BFD session mode.

Use undo bfd demand enable to restore the default.

Syntax

bfd demand enable

undo bfd demand enable

Default

The BFD session is in Asynchronous mode.

Views

Interface view

Predefined user roles

network-admin

Usage guidelines

In Demand mode, the device periodically sends BFD control packets. If the peer end is operating in Asynchronous mode (default), the peer end stops sending BFD control packets. If the peer end is operating in Demand mode, both ends stop sending BFD control packets. When the connectivity to another system needs to be verified explicitly, a system sends several BFD control packets with the Poll (P) bit set at the negotiated transmit interval. If no response is received within the detection interval, the session is considered down. If the connectivity is found to be up, no more BFD control packets are sent until the next command is issued.

In Asynchronous mode, the device periodically sends BFD control packets. The device considers that the session is down if it does not receive any BFD control packets within a specific interval.

BFD version 0 does not support this command. The configuration does not take effect.

Examples

# Enable the Demand BFD session mode on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd demand enable

bfd detect-interface first-fail-timer

Use bfd detect-interface first-fail-timer to configure the timer that delays reporting the first BFD session establishment failure to the data link layer.

Use undo bfd detect-interface first-fail-timer to restore the default.

Syntax

bfd detect-interface first-fail-timer seconds

undo bfd detect-interface first-fail-timer

Default

The first BFD session establishment failure is not reported to the data link layer.

Views

Interface view

Predefined user roles

network-admin

Parameters

seconds: Specifies the timeout time that reports the first BFD session establishment failure to the data link layer. The value range for this argument is 1 to 10000 seconds.

Usage guidelines

If the BFD session fails to be established when the timer expires, BFD reports the failure to the data link layer and sets the data link layer state of the interface to DOWN(BFD). This behavior rapidly identifies the interfaces for which BFD sessions fail to be established. In this case, the BFD session state is displayed as Down in the display bfd session command output. The line protocol state of the interface is displayed as DOWN(BFD) in the display interface command output.

If the local end is configured with the bfd detect-interface command, the BFD session for detecting the local interface state fails to be established when the following conditions exist:

·     The remote end is not configured with the bfd detect-interface command.

·     The local and remote ends have mismatching BFD authentication settings.

Examples

# Configure the timer that delays reporting the first BFD session establishment failure as 10 seconds.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0/1

[Sysname-GigabitEthernet1/0/1] bfd detect-interface first-fail-timer 10

Related commands

bfd detect-interface

display interface (Interface Command Reference)

bfd detect-interface source-ip

Use bfd detect-interface source-ip to associate the interface state with BFD.

Use undo bfd detect-interface to remove the association between the interface state and BFD.

Syntax

bfd detect-interface source-ip ip-address [ discriminator local local-value remote remote-value ] [ template template-name ]

undo bfd detect-interface

Default

The interface state is not associated with BFD. BFD does not set the link layer protocol of the interface to DOWN(BFD) state when detecting a failure.

Views

Interface view

Predefined user roles

network-admin

Parameters

ip-address: Specifies the source IP address for BFD control packets.

discriminator: Specifies BFD session discriminators. If you do not specify discriminators, the device obtains BFD session discriminators through autonegotiation.

local local-value: Specifies the local discriminator. The value range for the local-value argument is 1 to 32768.

remote remote-value: Specifies the remote discriminator in the range of 1 to 4294967295.

template template-name: Specifies a template by its name, a case-sensitive string of 1 to 63 characters. If you do not specify a template, the BFD session uses the BFD parameters configured in interface view.

Usage guidelines

By creating a BFD session for single-hop detection through exchange of BFD control packets, this feature implements fast link detection. When BFD detects a link fault, it sets the link layer protocol state to DOWN(BFD). This behavior helps applications relying on the link layer protocol state achieve fast convergence.

The source IP address of control packets is specified manually, and the destination IP address is fixed at 224.0.0.184. As a best practice, specify the IP address of the interface as the source IP address. If the interface does not have an IP address, specify a unicast IP address other than 0.0.0.0 as the source IP address.

·     Layer 2 Ethernet interfaces.

·     Member ports in a Layer 2 aggregation group.

·     Layer 3 Ethernet interfaces.

·     Member ports in a Layer 3 aggregation group.

·     Layer 2 aggregate interfaces.

·     Layer 3 aggregate interfaces.

This command must be executed on both ends of the link for a BFD session to be established.

If you execute both the bfd detect-interface and bfd echo enable commands for an interface, only the bfd detect-interface command takes effect.

To configure this command on both a Layer 3 aggregate interface and its member port, you must manually specify the local and remote discriminators on them. As a best practice, do not configure this command on them at the same time.

For BFD detection to take effect, do not execute this command on both a Layer 2 aggregate interface and its member port.

If the peer device does not support obtaining BFD session discriminators through autonegotiation, you must specify the discriminators on both the local and peer devices. Without the discriminators, the BFD session cannot come up.

The BFD session discriminators must match on the local and peer devices. For example, if you configure bfd detect-interface source-ip 20.1.1.1 discriminator local 513 remote 514 on the local device, you must configure bfd detect-interface source-ip 20.1.1.2 discriminator local 514 remote 513 on the peer device.

