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

Usage guidelines

Use this command to enhance BFD session security.

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

Examples

# Configure HundredGigE 1/0/1 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 hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] 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 HundredGigE 1/0/1.

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] bfd demand enable

Related commands

bfd echo enable

bfd detect-interface

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 ]

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 6001 to 8000.

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

Usage guidelines

By creating a BFD session for single-hop detection through exchange of BFD control packets, this feature implements fast link detection.. When BFD detects a link fault, it sets the link layer protocol state to DOWN(BFD). This behavior helps applications relying on the link layer protocol state achieve fast convergence. The source IP address of control packets is specified manually, and the destination IP address is fixed at 224.0.0.184. As a best practice, specify the IP address of the interface as the source IP address. If the interface does not have an IP address, specify a unicast IP address other than 0.0.0.0 as the source IP address.

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

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

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 6002 remote 6020 on the local device, you must configure bfd detect-interface source-ip 20.1.1.1 discriminator local 6020 remote 6002 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 HundredGigE 1/0/1 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 hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] bfd detect-interface source-ip 20.1.1.1

bfd detect-multiplier

Use bfd detect-multiplier to set the single-hop detection time multiplier for control mode and the detection time multiplier for echo 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 mode and the detection time multiplier for echo mode are both 5.

Views

Interface view

BFD template view

Predefined user roles

network-admin

Parameters

value: Specifies a detection time multiplier. The value range for this argument is 3 to 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 mode	Detection time multiplier of the sender × actual packet sending interval of the sender
Control-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-mode BFD session in demand mode	Detection time multiplier of the sender × MAX (minimum sending interval supported by the sender, minimum receiving interval supported by the receiver)

Examples

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

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] bfd detect-multiplier 6

bfd echo enable

Use bfd echo enable to enable the echo function.

Use undo bfd echo enable to disable the echo function.

Syntax

bfd echo [ receive | send ] enable

undo bfd echo [ receive | send ] enable

Default

The echo function is disabled.

Views

Interface view

Predefined user roles

network-admin

Parameters

receive: Specifies the echo packet receiving capability.

send: Specifies the echo packet sending capability.

Usage guidelines

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

· Periodically sends echo packets to detect link connectivity.

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

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

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

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

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

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

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

Examples

# Enable the echo function on HundredGigE 1/0/1.

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] 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, do not configure the source IP address to be on the same network segment as any local interface's IP address. If you configure such a source IP address, a large number of ICMP redirect packets might be sent from the peer, resulting in link congestion.

Examples

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

<Sysname> system-view

[Sysname] bfd echo-source-ip 8.8.8.8

bfd echo-source-ipv6

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

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

Syntax

bfd echo-source-ipv6 ipv6-address

undo bfd echo-source-ipv6

Default

No source IPv6 address is configured for BFD echo packets.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

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

Examples

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

<Sysname> system-view

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

bfd min-echo-receive-interval

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

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

Syntax

bfd min-echo-receive-interval interval

undo bfd min-echo-receive-interval

Default

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

Views

Interface view

BFD template view

Predefined user roles

network-admin

Parameters

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

Examples

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

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] 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

Predefined user roles

network-admin

Parameters

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

Examples

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

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] bfd min-receive-interval 500

bfd min-transmit-interval

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

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

Syntax

bfd min-transmit-interval interval

undo bfd min-transmit-interval

Default

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

Views

Interface view

BFD template view

Predefined user roles

network-admin

Parameters

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

Examples

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

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] bfd min-transmit-interval 500

bfd multi-hop authentication-mode

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

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

Syntax

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

undo bfd multi-hop authentication-mode

Default

No authentication is performed.

Views

System view

Predefined user roles

network-admin

Parameters

m-md5: Specifies the Meticulous MD5 algorithm.

m-sha1: Specifies the Meticulous SHA1 algorithm.

md5: Specifies the MD5 algorithm.

sha1: Specifies the SHA1 algorithm.

simple: Specifies the simple authentication mode.

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

cipher: Specifies a key in encrypted form.

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

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

Usage guidelines

Use this command to enhance BFD session security.

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

Examples

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

<Sysname> system-view

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

bfd multi-hop destination-port

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

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

Syntax

bfd multi-hop destination-port port-number

undo bfd multi-hop destination-port

Default

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

Views

System view

Predefined user roles

network-admin

Parameters

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

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 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 mode is 5.

