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.

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

Examples

# Configure GigabitEthernet 1/0 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 gigabitethernet 1/0

[Sysname-GigabitEthernet1/0] bfd authentication-mode simple 1 plain 123456

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. As a best practice, configure the bfd echo enable command together with this command to detect connectivity by sending Echo packets. If the device does not receive any Echo packets from the peer end, it considers the session down.

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 GigabitEthernet 1/0.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0

[Sysname-GigabitEthernet1/0] bfd demand enable

Related commands

bfd echo enable

bfd detect-interface source-ip

Use bfd detect-interface source-ip to associate the interface state with BFD and specify the source IP address for BFD control packets.

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 ]

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, in dotted decimal notation.

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.

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.

You can associate the state of a Layer 3 Ethernet interface or VLAN interface with BFD.

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.

To modify your configuration, remove it by using the undo form of the command and then execute the bfd detect-interface source-ip command again.

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

Examples

# Associate GigabitEthernet 1/0 with BFD to detect the interface state, and specify the source IP address as 20.1.1.1.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0

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

Related commands

bfd demand enable

bfd echo enable

bfd template

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 is 3 for control packet mode and echo packet mode.

Views

Interface view

BFD template view

Predefined user roles

network-admin

Parameters

value: Specifies a detection time multiplier. The value range for this argument is 3 to 200.

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)

Examples

# Set the single-hop detection time multiplier for control packet mode and echo packet mode to 6 on GigabitEthernet 1/0.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0

[Sysname-GigabitEthernet1/0] 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

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.

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

Examples

# Enable the echo function on GigabitEthernet 1/0.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0

[Sysname-GigabitEthernet1/0] 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

As a best practice, configure this command on the source end of an echo-packet-mode BFD session. In addition, make sure the source IP address is not in the same network segment as any interfaces on the device. This avoids the following situations:

· A large number of ICMP redirect packets might be sent from the peer, resulting in link congestion.

· With malformed packet attack detection and prevention enabled, the local end might filter echo packets sent from the peer as malformed packets, resulting in BFD session establishment failure. For more information about malformed packet attack detection and prevention, see attack detection and prevention in Security Configuration Guide.

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.

As a best practice, configure this command on the source end of an echo-packet-mode BFD session. In addition, make sure the source IPv6 address is not in the same network segment as any interfaces on the device. This avoids the following situations:

· A large number of ICMPv6 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 ignore-receive-interface

Use bfd ignore-receive-interface to ignore the echo response receiving interface.

Use undo bfd ignore-receive-interface to restore the default.

Syntax

bfd ignore-receive-interface

undo bfd ignore-receive-interface

Default

The device checks the echo response receiving interface. If it is consistent with the echo packet sending interface, the device receives the echo response packet. If it is different from the echo packet sending interface, the device discards the echo response packet.

Views

Static BFD session view

Predefined user roles

network-admin

Usage guidelines

Application scenarios

As a best practice, configure this command when multiple paths are available for a static BFD session in echo packet mode between directly connected devices. This can avoid BFD session failure when the echo response receiving interface is different from the echo packet sending interface.

Operating mechanism

This command takes effect only on BFD sessions that are not in up state.

· After you configure the bfd ignore-receive-interface command, the device checks the BFD session state. Only when the BFD session is not in up state, the device ignores the receiving interface for echo responses.

· After you configure the bfd ignore-receive-interface command, the BFD session might come up. At this time, if you execute the undo bfd ignore-receive-interface command, the BFD session with inconsistent echo response receiving and sending interfaces does not go down. BFD checks the echo response receiving interface only when the BFD session goes down due to other reasons and attempts to come up again.

Restrictions and guidelines

A static BFD session supports this command only when it is in IPv4 or IPv6 echo packet mode.

Examples

# Create static BFD session aaa in echo packet mode, and disable checking the echo response receiving interface.

<Sysname> system-view

[Sysname] bfd static aaa peer-ip 192.168.12.2 interface gigabitethernet 1/0 destination-ip 192.168.12.1 source-ip 1.1.1.1 one-arm-echo discriminator auto

[Sysname-bfd-static-session-aaa] bfd ignore-receive-interface

Related commands

bfd static

bfd init-fail timer

Use bfd init-fail-timer to set the delay timer for BFD to notify upper-layer protocols of session establishment failures.

Use undo bfd init-fail-timer to restore the default.

Syntax

bfd init-fail-timer seconds

undo bfd init-fail-timer

Default

BFD does not notify upper-layer protocols of session establishment failures.

