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

Application scenarios

Use this command to enhance BFD session security.

Restrictions and guidelines

BFD session negotiation can succeed only when both ends have consistent BFD session authentication settings.

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

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

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

bfd dampening

Use bfd dampening to configure BFD session flapping suppression.

Use undo bfd dampening to disable BFD session flapping suppression.

Syntax

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

undo bfd dampening

Default

BFD sessions are not suppressed.

Views

System view

Predefined user roles

network-admin

Parameters

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

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

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

Usage guidelines

Application scenarios

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.

Operating mechanism

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

Application scenarios

BFD supports the Asynchronous and Demand detection modes. By default, the BFD session operates in Asynchronous mode. If a large number of BFD sessions exist in the system, you can specify the Demand mode to prevent periodic sending of BFD control packets from affecting system operations.

Operating mechanism

In Demand mode, the device periodically sends BFD control packets. If the peer end is operating in Asynchronous mode (default), the peer end stops sending BFD control packets. If the peer end is operating in Demand mode, both ends stop sending BFD control packets. When the connectivity to another system needs to be verified explicitly, a system sends several BFD control packets with the Poll (P) bit set at the negotiated transmit interval. If no response is received within the detection interval, the session is considered down. If the connectivity is found to be up, no more BFD control packets are sent until the next command is issued. As a best practice, use the bfd echo enable command to enable the echo function for the device to periodically send echo packets to detect link connectivity. If the device does not receive echo packets from the peer within the detection time, 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.

Restrictions and guidelines

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

The bfd demand enable command cannot take effect when any of the conditions exist:

· An echo-packet-mode BFD session exists on the device.

· An SBFD session exists on the device.

· A BFD session for detecting an aggregate link exists on the device.

· You configure the bfd detect-interface first-fail-timer and bfd detect-interface special-processing commands after associating the interface state with BFD.

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd demand enable

Related commands

bfd echo enable

bfd detect-interface first-fail-timer

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

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

Syntax

bfd detect-interface first-fail-timer seconds

undo bfd detect-interface first-fail-timer

Default

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

Views

Interface view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

Application scenarios

With the bfd detect-interface source-ip command configured, the local end attempts to establish a BFD session for detecting the interface state. The first BFD session for detecting the interface state fails to be established when the following conditions exist:

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

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

You can use this command for the following purposes:

· Disable the data link layer for the interface.

· Fast locate the interface where the first attempt to establish the BFD session for detecting interface state failed.

Operating mechanism

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.

Restrictions and guidelines

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

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

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

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd detect-interface first-fail-timer 10

Related commands

bfd detect-interface source-ip

display interface (Interface Command Reference)

bfd detect-interface source-ip

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

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

Syntax

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

undo bfd detect-interface

Default

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

Views

Interface view

Predefined user roles

network-admin

Parameters

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

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

local local-value: Specifies the local discriminator. The value range for the local-value argument is 97 to 128.

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

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

Usage guidelines

Application scenarios

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.

Recommended configuration

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.

Restrictions and guidelines

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.

· VLAN interfaces.

· Layer 2 aggregate interfaces.

· Layer 3 aggregate interfaces.

· Layer 3 aggregate subinterfaces.

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

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

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

For BFD detection to take effect, do not execute this command on both a Layer 2 Ethernet interface and the VLAN interface created for the VLAN to which the Layer 2 Ethernet interface is assigned.

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 subinterface of the 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.

For BFD detection to take effect, do not execute this command on the following interfaces at the same time:

· A Layer 2 aggregate interface.

· A member port of the Layer 2 aggregate interface.

· The VLAN interface to which the Layer 2 aggregate interface belongs.

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 20.1.1.2 discriminator local 514 remote 513 on the peer device.

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

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

Examples

# Create a BFD session to detect the state of VLAN-interface 10, and specify the source IP address as 20.1.1.1.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] bfd detect-interface source-ip 20.1.1.1

bfd detect-interface special-processing

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

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

Syntax

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

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

Default

All types of special processing for BFD sessions are disabled.

Views

Interface view

Predefined user roles

network-admin

Parameters

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

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

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

Usage guidelines

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

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

· Change the authentication mode for BFD packets.

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

Examples

# Enable all types of special processing for BFD sessions on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd detect-interface special-processing admin-down authentication-change session-up

bfd detect-multiplier

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

Use undo bfd detect-multiplier to restore the default.

Syntax

bfd detect-multiplier value

undo bfd detect-multiplier

Default

The single-hop detection time multiplier for control packet mode and echo packet mode is 3.

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

Application scenarios

You can adjust the detection time multiplier based on the actual network condition in order to adjust the BFD detection time.

Operating mechanism

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)

‌

Operating mechanism

The timers for BFD sessions in different directions are independently negotiated. Bidirectional session timers can be different.

When the BFD session is valid, the control packet transmission interval and detection time can be renegotiated at any time without affecting the session status.

Only the following static BFD sessions support this command:

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

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

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

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

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

bfd echo enable

Use bfd echo enable to enable the echo function.

