session-name: Specify a static BFD session by its name, a case-sensitive string of 1 to 64 characters. The specified static BFD session cannot be the current static BFD session.

re-negotiate seconds: Specifies the maximum amount of time that the associated static BFD session can perform negotiation. The value range for the seconds argument is 10 to 600 seconds. The default is 60 seconds. This option takes effect only on bidirectional associations.

Usage guidelines

The device supports the following association types for two static BFD sessions (static BFD session a and static BFD session b are used for illustration):

· Unidirectional association—Session a is associated with session b in the view of session a, or session b is associated with session a in the view of session b.

· Bidirectional association—Session a is associated with session b in the view of session a, and session b is associated with session a in the view of session b.

A unidirectional association works as follows (the association configured in the view of static BFD session a is taken as an example):

1. When session a changes to the Down state, session b also changes to the Down state. Before session a comes up, session b is not allowed to perform negotiation.

2. When session a changes to the Up state, static BFD session b starts to perform negotiation. The state of session a is not affected even if session b cannot come up through negotiation.

A bidirectional association works as follows:

1. When session a changes to the Down state, session b also changes to the Down state. Before session a comes up, session b is not allowed to perform negotiation.

2. When session a changes to the Up state, session b starts to perform negotiation.

¡ If session b comes up through negotiation in the specified time, both static BFD sessions are placed in Up state.

¡ If session b fail to come up through negotiation in the specified time, both static BFD sessions are placed in Down state.

3. The same rules apply to the state changes of session a if session b first changes to the Down state.

To change an associated static BFD session, first execute the undo associate-static-session command and then associate a new static BFD session by using the associate-static-session command.

Examples

# Associate static BFD session aaa with static BFD session bbb.

<Sysname> system-view

[Sysname] bfd static aaa

[Sysname-bfd-static-session-aaa] associate-static-session bbb

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.

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 single-hop detection.

Examples

# Configure Ten-GigabitEthernet 3/1/1 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 ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] 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 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 a system in Demand mode wants to verify the connectivity to another system, it 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. 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 Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd demand enable

bfd destination-port

Use bfd destination-port to configure the destination port number for a static BFD session used to detect SRv6 PWs.

Use undo bfd destination-port to restore the default.

Syntax

bfd destination-port port-number

undo bfd destination-port

Default

The destination port number is not configured for a static BFD session used to detect SRv6 PWs. The port number configured by using the bfd destination-port evpn-vpls-srv6 or bfd destination-port evpn-vpws-srv6 command in system view applies.

Views

Static BFD session view

Predefined user roles

network-admin

Parameters

port-number: Specifies the destination port number for BFD control packets, which takes 4784.

Usage guidelines

Application scenarios

An H3C device and a device from another vendor can establish an SRv6 PW. When you use BFD to detect such an SRv6 PW, the two ends of the BFD session might be configured with different port numbers. Port number inconsistency will cause BFD session negotiation to fail. To resolve the issue, use this command to edit the destination port number for the static BFD session used for SRv6 PW detection on the H3C device.

Restrictions and guidelines

This command configured in static BFD session view takes effect only for that session. For the configuration to take effect globally, configure the bfd destination-port evpn-vpls-srv6 or bfd destination-port evpn-vpws-srv6 command in system view.

Only the following static BFD sessions support this command:

· Static BFD sessions used to detect SRv6 PWs on EVPN VPLS over SRv6 networks.

· Static BFD sessions used to detect SRv6 PWs on EVPN VPWS over SRv6 networks.

Examples

# Create static BFD session abc to detect the SRv6 PW in VSI aaa. The IPv6 address of the remote PE is 20::1 for the SRv6 PW. Configure the destination port number as 4784 for the static BFD session.

<Sysname> system-view

[Sysname] bfd static abc evpn-vpls-srv6 vsi aaa remote-peer 20::1

[Sysname-bfd-static-session-abc] bfd destination-port 4784

# Create static BFD session abc to detect the SRv6 PW associated with the cross-connect. The interface associated with the cross-connect is Ten-GigabitEthernet3/1/1, and the IPv6 address of the remote PE is 20::1. Configure the destination port number as 4784 for the static BFD session.

<Sysname> system-view

[Sysname] bfd static abc evpn-vpws-srv6 interface ten-gigabitethernet 3/1/1 remote-peer 20::1

[Sysname-bfd-static-session-abc] bfd destination-port 4784

Related commands

bfd static evpn-vpls-srv6 (Segment Routing Command Reference)

bfd static evpn-vpws-srv6 (Segment Routing Command Reference)

bfd destination-port evpn-vpls-srv6

Use bfd destination-port evpn-vpls-srv6 to configure the destination port number for all static BFD sessions used to detect SRv6 PWs on EVPN VPLS over SRv6 networks.

Use undo bfd destination-port evpn-vpls-srv6 to restore the default.

Syntax

bfd destination-port evpn-vpls-srv6 port-number

undo bfd destination-port evpn-vpls-srv6

Default

The destination port number is 3784 for static BFD sessions used to detect SRv6 PWs on EVPN VPLS over SRv6 networks.

Views

System view

Predefined user roles

network-admin

Parameters

port-number: Specifies the destination port number for BFD control packets, which takes 4784.

Usage guidelines

Application scenarios

An H3C device and a device from another vendor can establish an SRv6 PW on an EVPN VPLS over SRv6 network. When you use BFD to detect such an SRv6 PW, the two ends of the BFD session might be configured with different port numbers. Port number inconsistency will cause BFD session negotiation to fail. To resolve the issue, use this command to edit the destination port number for the static BFD session used for SRv6 PW detection on the H3C device.

Restrictions and guidelines

You can configure the destination port number for BFD control packets in system view or static BFD session view.

· The bfd destination-port evpn-vpls-srv6 command configured in system view takes effect for all static BFD sessions used to detect SRv6 PWs on EVPN VPLS over SRv6 networks.

· The bfd destination-port command configured in static BFD session view takes effect only for that session.

Examples

# Configure the destination port number as 4784 for all static BFD sessions used to detect SRv6 PWs on EVPN VPLS over SRv6 networks.