Views

System view

Predefined user roles

network-admin

Parameters

seconds: Specifies the delay time in the range of 5 to 600 seconds. After the delay time, BFD notifies the upper-layer protocol of session establishment failures.

Usage guidelines

CAUTION:

For session establishment failures caused by configuration mismatches at the two ends, this command can cause the upper-layer protocol to act incorrectly. Therefore, use this command with caution. BFD status mismatch and BFD authentication configuration mismatch are examples of configuration mismatches.

This command takes effect only for control packet mode.

In some cases, for an upper-layer protocol to act correctly, BFD must notify the upper-layer protocol of session establishment failures. For example, with this command configured, the link aggregation module can promptly set the state of a member port from Selected to Unselected in the case of a link failure.

Examples

# Set the delay timer to 10 seconds for BFD to notify upper-layer protocols of session establishment failures.

<Sysname> system-view

[Sysname] bfd init-fail-timer 10

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 500 milliseconds.

Views

Interface view

BFD template 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 10 to 2000.

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 function is enabled on the local end.

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

Examples

# Set the minimum interval for receiving BFD echo packets to 500 milliseconds on GigabitEthernet 1/0.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0

[Sysname-GigabitEthernet1/0] 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 500 milliseconds.

Views

Interface view

BFD template view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving single-hop BFD control packets, in milliseconds. The value range for this argument is 10 to 2000.

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.

Examples

# Set the minimum interval for receiving single-hop BFD control packets to 500 milliseconds on GigabitEthernet 1/0.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0

[Sysname-GigabitEthernet1/0] 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 500 milliseconds.

Views

Interface view

BFD template view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting single-hop BFD control packets, in milliseconds. The value range for this argument is 10 to 2000.

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.

Examples

# Set the minimum interval for transmitting single-hop BFD control packets to 500 milliseconds on GigabitEthernet 1/0.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0

[Sysname-GigabitEthernet1/0] 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{ 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

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.

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

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

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

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 is 3 for control packet mode and echo packet mode.

Views

System 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
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 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

bfd multi-hop min-echo-receive-interval

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

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

Syntax

bfd multi-hop min-echo-receive-interval interval

undo bfd multi-hop min-echo-receive-interval

Default

The minimum interval for receiving multihop BFD echo packets is 500 milliseconds.

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving multihop BFD echo packets, in milliseconds. The value takes 0 or is in the range of 10 to 2000.

Usage guidelines

The interval for receiving multihop BFD echo packets is also the interval for sending multihop BFD echo packets. By executing this command, you can control both the receiving interval and sending interval for multihop BFD echo packets.

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.

This command takes effect only on static BFD sessions for multihop detection with echo packets.

Examples

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

<Sysname> system-view

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

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 500 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 millis econds. The value range for this argument is 10 to 2000.

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 echo 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

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 500 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 for this argument is 10 to 2000.

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

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 session-negotiation delay-upon-down

Use bfd session-negotiation delay-upon-down to enable session negotiation delay for down BFD sessions and set a delay timer.

Use undo bfd session-negotiation delay-upon-down to restore the default.

Syntax

bfd session-negotiation delay-upon-down interval

undo bfd session-negotiation delay-upon-down

Default

Session negotiation delay is disabled for down BFD sessions.

Views

System view

Predefined user roles

network-admin

Parameters

interval: Specifies a delay timer in the range of 1 to 1200 seconds.

Usage guidelines

If an upper-layer protocol uses BFD to detect the active path, an active/standby path switchover is triggered after the active path goes down. If the BFD session comes up before the active path recovers, the traffic on the standby path will be switched over to the active path. In this case, traffic loss will occur.

The session negotiation delay function starts a delay timer for each BFD session from up to down state and each newly created session. Before the timer expires, the device does not perform session negotiation on each BFD session. The delay timer allows the active path to recover completely before the BFD session comes up again.

Examples

# Enable session negotiation delay for down BFD sessions and set the delay timer to 6 seconds.

<Sysname> system-view

[Sysname] bfd session-negotiation delay-upon-down 6

Related commands

display bfd session

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]

display bfd session

Use display bfd session to display BFD session information.

Syntax

display bfd session [ discriminator local local-value | 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.

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

verbose: Displays detailed BFD session information.