Use undo bfd echo enable to disable the echo function.

Syntax

bfd echo [ receive | send ] enable

undo bfd echo [ receive | send ] enable

Default

The echo function is disabled.

Views

Interface view

Static BFD session view

Predefined user roles

network-admin

Parameters

receive: Specifies the echo packet receiving capability.

send: Specifies the echo packet sending capability.

Usage guidelines

Application scenarios

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.

Operating mechanism

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.

Restrictions and guidelines

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

The echo function does not take effect on control-mode BFD sessions established with IPv6 link-local addresses.

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

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

Examples

# Enable the echo function on VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd echo enable

bfd echo-source-ip

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

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

Syntax

bfd echo-source-ip ip-address

undo bfd echo-source-ip

Default

No source IP address is configured for BFD echo packets.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

Examples

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

<Sysname> system-view

[Sysname] bfd echo-source-ip 8.8.8.8

bfd echo-source-ipv6

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

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

Syntax

bfd echo-source-ipv6 ipv6-address

undo bfd echo-source-ipv6

Default

No source IPv6 address is configured for BFD echo packets.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

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

Examples

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

<Sysname> system-view

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

bfd event-log enable

Use bfd event-log enable to enable BFD event logging.

Use undo bfd event-log enable to disable BFD event logging.

Syntax

bfd event-log enable { down [ log-size ] | driver-packet [ detection-abnormal-autostop ] }

undo bfd event-log enable { down | driver-packet }

Default

BFD event logging is disabled.

Views

System view

Predefined user roles

network-admin

Parameters

down: Enables logging for BFD session down events.

log-size: Specifies the maximum number of BFD session down event logs allowed, which takes value 0 or is in the range of 200 to 60000. The default is 1000. To disable BFD session down event logging, set the value for the log-size argument to 0.

driver-packet: Enables logging for driver packet-sending events.

detection-abnormal-autostop: Logs a BFD error that occurs and then immediately disables logging for driver packet-sending events. BFD errors include the following types:

· The BFD detection timer times out.

· A BFD session goes down.

If you do not specify this option, driver packet-sending events are logged until the logging is administratively disabled.

Usage guidelines

Application scenarios

Use this feature to enable the device to record the following types of BFD event logs to help you locate the reason for BFD session state anomalies:

· BFD session down events.

· Driver packet-sending events.

Restrictions and guidelines

You can repeat this command to modify the maximum number of logs allowed for BFD session down events. After modification, the device clears recorded logs.

The device can record a maximum number of 8192 logs for driver packet-sending events.

Examples

# Enable BFD session down event logging, and set the maximum number of BFD session down event logs allowed to 500.

<Sysname> system-view

[Sysname] bfd event-log enable down 500

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.

Application scenarios

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.

Restrictions and guidelines

This command takes effect only for control packet mode.

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 400 milliseconds.

Views

Interface view

Static BFD session view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

Application scenarios

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

Restrictions and guidelines

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

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

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

Only the following static BFD sessions support this command:

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

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

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

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

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

bfd min-receive-interval

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

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

Syntax

bfd min-receive-interval interval

undo bfd min-receive-interval

Default

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

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving single-hop BFD control packets, in milliseconds. The value range for this argument is 3 to 1000.

Usage guidelines

Application scenarios

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.

Restrictions and guidelines

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

You can use the bfd min-receive-interval and bfd min-control-interval commands to adjust the minimum interval for receiving single-hop BFD control packets. Follow these guidelines when you configure the commands:

· If you configure both the bfd min-receive-interval and bfd min-control-interval commands, the time interval configured by the bfd min-receive-interval command takes precedence.

· If you do not configure the bfd min-receive-interval or bfd min-control-interval command, the device uses the default value for the bfd min-receive-interval command as the minimum interval for receiving single-hop BFD control packets.

· If you configure either the bfd min-receive-interval or bfd min-control-interval command, the device uses the value configured for that command as the minimum interval for receiving single-hop BFD control packets.

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

Related commands

bfd min-control-interval

bfd min-transmit-interval

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

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

Syntax

bfd min-transmit-interval interval

undo bfd min-transmit-interval

Default

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

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting single-hop BFD control packets, in milliseconds. The value range for this argument is 3 to 1000.

Usage guidelines

Application scenarios

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

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

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

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

The values that can actually take effect for this command are 3, 10, 100, 400, and 1000. If the negotiated interval is none of these values, the smallest one closest to the negotiated interval applies. For example, the actual single-hop BFD control packet transmitting interval on the local end is 400 milliseconds if the following conditions exist:

· The minimum interval for transmitting single-hop BFD control packets on the local end is 500 milliseconds.

· The minimum interval for receiving single-hop BFD control packets on the peer end is 3 milliseconds.

· The negotiated interval is 500 milliseconds.