<Sysname> system-view

[Sysname] bfd destination-port evpn-vpls-srv6 4784

Related commands

bfd destination-port

bfd destination-port evpn-vpws-srv6

Use bfd destination-port evpn-vpws-srv6 to configure the destination port number for all static BFD sessions used to detect SRv6 PWs on EVPN VPWS over SRv6 networks.

Use undo bfd destination-port evpn-vpws-srv6 to restore the default.

Syntax

bfd destination-port evpn-vpws-srv6 port-number

undo bfd destination-port evpn-vpws-srv6

Default

The destination port number is 3784 for static BFD sessions used to detect SRv6 PWs on EVPN VPWS over SRv6 networks.

Views

System view

Predefined user roles

network-admin

Parameters

port-number: Specifies the destination port number for BFD control packets, which takes 4784. The default value and value range for this argument vary by BFD session type.

Usage guidelines

Application scenarios

An H3C device and a device from another vendor can establish an SRv6 PW on an EVPN VPWS over SRv6 network. When you use BFD to detect such an SRv6 PW, the two ends of the BFD session might be configured with different port numbers. Port number inconsistency will cause BFD session negotiation to fail. To resolve the issue, use this command to edit the destination port number for the static BFD session used for SRv6 PW detection on the H3C device.

Restrictions and guidelines

You can configure the destination port number for BFD control packets in system view or static BFD session view.

· The bfd destination-port evpn-vpws-srv6 command configured in system view takes effect for all static BFD sessions used to detect SRv6 PWs on EVPN VPWS over SRv6 networks.

· The bfd destination-port command configured in static BFD session view takes effect only for that session.

Examples

# Configure the destination port number as 4784 for all static BFD sessions used to detect SRv6 PWs on EVPN VPWS over SRv6 networks.

<Sysname> system-view

[Sysname] bfd destination-port evpn-vpws-srv6 4784

Related commands

bfd destination-port

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 you execute the bfd detect-interface source-ip command on the local end, the BFD session for detecting the local interface state fails to be established when the following conditions exist:

· The bfd detect-interface source-ip command is not executed on the remote end.

· 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 for Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd detect-interface first-fail-timer 10

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.

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 specify a nonexistent template or do not specify a template, the BFD session uses the BFD parameters configured in interface view. If you first specify a nonexistent template and then create the template, the BFD session uses the parameters configured in the template.

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 the following interfaces with BFD:

· 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 3 Ethernet subinterfaces.

· Layer 3 aggregate interfaces.

· Serial interfaces, POS interfaces, serial interfaces created from E1, E3, T1, or T3, MP-group interfaces, member interfaces of an MP-group interface, HDLC link bundle interfaces, and member interfaces of an HDLC link bundle interface.

If the link layer protocol of an interface is modified by using the link-protocol command, the association between the interface state and BFD is automatically cancelled. When associating the state of a member interface of an MP-group interface or of an HDLC link bundle interface, you must specify the discriminator parameter.

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

For BFD detection to take effect, do not configure this command on both a Layer 3 Ethernet interface and its subinterface.

To configure this command on the following interfaces at the same time, you must manually specify the local and remote discriminators on each of the interfaces:

· A Layer 3 aggregate interface.

· A member port of the Layer 3 aggregate interface.

As a best practice, do not configure this command on these interfaces at the same time.

To associate the interface state with BFD successfully and avoid session state exceptions, as a best practice, do not set demand mode for the BFD session.

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 20.1.1.1 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

# Associate Ten-GigabitEthernet 3/1/1 with BFD to detect the interface state, and specify the source IP address for BFD control packets as 20.1.1.1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd detect-interface source-ip 20.1.1.1

Related commands

link-protocol (Interface Command Reference)

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 on which 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 a large number of BFD sessions exist, 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 Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] 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 is 3 for control packet mode and echo packet mode.

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 Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd detect-multiplier 6

Related commands

bfd static

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 Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] 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 can avoid link congestion caused by a large number of ICMP redirect packets sent from the peer.

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 can avoid link congestion caused by a large number of ICMPv6 redirect packets sent from the peer.

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 ten-gigabitethernet 3/1/1 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 100 milliseconds.

Views

Interface view

BFD template 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 3 to 10000.

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 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 Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd min-echo-receive-interval 500

Related commands

bfd static

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 100 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 3 to 10000.

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 Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd min-receive-interval 500

Related commands

bfd static

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 100 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 3 to 10000.

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 Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd min-transmit-interval 500

Related commands

bfd static

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 is 3 for control packet mode and echo packet mode.

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
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

Related commands

bfd static

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 100 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 for this argument takes 0 or is in the range of 3 to 10000. After you set the value to 0, the device stops receiving echo packets.

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.

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 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 100 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 3 to 10000.

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 100 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 3 to 10000.

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 change-board

Use bfd session change-board to migrate all BFD sessions on a card to another card.

Syntax

In standalone mode:

bfd session change-board from slot slot-number to slot slot-number

In IRF mode:

bfd session change-board from chassis chassis-number slot slot-number to chassis chassis-number slot slot-number

Views

System view

Predefined user roles

network-admin

Parameters

from: Specifies the card that maintains BFD sessions before migration.

to: Specifies the target card for BFD session migration.

slot slot-number: Specifies a card by its slot number. (In standalone mode.)

chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument represents the member ID of the member device. The slot-number argument represents the slot number of the card. (In IRF mode.)

Usage guidelines

After a BFD session comes up, the device automatically selects a card to periodically send BFD packets and maintain BFD session state. Such a card is a BFD session maintenance card.

Due to the complex selection of a BFD session maintenance card, the card that actually maintains BFD sessions might be different from the card through which an upper-layer protocol forwards packets. In the output from the display bfd session verbose command, you can view that the card of the packet outgoing interface for the upper-layer protocol is different from the card where the BFD session resides. In this case, if the card where the BFD session resides fails, the upper-layer protocol might incorrectly switch packets to the backup path for forwarding or disconnect neighbor relationships. To avoid the previous issues, use this command to migrate BFD sessions to the card through which the upper-layer protocol forwards packets.