Examples

# Display brief information about all BFD sessions.

<Sysname> display bfd session

Total sessions: 9 Up sessions: 9 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 GE1/0

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: GE1/0

Hold time: 2142ms

IPv4 static session working in echo mode:

LD SourceAddr DestAddr State Holdtime Interface

1226 192.168.51.1 192.168.51.5 Up 4238ms GE1/0

IPv6 static session working in echo mode:

Local discr: 2012

Source IP: 15::1

Destination IP: 15::5

Session state: Up Interface: GE1/0

Hold time: 4626ms

MPLS LSP session working in control packet mode:

LD/RD SourceAddr DestAddr State Holdtime Interface

32769/32769 2.2.2.9 127.0.0.1 Up 4990ms N/A

MPLS TE session working in echo mode:

LD SourceAddr DestAddr State Holdtime Interface

32777 1.1.1.1 3.3.3.3 Up 4430ms Tun0

MPLS PW session working in control packet mode:

LD/RD SourceAddr DestAddr State Holdtime Interface

20481/20481 2.2.2.2 127.0.0.1 Up 2489ms N/A

Table 3 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 echo mode. · IPv6 static session working in echo mode. · MPLS LSP session working in control packet mode—BFD session in control mode used to detect failures in an LSP. · MPLS LSP session working in echo mode—BFD session in echo mode used to detect failures in an LSP. · MPLS TE session working in control packet mode. · MPLS TE session working in echo mode. · MPLS PW session working in control packet mode. · IPv4 SDWAN session working in control packet mode. · IPv6 SDWAN session working in control packet mode.
LD/RD	Local discriminator/Remote discriminator of the session.
SourceAddr	Source IPv4 address of the session.
DestAddr	Destination IPv4 address of the session.
State	Session state: Down, Init, Adown, or Up.
Holdtime	Length of time before session detection timer expires. For a BFD session in Down state, this field displays 0ms.
Interface	Name of the interface of the session.
Local discr	Local discriminator of the session.
Remote discr	Remote discriminator of the session.
Session state	Session state: Down, Adown, Init, or Up.
Hold time	Length of time before session detection timer expires. For a BFD session in Down state, this field displays 0ms.

‌

# Display detailed information about all BFD sessions.

<Sysname> display bfd session verbose

Total sessions: 9 Up sessions: 9 Init mode: Active

IPv4 session working in control packet mode:

Local discr: 33793 Remote discr: 33793

Source IP: 23.1.1.2 Destination IP: 23.1.1.3

Destination port: 3784 Session state: Up

Interface: GigabitEthernet1/0

Min Tx interval: 1000ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 133 Tx count: 142

Connection type: Direct Up duration: 00:02:01

Hold time: 4571ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: OSPF

Version: 1

Diag info: No Diagnostic

IPv6 session working in control packet mode:

Local discr: 33794 Remote discr: 33794

Source IP: FE80::5457:A5FF:FE0F:306

Destination IP: FE80::5457:A1FF:FEB5:206

Destination port: 3784 Session state: Up

Interface: GigabitEthernet1/0

Min Tx interval: 1000ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 3262 Tx count: 3048

Connection type: Direct Up duration: 00:44:26

Hold time: 4409ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: OSPFv3

Version: 1

Diag info: No Diagnostic

IPv4 static session working in echo mode:

Session name: aa

Local discr: 1226

Source IP: 192.168.51.1 Destination IP: 192.168.51.5

Destination port: 3785 Session state: Up

Interface: GigabitEthernet1/0

Hold time: 4965ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 308 Tx count: 308

Connection type: Direct Up duration: 00:04:28

Detection mode: Async Slot: 0

Protocol: STATIC_IPv4

Version: 1

Diag info: No Diagnostic

IPv6 static session working in echo mode:

Session name: bb

Local discr: 2012

Source IP: 15::1 Destination IP: 15::5

Destination port: 3785 Session state: Up

Interface: GigabitEthernet1/0

Hold time: 4426ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 193 Tx count: 193

Connection type: Direct Up duration: 00:02:46

Detection mode: Async Slot: 0

Protocol: STATIC_IPv6

Version: 1

Diag info: No Diagnostic

MPLS LSP session working in control packet mode:

Local discr: 32769 Remote discr: 32769

Source IP: 3.3.3.9 Destination IP: 2.2.2.9

Destination port: 4784 Session state: Up

Interface: N/A

Min Tx interval: 1000ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 1778 Tx count: 1669

Connection type: Indirect Up duration: 00:24:14

Hold time: 4248ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1

Diag info: No Diagnostic

MPLS TE session working in echo mode:

Local discr: 32777

Source IP: 1.1.1.1 Destination IP: 3.3.3.3

Destination port: 3785 Session state: Up

Interface: Tunnel0

Hold time: 4450ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 320 Tx count: 320