Restrictions and guidelines

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

You can use the bfd min-transmit-interval and bfd min-control-interval commands to adjust the minimum interval for transmitting single-hop BFD control packets. Follow these guidelines when you configure the commands:

· If you configure both the bfd min-transmit-interval and bfd min-control-interval commands, the time interval configured by the bfd min-transmit-interval command takes precedence.

· If you do not configure the bfd min-transmit-interval or bfd min-control-interval command, the device uses the default value for the bfd min-transmit-interval command as the minimum interval for transmitting single-hop BFD control packets.

· If you configure either the bfd min-transmit-interval or bfd min-control-interval command, the device uses the value configured for that command as the minimum interval for transmitting single-hop BFD control packets.

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

Related commands

bfd min-control-interval

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

Application scenarios

Use this command to enhance BFD session security.

Restrictions and guidelines

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

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

Examples

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

<Sysname> system-view

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

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

Application scenarios

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.

Restrictions and guidelines

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

Examples

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

<Sysname> system-view

[Sysname] bfd multi-hop destination-port 3784

bfd multi-hop detect-multiplier

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

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

Syntax

bfd multi-hop detect-multiplier value

undo bfd multi-hop detect-multiplier

Default

The multihop detection time multiplier for control packet mode and echo packet mode is 3.

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

Application scenarios

You can adjust the detection time multiplier based on the actual network condition in order to adjust the BFD detection time.

Operating mechanism

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

Table 2 Actual detection interval calculation method

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

Restrictions and guidelines

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 400 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 1000.

Usage guidelines

Application scenarios

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.

Restrictions and guidelines

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 400 milliseconds.

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for receiving multihop BFD control packets, in milliseconds. The value range for this argument is 3 to 1000.

Usage guidelines

Application scenarios

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.

Restrictions and guidelines

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

You can use the bfd multi-hop min-receive-interval and bfd multi-hop min-control-interval commands to adjust the minimum interval for receiving multihop BFD control packets. Follow these guidelines when you configure the commands:

· If you configure both the bfd multi-hop min-receive-interval and bfd multi-hop min-control-interval commands, the time interval configured by the bfd multi-hop min-receive-interval command takes precedence.

· If you do not configure the bfd multi-hop min-receive-interval or bfd multi-hop min-control-interval command, the device uses the default value for the bfd multi-hop min-receive-interval command as the minimum interval for receiving multihop BFD control packets.

· If you configure either the bfd multi-hop min-receive-interval or bfd multi-hop min-control-interval command, the device uses the value configured for that command as the minimum interval for receiving multihop BFD control packets.

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 multi-hop min-control-interval

bfd static

bfd multi-hop min-transmit-interval

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

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

Syntax

bfd multi-hop min-transmit-interval interval

undo bfd multi-hop min-transmit-interval

Default

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

Views

System view

Static BFD session view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting multihop BFD control packets, in milliseconds. The value range for this argument is 3 to 1000.

Usage guidelines

Application scenarios

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

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

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

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

The values that can actually take effect for this command are 3, 10, 100, 400, and 1000. If the negotiated interval is none of these values, the smallest one closest to the negotiated interval applies. For example, the actual multihop BFD control packet transmitting interval on the local end is 400 milliseconds if the following conditions exist:

· The minimum interval for transmitting multihop BFD control packets on the local end is 500 milliseconds.

· The minimum interval for receiving multihop BFD control packets on the peer end is 3 milliseconds.

· The negotiated interval is 500 milliseconds.

Restrictions and guidelines

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

You can use the bfd multi-hop min-transmit-interval and bfd multi-hop min-control-interval commands to adjust the minimum interval for transmitting multihop BFD control packets. Follow these guidelines when you configure the commands:

· If you configure both the bfd multi-hop min-transmit-interval and bfd multi-hop min-control-interval commands, the time interval configured by the bfd multi-hop min-transmit-interval command takes precedence.

· If you do not configure the bfd multi-hop min-transmit-interval or bfd multi-hop min-control-interval command, the device uses the default value for the bfd multi-hop min-transmit-interval command as the minimum interval for transmitting multihop BFD control packets.

· If you configure either the bfd multi-hop min-transmit-interval or bfd multi-hop min-control-interval command, the device uses the value configured for that command as the minimum interval for transmitting multihop BFD control packets.

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 multi-hop min-control-interval

bfd static

bfd session init-mode

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

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

Syntax

bfd session init-mode { active | passive }

undo bfd session init-mode

Default

BFD uses the active mode.

Views

System view

Predefined user roles

network-admin

Parameters

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

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

Usage guidelines

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

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

Examples

# Configure the session establishment mode as passive.

<Sysname> system-view

[Sysname] bfd session init-mode passive

bfd static

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

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

Syntax

For IPv4 single-hop detection with 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 [ bind-route-aggregation peer-ip ipv4-address interface interface-type interface-number source-ip ipv4-address discriminator auto ]

For IPv4 multihop detection with control packets:

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

For IPv4 single-hop detection with 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 } ] ]

For IPv4 multihop detection with 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 } ] ]

For IPv6 single-hop detection with 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 [ bind-route-aggregation peer-ipv6 ipv6-address interface interface-type interface-number source-ipv6 ipv6-address discriminator auto ]‌

For IPv6 multihop detection with control packets:

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

For IPv6 single-hop detection with 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 } ] ]

For IPv6 multihop detection with 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 } ] ]

undo bfd static session-name

Default

No static BFD sessions exist.