The local discriminators of BFD sessions for interfaces on the same device must be different.

The echo function does not take effect on BFD sessions associated with interface states.

Examples

# Create a BFD session to detect the state of GigabitEthernet 1/0/1, and specify the source IP address as 20.1.1.1.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0/1

[Sysname-GigabitEthernet1/0/1] bfd detect-interface source-ip 20.1.1.1

bfd detect-interface special-processing

Use bfd detect-interface special-processing to enable special processing for BFD sessions.

Use undo bfd detect-interface special-processing to disable special processing for BFD sessions.

Syntax

bfd detect-interface special-processing [ admin-down | authentication-change | session-up ] *

undo bfd detect-interface special-processing [ admin-down | authentication-change | session-up ] *

Default

All types of special processing for BFD sessions are disabled.

Views

Interface view

Predefined user roles

network-admin

Parameters

admin-down: Notifies a session down event to the data link layer upon receipt of a BFD packet with the State field as AdminDown. This keyword helps rapidly discover interfaces that BFD sessions are manually shut down. If you do not specify this keyword, the device sets the BFD session state to Down, but does not notify the session down event to the data link layer.

authentication-change: Immediately sets the session to down state upon a local authentication information change. This keyword helps rapidly discover interfaces with authentication information changes. If you do not specify this keyword, the device sets the session to down state if authentication information inconsistency still persists after a period of time.

session-up: Ignores authentication information inconsistency when the local session is up. If there is a large number of BFD sessions, examining authentication information consistency affects device performance. If you do not specify this keyword, the device examines authentication information in incoming BFD packets when the local session state is up. If the authentication information does not match on the two ends, the BFD session is declared down.

Usage guidelines

If you do not specify any parameters, this command enables or disables all types of special processing.

When the authentication mode for BFD packets is M-MD5, M-SHA1, HMAC-MMD5, or HMAC-MSHA1, configuring the bfd detect-interface special-processing session-up command on only the local or remote end will cause BFD session flapping. To avoid this issue, perform one of the following tasks:

·     Change the authentication mode for BFD packets.

·     Configure the bfd detect-interface special-processing session-up command on both of the local and remote ends.

Examples

# Enable all types of special processing for BFD sessions on GigabitEthernet 1/0/1.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0/1

[Sysname-GigabitEthernet1/0/1] bfd detect-interface special-processing admin-down authentication-change session-up

bfd detect-multiplier

Use bfd detect-multiplier to set the single-hop detection time multiplier for control packet mode and echo packet mode.

Use undo bfd detect-multiplier to restore the default.

Syntax

bfd detect-multiplier value

undo bfd detect-multiplier

Default

The single-hop detection time multiplier for both control packet mode and echo packet mode is 5.

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

value: Specifies a detection time multiplier. The value range for this argument is 3 to 50.

Usage guidelines

The detection time multiplier determines the maximum number of concurrent BFD packets (including control packets and echo packets) that can be discarded.

Table 1 Actual detection interval calculation method

Mode	Actual detection interval of the sender
Echo packet mode	Detection time multiplier of the sender × actual packet sending interval of the sender
Control packet mode BFD session in asynchronous mode	Detection time multiplier of the receiver × MAX (minimum receiving interval supported by the sender, minimum sending interval supported by the receiver)
Control packet mode BFD session in demand mode	Detection time multiplier of the sender × MAX (minimum sending interval supported by the sender, minimum receiving interval supported by the receiver)

 

Only the following static BFD sessions support this command:

·     Static BFD sessions in IPv4 control packet mode used for single-hop detection.

·     Static BFD sessions in IPv4 echo packet mode used for single-hop detection.

·     Static BFD sessions in IPv6 control packet mode used for single-hop detection.

·     Static BFD sessions in IPv6 echo packet mode used for single-hop detection.

Examples

# Set the single-hop detection time multiplier for control packet mode and echo packet mode to 6 on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd detect-multiplier 6

bfd echo enable

Use bfd echo enable to enable the echo function.

Use undo bfd echo enable to disable the echo function.

Syntax

bfd echo [ receive | send ] enable

undo bfd echo [ receive | send ] enable

Default

The echo function is disabled.

Views

Interface view

Static BFD session view

Predefined user roles

network-admin

Parameters

receive: Specifies the echo packet receiving capability.

send: Specifies the echo packet sending capability.

Usage guidelines

If you enable the echo function for a BFD session in which control packets are sent and the session comes up, BFD performs the following operations:

·     Periodically sends echo packets to detect link connectivity.

·     Decreases the control packet receiving rate at the same time.

To enable only the echo packet receiving capability, use the bfd echo receive enable command.

To enable only the echo packet sending capability, use the bfd echo send enable command.

If you do not specify the receive or send keyword, the command enables both the echo packet receiving and sending capabilities.

The echo function does not take effect on BFD sessions associated with interface states.

The echo function does not take effect on BFD sessions in control packet mode that use IPv6 link-local addresses.

A static BFD session supports this command only when it is in IPv4 or IPv6 control packet mode used for single-hop detection.

BFD version 0 does not support this command. The configuration does not take effect.

Examples

# Enable the echo function on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd echo enable

bfd echo-source-ip

Use bfd echo-source-ip to configure the source IP address of BFD echo packets.