Connection type: Indirect Up duration: 00:04:35

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1

Diag info: No Diagnostic

MPLS PW session working in control packet mode:

Local discr: 20481 Remote discr: 20481

Source IP: 2.2.2.2 Destination IP: 127.0.0.1

Destination port: 3784 Session state: Up

Interface: N/A

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

Min Rx interval: 500ms Detection time: 2500ms

Rx count: 72 Tx count: 73

Connection type: Indirect Up duration: 00:00:30

Hold time: 2489ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

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 echo mode. · IPv6 static session working in echo mode. · MPLS LSP session working in control packet mode—BFD session in control mode used to detect failures in an LSP. · MPLS LSP session working in echo mode—BFD session in echo mode used to detect failures in an LSP. · MPLS TE session working in control packet mode. · MPLS TE session working in echo mode. · MPLS PW session working in control packet mode. · IPv4 SDWAN session working in control packet mode. · IPv6 SDWAN session working in control packet mode.
Local discr	Local ID of the session.
Remote discr	Remote ID of the session.
Source IP	Source IP address of the session.
Destination IP	Destination IP address of the session.
Session state	Session state: Down, 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. If BFD session negotiation delay is configured, this field displays a hyphen (-) before the delay timer expires.
Detection time	Actual session detection timer.
Rx count	Number of packets received.
Tx count	Number of packets sent.
Connection type	Connection type of the interface: Direct or indirect.
Up duration	Time period for which the session has been up.
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: · None. · Simple. · MD5. · MMD5—Meticulous MD5. · SHA1. · MSHA1—Meticulous SHA1. · HMAC-MD5. · HMAC-MMD5—HMAC Meticulous MD5. · HMAC-SHA1. · HMAC-MSHA1—HMAC Meticulous SHA1. Changing the authentication mode for a session triggers an smooth authentication transition. During this process, BFD will send packets with both the old and new authentication modes to keep the BFD session in up state. During the transition, the value for this field is displayed in the format of Old_Authentication_Mode(New_Authentication_Mode), for example: Simple(MD5).
Connect type	Connection type of the interface: Direct or indirect.
Up duration	Time period for which the session has been up.
Detection mode	Detection mode: · Async—Asynchronous mode. · Demand—Demand mode. · Async/Echo—Asynchronous mode with echo function enabled. · Demand/Echo—Demand mode with echo function enabled.
Slot	(In standalone mode.) Slot number of the device. (In IRF mode.) Slot number of the card where the BFD session resides.
Remaining delay time	Remaining time of the delay timer, in seconds. If BFD session negotiation delay is not configured or the delay timer has expired, this field is not displayed.
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. · MPLS_RSVP. · STATIC4—IPv4 static routing. · TRACK—Track. · RIP. · IPFRR—FIB IP FRR. · MAD. · MPLS_LSPV. · OSPFv3. · BGP4+. · PIM. · PIM6—IPv6 PIM. · STATIC6—IPv6 static routing. · RIPNG—RIPng. · Interface—Interface state. · TUNNEL. · VTEP—BFD session used to detect VTEPs. · LAGG—Link aggregation.
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.

‌

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

SBFD commands

bfd detect-multiplier

Use bfd detect-multiplier to set the detection time multiplier in BFD template view.

Use undo bfd detect-multiplier to restore the default.

Syntax

bfd detect-multiplier value

undo bfd detect-multiplier

Default

The SBFD detection time multiplier is 3.

Views

BFD template view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

The detection time multiplier determines the maximum number of SBFD control packets that an initiator can discard continuously.

The detection time is the detection time multiplier of the initiator multiplied by the minimum SBFD packet sending interval of the initiator.

Examples

# In BFD template abc, set the detection time multiplier to 6.

<Sysname> system-view

[Sysname] bfd template abc

[Sysname-bfd-template-abc] bfd detect-multiplier 6

Related commands

bfd min-transmit-interval

Use bfd min-transmit-interval to set the minimum interval for transmitting SBFD control packets in BFD template view.

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 SBFD control packets in BFD template view is 500 milliseconds.

Views

BFD template view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting SBFD control packets, in milliseconds. The value range for this argument is 10 to 2000.

Usage guidelines

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

The actual SBFD control packet transmitting interval is the set minimum interval.

Examples

# In BFD template abc, set the minimum interval for transmitting SBFD control packets to 500 milliseconds.

<Sysname> system-view

[Sysname] bfd template abc

[Sysname-bfd-template-abc] bfd min-transmit-interval 500

Related commands

bfd detect-multiplier

bfd multi-hop detect-multiplier

Use bfd multi-hop detect-multiplier to set the detection time multiplier in system view.