As a best practice, migrate BFD sessions with different commands depending on the following situations:

· If all upper-layer protocols on the device forward packets through the same card, and this card is not the card that maintains BFD sessions, use the bfd session change-board command to migrate BFD sessions.

· Except for the previous situation, use the change bfd session select-board command to migrate BFD sessions to the card through which an upper-layer protocol forwards packets.

When you use this command to migrate BFD sessions, follow these guidelines:

· You cannot migrate the following types of BFD sessions:

¡ BFD sessions for detecting the link between selected ports of an aggregation group.

¡ BFD sessions for detecting the interface state.

¡ BFD sessions for MAD.

¡ Single-hop BFD sessions whose outgoing interface is a local physical interface.

· BFD sessions change to AdminDown state after migration. BFD sessions in AdminDown state do not trigger the upper-layer protocols to perform operations such as active/standby switchover. BFD sessions in AdminDown state automatically try to come up, and can detect the forwarding paths of upper-layer protocols until they come up.

· You can execute this command again only after the migration is completed.

· In private-mode system view or exclusive-mode system view, this command takes effect immediately after configuration. You do not need to execute the commit command.

Examples

# Migrate all BFD sessions on slot 1 to slot 2.

<Sysname> system-view

[Sysname] bfd session change-board from slot 1 to slot 2

Related commands

commit (Fundamentals Command Reference)

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 session-negotiation delay-upon-reboot

Use bfd session-negotiation delay-upon-reboot to enable BFD session negotiation delay upon a device reboot and set a delay timer.

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

Syntax

bfd session-negotiation delay-upon-reboot interval

undo bfd session-negotiation delay-upon-reboot

Default

BFD session negotiation delay upon a device reboot is disabled.

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 upon a device reboot. If the BFD session comes up after a device reboot, the traffic on the standby path will be switched over to the active path. In this case, traffic loss will occur if the active path of the upper-layer protocol has not recovered completely.

The session negotiation delay function starts a delay timer when the device reboots successfully. Before this timer expires, the device does not perform session negotiation on BFD sessions in down state or newly created sessions. The delay timer allows the active path to recover completely before the BFD session comes up again.

If both the bfd session-negotiation delay-upon-reboot and bfd session-negotiation delay-upon-down commands are executed, the device uses the longer delay time configured in the two commands after a reboot.

Examples

# Enable BFD session negotiation delay upon a device reboot and set the delay timer to 6 seconds.

<Sysname> system-view

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

Related commands

bfd session-negotiation delay-upon-down

display bfd session

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

Static BFD session for single-hop detection with IPv4 control packets:

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

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

Static BFD session for multihop detection with IPv4 control packets:

In standalone mode:

bfd static session-name [ peer-ip ipv4-address [ vpn-instance vpn-instance-name ] source-ip ipv4-address [ discriminator auto [ track-interface interface-type interface-number ] | discriminator local local-value remote remote-value [ track-interface interface-type interface-number ] [ select-board slot slot-number1 [ slot slot-number2 ] ] ] ]

bfd static session-name [ peer-ip ipv4-address [ vpn-instance vpn-instance-name ] [ discriminator local local-value remote remote-value [ track-interface interface-type interface-number ] [ select-board slot slot-number1 [ slot slot-number2 ] ] ] ]

In IRF mode:

Static BFD session for single-hop detection with IPv4 echo packets:

bfd static session-name [ peer-ip ipv4-address interface interface-type interface-number destination-ip ipv4-address [ source-ip ipv4-address ] one-arm-echo [ discriminator { auto | local local-value } ] ]

Static BFD session for multihop detection with IPv4 echo packets:

bfd static session-name [ peer-ip ipv4-address [ vpn-instance vpn-instance-name ] destination-ip ipv4-address [ source-ip ipv4-address ] one-arm-echo [ discriminator { auto | local local-value } ] ]

Static BFD session for single-hop detection with IPv6 control packets:

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

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

Static BFD session for multihop detection with IPv6 control packets:

In standalone mode:

bfd static session-name [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] source-ipv6 ipv6-address [ discriminator auto [ track-interface interface-type interface-number ] | discriminator local local-value remote remote-value [ track-interface interface-type interface-number ] [ select-board slot slot-number1 [ slot slot-number2 ] ] ] ]

bfd static session-name [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] [ discriminator local local-value remote remote-value [ track-interface interface-type interface-number ] [ select-board slot slot-number1 [ slot slot-number2 ] ] ] ]

In IRF mode:

Static BFD session for single-hop detection with IPv6 echo packets:

bfd static session-name [ peer-ipv6 ipv6-address interface interface-type interface-number destination-ipv6 ipv6-address [ source-ipv6 ipv6-address ] one-arm-echo [ discriminator { auto | local local-value } ] ]

Static BFD session for multihop detection with IPv6 echo packets:

bfd static session-name [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] destination-ipv6 ipv6-address [ source-ipv6 ipv6-address ] one-arm-echo [ discriminator { auto | local local-value } ] ]

Static BFD session for single-hop detection with IPv4 control packets (the peer address is fixed at 224.0.0.184):

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

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. For a static BFD session in control packet mode, the peer IPv4 address and the source IPv4 address determine the path to be detected. For a static BFD session in echo packet mode, the peer IPv4 address and the destination IPv4 address determine the path to be detected.

peer-ipv6 ipv6-address: Specifies the peer IPv6 address. For a static BFD session in control packet mode, the peer IPv6 address and the source IPv6 address determine the path to be detected. For a static BFD session in echo packet mode, the peer IPv6 address and the destination IPv6 address determine the path to be detected.

default-ip: Specifies the peer IPv4 address as 224.0.0.184.

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.

destination-ip ipv4-address: Specifies the destination IPv4 address for echo packets, in dotted decimal notation. It must be a valid unicast IPv4 address of the local end.

destination-ipv6 ipv6-address: Specifies the destination IPv6 address for echo packets. It must be the IPv6 address of the local end.