Views

System view

Predefined user roles

network-admin

Parameters

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

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

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

bind-route-aggregation: Creates a static BFD session for detecting the aggregate link of a Layer 3 aggregate interface.

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 IPv4 destination address for echo packets, in dotted decimal notation. The IPv4 destination address must be a valid unicast IPv4 address of the local device.

destination-ipv6 ipv6-address: Specifies the IPv6 destination address for echo packets. The IPv6 destination address must be the IP address of the local device.

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

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

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

discriminator: Specifies BFD session discriminators.

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

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

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 supports monitoring the following interface types:

· 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.

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.

Recommended configuration (for Ethernet link aggregation)

To use BFD to detect an aggregate link, choose one as needed:

· Method 1: Execute the link-aggregation bfd command to enable BFD for an aggregation group.

· Method 2: Execute the bfd static command with the bind-route-aggregation keyword specified to create static BFD sessions for detecting an aggregate link and its member links.

If you use Method 1, the Ethernet link aggregation module will mistakenly consider the aggregation link unavailable when the BFD session goes down due to the failure of a single member link. To avoid this issue, use Method 2. To perform multihop detection, use Method 1, because Method 2 only supports single-hop detection.

The operating mechanisms and restrictions and guidelines of the two methods are as shown in Table 3. You can choose only one of the methods.

Table 3 Methods of using BFD to detect an aggregate link

Method	Operating mechanism	Single-hop/multihop detection	Restrictions and guidelines
Method 1	Create a BFD session for detecting the aggregate link. Each member interface of the aggregate link takes turns to send BFD packets.	Both single-hop detection and multihop detection are supported.	· Make sure the source and destination IP addresses are reversed between the two ends of the aggregate link. For example, if you execute link-aggregation bfd ipv4 source 1.1.1.1 destination 2.2.2.2 at the local end, execute link-aggregation bfd ipv4 source 2.2.2.2 destination 1.1.1.1 at the peer end. The source and destination IP addresses must be different unicast addresses other than 0.0.0.0. · You can configure only one static BFD session to detect the aggregate link of an aggregate interface. · You cannot execute the bfd static bind-route-aggregation command for aggregate sub-interfaces.
Method 2	1. Create a static BFD session to associate with the aggregated link. 2. Create a static BFD sub-session for detecting each member interface of the aggregated link. 3. The BFD session is in up state as long as a sub-session is in up state, indicating the aggregated link is available. The BFD session goes down only when all sub-sessions are in down state, indicating the aggregated link is unavailable.	Only single-hop detection is supported.	· Make sure the source and destination IP addresses are reversed between the two ends. For example, if you execute bfd static abc bind-route-aggregation peer-ipv4 1.1.1.1 interface route-aggregation 1 source-ipv4 1.1.1.2 discriminator auto at the local end, execute bfd static abc bind-route-aggregation peer-ipv4 1.1.1.2 interface route-aggregation 1 source-ipv4 1.1.1.1 discriminator auto at the peer end. The source and destination IP addresses must be different unicast addresses other than 0.0.0.0. · You can configure only one static BFD session to detect the aggregate link of an aggregate interface. · You cannot execute the bfd static bind-route-aggregation command for aggregate sub-interfaces.

Method

Operating mechanism

Single-hop/multihop detection

Restrictions and guidelines

Method 1

Create a BFD session for detecting the aggregate link. Each member interface of the aggregate link takes turns to send BFD packets.

Both single-hop detection and multihop detection are supported.

· Make sure the source and destination IP addresses are reversed between the two ends of the aggregate link. For example, if you execute link-aggregation bfd ipv4 source 1.1.1.1 destination 2.2.2.2 at the local end, execute link-aggregation bfd ipv4 source 2.2.2.2 destination 1.1.1.1 at the peer end. The source and destination IP addresses must be different unicast addresses other than 0.0.0.0.

· You can configure only one static BFD session to detect the aggregate link of an aggregate interface.

· You cannot execute the bfd static bind-route-aggregation command for aggregate sub-interfaces.

Method 2

1. Create a static BFD session to associate with the aggregated link.

2. Create a static BFD sub-session for detecting each member interface of the aggregated link.

3. The BFD session is in up state as long as a sub-session is in up state, indicating the aggregated link is available. The BFD session goes down only when all sub-sessions are in down state, indicating the aggregated link is unavailable.

Only single-hop detection is supported.