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 SBFD detection time multiplier is 3.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

The detection time multiplier determines the maximum number of SBFD control packets that an initiator can discard continuously.

The detection time is the detection time multiplier of the initiator multiplied by the minimum SBFD packet sending interval of the initiator.

Examples

# Set the detection time multiplier to 6.

<Sysname> system-view

[Sysname] bfd multi-hop detect-multiplier 6

bfd multi-hop min-transmit-interval

Use bfd multi-hop min-transmit-interval to set the minimum interval for transmitting SBFD control packets in system view.

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 SBFD control packets in system view is 500 milliseconds.

Views

System view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting SBFD control packets, in milliseconds. The value range for this argument is 10 to 2000.

Usage guidelines

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

The actual SBFD control packet transmitting interval is the set minimum interval.

Examples

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

<Sysname> system-view

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

bfd session-negotiation delay-upon-down

Use bfd session-negotiation delay-upon-down to enable session negotiation delay for down SBFD sessions and set a delay timer.

Use undo bfd session-negotiation delay-upon-down to restore the default.

Syntax

bfd session-negotiation delay-upon-down interval

undo bfd session-negotiation delay-upon-down

Default

Session negotiation delay is disabled for down SBFD sessions.

Views

System view

Predefined user roles

network-admin

Parameters

interval: Specifies a delay timer in the range of 1 to 1200 seconds.

Usage guidelines

If an upper-layer protocol uses SBFD to detect the active path, an active/standby path switchover is triggered after the active path goes down. If the SBFD session comes up before the active path recovers, the traffic on the standby path will be switched over to the active path. In this case, traffic loss will occur.

The session negotiation delay function starts a delay timer for each SBFD session from up to down state and each newly created session. Before the timer expires, the device does not perform session negotiation on each SBFD session. The delay timer allows the active path to recover completely before the SBFD session comes up again.

Examples

# Enable session negotiation delay for down SBFD sessions and set the delay timer to 6 seconds.

<Sysname> system-view

[Sysname] bfd session-negotiation delay-upon-down 6

Related commands

display sbfd session

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]

display sbfd session

Use display sbfd session to display SBFD session information.

Syntax

display sbfd session { initiator | reflector } [ discriminator value | verbose ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

initiator: Displays SBFD session information for the initiator.

reflector: Displays SBFD session information for the reflector.

discriminator value: Specifies a local discriminator in the range of 1 to 4294967295.

verbose: Displays detailed information about all SBFD sessions.

Usage guidelines

If you do not specify the discriminator or verbose keyword, this command displays brief information about all SBFD sessions.

Examples

# Display brief information about all SBFD sessions for the initiator.

<Sysname> display sbfd session initiator

Total sessions: 1 Up sessions: 1

SBFD session (SRV6 PLY):

Local discr: 33794 Remote discr: 16777001

Source IP: 1::1

Destination IP: 4::4

Session state: Up

Hold time: 2235ms

Table 5 Command output

Field	Description
Total sessions	Total number of SBFD sessions.
Up sessions	Number of active SBFD sessions.
SBFD session (SRV6 PLY)	SBFD sessions created for an SRv6-TE policy.
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.
Session state	Session state: Down or Up.
Hold time	Length of time before the session detection timer expires, in milliseconds. For an SBFD session in Down state, this field displays 0ms.