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

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

one-arm-echo: Specifies the static BFD session mode as echo packet mode.

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.

auto: Enables the device to automatically assign local discriminator values to static BFD sessions.

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. A static BFD session can monitor the following interfaces:

· Layer 2 Ethernet interfaces.

· Layer 3 Ethernet interfaces and their subinterfaces.

· Layer 2 aggregate interfaces and their member ports.

· Layer 3 aggregate interfaces and their subinterfaces and member ports.

select-board: Specifies a card to preferentially maintain the BFD session. If you specify both of the slot-number1 and slot-number2 arguments, BFD preferentially selects slot-number1. If BFD fails to select slot-number1, it selects slot-number2. After selecting slot-number2, BFD does not migrate BFD sessions to slot-number1 when it is available. If BFD fails to select slot-number1 or slot-number2, it does not select any card to maintain BFD sessions. If you do not specify this option, BFD selects a card according to the maintenance card selection mechanism that varies by device model. You can specify only interface cards for slot-number1 and slot-number2, and they cannot be the same card.

slot slot-number: Specifies a card by its slot number. If you do not specify a card, this command displays BFD session information for the active MPU. (In standalone mode.)

chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument represents the member ID of the IRF member device. The slot-number argument represents the slot number of the card. (In IRF mode.)

Usage guidelines

Application scenarios

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.

Mechanism of selecting the source and destination IP addresses for BFD packets

For a static BFD session in control packet mode, the source IP address of BFD packets is the IP address specified for the source-ip/source-ipv6 keyword, and the destination IP address is the IP address specified for the peer-ip/peer-ipv6 keyword. Without the source-ip/source-ipv6 keyword specified, the device selects the source IP address for sending BFD packets in the following order:

1. The device looks up its its local routing table to search for a route to the IP address or IPv6 address specified with the peer-ip/peer-ipv6 keyword. It selects the output interface IP address of that route as the source IP address for BFD packets.

2. If you edit the IP address of the output interface after the static BFD session is configured, whether the device updates the source IP address for BFD packets depends on the phase of the session:

¡ If the BFD session is in negotiation phase, the device updates the source IP address for BFD packets.

¡ If the BFD session is in detection phase, the device does not update the source IP address for BFD packets.

3. If the network-slice command is executed in static BFD session view, the device selects the network slicing address. If the network slicing address is invalid, the device cannot send BFD packets.

For a static BFD session in echo packet mode, the source IP address of BFD packets is the IP address specified for the source-ip/source-ipv6 keyword, and the destination IP address is the IP address specified for the destination-ip/destination-ipv6 keyword. Without the source-ip/source-ipv6 or bfd echo-source-ip/bfd echo-source-ipv6 keyword specified, the device uses the IPv4 or IPv6 address specified for the destination-ip/destination-ipv6 keyword as the source IPv4 or IPv6 address of echo packets.

Recommended configuration for a VPN VPWS dual-homed network

In a VPN VPWS dual-homed network, when the AC of a DF fails, the BDF cannot quickly detect the failure to take over. To solve this problem, you can configure a static BFD session on the DF to monitor the AC state and execute the evpn track bfd command on the BDF. The takeover process occurs as follows:

1. When the AC of the DF fails, the DF sets the static BFD session to the down state and notifies the BDF.

2. The BDF quickly takes over as the DF, which minimizes packet loss.

For more information about EVPN VPWS networking and DF election, see EVPN VPWS configuration in EVPN Configuration Guide.

Recommended configuration for selecting a card to maintain BFD sessions

After a BFD session comes up, the device automatically selects a card to periodically send BFD packets and maintain BFD session state. To preferentially select a card for maintaining BFD sessions, specify the select-board option when you configure this command. For the configuration to take effect, make sure the specified card is installed.

Restrictions and guidelines

If a static BFD session in control packet mode is created on the peer device, you must use this command to create a static BFD session on the local device. 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.

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 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.

You need to create a static BFD session on only the local device if you use the echo packet mode for detection. As a best practice, specify the source IP address for echo packets when creating a static BFD session. Make sure the specified source IP address does not belong to the subnet where a local interface resides. Without a source IP address specified, the device uses the IP address specified in the bfd echo-source-ip or bfd echo-source-ipv6 command as the source IP address of echo packets.

Without the source-ip/source-ipv6 or bfd echo-source-ip/bfd echo-source-ipv6 keyword specified, the device uses the IPv4 or IPv6 address specified for the destination-ip/destination-ipv6 keyword as the source IPv4 or IPv6 address of echo packets.

To use a static BFD session in control packet mode for single-hop detection, you must perform the following configuration:

· Specify the IP address of the peer interface for the peer-ip/peer-ipv6 keyword.

· Specify the IP address of the local interface for the source-ip/source-ipv6 keyword.

If you specify an interface, make sure the following requirements are met for the static 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.

Examples

# Create a static BFD session and enter its view. The static BFD session detects the path between 1.1.1.1 and 1.1.1.2 and uses Ten-GigabitEthernet 3/1/1 to send BFD packets with source IP address 1.1.1.1 and destination IP address is 1.1.1.2. 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 ten-gigabitethernet 3/1/1 source-ip 1.1.1.1 discriminator local 1537 remote 2048

[Sysname-bfd-static-session-abc]

# Create a static BFD session in echo mode and enter its view. The static BFD session detects the path between 1.1.1.1 and 1.1.1.2 and uses Ten-GigabitEthernet 3/1/1 to send BFD packets with source IP address 9.9.9.9 and destination IP address is 1.1.1.2.

<Sysname> system-view

[Sysname] bfd static abc peer-ip 1.1.1.1 interface ten-gigabitethernet 3/1/1 destination-ip 1.1.1.2 source-ip 9.9.9.9 one-arm-echo discriminator auto

[Sysname-bfd-static-session-abc]

Related commands

bfd echo-source-ip

bfd echo-source-ipv6

discriminator

evpn track bfd (EVPN Command Reference)

network slice (Segment Routing Command Reference)

track bfd (High Availability Command Reference)

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]

bfd whitelist enable

Use bfd whitelist enable to enable the BFD whitelist feature.

undo bfd whitelist enable to disable the BFD whitelist feature.