Views

System 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

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-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-mode BFD session in demand mode	Detection time multiplier of the sender × MAX (minimum sending interval supported by the sender, minimum receiving interval supported by the receiver)

Examples

# Set the multihop detection time multiplier to 6 for control mode.

<Sysname> system-view

[Sysname] bfd multi-hop detect-multiplier 6

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

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 10 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.

Examples

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

<Sysname> system-view

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

bfd multi-hop min-transmit-interval

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

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

Syntax

bfd multi-hop min-transmit-interval interval

undo bfd multi-hop min-transmit-interval

Default

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

Views

System view

Predefined user roles

network-admin

Parameters

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

Examples

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

<Sysname> system-view

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

bfd session init-mode

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

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

Syntax

bfd session init-mode { active | passive }

undo bfd session init-mode

Default

BFD uses the active mode.

Views

System view

Predefined user roles

network-admin

Parameters

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

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

Usage guidelines

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

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

Examples

# Configure the session establishment mode as passive.

<Sysname> system-view

[Sysname] bfd session init-mode passive

bfd template

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

Use undo bfd template to delete the BFD template.

Syntax

bfd template template-name

undo bfd template template-name

Default

No BFD templates exist.

Views

System view

Predefined user roles

network-admin

Parameters

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

Examples

# Create BFD template bfd1 and enter BFD template view.

<Sysname> system-view

[Sysname] bfd template bfd1

[Sysname-bfd-template-bfd1]

display bfd session

Use display bfd session to display BFD session information.

Syntax

display bfd session [ discriminator value | verbose ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

discriminator value: Specifies a BFD session by its local discriminator in the range of 1 to 4294967295. If you do not specify this option, the command displays brief information about all BFD sessions.

verbose: Displays detailed BFD session information. If you do not specify this keyword, the command displays brief BFD session information.

Examples

# Display brief information about all BFD sessions.

<Sysname> display bfd session

Total Session Num: 4 Up Session Num: 4 Init Mode: Active

IPv4 Session Working Under Ctrl Mode:

LD/RD SourceAddr DestAddr State Holdtime Interface

513/513 1.1.1.1 1.1.1.2 Up 2297ms HGE1/0/1

IPv6 Session Working Under Ctrl 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: HGE1/0/2

Hold time: 2142ms

MPLS LSP session working in control packet mode:

LD/RD SourceIP DestinationIP State Holdtime Interface

32769/32769 2.2.2.9 127.0.0.1 Up 4990ms N/A

MPLS TE session working in echo mode:

LD SourceIP DestinationIP State Holdtime Interface

32777 1.1.1.1 3.3.3.3 Up 4430ms Tun0

Table 3 Command output

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

‌

# Display detailed BFD session information.

<Sysname> display bfd session verbose

Total Session Num: 4 Up Session Num: 4 Init Mode: Active

IPv4 Session Working Under Ctrl Mode:

Local Discr: 513 Remote Discr: 513

Source IP: 1.1.1.1 Destination IP: 1.1.1.2

Session State: Up Interface: HundredGigE1/0/1

Min Tx Inter: 500ms Act Tx Inter: 500ms

Min Rx Inter: 500ms Detect Inter: 2500ms

Rx Count: 42 Tx Count: 43

Connect Type: Direct Running Up for: 00:00:20

Hold Time: 2078ms Auth mode: None

Detect Mode: Async Slot: 0

Protocol: OSPF

Version: 1

Diag Info: No Diagnostic

IPv6 Session Working Under Ctrl 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: HundredGigE1/0/2

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

MPLS LSP session working in control packet mode:

Local discr: 32769 Remote discr: 32769

Source IP: 3.3.3.9 Destination IP: 2.2.2.9

Session state: Up

Interface: N/A

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

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 1778 Tx count: 1669

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

Hold time: 4248ms Auth mode: None

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1

Diag info: No Diagnostic

MPLS TE session working in echo mode:

Local discr: 32777

Source IP: 1.1.1.1 Destination IP: 3.3.3.3

Session state: Up

Interface: Tunnel0

Hold time: 4450ms Actual Tx interval: 1000ms

Min Rx interval: 1000ms Detection time: 5000ms

Rx count: 320 Tx count: 320

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

Detection mode: Async Slot: 0

Protocol: MPLS_LSPV

Version: 1

Diag info: No Diagnostic

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 Under Ctrl Mode	BFD session type and operating mode: · IPv4 Session Working Under Ctrl Mode—IPv4 session in control mode. · IPv4 Session Working Under Echo Mode. · IPv6 Session Working Under Ctrl Mode—IPv6 session in control mode. · IPv6 Session Working Under Echo Mode. · MPLS LSP session working in control packet mode—BFD session in control mode used to detect failures in an LSP. · MPLS LSP session working in echo mode—BFD session in echo mode used to detect failures in an LSP. · MPLS TE session working in control packet mode. · MPLS TE session working in echo mode.
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, Adown, Init, or Up.
Interface	Name of the interface of the session.
Min Tx Inter	Minimum transmit interval.
Min Rx Inter	Minimum receive interval.
Act Tx Inter	Actual transmit interval.
Detect Inter	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.
Auth mode	Session authentication mode.
Connect Type	Connection type of the interface: Direct or indirect.
Running up for	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.
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.

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reset bfd session statistics

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

Syntax

reset bfd session statistics

Views

User view

Predefined user roles

network-admin

Examples

# Clear the BFD session statistics.

<Sysname> reset bfd session statistics

snmp-agent trap enable bfd

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

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

Syntax

snmp-agent trap enable bfd

undo snmp-agent trap enable bfd

Default

All SNMP notifications are enabled for BFD.

Views

System view

Predefined user roles

network-admin

Usage guidelines

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

Examples

# Disable SNMP notifications for BFD.

<Sysname> system-view

[Sysname] undo snmp-agent trap enable bfd

SBFD commands

bfd detect-multiplier

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

Use undo bfd detect-multiplier to restore the default.

Syntax

bfd detect-multiplier value

undo bfd detect-multiplier

Default

The detection time multiplier is 5.

Views

BFD template 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 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

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 400 milliseconds.

Views

BFD template view

Predefined user roles

network-admin

Parameters

interval: Specifies the minimum interval for transmitting SBFD control packets, in milliseconds. The value range for this argument is 10 to 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 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 detection time multiplier is 5.

Views

System 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 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 400 milliseconds.

Views

System view

Predefined user roles

network-admin

Parameters

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

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

Use undo bfd template to delete the BFD template.

Syntax

bfd template template-name

undo bfd template template-name

Default

No BFD templates exist.

Views

System view

Predefined user roles

network-admin

Parameters

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

Examples

# Create BFD template bfd1 and enter BFD template view.

<Sysname> system-view

[Sysname] bfd template bfd1

[Sysname-bfd-template-bfd1]

display sbfd session

Use display sbfd session to display SBFD session information.

Syntax

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

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

initiator: Displays SBFD session information for the initiator.

reflector: Displays SBFD session information for the reflector.

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

verbose: Displays detailed information about all SBFD sessions.

Usage guidelines

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

Examples

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

<Sysname> display sbfd session initiator

Total Session Num: 1 Up Session Num: 1

SBFD Session (MPLS LSP):

Local Discr: 1 Remote Discr: 1000001

Source IP: 1.1.1.1

Destination IP: 127.0.0.1

Session State: Up

Hold Time: 2184ms

Table 5 Command output

Field	Description
Total Session Num	Total number of SBFD sessions.
Up Session Num	Number of active SBFD sessions.
SBFD Session (MPLS LSP)	SBFD sessions created by MPLS.
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 2 for the initiator.

<Sysname> display sbfd session initiator discriminator 2

Local Discr: 2 Remote Discr: 1000002

Source IP: 1.1.1.2 Destination IP: 127.0.0.2

Session State: Up Hold Time: 4130ms

Min Tx Inter: 500ms Act Tx Inter: 1000ms

Detect Inter: 5000ms Running Up for: 00:01:30

Rx Count: 100 Tx Count: 100

Slot: 0

Protocol: MPLS_LSPV

Diag Info: No Diagnostic

Template Name: abc

Table 6 Command output

Field	Description
Local Discr	Local discriminator of the session.
Remote Discr	Remote discriminator of the session.
Source IP	Source IP address of the session.
Destination IP	Destination IP address of the session.
Session State	Session state: Down or Up.
Hold Time	Length of time before the session detection timer expires, in milliseconds. For an SBFD session in Down state, this field displays 0ms.
Min Tx Inter	Minimum SBFD packet transmission interval in milliseconds.
Act Tx Inter	Actual SBFD packet transmission interval in milliseconds.
Detect Inter	Actual session detection timer in milliseconds.
Running up for	Time period for which the session has been up.
Rx Count	Number of packets received.
Tx Count	Number of packets sent.
Slot	Slot number of the card where the BFD session resides.
Diag Info	Diagnostic information about the session: · No Diagnostic. · Control Detection Time Expired—The SBFD session goes down because local detection times out. · Neighbor Signaled Session Down—The remote end notifies the local end of SBFD session down.
Template Name	Template associated with the session. If no template is associated, this field is not displayed.