# Display detailed information about the SBFD session with local discriminator 33794 for the initiator.

<Sysname> display sbfd session initiator discriminator 33794

Local discr: 33794 Remote discr: 16777001

Source IP: 1::1 Destination IP: 4::4

Session state: Up Hold time: 2061ms

Color: 20 NID: 2149580802

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

Detection time: 2500ms Up duration: 00:15:36

Rx count: 2137 Tx count: 2142

Slot: 2

Protocol: SRV6PLY

Diag info: No Diagnostic

Template name: 2

Table 6 Command output

Field	Description
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.
Session state	Session state: Down or Up.
Hold time	Length of time before the session detection timer expires, in milliseconds. For an SBFD session in Down state, this field displays 0ms.
Color	Color attribute of the SRv6-TE policy.
NID	NHLFE entry index for an SID list.
Min Tx interval	Minimum SBFD packet transmission interval in milliseconds.
Actual Tx interval	Actual SBFD packet transmission interval in milliseconds. If SBFD session negotiation delay is configured, this field displays a hyphen (-) before the delay timer expires.
Detection time	Actual session detection timer in milliseconds.
Up duration	Time period for which the session has been up.
Rx count	Number of packets received.
Tx count	Number of packets sent.
Slot	(In standalone mode.) Slot number of the device. (In IRF mode.) Slot number of the card where the BFD session resides.
Remaining delay time	Remaining time of the delay timer, in seconds. If SBFD session negotiation delay is not configured or the delay timer has expired, this field is not displayed.
Diag info	Diagnostic information about the session: · No Diagnostic. · Control Detection Time Expired—The SBFD session goes down because local detection times out. · Neighbor Signaled Session Down—The remote end notifies the local end of SBFD session down.
Template name	Template associated with the session. If no template is associated, this field is not displayed.

# Display detailed information about all SBFD sessions for the initiator.

<Sysname> display sbfd session initiator verbose

Total sessions: 1 Up sessions: 1

SBFD session (SRV6 PLY):

Local discr: 33794 Remote discr: 16777001

Source IP: 1::1 Destination IP: 4::4

Session state: Up Hold time: 2061ms

Color: 20 NID: 2149580802

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

Detection time: 2500ms Up duration: 00:15:36

Rx count: 2137 Tx count: 2142

Slot: 2

Protocol: SRV6PLY

Diag info: No Diagnostic

Template name: 2

Table 7 Command output

Field	Description
Total sessions	Total number of SBFD sessions.
Up sessions	Number of active SBFD sessions.
SBFD session (SRV6 PLY)	SBFD sessions created for an SRv6-TE policy.
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.
Session state	Session state: Down or Up.
Hold time	Length of time before the session detection timer expires, in milliseconds. For an SBFD session in Down state, this field displays 0ms.
Color	Color attribute of the SRv6-TE policy.
NID	NHLFE entry index for an SID list.
Min Tx interval	Minimum SBFD packet transmission interval.
Actual Tx interval	Actual SBFD packet transmission interval in milliseconds. If SBFD session negotiation delay is configured, this field displays a hyphen (-) before the delay timer expires.
Detection time	Actual session detection timer.
Up duration	Time period for which the session has been up.
Rx count	Number of packets received.
Tx count	Number of packets sent.
Slot	(In standalone mode.) Slot number of the device. (In IRF mode.) Slot number of the card where the BFD session resides.
Remaining delay time	Remaining time of the delay timer, in seconds. If SBFD session negotiation delay is not configured or the delay timer has expired, this field is not displayed.
Diag info	Diagnostic information about the session: · No Diagnostic. · Control Detection Time Expired—The SBFD session goes down because local detection times out. · Neighbor Signaled Session Down—The remote end notifies the local end of SBFD session down.
Template name	Template associated with the session. If no template is associated, this field is not displayed.

# Display brief information about all SBFD sessions for the reflector.

<Sysname> display sbfd session reflector

Local discriminator 1000001 on slot 0

Configured mode: Explicit Value

Total sessions: 1

Local discr: 1000001 Remote discr: 32770

Source IP: 3.2.1.2

Destination IP: 1.1.1.1

Hold time: 29296ms

VRF name: -

Table 8 Command output

Field	Description
Configured mode	Discriminator type: · IP Address—IPv4 address. · Explicit Value—Integer.
Total sessions	Total number of SBFD sessions.
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. For an indirect BFD session whose packets are forwarded through IP routes, upon receiving a packet, the local end uses its destination port number for sending packets if it is different from the local port number.
Hold time	Length of time before the session detection timer expires, in milliseconds. For an SBFD session in Down state, this field displays 0ms.
VRF name	VPN instance bound to the interface where the packets of the SBFD session are received. If no VPN instance is bound to the interface, this field displays a hyphen (-).