Syntax

bfd whitelist enable

undo bfd whitelist enable

Default

The BFD whitelist feature is enabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

If the attacker sends a large number of invalid BFD packets, the CPU cannot receive and process normal BFD packets for maintaining the BFD session state. The BFD whitelist feature allows the device to create ACL rules based on five-tuple information of BFD sessions. BFD packets that match ACL rules in the BFD whitelist are reported with higher priority than packets that match no ACL rules, to the CPU.

The BFD whitelist feature works as follows:

· Upon receiving BFD control packets from the peer for session establishment, the device creates an ACL rule based on session five-tuple information, and adds the rule to the whitelist.

· Upon receiving echoed BFD echo packets from the peer, the device creates an ACL rule based on session five-tuple information, and adds the rule to the whitelist.

· The device adds BFD packets that match ACL rules to the BFD whitelist queue and packets that match no ACL rules to the ordinary queue. BFD packets in the BFD whitelist queue are processed at a higher processing rate. Packets for multiple protocols in the ordinary queue are processed at a lower processing rate. This feature allows packets that match the ACL rules to be separately reported to the CPU at a high rate.

To view ACL rules added to the BFD whitelist, use the display acl whitelist command. For more information about the display acl whitelist command, see ACL in ACL and QoS Command Reference.

Examples

# Enable the BFD whitelist feature.

<Sysname> system-view

[Sysname] bfd whitelist enable

Related commands

display acl whitelist (ACL and QoS Command Reference)

change bfd session select-board

Use change bfd session select-board to migrate a BFD session to another card.

Syntax

In standalone mode:

change bfd session local-discr-value select-board slot slot-number

In IRF mode:

change bfd session local-discr-value select-board chassis chassis-number slot slot-number

Views

System view

Predefined user roles

network-admin

Parameters

local-discriminator-value: Specifies a BFD session by its local discriminator in the range of 1 to 4294967295. The local-discriminator-value argument must be the local discriminator of an existing BFD session.

slot slot-number: Specifies a card by its slot number. (In standalone mode.)

Usage guidelines

After a BFD session comes up, the device automatically selects a card to periodically send BFD packets and maintain BFD session state. Such a card is a BFD session maintenance card.

As a best practice, migrate BFD sessions with different commands depending on the following situations:

· Except for the previous situation, use the change bfd session select-board command to migrate BFD sessions to the card through which an upper-layer protocol forwards packets.

When you use this command to migrate BFD sessions, follow these guidelines:

· You cannot migrate the following types of BFD sessions:

¡ BFD sessions for detecting the link between selected ports of an aggregation group.

¡ BFD sessions for detecting the interface state.

¡ BFD sessions for MAD.

¡ Single-hop BFD sessions whose outgoing interface is a local physical interface.

· In private-mode system view or exclusive-mode system view, this command takes effect immediately after configuration. You do not need to execute the commit command.

Examples

# Migrate the BFD session with local discriminator 10010 to slot 2.

<Sysname> system-view

[Sysname] change bfd session 10010 select-board slot 2

Related commands

commit (Fundamentals Command Reference)

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

In standalone mode:

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

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 ] ] [ slot slot-number ]

display bfd session [ [ dynamic ] [ control | echo ] [ lsp | te | pw | srv6-policy ] [ state { down | admin-down | init | up } ] [ discriminator remote remote-value ] [ [ peer-ip ipv4-address [ vpn-instance vpn-instance-name ] ] | [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] ] ] [ verbose ] ] [ slot slot-number ]

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 ] [ slot slot-number ]

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 ] [ slot slot-number ]

In IRF mode:

display bfd session [ discriminator local local-value | static name session-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 name 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.

lsp: Specifies BFD sessions used to detect MPLS LSPs.

te: Specifies BFD sessions used to detect MPLS TE tunnels.

pw: Specifies BFD sessions used to detect PWs.

srv6-policy: Specifies BFD sessions used to detect SRv6 policies.

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.

slot slot-number: Specifies a card by its slot number. If you do not specify a card, this command displays BFD session information for the active MPU. (In standalone mode.)

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: 10 Up sessions: 10 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 XGE3/1/1

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: XGE3/1/2

Hold time: 2142ms

MPLS LSP session working in control packet mode:

LD/RD SourceAddr DestAddr State Holdtime Interface

32773/32770 1.1.1.9 3.3.3.9 Up 0ms N/A

IPv6 SR session working in echo mode:

Local discr: 2049

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

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

Session state: Up Interface: Tun1

Hold time: 2142ms

IPv6 SR policy session working in echo mode:

Local discr: 33793

Source IP: 1::1

Destination IP: 4::4

Session state: Up Interface: XGE3/1/1

Hold time: 2357ms

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 XGE3/1/1

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: XGE3/1/2

Hold time: 2142ms

MPLS TE session working in control packet mode:

LD/RD SourceAddr DestAddr State Holdtime Interface

2050/2050 1.1.1.1 127.0.0.1 Up 2458ms N/A

MPLS TE session working in echo mode:

LD SourceAddr DestAddr State Holdtime Interface

2051 1.1.1.1 3.3.3.3 Up 4851ms Tun2

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. · MPLS LSP session working in control packet mode—BFD session in control packet 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. · IPv6 SR session working in echo mode—BFD session in echo mode used to detect failures in an SRv6 tunnel. · IPv4 static session working in control packet mode. · IPv6 static session working in control packet mode. · MPLS TE session working in control packet mode. · MPLS TE session working in echo mode. · MPLS PW session working in control packet mode. · IPv6 SR policy session working in echo mode—BFD session in echo mode used to detect SRv6 policies.
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, AdmDown, 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.
Source IP	Source IPv6 address of the session. This field displays N/A if you do not configure the source IP address.
Destination IP	Destination IPv6 address of the session.
Session state	Session state: Down, AdmDown, 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: 513 Remote discr: 513