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

<Sysname> display sbfd session initiator verbose

Total Session Num: 1 Up Session Num: 1

SBFD Session (MPLS LSP):

Local Discr: 1 Remote Discr: 1000001

Source IP: 1.1.1.1 Destination IP: 127.0.0.1

Session State: Up Hold Time: 4130ms

Min Tx Inter: 500ms Act Tx Inter: 1000ms

Detect Inter: 5000ms Running Up for: 00:01:30

Rx Count: 100 Tx Count: 100

Slot: 0

Protocol: MPLS_LSPV

Diag Info: No Diagnostic

Template Name: abc

Table 7 Command output

Field	Description
Total Session Num	Total number of SBFD sessions.
Up Session Num	Number of active SBFD sessions.
SBFD Session (MPLS LSP)	SBFD sessions created by MPLS.
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.
Min Tx Inter	Minimum SBFD packet transmission interval.
Act Tx Inter	Actual SBFD packet transmission interval.
Detect Inter	Actual session detection timer.
Running up for	Time period for which the session has been up.
Rx Count	Number of packets received.
Tx Count	Number of packets sent.
Slot	Slot number of the card where the BFD session resides.
Diag Info	Diagnostic information about the session: · No Diagnostic. · Control Detection Time Expired—The SBFD session goes down because local detection times out. · Neighbor Signaled Session Down—The remote end notifies the local end of SBFD session down.
Template Name	Template associated with the session. If no template is associated, this field is not displayed.

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

<Sysname> display sbfd session reflector

Local discriminator 1000001 on slot 0

Configured mode: Explicit value

Total Session Num: 1

Local Discr: 1000001 Remote Discr: 1

Source IP: 2.2.2.1

Destination IP: 1.1.1.1

Hold Time: 2200ms

VRF Name: vpn1

Table 8 Command output

Field	Description
Configured mode	Discriminator type: · IP Address—IPv4 address. · Explicit Value—Integer.
Total Session Num	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 Session Num: 2

Local Discr: 1000001 Remote Discr: 1

Source IP: 2.2.2.1 Destination IP: 1.1.1.1

Min Tx Inter: 500ms Min Rx Inter: 10ms

Detect Multi: 5 Running Up for: 00:02:30

Rx Count: 100 Tx Count: 100

Max Rx Period: 498ms Max Tx Period: 1280us

Hold Time: 2200ms

VRF Name: vpn1

Local Discr: 1000001 Remote Discr: 2

Source IP: 2.2.2.2 Destination IP: 1.1.1.2

Min Tx Inter: 1000ms Min Rx Inter: 3790ms

Detect Multi: 5 Running Up for: 00:10:59

Rx Count: 123 Tx Count: 122

Max Rx Period: 980ms Max Tx Period: 580us

Hold Time: 2500ms

VRF Name: vpn2

Table 9 Command output

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

Related commands

sbfd local-discriminator

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

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

Syntax

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

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

Default

No local discriminator is set for the reflector.

Views

System view

Predefined user roles

network-admin

Parameters

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

integer-value: Specifies an integer as the local discriminator. In Release 5110, the value range for this argument is 1000001 to 16777215. In Release 5111 and later, 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 maintain SBFD session state.

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

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

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

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

Examples

# Specify 1.1.1.1 as the local discriminator for the reflector.

<Sysname> system-view

[Sysname] sbfd local-discriminator 1.1.1.1

# Specify 1000001 as the local discriminator for the reflector.

<Sysname> system-view

[Sysname] sbfd local-discriminator 1000001

Related commands

display sbfd session

mpls bfd (MPLS Command Reference)

15-High Availability Command Reference

BFD commands

bfd multi-hop destination-port

reset bfd session statistics

snmp-agent trap enable bfd

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