· Make sure the source and destination IP addresses are reversed between the two ends. For example, if you execute bfd static abc bind-route-aggregation peer-ipv4 1.1.1.1 interface route-aggregation 1 source-ipv4 1.1.1.2 discriminator auto at the local end, execute bfd static abc bind-route-aggregation peer-ipv4 1.1.1.2 interface route-aggregation 1 source-ipv4 1.1.1.1 discriminator auto at the peer end. The source and destination IP addresses must be different unicast addresses other than 0.0.0.0.

· You can configure only one static BFD session to detect the aggregate link of an aggregate interface.

· You cannot execute the bfd static bind-route-aggregation command for aggregate sub-interfaces.

‌

Restrictions and guidelines

If the peer device creates a static BFD session in control packet mode, you must use this command the local device to create a static BFD session. The BFD session discriminators must match on the local and peer devices. For example, if you configure bfd static abc peer-ip 20.1.1.1 vpn-instance vpn1 source-ip 20.1.1.2 discriminator local 513 remote 514 on the local device, you must configure bfd static bcd peer-ip 20.1.1.2 vpn-instance vpn1 source-ip 20.1.1.1 discriminator local 514 remote 513 on the peer device.

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

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

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

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

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

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

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

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

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

Different static BFD sessions cannot have the same local discriminator.

To specify the TTL value for BFD packets by using the bfd ttl command after creating a static BFD session for detecting the aggregate link by using the bfd static bind-route-aggregation command, follow these restrictions and guidelines:

· To make sure the static BFD session goes up correctly, specify different peer-ip options in the bfd ttl and bfd static bind-route-aggregation commands.

· To make sure the static BFD session goes up correctly, specify different peer-ipv6 options in the bfd ttl and bfd static bind-route-aggregation commands.

Examples

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

<Sysname> system-view

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

[Sysname-bfd-static-session-abc]

# 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 VLAN-interface 10 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 vlan-interface 11 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 ttl

discriminator

track bfd

bfd template

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

Use undo bfd template to delete the BFD template.

Syntax

bfd template template-name

undo bfd template template-name

Default

No BFD templates exist.

Views

System view

Predefined user roles

network-admin

Parameters

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

Examples

# Create BFD template bfd1 and enter BFD template view.

<Sysname> system-view

[Sysname] bfd template bfd1

[Sysname-bfd-template-bfd1]

bfd ttl

Use bfd ttl to specify the TTL value for BFD packets.

Use undo bfd ttl to restore the default.

Syntax

bfd { peer-ip ipv4-address mask-length | peer-ipv6 ipv6-address prefix-length } ttl { single-hop | multi-hop } ttl-value

undo bfd { peer-ip ipv4-address mask-length | peer-ipv6 ipv6-address prefix -length } ttl { single-hop | multi-hop }

Default

The TTL value of a single-hop BFD packet is 255. The TTL value of a multihop BFD packet is 64.

Views

System view

Predefined user roles

network-admin

Parameters

peer-ip ipv4-address mask-length: Specifies a peer IPv4 address range for the BFD session. The ipv4-address argument represents a valid unicast IPv4 address in dotted decimal notion. The mask-length argument represents the mask length in the range of 8 to 32.

peer-ipv6 ipv6-address prefix-length: Specifies a peer IPv6 address range for the BFD session. The ipv6-address argument represents an IPv6 address. The prefix-length argument represents a prefix length in the range of 16 to 128.

single-hop: Specifies single-hop BFD sessions.

multi-hop: Specifies multihop BFD sessions.

ttl-value: Specifies the TTL value for BFD packets, in the range of 1 to 255.

Usage guidelines

Application scenarios

When you connect an H3C device to a third-party device, for successful BFD session negotiation, make sure the TTL value settings for BFD packets on both ends of the BFD session are the same.

Operating mechanism

When the device receives a BFD packet in DOWN or INIT state from its peer, it verifies the TTL value of the packet and performs one of the following actions:

· For a single-hop BFD session, if the device receives a packet that carries a TTL value that is different from the TTL value specified with this command, the device drops the packet.

· For a multihop BFD session, if the device receives a packet that carries a TTL value that is greater than the TTL value specified with this command, the device drops the packet.

· If the BFD session is already up, the device sets the BFD session state to AdminDown, which triggers a BFD session renegotiation.

Restrictions and guidelines

Follow these guidelines when you set the TTL value for BFD packets:

· This command does not take effect on BFD sessions in echo packet mode.

· The device does not verify the TTL value in SBFD packets.

· For an IPv4 or IPv6 address with different mask lengths or prefix lengths, the device uses the TTL value specified with the longest mask or prefix length. For example, if the peer IP address of a BFD session is 10.10.10.1 and the following commands are configured, the device uses TTL value 253 for BFD packets.

¡ bfd peer-ip 10.10.10.0 23 ttl single-hop 254

¡ bfd peer-ip 10.10.10.0 24 ttl single-hop 253

· For an IPv4 or IPv6 subnet, the TTL value of single-hop BFD packets must be greater than the TTL value of multihop BFD packets.

· To make sure the static BFD session goes up correctly, specify different peer-ip options in the bfd ttl and bfd static bind-route-aggregation commands.