Source IP: 1.1.1.1 Destination IP: 1.1.1.2

Destination port: 3784 Session state: Up

Interface: Ten-GigabitEthernet3/1/1

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: OSPF

Version: 1

Diag info: No Diagnostic

Hardware mode: Disable

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: Ten-GigabitEthernet3/1/2

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

Hardware mode: Disable

MPLS LSP session working in control packet mode:

Local discr: 32774 Remote discr: 32770

Source IP: 1.1.1.9 Destination IP: 3.3.3.9

Destination port: 4784 Session state: Up

Interface: N/A

Min Tx interval: 1000ms Actual Tx interval: 3000ms

Min Rx interval: 1000ms Detection time: 150000ms

Rx count: 1 Tx count: 13

Connection type: Indirect Up duration: 00:00:36

Hold time: 149536ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1

Diag info: No Diagnostic

Hardware mode: Disable

IPv6 SR session working in echo mode:

Local discr: 2049

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

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

Destination port: 3785 Session state: Up

Interface: Tunnel1

Hold time: 2049ms Actual Tx interval: 500ms

Min Rx interval: 500ms Detection time: 2500ms

Rx count: 7065 Tx count: 7065

Connection type: Indirect Up duration: 00:50:08

Detection mode: Async Slot: 2

Protocol: SRv6

Version: 1

Diag info: No Diagnostic

Hardware mode: Disable

IPv4 static session working in control packet mode:

Session name: abc

Local discr: 310 Remote discr: 308

Source IP: 12.1.1.1 Destination IP: 12.1.1.2

Destination port: 3784 Session state: Up

Interface: Ten-GigabitEthernet3/1/1

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

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 59 Tx count: 1003

Connection type: Direct Up duration: 00:19:26

Hold time: 4426ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: STATIC_IPv4

Version: 1

Diag info: No Diagnostic

Hardware mode: Disable

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: Ten-GigabitEthernet3/1/2

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

Hardware mode: Disable

MPLS TE Session working in control packet mode:

Local discr: 2050 Remote discr: 2050

Source IP: 1.1.1.1 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: 2458ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1

Diag info: No Diagnostic

Hardware mode: Disable

MPLS TE session working in echo mode:

Local discr: 2051

Source IP: 1.1.1.1 Destination IP: 3.3.3.3

Destination port: 3785 Session state: Up

Interface: Tunnel2

Hold time: 4851ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 9083 Tx count: 9637

Connection type: Indirect Up duration: 02:20:42

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1

Diag info: No Diagnostics

Hardware mode: Disable

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

Hardware mode: Disable

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. · MPLS LSP session working in control packet mode—BFD session in control packet 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. · IPv6 SR session working in echo mode—BFD session in echo mode used to detect failures in an SRv6 tunnel. · IPv4 static session working in control packet mode. · IPv6 static session working in control packet mode. · MPLS TE session working in control packet mode. · MPLS TE session working in echo mode. · MPLS PW 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. This field displays N/A if you do not configure the source IP address.
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. 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.
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.
Detection 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	(In standalone mode.) Slot number of the card where the BFD session resides. (In IRF mode.) Slot number of the card where the BFD session resides, in the form of chassis-number/slot-number. chassis-number represents the member ID of the IRF member device. slot-number represents the slot number of the card.
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. · LAGG—Link aggregation. · SRv6. · SRv6PLY—SRv6 TE policy. · STATIC_IPv4—IPv4 static BFD session. · STATIC_IPv6—IPv6 static BFD session. · TRACK_EVPN_AC—EVPN 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. · Dampening Down (Remaining time: XXs)—A BFD session is suppressed within the specified interval. Remaining time is the remaining suppression time in seconds.
Hardware mode	Mode in which BFD packets are processed in hardware: · Enabled. · Disable—BFD packets are processed in software.
Encapsulation mode	Mode in which BFD packets for SRv6 TE policy detection are encapsulated. · Encaps—Normal encapsulation. · Insert—Insert encapsulation.
Tracked interface	Interface monitored by the static BFD session.

‌

Related commands

bfd static

display bfd working-mode

Use display bfd working-mode to display the BFD working mode, hardware resource usage, and session information.

Syntax

display bfd working-mode

Views

Any view

Predefined user roles

network-admin

Examples

# Display the BFD working mode, hardware resource usage, and session information.

<Sysname> display bfd working-mode

Working in hardware BFD mode:

---------------------------------------------------------------------

Total Reserved Configured Remaining

---------------------------------------------------------------------

8 1 0 7

Machine0: reserved interval: refcnt:0

Machine1: dynamic interval: refcnt:0

Machine2: dynamic interval: refcnt:0

Machine3: dynamic interval: refcnt:0

Machine4: dynamic interval: refcnt:0

Machine5: dynamic interval: refcnt:0

Machine6: dynamic interval: refcnt:0

Machine7: dynamic interval: refcnt:0

hardware bfd enable

Use hardware bfd enable to enable hardware BFD.

Use undo hardware bfd enable to disable hardware BFD.

Syntax

hardware bfd enable [ high-precision ]

undo hardware bfd enable

Default

Hardware BFD and high-precision hardware BFD are disabled.

Views

System view

Predefined user roles

network-admin

Parameters

high-precision: Enables high-precision hardware BFD.

Usage guidelines

To avoid incorrect operation of BFD sessions, follow these guidelines when you enable or disable hardware BFD:

· Before you enable hardware BFD, make sure only the cards in Table 5 are installed in the device:

After you enable hardware BFD, do not install any cards except those cards mentioned above.

· Make sure no BFD sessions exist when you enable or disable hardware BFD.

Hardware BFD and high-precision hardware BFD take effect only on new BFD sessions.

High-precision hardware BFD supports the shortest detection time of 3 milliseconds.

Table 5 Card information

Card category	Cards
CEPC	NP5 cards-CEPC, NPS400 cards-CEPC
CSPEX	NP5 cards-CSPEX, NPS400 cards-CSPEX
SPE	NP5 cards-SPE, NPS400 cards-SPE

‌

Examples

# Enable hardware BFD.

<Sysname> system-view

[Sysname] hardware bfd enable

The operation will enable hardware BFD. Are you sure you want to continue? [Y/N]:y

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 SBFD 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

Interface view

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

bfd min-echo-receive-interval

Use bfd min-echo-receive-interval to set the minimum interval for receiving SBFD 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 SBFD echo packets is 100 milliseconds.