Use undo bfd echo-source-ip to remove the configured source IP address of BFD echo packets.

Syntax

bfd echo-source-ip ip-address

undo bfd echo-source-ip

Default

No source IP address is configured for BFD echo packets.

Views

System view

Predefined user roles

network-admin

Parameters

ip-address: Specifies the source IP address of BFD echo packets. The source IP address must be a valid unicast IPv4 address in dotted decimal notation.

Usage guidelines

The source IP address cannot be on the same network segment as any local interface's IP address. Otherwise, a large number of ICMP redirect packets might be sent from the peer, resulting in link congestion.

Examples

# Configure the source IP address of BFD echo packets as 8.8.8.8.

<Sysname> system-view

[Sysname] bfd echo-source-ip 8.8.8.8

bfd echo-source-ipv6

Use bfd echo-source-ipv6 to configure the source IPv6 address of BFD echo packets.

Use undo bfd echo-source-ipv6 to remove the configured source IPv6 address of BFD echo packets.

Syntax

bfd echo-source-ipv6 ipv6-address

undo bfd echo-source-ipv6

Default

No source IPv6 address is configured for BFD echo packets.

Views

System view

Predefined user roles

network-admin

Parameters

ipv6-address: Specifies the source IPv6 address for BFD echo packets.

Usage guidelines

The source IPv6 address of echo packets can only be a global unicast address.

The source IPv6 address cannot be on the same network segment as any local interface's IP address. Otherwise, a large number of ICMP redirect packets might be sent from the peer, resulting in link congestion.

Examples

# Configure the source IPv6 address of BFD echo packets as 80::2.

<Sysname> system-view

[Sysname] bfd echo-source-ipv6 80::2

bfd min-echo-receive-interval

Use bfd min-echo-receive-interval to set the minimum interval for receiving BFD echo packets.

Use undo bfd min-echo-receive-interval to restore the default.

Syntax

bfd min-echo-receive-interval interval

undo bfd min-echo-receive-interval

Default

The minimum interval for receiving BFD echo packets is 400 milliseconds.

Views

Interface view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving BFD echo packets, in milliseconds. The value takes 0 or is in the range of 100 to 1000.

Usage guidelines

This command sets the BFD echo packet receiving interval, which is the actual BFD echo packet sending interval.

The local end stops sending echo packets after autonegotiation with the remote end if the following conditions are met:

·     The echo packet mode is enabled on the local end.

·     The minimum interval for receiving BFD echo packets is set to 0 milliseconds on the remote end.

Only the following static BFD sessions support this command:

·     Static BFD sessions in IPv4 control packet mode used for single-hop detection.

·     Static BFD sessions in IPv4 echo packet mode used for single-hop detection.

·     Static BFD sessions in IPv6 control packet mode used for single-hop detection.

·     Static BFD sessions in IPv6 echo packet mode used for single-hop detection.

Examples

# Set the minimum interval for receiving BFD echo packets to 500 milliseconds on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd min-echo-receive-interval 500

bfd min-receive-interval

Use bfd min-receive-interval to set the minimum interval for receiving single-hop BFD control packets.

Use undo bfd min-receive-interval to restore the default.

Syntax

bfd min-receive-interval interval

undo bfd min-receive-interval

Default

The minimum interval for receiving single-hop BFD control packets is 400 milliseconds.

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving single-hop BFD control packets, in milliseconds. The value range is 100 to 1000.

Usage guidelines

Use this command to prevent the control packet sending rate of the peer end from exceeding the control packet receiving rate of the local end.

The actual control packet sending interval of the peer end takes the greater value between the following values:

·     Minimum interval for transmitting BFD control packets on the peer end.

·     Minimum interval for receiving BFD control packets on the local end.

A static BFD session supports this command only when it is in IPv4 or IPv6 control packet mode used for single-hop detection.

Examples

# Set the minimum interval for receiving single-hop BFD control packets to 500 milliseconds on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd min-receive-interval 500

bfd min-transmit-interval

Use bfd min-transmit-interval to set the minimum interval for transmitting single-hop BFD control packets.

Use undo bfd min-transmit-interval to restore the default.

Syntax

bfd min-transmit-interval interval

undo bfd min-transmit-interval

Default

The minimum interval for transmitting single-hop BFD control packets is 400 milliseconds.

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting single-hop BFD control packets, in milliseconds. The value range is 100 to 1000.

Usage guidelines

Use this command to prevent the BFD packet sending rate from exceeding the device capability.

The actual BFD control packet transmitting interval on the local end is the greater value between the following values:

·     Minimum interval for transmitting BFD control packets on the local end.

·     Minimum interval for receiving BFD control packets on the peer end.

A static BFD session supports this command only when it is in IPv4 or IPv6 control packet mode used for single-hop detection.

Examples

# Set the minimum interval for transmitting single-hop BFD control packets to 500 milliseconds on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd min-transmit-interval 500

bfd multi-hop authentication-mode

Use bfd multi-hop authentication-mode to configure the authentication mode for multihop BFD control packets.

Use undo bfd multi-hop authentication-mode to restore the default.