· To make sure the static BFD session goes up correctly, specify different peer-ipv6 options in the bfd ttl and bfd static bind-route-aggregation commands.

Examples

# Set the TTL value of single-hop BFD packets to 254, and specify the peer IP address of the BFD session as 10.10.10.0 and the mask length as 24.

<Sysname> system-view

[Sysname] bfd peer-ip 10.10.10.0 24 ttl single-hop 254

Related commands

bfd static

display bfd ttl

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

Application scenarios

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

Restrictions and guidelines

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

Different static BFD sessions cannot have the same local discriminator.

Examples

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

<Sysname> system-view

[Sysname] bfd static abc

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

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

Related commands

bfd static

display bfd session

Use display bfd session to display BFD session information.

Syntax

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

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

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

display bfd session [ [ dynamic ] [ control | echo ] [ lsp | te | pw ] [ 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 ] ]

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

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

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

discriminator local local-value: Specifies a BFD session by its local discriminator. The value range for the local-value argument is 1 to 4294967295.

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

dynamic: Specifies dynamic BFD sessions.

static: Specifies static BFD sessions.

control: Specifies BFD sessions in control packet mode.

echo: Specifies BFD sessions in echo mode. ‌

ip: Specifies BFD sessions used to detect IPv4 links.

ipv6: Specifies BFD sessions used to detect IPv6 links.

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.

state: Displays BFD sessions by session state.

down: Specifies BFD sessions in Down state.

admin-down: Specifies BFD sessions in AdminDown state.

init: Specifies BFD sessions in Init state.

up: Specifies BFD sessions in Up state.

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

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

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

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

verbose: Displays detailed BFD session information.

Usage guidelines

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

Examples

# Display brief information about all BFD sessions.

<Sysname> display bfd session

Total sessions: 8 Up sessions: 8 Init mode: Active

IPv4 session working in control packet mode:

LD/RD SourceAddr DestAddr State Holdtime Interface

513/513 1.1.1.1 1.1.1.2 Up 2297ms Vlan100

IPv6 session working in control packet mode:

Local discr: 513 Remote discr: 513

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

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

Session state: Up Interface: Vlan100

Hold time: 2142ms

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

IPv4 static session working in control packet mode:

LD/RD SourceAddr DestAddr State Holdtime Interface

1600/1600 1.1.1.1 1.1.1.2 Up 2290ms Vlan100

IPv6 static session working in control packet mode:

Local discr: 1700 Remote discr: 1700

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

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

Session state: Up Interface: Vlan100

Hold time: 2142ms

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 4 Command output

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

‌

# Display detailed BFD session information.

<Sysname> display bfd session verbose

Total sessions: 8 Up sessions: 8 Init mode: Active

IPv4 session working in control packet mode:

Local discr: 513 Remote discr: 513

Source IP: 1.1.1.1 Destination IP: 1.1.1.2

Destination port: 3784 Session state: Up

Interface: Vlan-interface100

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

Min Rx interval: 500ms Detection time: 2500ms

Rx count: 42 Tx count: 43

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

Hold time: 2078ms Auth mode: None

Detect mode: Async Slot: 0

Protocol: OSPF

Version: 1 TTL: 255

Diag info: No Diagnostic

Hardware mode: Disable

Tracked interface: Vlan-interface100

IPv6 session working in control packet mode:

Local discr: 513 Remote discr: 513

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

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

Destination port: 3784 Session state: Up

Interface: Vlan-interface100

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

Min Rx interval: 500ms Detection time: 2500ms

Rx count: 38 Tx count: 38

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

Hold time: 2211ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: OSPFv3

Version: 1 TTL: 255

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: 0ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1 TTL: 255

Diag info: No Diagnostic

Hardware mode: Disable

IPv4 static session working in control packet mode:

Session name: aaaa

Local discr: 1600 Remote discr: 1600

Source IP: 1.1.1.1 Destination IP: 1.1.1.2

Destination port: 3784 Session state: Up

Interface: Vlan-interface100

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

Min Rx interval: 500ms Detection time: 2500ms

Rx count: 42 Tx count: 43

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

Hold time: 2078ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: STATIC_IPv4

Version: 1 TTL: 255

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: Vlan-interface100

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

Min Rx interval: 500ms Detection time: 2500ms

Rx count: 38 Tx count: 38

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

Hold time: 2211ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: STATIC_IPv6

