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10-BFD commands

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BFD commands

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 VLAN-interface 11.

<Sysname> system-view

[Sysname] interface vlan-interface 11

[Sysname-Vlan-interface11] bfd demand enable

Related commands

bfd echo enable

bfd detect-multiplier

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

Use undo bfd detect-multiplier to restore the default.

Syntax

bfd detect-multiplier value

undo bfd detect-multiplier

Default

The single-hop detection time multiplier is 5.

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

Table 1 Actual detection interval calculation method

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

Only the following static BFD sessions support this command:

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

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

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

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

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

bfd echo enable

Use bfd echo enable to enable the echo function.

Use undo bfd echo enable to disable the echo function.

Syntax

bfd echo [ receive | send ] enable

undo bfd echo [ receive | send ] enable

Default

The echo function is disabled.

Views

Interface view

Static BFD session view

Predefined user roles

network-admin

Parameters

receive: Specifies the echo packet receiving capability.

send: Specifies the echo packet sending capability.

Usage guidelines

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

· Periodically sends echo packets to detect link connectivity.

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

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

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

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

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

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

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.

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

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

As a best practice, execute this command only one end, and 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.

As a best practice, execute this command only one end. 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 init-fail-timer

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

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

Syntax

bfd init-fail-timer seconds

undo bfd init-fail-timer

Default

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

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

CAUTION:

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

This command takes effect only for control packet mode.

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

Examples

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

<Sysname> system-view

[Sysname] bfd init-fail-timer 10

bfd min-echo-receive-interval

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

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

Syntax

bfd min-echo-receive-interval interval

undo bfd min-echo-receive-interval

Default

The minimum interval for receiving BFD echo packets is 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 BFD echo packets, in milliseconds. The value takes 0 or is in the range of 3 to 10000.

Usage guidelines

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

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

· The echo mode is enabled on the local end.

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

Only the following static BFD sessions support this command:

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

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

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

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

Examples

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

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

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

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

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

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

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

bfd min-transmit-interval

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

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

Syntax

bfd min-transmit-interval interval

undo bfd min-transmit-interval

Default

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

Views

Interface view

BFD template view

Static BFD session view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

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

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

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

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

Examples

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

<Sysname> system-view

[Sysname] interface vlan-interface 11

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

bfd multi-hop destination-port

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

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

Syntax

bfd multi-hop destination-port port-number

undo bfd multi-hop destination-port

Default

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

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

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

Examples

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

<Sysname> system-view

[Sysname] bfd multi-hop destination-port 3784

bfd multi-hop detect-multiplier

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

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

Syntax

bfd multi-hop detect-multiplier value

undo bfd multi-hop detect-multiplier

Default

The multihop detection time multiplier for control mode is 5.

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

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

Table 2 Actual detection interval calculation method

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

Only the following static BFD sessions support this command:

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

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

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

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

Examples

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

<Sysname> system-view

[Sysname] bfd multi-hop detect-multiplier 6

bfd multi-hop min-echo-receive-interval

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

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

Syntax

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

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

Default

The minimum interval for receiving multihop BFD echo packets is 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

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

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

Examples

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

<Sysname> system-view

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

Related commands

bfd static

bfd multi-hop min-receive-interval

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

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

Syntax

bfd multi-hop min-receive-interval interval

undo bfd multi-hop min-receive-interval

Default

The minimum interval for receiving multihop BFD control packets is 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

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

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

Examples

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

<Sysname> system-view

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

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

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

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

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

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

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

Examples

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

<Sysname> system-view

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

bfd session init-mode

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

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

Syntax

bfd session init-mode { active | passive }

undo bfd session init-mode

Default

BFD uses the active mode.