# Display detailed information about the SBFD session with local discriminator 1000001 for the reflector.

<Sysname> display sbfd session reflector discriminator 1000001

Local discriminator 1000001 on slot 0

Configured mode: IP Address

Total sessions: 1

Local discr: 1000001 Remote discr: 32770

Source IP: 3.2.1.2 Destination IP: 1.1.1.1

Min Tx interval: 1000ms Min Rx interval: 10ms

Detect multi: 5 Up duration: 00:16:51

Rx count: 967 Tx count: 967

Max Rx period: 3008ms Max Tx period: 1000us

Hold time: 29374ms

VRF name: -

Table 9 Command output

Field	Description
Configured mode	Discriminator type: · IP Address—IPv4 address. · Explicit Value—Integer.
Total sessions	Total number of SBFD sessions.
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.
Min Tx interval	Minimum transmission interval of incoming SBFD packets.
Min Rx interval	Minimum SBFD packet receiving interval.
Detect multi	Session detection time multiplier carried in incoming SBFD packets.
Up duration	Time period for which the session has been up.
Rx count	Number of packets received.
Tx count	Number of packets sent.
Max Rx period	Maximum SBFD packet receiving interval in milliseconds.
Max Tx period	Maximum response packet transmission interval, in microseconds.
Hold time	Length of time before the session detection timer expires, in milliseconds. For an SBFD session in Down state, this field displays 0ms.
VRF name	VPN instance bound to the interface where the packets of the SBFD session are received. If no VPN instance is bound to the interface, this field displays a hyphen (-).

Related commands

sbfd local-discriminator

sbfd destination ipv4 remote-discriminator

Use sbfd destination ipv4 remote-discriminator to associate the destination IPv4 address of the detected path with the remote discriminator of the SBFD session for the initiator.

Use undo sbfd destination ipv4 to cancel the association between the destination IPv4 address of the detected path and the remote discriminator of the SBFD session for the initiator.

Syntax

sbfd destination ipv4 destination-ipv4-address remote-discriminator { ipv4-address | integer-value }

undo sbfd destination ipv4 destination-ipv4-address

Default

The destination IPv4 address of the detected path is not associated with the remote discriminator of the SBFD session for the initiator.

Views

System view

Predefined user roles

network-admin

Parameters

destination-ipv4-address: Specifies a valid unicast IPv4 address as the destination IPv4 address of the detected path.

ipv4-address: Specifies a valid unicast IPv4 address as the remote discriminator.

integer-value: Specifies an integer as the remote discriminator. The value range for this argument is 1 to 4294967295.

Usage guidelines

This command allows you to use the specified remote discriminator for an SBFD session to detect an LSP, MPLS TE tunnel, or SR-MPLS TE policy.

The initiator selects a remote discriminator for an SBFD session as follows:

1. Selects the remote discriminator of the SBFD session used for path connectivity detection. For example, the remote discriminator of the SBFD session specified in the mpls sbfd command.

2. Selects the remote discriminator specified in this command.

3. Selects the destination IPv4 address of the detected path. For example, when you use SBFD to detect an SR-MPLS TE policy, the endpoint address is used as the remote discriminator of the SBFD session.

You can execute this command repeatedly to configure multiple associations between destination IPv4 addresses and remote discriminators for the initiator.

When configuring or canceling an association, the SBFD session might flap if it is in up state.

Examples

# Associate destination IPv4 address 22.22.2.2/32 of the detected LSP with remote discriminator 1.1.1.1 of the SBFD session for the initiator.

<Sysname> system-view

[Sysname] mpls bfd enable

[Sysname] mpls sbfd 22.22.2.2 32

[Sysname] sbfd destination ipv4 22.22.2.2 remote-discriminator 1.1.1.1

Related commands

mpls bfd (MPLS Command Reference)

sbfd (Segment Routing Command Reference)

sbfd local-discriminator

sr-policy sbfd enable (Segment Routing Command Reference)

sbfd destination ipv6 remote-discriminator

Use sbfd destination ipv6 remote-discriminator to associate the destination IPv6 address of the detected path with the remote discriminator of the SBFD session for the initiator.

Use undo sbfd destination ipv6 to cancel the association between the destination IPv6 address of the detected path and the remote discriminator of the SBFD session for the initiator.

Syntax

sbfd destination ipv6 destination-ipv6-address remote-discriminator { ipv4-address | integer-value }

undo sbfd destination ipv6 destination-ipv6-address

Default

The destination IPv6 address of the detected path is not associated with the remote discriminator of the SBFD session for the initiator.

Views

System view

Predefined user roles

network-admin

Parameters

destination-ipv6-address: Specifies a valid global unicast IPv6 address as the destination IPv6 address of the detected path.

ipv4-address: Specifies a valid unicast IPv4 address as the remote discriminator.

integer-value: Specifies an integer as the remote discriminator. The value range for this argument is 1 to 4294967295.

Usage guidelines

This command allows you to use the specified remote discriminator for an SBFD session to detect an SRv6 TE policy.

The initiator selects a remote discriminator for an SBFD session as follows:

1. Selects the remote discriminator of the SBFD session used for SRv6 TE policy connectivity detection.

2. Selects the remote discriminator specified in this command.

If you do not specify the remote discriminator for SBFD to detect an SRv6 TE policy, the SBFD session cannot be established.