Syntax

bfd multi-hop authentication-mode { hmac-md5 | hmac-mmd5 | hmac-msha1 | hmac-sha1 | m-md5 | m-sha1 | md5 | sha1 | simple } key-id { cipher | plain } string

undo bfd multi-hop authentication-mode

Default

No authentication is performed.

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

hmac-md5: Specifies the HMAC MD5 algorithm.

hmac-mmd5: Specifies the HMAC Meticulous MD5 algorithm.

hmac-msha1: Specifies the HMAC Meticulous SHA1 algorithm.

hmac-sha1: Specifies the HMAC SHA1 algorithm.

m-md5: Specifies the Meticulous MD5 algorithm.

m-sha1: Specifies the Meticulous SHA1 algorithm.

md5: Specifies the MD5 algorithm.

sha1: Specifies the SHA1 algorithm.

simple: Specifies the simple authentication mode.

key-id: Sets the authentication key ID in the range of 1 to 255.

cipher: Specifies a key in encrypted form.

plain: Specifies a key in plaintext form. For security purposes, the key specified in plaintext form will be stored in encrypted form.

string: Specifies the key. Its plaintext form is a case-sensitive string of 1 to 16 characters. Its encrypted form is a case-sensitive string of 33 to 53 characters.

Usage guidelines

Use this command to enhance BFD session security.

A static BFD session supports this command only when it is in IPv4 or IPv6 control packet mode used for multihop detection.

BFD version 0 does not support this command. The configuration does not take effect.

Examples

# Configure the simple authentication mode for multihop BFD control packets, setting the authentication key ID to 1 and key to 123456.

<Sysname> system-view

[Sysname] bfd multi-hop authentication-mode simple 1 plain 123456

Related commands

bfd static

bfd multi-hop destination-port

Use bfd multi-hop destination-port to configure the destination port number for multihop BFD control packets.

Use undo bfd multi-hop destination-port to restore the default.

Syntax

bfd multi-hop destination-port port-number

undo bfd multi-hop destination-port

Default

The destination port number for multihop BFD control packets is 4784.

Views

System view

Predefined user roles

network-admin

Parameters

port-number: Specifies the destination port number of multihop BFD control packets, 3784 or 4784.

Usage guidelines

IANA assigned port number 4784 to BFD for multihop BFD detection in control packet mode. By default, H3C devices use 4784 as the destination port number for multihop BFD control packets, while devices from other vendors might use 3784. To avoid BFD session establishment failures, make sure the devices on both ends of the BFD session use the same destination port number for multihop BFD control packets.

This command applies to only new multihop BFD sessions in control packet mode.

Examples

# Specify the destination port number for multihop BFD control packets as 3784.

<Sysname> system-view

[Sysname] bfd multi-hop destination-port 3784

bfd multi-hop detect-multiplier

Use bfd multi-hop detect-multiplier to set the multihop detection time multiplier for control packet mode and echo packet mode.

Use undo bfd multi-hop detect-multiplier to restore the default.

Syntax

bfd multi-hop detect-multiplier value

undo bfd multi-hop detect-multiplier

Default

The multihop detection time multiplier for control packet mode and echo packet mode is 5.

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

value: Specifies the multihop detection time multiplier in the range of 3 to 50.

Usage guidelines

The detection time multiplier determines the maximum number of concurrent BFD control packets that can be discarded.

Table 2 Actual detection interval calculation method

Mode	Actual detection interval of the sender
Control packet mode BFD session in asynchronous mode	Detection time multiplier of the receiver × MAX (minimum receiving interval supported by the sender, minimum sending interval supported by the receiver)
Control packet mode BFD session in demand mode	Detection time multiplier of the sender × MAX (minimum sending interval supported by the sender, minimum receiving interval supported by the receiver)

 

Only the following static BFD sessions support this command:

·     Static BFD sessions in IPv4 control packet mode used for multihop detection.

·     Static BFD sessions in IPv4 echo packet mode used for multihop detection.

·     Static BFD sessions in IPv6 control packet mode used for multihop detection.

·     Static BFD sessions in IPv6 echo packet mode used for multihop detection.

Examples

# Set the multihop detection time multiplier to 6.

<Sysname> system-view

[Sysname] bfd multi-hop detect-multiplier 6

Related commands

bfd static

bfd multi-hop min-receive-interval

Use bfd multi-hop min-receive-interval to set the minimum interval for receiving multihop BFD control packets.

Use undo bfd multi-hop min-receive-interval to restore the default.

Syntax

bfd multi-hop min-receive-interval interval

undo bfd multi-hop min-receive-interval

Default

The minimum interval for receiving multihop BFD control packets is 400 milliseconds.

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving multihop BFD control packets, in milliseconds. The value range is 100 to 1000.

Usage guidelines

Use this command to prevent the packet sending rate of the peer end from exceeding the packet receiving capability (minimum control packet receiving interval) of the local end. If the receiving capability is exceeded, the peer end dynamically adjusts the BFD control packet sending interval to the minimum control packet receiving interval of the local end.

A static BFD session supports this command only when it is in IPv4 or IPv6 control packet mode used for multihop detection.