Views

System view

Predefined user roles

network-admin

Parameters

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

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

Usage guidelines

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

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

Examples

# Configure the session establishment mode as passive.

<Sysname> system-view

[Sysname] bfd session init-mode passive

bfd session-negotiation delay-upon-down

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

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

Syntax

bfd session-negotiation delay-upon-down interval

undo bfd session-negotiation delay-upon-down

Default

Session negotiation delay is disabled for down BFD sessions.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

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

Examples

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

<Sysname> system-view

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

Related commands

display bfd session

bfd session-negotiation delay-upon-reboot

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

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

Syntax

bfd session-negotiation delay-upon-reboot interval

undo bfd session-negotiation delay-upon-reboot

Default

BFD session negotiation delay upon a device reboot is disabled.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

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

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

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

Examples

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

<Sysname> system-view

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

Related commands

bfd session-negotiation delay-upon-down

display bfd session

bfd static

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

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

Syntax

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

bfd static session-name [ peer-ip ipv4-address interface interface-type interface-number source-ip ipv4-address ]

undo bfd static session-name

Static BFD session for multihop detection with IPv4 control packets:

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

undo bfd static session-name

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

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

undo bfd static session-name

Static BFD session for multihop detection with IPv4 echo packets:

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

undo bfd static session-name

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

bfd static session-name [ peer-ipv6 ipv6-address interface interface-type interface-number source-ipv6 ipv6-address ]

undo bfd static session-name

Static BFD session for multihop detection with IPv6 control packets:

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

undo bfd static session-name

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

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

undo bfd static session-name

Static BFD session for multihop detection with IPv6 echo packets:

bfd static session-name [ peer-ipv6 ipv6-address [ vpn-instance vpn-instance-name ] destination-ipv6 ipv6-address [ source-ipv6 ipv6-address ] one-arm-echo [ discriminator auto ] ]

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

bfd static session-name [ peer-ip default-ip interface interface-type interface-number source-ip ip-address ]

undo bfd static session-name

Default

No static BFD sessions exist.

Views

System view

Predefined user roles

network-admin

Parameters

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

peer-ip ipv4-address: Specifies the peer IPv4 address in dotted decimal notation. It must be a valid unicast IPv4 address. For a static BFD session in control packet mode, the peer IPv4 address and the source IPv4 address determine the path to be detected. For a static BFD session in echo packet mode, the peer IPv4 address and the destination IPv4 address determine the path to be detected.

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

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

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

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

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

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

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

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

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

discriminator: Specifies BFD session discriminators.

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 this option, the static BFD session does not monitor any interfaces.

Usage guidelines

Application scenarios

A static BFD session can be used for single-hop detection and multihop detection.

Operating mechanism

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

For a static BFD session in control packet mode, the source IP address of BFD packets is the IP address specified for the source-ip/source-ipv6 keyword, and the destination IP address is the IP address specified for the peer-ip/peer-ipv6 keyword.

For a static BFD session in echo packet mode, the source IP address of BFD packets is the IP address specified for the source-ip/source-ipv6 keyword, and the destination IP address is the IP address specified for the destination-ip/destination-ipv6 keyword. If no source IP address is specified, the device uses the IP address specified in the destination-ip or destination-ipv6 command as the source IP address of echo packets.

Recommended configuration

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

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

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

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

A static BFD session can monitor the following interfaces:

· Layer 2 Ethernet interfaces.

· Layer 3 Ethernet interfaces and their subinterfaces.

· Layer 2 aggregate interfaces and their member ports.

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

Restrictions and guidelines

If a static BFD session in control packet mode is created on the peer device, you must use this command to create a static BFD session on the local device. The BFD session discriminators must match on the local and peer devices. For example, if you execute the bfd static abc peer-ip 20.1.1.1 source-ip 20.1.1.2 command in system view and the discriminator local 513 and discriminator remote 514 commands in static BFD session on the local device, you must execute the bfd static abc peer-ip 20.1.1.2 source-ip 20.1.1.1 command and the discriminator local 514 and discriminator remote 513 commands on the peer device.

When creating a static BFD session, you must specify a peer IP address. The system checks only the format of the IP address but not its correctness. If the peer IPv4 or IPv6 address is incorrect, the static BFD session cannot be established. The bfd static session-name command without any parameters specified can only be used to enter the view of an existing static BFD session.

For a static BFD session in control packet mode, you must use the discriminator command to specify its local and remote discriminators. Otherwise, the static BFD session does not take effect.