When the peer CE is dual-homed to two PEs in public network IP over SRv6 BE, IP L3VPN over SRv6 BE, or EVPN L3VPN over SRv6 BE, the local PE generates a primary path and a backup path after you enable FRR on it. To quickly detect failures and forward traffic through the backup path when the primary path fails, you can configure SBFD to detect the SRv6 locator route advertised through BGP by the peer PE. For this function to take effect, perform the following tasks:

· Execute the sbfd destination ipv6 remote-discriminator command on the local PE to specify the remote discriminator for an SBFD session to detect the SRv6 locator.

· Execute the sbfd local-discriminator command on the peer PE of the primary path to specify the local discriminator for the reflector.

· Make sure the remote discriminator on the local PE is consistent with the local discriminator on the peer PE.

You can execute this command repeatedly to configure multiple associations between destination IPv6 addresses and remote discriminators for the initiator.

When configuring or canceling an association, the SBFD session might flap if it is in up state.

Examples

# Enable SBFD for all SRv6 TE policies, and associate destination IPv6 address 10::1 of the SRv6 TE policy with remote discriminator 1.1.1.1 of the SBFD session for the initiator.

<Sysname> system-view

[Sysname] segment-routing ipv6

[Sysname-segment-routing-ipv6] traffic-engineering

[Sysname-srv6-te] srv6-policy sbfd

[Sysname-srv6-te] quit

[Sysname-segment-routing-ipv6] quit

[Sysname] sbfd destination ipv6 10::1 remote-discriminator 1.1.1.1

Related commands

locator-sbfd enable (Segment Routing Command Reference)

sbfd (Segment Routing Command Reference)

sbfd local-discriminator

srv6-policy sbfd (Segment Routing Command Reference)

sbfd local-discriminator

Use sbfd local-discriminator to set the local discriminator for the reflector.

Use undo sbfd local-discriminator to remove the local discriminator setting for the reflector.

Syntax

sbfd local-discriminator { ipv4-address | integer-value }

undo sbfd local-discriminator { ipv4-address | integer-value }

Default

No local discriminator is set for the reflector.

Views

System view

Predefined user roles

network-admin

Parameters

ipv4-address: Specifies a valid unicast IPv4 address as the local discriminator.

integer-value: Specifies an integer as the local discriminator, in the range of 1000001 to 4294967295.

Usage guidelines

In a BFD session, both ends periodically send BFD packets to detect bidirectional forwarding path failures. SBFD is a unidirectional failure detection mechanism that provides shorter detection time than BFD. SBFD is used in scenarios where only one end of a link requires failure detection.

An SBFD session involves the following roles:

· Initiator—Periodically sends SBFD control packets to detect connectivity to remote entities. An initiator initiates SBFD sessions and maintains SBFD session state.

· Reflector—Listens for incoming SBFD control packets on local entities and replies with response SBFD control packets.

The remote discriminator in SBFD control packets sent by the initiator must be specified in the sbfd local-discriminator command. Otherwise, the reflector does not reply with response SBFD control packets.

You can execute this command multiple times to configure multiple local discriminators.

A node can act as the initiator of one session and the reflector of another session at the same time.

Examples

# Specify 1.1.1.1 as the local discriminator for the reflector.

<Sysname> system-view

[Sysname] sbfd local-discriminator 1.1.1.1

# Specify 1000001 as the local discriminator for the reflector.

<Sysname> system-view

[Sysname] sbfd local-discriminator 1000001

Related commands

display sbfd session

sbfd source-ipv6

Use sbfd source-ipv6 to specify the source IPv6 address used by the initiator to send SBFD control packets.

Use undo sbfd source-ipv6 to restore the default.

Syntax

sbfd source-ipv6 ipv6-address

undo sbfd source-ipv6

Default

No source IPv6 address is specified for SBFD control packets.

Views

System view

Predefined user roles

network-admin

Parameters

ipv6-address: Specifies a unicast IPv6 address. You can configure the source IPv6 address used by the initiator to send SBFD control packets as a site-local address.

Usage guidelines

To use SBFD to detect the connectivity of forwarding paths in an SRv6-TE policy, you must execute this command on the initiator. In addition, a route to the specified IPv6 address must exist on the reflector.

Examples

# Specify 80::2 as the source IPv6 address for SBFD control packets.

<Sysname> system-view

[Sysname] sbfd source-ipv6 80::2

12-High Availability Command Reference

BFD commands

bfd multi-hop authentication-mode

reset bfd session statistics

snmp-agent trap enable bfd

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