Examples

# Set the minimum interval for receiving multihop BFD control packets to 500 milliseconds.

<Sysname> system-view

[Sysname] bfd multi-hop min-receive-interval 500

Related commands

bfd static

bfd multi-hop min-transmit-interval

Use bfd multi-hop min-transmit-interval to set the minimum interval for transmitting multihop BFD control packets.

Use undo bfd multi-hop min-transmit-interval to restore the default.

Syntax

bfd multi-hop min-transmit-interval interval

undo bfd multi-hop min-transmit-interval

Default

The minimum interval for transmitting multihop BFD control packets is 400 milliseconds.

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting multihop BFD control packets, in milliseconds. The value range is 100 to 1000.

Usage guidelines

Use this command to prevent the BFD packet sending rate from exceeding the device capability.

The actual BFD control packet transmitting interval on the local end is the greater value between the following values:

·     Minimum interval for transmitting BFD control packets on the local end.

·     Minimum interval for receiving BFD control packets on the peer end.

A static BFD session supports this command only when it is in IPv4 or IPv6 control packet mode used for multihop detection.

Examples

# Set the minimum interval for transmitting multihop BFD control packets to 500 milliseconds.

<Sysname> system-view

[Sysname] bfd multi-hop min-transmit-interval 500

Related commands

bfd static

bfd session init-mode

Use bfd session init-mode to configure the mode for establishing a BFD session.

Use undo bfd session init-mode to restore the default.

Syntax

bfd session init-mode { active | passive }

undo bfd session init-mode

Default

BFD uses the active mode.

Views

System view

Predefined user roles

network-admin

Parameters

active: Specifies the active mode. In active mode, BFD actively transmits BFD control packets to the remote device, regardless of whether it receives a BFD control packet from the remote device.

passive: Specifies the passive mode. In passive mode, BFD does not actively transmit a BFD control packet to the remote end; it transmits a BFD control packet only after receiving a BFD control packet from the remote end.

Usage guidelines

A minimum of one end must operate in active mode for a BFD session to be established.

BFD version 0 does not support this command. The configuration does not take effect.

Examples

# Configure the session establishment mode as passive.

<Sysname> system-view

[Sysname] bfd session init-mode passive

bfd static

Use bfd static to create a static BFD session and enter its view, or enter the view of an existing static BFD session.

Use undo bfd static to delete a static BFD session and all its settings.

Syntax

For IPv4 single-hop detection:

bfd static session-name [ peer-ip ipv4-address interface interface-type interface-number source-ip ipv4-address [ discriminator local local-value remote remote-value ] ]

For IPv6 single-hop detection:

bfd static session-name [ peer-ipv6 ipv6-address interface interface-type interface-number source-ipv6 ipv6-address[ discriminator local local-value remote remote-value ] ]

For IPv4 multihop detection:

bfd static session-name [ peer-ip ipv4-address [ vpn-instance vpn-instance-name ] source-ip ipv4-address [ discriminator local local-value remote remote-value ] [ track-interface interface-type interface-number ] ]

For IPv6 multihop detection:

bfd static session-name [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] source-ipv6 ipv6-address [ discriminator local local-value remote remote-value ] [ track-interface interface-type interface-number ] ]

undo bfd static session-name

Default

No static BFD sessions exist.

Views

System view

Predefined user roles

network-admin

Parameters

session-name: Specifies a static BFD session name, a case-sensitive string of 1 to 64 characters.

peer-ip ipv4-address: Specifies the peer IPv4 address in dotted decimal notation. It must be a valid unicast IPv4 address. The peer IPv4 address and the source IPv4 address determine the path to be detected.

peer-ipv6 ipv6-address: Specifies the peer IPv6 address. The peer IPv6 address and the source IPv6 address determine the path to be detected.

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. If you do not specify this option, the static BFD session belongs to the public network.

interface interface-type interface-number: Specifies an interface by its type and number. BFD uses the specified interface as the outgoing interface for outgoing packets.

source-ip ipv4-address: Specifies the source IPv4 address for control packets, in dotted decimal notation. It must be a valid unicast IPv4 address.

peer-ipv6 ipv6-address: Specifies the source IPv6 address for control packets.

discriminator: Specifies BFD session discriminators.

local local-value: Specifies the local discriminator in the range of 1 to 32768.

remote remote-value: Specifies the remote discriminator in the range of 1 to 4294967295.

track-interface interface-type interface-number: Specifies an interface monitored by the static BFD session. When the monitored interface fails, the static BFD session changes to the down state. If you do not specify an interface, the static BFD session does not monitor any interfaces.

Usage guidelines

A static BFD session can be used for single-hop detection and multihop detection. By working with Track, a static BFD session can provide fast failure detection. For more information about Track association with BFD, see Track in High Availability Configuration Guide.

The BFD session discriminators must match on the local and peer devices. For example, if you configure bfd static abc peer-ip 20.1.1.1 vpn-instance vpn1 source-ip 20.1.1.2 discriminator local 513 remote 514 on the local device, you must configure bfd static bcd peer-ip 20.1.1.2 vpn-instance vpn1 source-ip 20.1.1.1 discriminator local 514 remote 513 on the peer device.

When creating a static BFD session, you must specify a peer IP address. The system checks only the format of the IP address but not its correctness. If the peer IPv4 or IPv6 address is incorrect, the static BFD session cannot be established.