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

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

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

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

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 detect data link layer connectivity for an interface, execute one of the following commands:

· bfd detect-interface source-ip

· bfd static session-name peer-ip default-ip interface interface-type interface-number source-ip ip-address

Use 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. An interface can use only one static BFD session to detect data link layer connectivity.

Examples

# Create a static BFD session and enter its view. The static BFD session detects the path between 1.1.1.1 and 1.1.1.2 and uses VLAN-interface 10 to send BFD packets with source IP address 1.1.1.1 and destination IP address is 1.1.1.2. The local discriminator is 1537, and the remote discriminator is 2048.

<Sysname> system-view

[Sysname] bfd static abc peer-ip 1.1.1.2 interface 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 11 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 detect-interface source-ip

bfd echo-source-ip

bfd echo-source-ipv6

discriminator

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

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. 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.

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.

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

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 discriminators for the static BFD session.

Syntax

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

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

Default

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

Views

Static BFD session view

Predefined user roles

network-admin

Parameters

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

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

Usage guidelines

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

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

Different static BFD sessions cannot have the same local discriminator.

Examples

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

<Sysname> system-view

[Sysname] bfd static abc

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

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

Related commands

bfd static

display bfd session

Use display bfd session to display BFD session information.

Syntax

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

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

display bfd session [ [ dynamic ] [ control | echo ] [ ipv6 ] [ state { admin-down | 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 { admin-down | 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 { admin-down | down | init | up } ] [ discriminator remote remote-value ] [ peer-ip { ipv4-address | default-ip } [ vpn-instance vpn-instance-name ] ] [ verbose ]

display bfd session [ [ static ] [ ipv6 ] [ state { admin-down | 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-value: Specifies a BFD session by its local discriminator in the range of 1 to 4294967295. If you do not specify a BFD session, this command displays information about all BFD sessions.

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

name session-name: Specifies a static BFD session by its name, a case-sensitive string of 1 to 15 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.

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

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

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

Usage guidelines

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

The discriminator local-value and discriminator local local-value parameters have the same effect. The only difference is that you do not need to enter local when using the latter.

Examples

# Display brief information about all IPv4 BFD sessions.

<Sysname> display bfd session

Total sessions: 3 Up sessions: 3 Init mode: Active

IPv4 session working in control mode:

LD/RD SourceAddr DestAddr State Running Up for Holdtime

Interface

513/513 1.1.1.1 1.1.1.2 Up 00:00:12 2297ms

Vlan100

IPv6 session working in control 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 Running Up for: 00:05:22

IPv4 static session working in echo packet mode:

LD SourceAddr DestAddr State Running Up for Holdtime

Interface

327 192.168.1.101 192.168.1.83 Up 00:04:19 2050ms

Vlan100

Table 3 Command output

Field	Description
Total Session Num	Total number of BFD sessions.
Up Session Num	Total number of active BFD sessions.
Init Mode	BFD operating mode: Active or passive.
XX session working in yy mode	BFD session type and operating mode: · IPv4 session working in control mode—IPv4 session in control mode. · IPv4 session working in echo mode. · IPv6 session working in control mode—IPv6 session in control mode. · IPv6 session working in echo mode. · IPv4 static session working in control packet mode. · IPv6 static session working in control packet mode. · IPv4 SDWAN session working in control packet mode. · IPv6 SDWAN session working in control packet mode.
LD/RD	Local discriminator/Remote discriminator of the session.
SourceAddr	Source IPv4 address of the session.
DestAddr	Destination IPv4 address of the session.
State	Session state: Down, Init, Adown, or Up.
Holdtime	Length of time before session detection timer expires. For a BFD session in Down state, this field displays 0ms.
Interface	Name of the interface of the session.
Local discr	Local discriminator of the session.
Remote discr	Remote discriminator of the session.
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.
Running Up for	Duration of the session in up state, in hh:mm:ss format. · hh—Represents the hours. · mm—Represents the minutes. · ss—Represents the seconds.
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 in control 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 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 TTL: 255