Views

Interface view

BFD template view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving SBFD echo packets, in milliseconds. The value takes 0 or is in the range of 3 to 10000. The value 0 indicates that the device does not receive echo packets.

Usage guidelines

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

Examples

# Set the minimum interval for receiving SBFD echo packets to 500 milliseconds on Ten-GigabitEthernet 3/1/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 3/1/1

[Sysname-Ten-GigabitEthernet3/1/1] bfd min-echo-receive-interval 500

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 is 100 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 is 3 to 10000.

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 SBFD 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 is 100 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 is 3 to 10000.

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 bfd session

bfd session-negotiation delay-upon-reboot

Use bfd session-negotiation delay-upon-reboot to enable SBFD session negotiation delay upon a device reboot and set a delay timer.

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

Syntax

bfd session-negotiation delay-upon-reboot interval

undo bfd session-negotiation delay-upon-reboot

Default

SBFD session negotiation delay upon a device reboot is disabled.

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 upon a device reboot. If the SBFD session comes up after a device reboot, the traffic on the standby path will be switched over to the active path. In this case, traffic loss will occur if the active path of the upper-layer protocol has not recovered completely.

The session negotiation delay function starts a delay timer when the device reboots successfully. Before this timer expires, the device does not perform session negotiation on SBFD sessions in down state or newly created sessions. The delay timer allows the active path to recover completely before the SBFD session comes up again.

Examples

# Enable SBFD session negotiation delay upon a device reboot and set the delay timer to 6 seconds.

<Sysname> system-view

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

Related commands

bfd session-negotiation delay-upon-down

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]

bfd whitelist enable

Use bfd whitelist enable to enable the BFD whitelist feature.

undo bfd whitelist enable to disable the BFD whitelist feature.

Syntax

bfd whitelist enable

undo bfd whitelist enable

Default

The BFD whitelist feature is enabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

If the attacker sends a large number of invalid SBFD packets, the CPU cannot receive and process normal SBFD packets for maintaining the SBFD session state. The SBFD whitelist feature allows the device to create ACL rules based on five-tuple information of BFD sessions. SBFD packets that match ACL rules in the SBFD whitelist are reported with higher priority than packets that match no ACL rules, to the CPU.

The SBFD whitelist feature works as follows:

· Upon receiving SBFD control packets from the peer for session establishment, the device creates an ACL rule based on session five-tuple information, and adds the rule to the whitelist.

· Upon receiving echoed SBFD echo packets from the peer, the device creates an ACL rule based on session five-tuple information, and adds the rule to the whitelist.

· The device adds SBFD packets that match ACL rules to the SBFD whitelist queue and packets that match no ACL rules to the ordinary queue. SBFD packets in the SBFD whitelist queue are processed at a higher processing rate. Packets for multiple protocols in the ordinary queue are processed at a lower processing rate. This feature allows packets that match the ACL rules to be separately reported to the CPU at a high rate.

To view ACL rules added to the SBFD whitelist, use the display acl whitelist command. For more information about the display acl whitelist command, see ACL in ACL and QoS Command Reference.

Examples

# Enable the BFD whitelist feature.

<Sysname> system-view

[Sysname] bfd whitelist enable

Related commands

· display acl whitelist (ACL and QoS Command Reference)

display sbfd session

Use display sbfd session to display SBFD session information.

Syntax

display sbfd session { initiator [ discriminator value | [ ipv6 [ peer-ipv6 ipv6-address ] | srv6-policy ] [ verbose ] | verbose ] | 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 an SBFD session by its local discriminator in the range of 1 to 4294967295.

ipv6: Specifies SBFD sessions used to detect IPv6 links.

peer-ipv6 ipv6-address: Specifies an SBFD session by the peer IPv6 address.

srv6-policy: Displays SBFD sessions used to detect SRv6 TE policies.

verbose: Displays detailed information about all SBFD sessions. If you do not specify this keyword, this command displays brief SBFD session information.

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: 2 Up sessions: 2

SBFD session (MPLS LSP):

Local discr: 32770 Remote discr: 1000001

Source IP: 1.1.1.1 Destination IP: 127.0.0.1

Session state: Up Hold time: 2184ms

SBFD session (SRv6 PLY):

Local discr: 33794 Remote discr: 1000001

Source IP: 15::15

Destination IP: 3::3

Session state: Up Hold time: 4201ms

Table 6 Command output

Field	Description
Total sessions	Total number of SBFD sessions.
Up sessions	Number of active SBFD sessions.
SBFD session (xxx)	Path type detected by the SBFD session: · MPLS LSP. · SRv6 PLY—SRv6 TE policy. · IPv6—IPv6 link.
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 32770 for the initiator.

<Sysname> display sbfd session initiator discriminator 32770

Local discr: 32770 Remote discr: 1000002

Source IP: 1.1.1.1 Destination IP: 127.0.0.1

Session state: Up Hold time: 4130ms

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

Detection time: 5000ms Up duration: 00:01:18

Rx count: 1 Tx count: 78

Slot: 0

Protocol: MPLS_LSPV

Diag info: No Diagnostic

Template name: temmpls

Hardware mode: Disable

Table 7 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 value of the SRv6 TE policy.
NID	Forwarding entry index of the SID list of the SRv6 TE policy.
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 card where the BFD session resides. (In IRF mode.) Slot number of the card where the BFD session resides, in the form of chassis-number/slot-number. chassis-number represents the member ID of the IRF member device. slot-number represents the slot number of the card.
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.
Hardware mode	Mode in which SBFD packets are processed in hardware: · Enabled. · Disable—SBFD packets are processed in software.
Encapsulation mode	Mode in which SBFD packets for SRv6 TE policy detection are encapsulated. · Encaps—Normal encapsulation. · Insert—Insert encapsulation.