If you do not specify the local discriminator or remote discriminator when creating a static BFD session, you must perform either of the following tasks for the BFD session to take effect:

·     Use the discriminator command to specify the local discriminator and remote discriminator for the static BFD session.

·     Execute the undo bfd static command and then execute the bfd static command to re-create the static BFD session with the local and remote discriminators specified.

The bfd static session-name command without any parameters specified can only be used to enter the view of an existing static BFD session.

If you use a static BFD session in control packet mode to perform single-hop detection, make sure the following requirements are met for the BFD session to be successfully established:

·     The IP address of the peer interface where the static BFD session resides is used as the peer IP address.

·     The IP address of the local interface where the static BFD session resides is used as the source IP address.

To modify a static BFD session, delete the static BFD session and then configure a new static BFD session.

Different static BFD sessions cannot have the same local discriminator.

A static BFD session can monitor the following interfaces:

·     Layer 2 Ethernet interfaces.

·     Layer 3 Ethernet interfaces.

·     Layer 2 aggregate interfaces and their member ports.

·     Layer 3 aggregate interfaces and their member ports.

Examples

# Create a static BFD session and enter its view. The static BFD session detects the link with the outgoing interface VLAN-interface 10 and the next hop 1.1.1.2. The source IP address for the session is 1.1.1.1, the local discriminator is 1537, and the remote discriminator is 2048.

<Sysname> system-view

[Sysname] bfd static abc peer-ip 1.1.1.2 interface vlan-interface 10 source-ip 1.1.1.1 discriminator local 1537 remote 2048

[Sysname-bfd-static-session-abc]

Related commands

discriminator

track bfd

bfd template

Use bfd template to create a BFD template and enter its view, or enter the view of an existing BFD template.

Use undo bfd template to delete the BFD template.

Syntax

bfd template template-name

undo bfd template template-name

Default

No BFD templates exist.

Views

System view

Predefined user roles

network-admin

Parameters

template-name: Specifies the template name, a case-sensitive string of 1 to 63 characters.

Examples

# Create BFD template bfd1 and enter BFD template view.

<Sysname> system-view

[Sysname] bfd template bfd1

[Sysname-bfd-template-bfd1]

discriminator

Use discriminator to specify the local and remote discriminators for a static BFD session.

Use undo discriminator to remove the local and remote discriminator for the static BFD session.

Syntax

discriminator { local local-value | remote remote-value }

undo discriminator { local local-value | remote remote-value }

Default

No local and remote discriminators are specified for a static BFD session.

Views

Static BFD session view

Predefined user roles

network-admin

Parameters

local local-value: Specifies the local discriminator in the range of 1 to 32768.

remote remote-value: Specifies the remote discriminator in the range of 1 to 4294967295.

Usage guidelines

Use this command only if you do not specify the local or remote discriminator when creating a static BFD session.

To modify the local or remote discriminator of a static BFD session, execute the undo discriminator and then the discriminator command to specify a new local or remote discriminator.

Different static BFD sessions cannot have the same local discriminator.

Examples

# Create local discriminator 1537 and remote discriminator 2048 for static BFD session abc.

<Sysname> system-view

[Sysname] bfd static abc

[Sysname-bfd-static-session-abc] discriminator local 1537

[Sysname-bfd-static-session-abc] discriminator remote 2048

Related commands

bfd static

display bfd session

Use display bfd session to display BFD session information.

Syntax

display bfd session [ discriminator local local-value | static session-name | verbose ]

display bfd session [ [ dynamic ] [ control | echo ] [ ip ] [ state { down | admin-down | init | up } ] [ discriminator remote remote-value ] [ peer-ip ipv4-address [ vpn-instance vpn-instance-name ] ] [ verbose ] ]

display bfd session [ [ dynamic ] [ control | echo ] [ ipv6 ] [ state { down | admin-down | init | up } ] [ discriminator remote remote-value ] [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] ] [ verbose ] ]

display bfd session [ [ static ] [ ip ] [ state { down | admin-down | init | up } ] [ discriminator remote remote-value ] [ peer-ip ipv4-address [ vpn-instance vpn-instance-name ] ] [ verbose ]

display bfd session [ [ static ] [ ipv6 ] [ state { down | admin-down | init | up } ] [ discriminator remote remote-value ] [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] ] [ verbose ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

discriminator local local-value: Specifies a BFD session by its local discriminator in the range of 1 to 4294967295.

static session-name: Specifies a static BFD session by its name, a case-sensitive string of 1 to 64 characters.

dynamic: Specifies dynamic BFD sessions.

static: Specifies static BFD sessions.

control: Specifies BFD sessions in control packet mode.

echo: Specifies BFD sessions in echo mode.

ip: Specifies BFD sessions used to detect IPv4 links.

ipv6: Specifies BFD sessions used to detect IPv6 links.

state: Displays BFD sessions by session state.

down: Specifies BFD sessions in Down state.

admin-down: Specifies BFD sessions in AdminDown state.

init: Specifies BFD sessions in Init state.

up: Specifies BFD sessions in Up state.

discriminator remote remote-value: Specifies a BFD session by its remote discriminator in the range of 1 to 4294967295.

peer-ip ipv4-address: Specifies a BFD session by the peer IPv4 address in dotted decimal notation.

peer-ipv6 ipv6-address: Specifies a BFD session by the peer IPv6 address.