Version: 1 TTL: 255

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 TTL: 255

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 TTL: 255

Diag info: No Diagnostic

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 TTL: 255

Diag info: No Diagnostic

Hardware mode: Disable

Table 5 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.
IPv4 session working in control packet 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. · 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. · MPLS PW session working in echo mode. · MPLS TE static session working in control packet mode. · MPLS TE static session working in echo mode. · MPLS PW static session working in control packet mode.
Local discr	Local discriminator of the session.
Remote discr	Remote discriminator of the session.
Source IP	Source IP address of the session.
Destination IP	Destination IP address of the session.
Destination port	Destination port number in BFD packets defined in Comware: · The destination port number in single-hop BFD control packets is 3784. · The destination port number in single-hop or multihop BFD echo packets is 3785. · The destination port number in multihop BFD control packets is 4784. · The destination port number in BFD control packets for association between link aggregation and BFD is 6784. The device uses the destination port number in incoming packets that are not defined in Comware as the destination port number in outgoing BFD packets.
Session state	Session state: Down, AdmDown, Init, or Up.
Interface	Name of the interface of the session.
Min Tx interval	Minimum transmit interval.
Min Rx interval	Minimum receive interval.
Actual Tx interval	Actual transmit interval.
Detection time	Actual session detection timer.
Rx count	Number of packets received.
Tx count	Number of packets sent.
Hold time	Length of time before session detection timer expires. For a BFD session in down state, this field displays 0ms.
Auth mode	Session authentication mode.
Connection type	Connection type of the interface: Direct or Indirect.
Up duration	Time period for which the session has been up.
Detect mode	Detection mode: · Async—Asynchronous mode. · Demand—Demand mode. · Async/Echo—Asynchronous mode with echo detection enabled. · Demand/Echo—Demand mode with echo detection enabled.
Slot	Slot number of the card where the BFD session resides. Slot number of the card where the BFD session resides.
Protocol	Protocol associated with BFD: · OSPF. · ISIS_BR_L1—IS-IS with the network type as broadcast and the router type as Level 1. · ISIS_BR_L2—IS-IS with the network type as broadcast and the router type as Level 2. · ISIS_P2P—IS-IS with the network type as P2P. · ISIS6_BR_L1—IPv6 IS-IS with the network type as broadcast and the router type as Level 1. · ISIS6_BR_L2—IPv6 IS-IS with the network type as broadcast and the router type as Level 2. · ISIS6_P2P—IPv6 IS-IS with the network type as P2P. · BGP. · 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. · STATIC_IPv4—IPv4 static BFD session. · STATIC_IPv6—IPv6 static BFD session.
TTL	TTL value of BFD packets.
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.
Hardware mode	Whether BFD packets are processed in hardware: · Enabled. · Disable—BFD packets are processed in software.
Tracked interface	Interface monitored by the static BFD session.

‌

Related commands

bfd static

display bfd session route-aggregation

Use display bfd session route-aggregation to display information about static BFD sessions created to detect the aggregate links and member links of Layer 3 aggregate interfaces.

Syntax

display bfd session route-aggregation [ interface interface-type interface-number ]

Views

System view

Predefined user roles

network-admin

network-operator

Parameters

interface interface-type interface-number: Specifies the type and number of a Layer 3 aggregate interface. If you do not specify this option, the command displays information about all Layer 3 aggregate interfaces.

Examples

# Display information about static BFD sessions created to detect the aggregate links and member links of all Layer 3 aggregate interfaces.

Total up/down main sessions : 1/0

Total up/down sub sessions : 3/0

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

Session name : lagg

Session state : Up

Local discr : 32833

Source IP : 192.168.1.1

Destination IP : 192.168.1.2

Interface : Route-Aggregation1

Min Tx interval : 400ms

Min Rx interval : 400ms

Auth mode : None

Up duration : 00:00:08

Connection type : Direct

Detection mode : Async

Protocol : STATIC_IPv4/LAGG(MAIN)