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

<Sysname> display sbfd session initiator verbose

Total sessions: 2 Up sessions: 2

SBFD session (MPLS LSP):

Local discr: 32770 Remote discr: 1000001

Source IP: 1.1.1.1 Destination IP: 127.0.0.1

Session state: Up Hold time: 4130ms

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

Detection time: 5000ms Up duration: 00:01:19

Rx count: 1 Tx count: 79

Slot: 0

Protocol: MPLS_LSPV

Diag info: No Diagnostic

Template name: abc

Hardware mode: Disable

SBFD session (SRv6 PLY):

Local discr: 33794 Remote discr: 1000001

Source IP: 15::15

Destination IP: 3::3

Session state: Up Hold time: 4201ms

Color: 10 NID: 2149580802

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

Detection time: 5000ms Up duration: 00:22:43

Rx count: 232 Tx count: 242

Slot: 0

Protocol: SRv6PLY

Diag info: No Diagnostic

Hardware mode: Disable

Table 8 Command output

Field	Description
Total sessions	Total number of SBFD sessions.
Up sessions	Number of active SBFD sessions.
SBFD session (xxx)	Path type detected by the SBFD session: · MPLS LSP. · SRv6 PLY—SRv6 TE policy. · IPv6—IPv6 link.
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 value of the SRv6 TE policy.
NID	Forwarding entry index of the SID list of the SRv6 TE policy.
Min Tx interval	Minimum SBFD packet transmission interval.
Actual Tx interval	Actual SBFD packet transmission interval. 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 card where the BFD session resides. (In IRF mode.) Slot number of the card where the BFD session resides, in the form of chassis-number/slot-number. chassis-number represents the member ID of the IRF member device. slot-number represents the slot number of the card.
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.
Protocol	Protocol associated with SBFD: · MPLS_LSPV—LSP. · SRv6PLY—SRv6 TE policy.
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.
Hardware mode	Mode in which SBFD packets are processed in hardware: · Enabled. · Disable—SBFD packets are processed in software.
Encapsulation mode	Mode in which SBFD packets for SRv6 TE policy detection are encapsulated. · Encaps—Normal encapsulation. · Insert—Insert encapsulation.

# 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: -

Local discriminator 1234567 on slot 0

Configured mode: Explicit Value

Total sessions: 1

Local discr: 1234567 Remote discr: 33793

Source IP: 2::22

Destination IP: 100::1

Hold time: 29678ms 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.
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: -

Hardware mode: Disable

# Display detailed information about the SBFD session with local discriminator 1234567 for the reflector.

<Sysname> display sbfd session reflector discriminator 1234567

Local discriminator 1234567 on slot 0

Configured mode: Explicit Value

Total sessions: 1

Local discr: 1234567 Remote discr: 33793

Source IP: 2::22

Destination IP: 100::1

Min Tx interval: 500ms Min Rx interval: 10ms

Detect multi: 5 Up duration: 05:35:20

Rx count: 46371 Tx count: 46371

Max Rx period: 611ms Max Tx period: 2000us

Hold time: 29622ms

VRF name: -

Hardware mode: Disable

Table 10 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 (-).
Hardware mode	Mode in which SBFD packets are processed in hardware: · Enabled. · Disable—SBFD packets are processed in software.

Related commands

sbfd local-discriminator

hardware sbfd-reflector enable

Use hardware sbfd-reflector enable to enable hardware reflection for the reflector of the SBFD session.

Use undo hardware sbfd-reflector enable to disable hardware reflection for the reflector of the SBFD session.

Syntax

hardware sbfd-reflector enable

undo hardware sbfd-reflector enable

Default

Hardware reflection is enabled for the reflector of the SBFD session.

Views

System view

Predefined user roles

network-admin

Usage guidelines

In standard system operating mode, the system does not support this feature.

In SDN-WAN system operating mode, only the following cards support this feature:

‌

Card category	Cards
CSPEX	NP5 cards-CSPEX

‌

Examples

# Enable hardware reflection for the reflector of the SBFD session.

<Sysname> system-view

[Sysname] hardware sbfd-reflector enable

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:

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

5. 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. The value range for this argument is 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, such as MPLS TE tunnel establishment through static SRLSP.

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.

As a best practice to avoid affecting packet processing performance, configure no more than 1000 SBFD reflectors.

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

mpls bfd (MPLS Command Reference)

sbfd initiator accept-down-response

Use sbfd initiator accept-down-response to enable the initiator to send SBFD packets in up state upon receiving SBFD packets in down state from the reflector during session establishment.

Use undo sbfd initiator accept-down-response to restore the default.

Syntax

sbfd initiator accept-down-response

undo sbfd initiator accept-down-response

Default

During session establishment, upon receiving an SBFD packet in down state from the reflector, the initiator drops the packet. The SBFD session cannot be established.

Views

System view

Predefined user roles

network-admin

Usage guidelines

Typically, to establish an SBFD session, the initiator first sends a SBFD packet in down state. If the reflector replies with an SBFD packet in down state, the initiator will drop the packet, and the SBFD session cannot be established. To resolve this issue, configure this command on the initiator. After configuration, when the initiator receives an SBFD packet in down state from the reflector, it sends an SBFD packet in up state for successful session establishment.

Examples

# Enable the initiator to send SBFD packets in up state upon receiving SBFD packets in down state from the reflector during session establishment.

<Sysname> system-view

[Sysname] sbfd initiator accept-down-response

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.

Usage guidelines

To use SBFD to detect the connectivity of forwarding paths in an SRv6 TE policy or SRv6 BE, 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

13-High Availability Command Reference

BFD commands

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Operating mechanism

Restrictions and guidelines

bfd multi-hop authentication-mode

Application scenarios

Mechanism of selecting the source and destination IP addresses for BFD packets

Recommended configuration for data link layer connectivity detection

Recommended configuration for a VPN VPWS dual-homed network

Recommended configuration for selecting a card to maintain BFD sessions

Restrictions and guidelines

display bfd working-mode

snmp-agent trap enable bfd

sbfd initiator accept-down-response

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