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. If you do not specify this option, the command displays the BFD sessions of the public network.

verbose: Displays detailed BFD session information.

Usage guidelines

If you do not specify the dynamic or static keyword, this command displays all dynamic and static BFD sessions.

Examples

# Display brief information about all BFD sessions.

<Sysname> display bfd session

 Total sessions: 4        Up sessions: 4        Init mode: Active

 

 IPv4 session working in control packet mode:

 

 LD/RD            SourceAddr      DestAddr        State  Holdtime    Interface

 513/513          1.1.1.1         1.1.1.2         Up     2297ms      Vlan100

 

 IPv6 session working in control packet mode:

 

       Local discr: 513                  Remote discr: 513

         Source IP: FE80::20C:29FF:FED4:7171

    Destination IP: FE80::20C:29FF:FE72:AC4D

     Session state: Up                      Interface: Vlan100

         Hold time: 2142ms

 

 IPv4 static session working in control packet mode:

 

 LD/RD            SourceAddr      DestAddr        State  Holdtime    Interface

 1600/1600        1.1.1.1         1.1.1.2         Up     2290ms      Vlan100

 

 IPv6 static session working in control packet mode:

 

       Local discr: 1700                  Remote discr: 1700

         Source IP: FE80::20C:29FF:FED4:7171

    Destination IP: FE80::20C:29FF:FE72:AC4D

     Session state: Up                      Interface: Vlan100

         Hold time: 2142ms

Table 3 Command output

Field	Description
Total Session Num	Total number of BFD sessions.
Up Session Num	Total number of active BFD sessions.
Init Mode	BFD operating mode: Active or passive.
XX session working in yy mode	BFD session type and operating mode: ·     IPv4 session working in control packet mode. ·     IPv4 session working in echo mode. ·     IPv6 session working in control packet mode. ·     IPv6 session working in echo mode. ·     IPv4 static session working in control packet mode. ·     IPv6 static session working in control packet mode.
LD/RD	Local discriminator/Remote discriminator of the session.
SourceAddr	Source IP address of the session.
DestAddr	Destination IP address of the session.
Session State/State	Session state: Down, Init, or Up.
Interface	Name of the interface of the session.
Hold Time/Holdtime	Length of time before the session detection timer expires, in milliseconds. For a BFD session in Down state, this field displays 0ms.
Local discr	Local discriminator of the session.
Remote discr	Remote discriminator of the session.
Source IP	Source IPv6 address of the session.
Destination IP	Destination IPv6 address of the session.

 

# Display detailed BFD session information.

<Sysname> display bfd session verbose

 Total sessions: 4        Up sessions: 4        Init mode: Active

 

 IPv4 session working in control packet mode:

 

          Local discr: 513                        Remote discr: 513

            Source IP: 1.1.1.1                  Destination IP: 1.1.1.2

     Destination port: 3784                      Session state: Up

            Interface: Vlan-interface100

      Min Tx interval: 500ms                Actual Tx interval: 500ms

      Min Rx interval: 500ms                    Detection time: 2500ms

             Rx count: 42                             Tx count: 43

      Connection type: Direct                      Up duration: 00:00:20

            Hold time: 2078ms                        Auth mode: None

          Detect mode: Async                              Slot: 0

             Protocol: OSPF

              Version:1

            Diag info: No Diagnostic

    Tracked interface: Vlan-interface100

 

 IPv6 session working in control packet mode:

          Local discr: 513                        Remote discr: 513

            Source IP: FE80::20C:29FF:FED4:7171

       Destination IP: FE80::20C:29FF:FE72:AC4D

     Destination port: 3784                      Session state: Up

            Interface: Vlan-interface100

      Min Tx interval: 500ms                Actual Tx interval: 500ms

      Min Rx interval: 500ms                    Detection time: 2500ms

             Rx count: 38                             Tx count: 38

      Connection type: Direct                      Up duration: 00:00:15

            Hold time: 2211ms                        Auth mode: None

       Detection mode: Async                              Slot: 0

             Protocol: OSPFv3

              Version: 1

            Diag info: No Diagnostic

 

 IPv4 static session working in control packet mode:

      Session name: aaaa

          Local discr: 1600                       Remote discr: 1600

            Source IP: 1.1.1.1                  Destination IP: 1.1.1.2

     Destination port: 3784                      Session state: Up

            Interface: Vlan-interface100

      Min Tx interval: 500ms                Actual Tx interval: 500ms

      Min Rx interval: 500ms                    Detection time: 2500ms

             Rx count: 42                             Tx count: 43

      Connection type: Direct                      Up duration: 00:00:20

            Hold time: 2078ms                        Auth mode: None

       Detection mode: Async                              Slot: 0

             Protocol: STATIC_IPv4

              Version: 1

            Diag info: No Diagnostic

 

 IPv6 static session working in control packet mode:

      Session name: bbbb

          Local discr: 1700                       Remote discr: 1700

            Source IP: FE80::20C:29FF:FED4:7171

       Destination IP: FE80::20C:29FF:FE72:AC4D

     Destination port: 3784                      Session state: Up

            Interface: Vlan-interface100

      Min Tx interval: 500ms                Actual Tx interval: 500ms

      Min Rx interval: 500ms                    Detection time: 2500ms

             Rx count: 38                             Tx count: 38

      Connection type: Direct                      Up duration: 00:00:15

            Hold time: 2211ms                        Auth mode: None

       Detection mode: Async                              Slot: 0

             Protocol: STATIC_IPv6

              Version: 1

            Diag info: No Diagnostic

Table 4 Command output

Field	Description
Total sessions	Total number of BFD sessions.
Up sessions	Total number of active BFD sessions.
Init mode	BFD operating mode: Active or passive.
XX session working in yy mode	BFD session type and operating mode: ·     IPv4 session working in control packet mode. ·     IPv4 session working in echo mode. ·     IPv6 session working in control packet mode. ·     IPv6 session working in echo mode. ·     IPv4 static session working in control packet mode. ·     IPv6 static session working in control packet mode.
Local discr	Local discriminator of the session.
Remote discr	Remote discriminator of the session.
Source IP	Source IP address of the session.
Destination IP	Destination IP address of the session.
Destination port	Destination port number in BFD packets defined in Comware: ·     The destination port number in single-hop BFD control packets is 3784. ·     The destination port number in single-hop or multihop BFD echo packets is 3785. ·     The destination port number in multihop BFD control packets is 4784. ·     The destination port number in BFD control packets for association between link aggregation and BFD is 6784. The device uses the destination port number in incoming packets that are not defined in Comware as the destination port number in outgoing BFD packets.
Session state	Session state: Down, AdmDown, Init, or Up.
Interface	Name of the interface of the session.
Min Tx interval	Minimum transmit interval.
Min Rx interval	Minimum receive interval.
Actual Tx interval	Actual transmit interval.
Detection time	Actual session detection timer.
Rx count	Number of packets received.
Tx count	Number of packets sent.
Hold time	Length of time before session detection timer expires. For a BFD session in down state, this field displays 0ms.
Auth mode	Session authentication mode.
Connection type	Connection type of the interface: Direct or Indirect.
Up duration	Time period for which the session has been up.
Detect mode	Detection mode: ·     Async—Asynchronous mode. ·     Demand—Demand mode. ·     Async/Echo—Asynchronous mode with echo detection enabled. ·     Demand/Echo—Demand mode with echo detection enabled.
Slot	Slot number of the card where the BFD session resides.
Protocol	Protocol associated with BFD: ·     OSPF. ·     ISIS_BR_L1—IS-IS with the network type as broadcast and the router type as Level 1. ·     ISIS_BR_L2—IS-IS with the network type as broadcast and the router type as Level 2. ·     ISIS_P2P—IS-IS with the network type as P2P. ·     ISIS6_BR_L1—IPv6 IS-IS with the network type as broadcast and the router type as Level 1. ·     ISIS6_BR_L2—IPv6 IS-IS with the network type as broadcast and the router type as Level 2. ·     ISIS6_P2P—IPv6 IS-IS with the network type as P2P. ·     BGP. ·     STATIC4—IPv4 static routing. ·     TRACK—Track. ·     RIP. ·     IPFRR—FIB IP FRR. ·     MAD. ·     OSPFv3. ·     BGP4+. ·     PIM. ·     PIM6—IPv6 PIM. ·     STATIC6—IPv6 static routing. ·     RIPNG—RIPng. ·     Interface—Interface state. ·     TUNNEL. ·     LAGG—Link aggregation. ·     STATIC_IPv4—IPv4 static BFD session. ·     STATIC_IPv6—IPv6 static BFD session.
Diag info	Diagnostic information about the session: ·     No Diagnostic. ·     Control Detection Time Expired—A control-mode BFD session goes down because local detection times out. ·     Echo Function Failed—An echo-mode BFD session goes down, because local detection times out or the source IP address of echo packets is deleted. ·     Neighbor Signaled Session Down—The remote end notifies the local end of BFD session down. ·     Administratively Down—The local system prevents a BFD session from being established.
Tracked interface	Interface monitored by the static BFD session.

‌

Related commands

bfd static

reset bfd session statistics

Use reset bfd session statistics to clear the BFD session statistics.

Syntax

reset bfd session statistics

Views

User view

Predefined user roles

network-admin

Examples

# Clear the BFD session statistics.

<Sysname> reset bfd session statistics

snmp-agent trap enable bfd

Use snmp-agent trap enable bfd to enable SNMP notifications for BFD.

Use undo snmp-agent trap enable bfd to disable SNMP notifications for BFD.

Syntax

snmp-agent trap enable bfd

undo snmp-agent trap enable bfd

Default

All SNMP notifications are enabled for BFD.

Views

System view

Predefined user roles

network-admin

Usage guidelines

To report critical BFD events to an NMS, enable SNMP notifications for BFD. For BFD event notifications to be sent correctly, you must also configure SNMP as described in the network management and monitoring configuration guide for the device.

Examples

# Disable SNMP notifications for BFD.

<Sysname> system-view

[Sysname] undo snmp-agent trap enable bfd