Slot : 1

Version : 1

Diag info : No Diagnostic

Sub Session Count : 3

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

Sub session number : 1

Session state : Up

Local discr : 32834

Remote discr : 32834

Source IP : 192.168.1.1

Destination IP : 192.168.1.2

Interface : Ten-GigabitEthernet1/0/1

Min Tx interval : 400ms

Min Rx interval : 400ms

Actual Tx interval : 400ms

Detection time : 2000ms

Rx count : 28

Tx count : 52

Hold time : 1621ms

Auth mode : None

Up duration : 00:00:08

Connection type : Direct

Detection mode : Async

Protocol : LAGG(SUB)/STATIC_IPv4

Slot : 1

Version : 1

Diag info : No Diagnostic

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

Sub session number : 2

Session state : Up

Local discr : 32835

Remote discr : 32835

Source IP : 192.168.1.1

Destination IP : 192.168.1.2

Interface : Ten-GigabitEthernet1/0/2

Min Tx interval : 400ms

Min Rx interval : 400ms

Actual Tx interval : 400ms

Detection time : 2000ms

Rx count : 28

Tx count : 52

Hold time : 1925ms

Auth mode : None

Up duration : 00:00:08

Connection type : Direct

Detection mode : Async

Protocol : LAGG(SUB)/STATIC_IPv4

Slot : 1

Version : 1

Diag info : No Diagnostic

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

Sub session number : 3

Session state : Up

Local discr : 32836

Remote discr : 32836

Source IP : 192.168.1.1

Destination IP : 192.168.1.2

Interface : Ten-GigabitEthernet1/0/3

Min Tx interval : 400ms

Min Rx interval : 400ms

Actual Tx interval : 400ms

Detection time : 2000ms

Rx count : 28

Tx count : 52

Hold time : 1705ms

Auth mode : None

Up duration : 00:00:08

Connection type : Direct

Detection mode : Async

Protocol : LAGG(SUB)/STATIC_IPv4

Slot : 1

Version : 1

Diag info : No Diagnostic

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

Table 6 Command output

Field	Description
Total up/down main sessions	Total number of static main BFD sessions in Up/Down state.
Total up/down sub sessions	Total number of static sub BFD sessions in Up/Down state.
Session state	Session state. Options include Down, Init, and Up.
Local discr	Local disclaimer of the session.
Remote discr	Local disclaimer of the session.
Source IP	Source IP address of the session.
Destination IP	Destination IP address of the session.
Interface	Name and number of the interface on which the session is created.
Min Tx interval	Minimum transmission interval in milliseconds.
Min Rx interval	Minimum receiving interval in milliseconds.
Auth mode	Session authentication mode. Options include: · M-MD5—Use the Meticulous MD5 algorithm for authentication. · M-SHA1—Use the Meticulous SHA1 algorithm for authentication. · MD5—Use the MD5 algorithm for authentication. · SHA1—Use the SHA1 algorithm for authentication. · Simple—Simple authentication. · None—No authentication.
Up duration	Session up duration in the hh:mm:ss format.
Connection type	Connection type of the interface. Options include: · Direct—Direct connection. · Indirect—Indirect connection.
Detection mode	Detection mode. Options include: · Async—Asynchronous mode. · Demand—Query mode. · Async/Echo—Asynchronous mode enabled with the echo function. · Demand/Echo—Query mode enabled with the echo function.
Protocol	Protocol used for BFD collaboration. Options include: · STATIC_IPv4/LAGG(MAIN)—Detect the static BFD main session for the IPv4 aggregate link of the aggregate interface. · STATIC_IPv6/LAGG(MAIN)—Detect the static BFD main session for the IPv6 aggregate link of the aggregate interface. · LAGG(SUB)/STATIC_IPv4—Detect the static BFD sub session for the IPv4 member link of the aggregate interface. · LAGG(SUB)/STATIC_IPv6—Detect the static BFD sub session for the IPv6 member link of the aggregate interface.
Slot	Slot number of the card where the BFD session resides. Slot number of the card where the BFD session resides.
Version	BFD session version.
Diag info	Session diagnosis information. Options include: · No Diagnostic—No diagnosis information. · Control Detection Time Expired—The local detection timer of the control session expired and the session is down. · Echo Function Failed—The local detection timer of the Echo session expired or the source IP address of the Echo packets is deleted. The session is down. · Neighbor Signaled Session Down—The peer notified the local end of the BFD session down event. · Administratively Down—The local system prevents the BFD session from being established.
Sub Session Count	Number of static BFD sub sessions.
Sub session number	Number of the static BFD sub session.
Actual Tx interval	Actual transmission interval in milliseconds.
Detection time	Actual detection interval in milliseconds.
Rx count	Number of received packets.
Tx count	Number of sent packets.
Hold time	Remaining time before session detection times out. When the BFD session is in down state, this field displays 0ms.

‌

display bfd ttl

Use display bfd ttl to display the TTL values for BFD packets.

Syntax

display bfd ttl

Views

Any view

Predefined user roles

network-admin

network-operator

Examples

# Display the TTL values for BFD packets.

<Sysname> display bfd ttl

Peer IP Mask length Type TTL value

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

10.10.10.0 24 single-hop 255

10.1.1.0 25 multi-hop 254

Peer IPv6 Prefix length Type TTL value

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

10:1:: 64 single-hop 255

11:1:: 96 multi-hop 255

Table 7 Command output

Field	Description
Peer IP	Peer IPv4 address of the BFD session.
Peer IPv6	Peer IPv6 address of the BFD session.
Mask length	Mask length of the IPv4 address.
Prefix length	Prefix length of the IPv6 address.
Type	Detection type of the BFD session: · single-hop—Single-hop detection. · multi-hop—Multihop detection.
TTL value	TTL value of BFD packets.

Related commands

bfd ttl

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

10-High Availability Command Reference

BFD commands

Application scenarios

Restrictions and guidelines

Application scenarios

Operating mechanism

Application scenarios

Operating mechanism

Restrictions and guidelines

Application scenarios

Operating mechanism

Restrictions and guidelines

Application scenarios

Recommended configuration

Restrictions and guidelines

Application scenarios

Operating mechanism

Operating mechanism

Application scenarios

Operating mechanism

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

bfd multi-hop authentication-mode

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Operating mechanism

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

Application scenarios

Recommended configuration (for Ethernet link aggregation)

Restrictions and guidelines

Application scenarios

Operating mechanism

Restrictions and guidelines

Application scenarios

Restrictions and guidelines

display bfd ttl

snmp-agent trap enable bfd

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