Diag Info: No Diagnostic

Hardware mode: Disable

IPv6 session working in control 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 Inter: 500ms Act Tx Inter: 5000ms

Min Rx Inter: 500ms Detect Inter: 25000ms

Rx Count: 38 Tx Count: 38

Connect Type: Direct Running Up for: 00:00:15

Hold Time: 2211ms Auth Mode: None

Detect Mode: Async Slot: 0

Protocol: OSPFv3

Version: 1 TTL: 255

Diag Info: No Diagnostic

Hardware mode: Disable

IPv4 session working in control mode:

Session name: abc

Local Discr: 310 Remote Discr: 308

Source IP: 12.1.1.1 Destination IP: 12.1.1.2

Destination port: 3784 Session State: Up

Interface: Vlan-interface100

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

Min Rx Inter: 500ms Detect Inter: 25000ms

Rx Count: 514 Tx Count: 514

Connect Type: Direct Running Up for: 00:00:15

Hold Time: 2120ms Auth Mode: None

Detect Mode: Async Slot: 0

Protocol: STATIC_IPv4

Version: 1 TTL: 255

Diag Info: No Diagnostic

Hardware mode: Disable

IPv6 session working in control 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 Inter: 500ms Act Tx Inter: 500ms

Min Rx Inter: 500ms Detect Inter: 25000ms

Rx Count: 38 Tx Count: 38

Connect Type: Direct Running Up for: 00:00:15

Hold Time: 2211ms Auth Mode: None

Detect Mode: Async Slot: 0

Protocol: STATIC_IPv6

Version: 1 TTL: 255

Diag Info: No Diagnostic

Hardware mode: Disable

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.
XX session working in yy mode	BFD session type and operating mode: · IPv4 session working in control mode—IPv4 session in control mode. · IPv4 session working in echo mode. · IPv6 session working in control mode—IPv6 session in control mode. · IPv6 session working in echo mode. · IPv4 static session working in control packet mode. · IPv6 static session working in control packet mode. · IPv4 SDWAN session working in control packet mode. · IPv6 SDWAN session working in control packet mode.
Session name	Static BFD session name. This field appears only for a static BFD session.
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, 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	Duration of the session in up state, in hh:mm:ss format. · hh—Represents the hours. · mm—Represents the minutes. · ss—Represents the seconds.
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.
Delay-up hold time	Remaining time of the delay timer, in seconds. If BFD session negotiation delay is not configured or the delay timer has expired, this field is not displayed.
Protocol	Protocol associated with BFD: · OSPF. · ISIS_BR_L1—IS-IS with the network type as broadcast and the router type as Level 1. · ISIS_BR_L2—IS-IS with the network type as broadcast and the router type as Level 2. · ISIS_P2P—IS-IS with the network type as P2P. · ISIS6_BR_L1—IPv6 IS-IS with the network type as broadcast and the router type as Level 1. · ISIS6_BR_L2—IPv6 IS-IS with the network type as broadcast and the router type as Level 2. · ISIS6_P2P—IPv6 IS-IS with the network type as P2P. · BGP. · MPLS_RSVP. · STATIC4—IPv4 static routing. · TRACK—Track. · RIP. · IPFRR—FIB IP FRR. · MAD. · MPLS_LSPV. · OSPFv3. · BGP4+. · PIM. · PIM6—IPv6 PIM. · STATIC6—IPv6 static routing. · RIPNG—RIPng. · Interface—Interface state. · TUNNEL. · VTEP. · LAGG—Link aggregation. · STATIC_IPv4—IPv4 static BFD session. · STATIC_IPv6—IPv6 static BFD session. · SDWAN—BFD session for SDWAN tunnels.
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.
Backup slot	Backup card that maintains the BFD session: Slot number of the backup card that maintains the BFD session.
Hardware mode	Hardware BFD mode: · Enabled. · Disable—Hardware BFD is disabled. BFD packets are processed by software.

‌

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 5 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

first-fail-timer

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

Use undo first-fail-timer to restore the default.

Syntax

first-fail-timer seconds

undo first-fail-timer

Default

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

Views

Static BFD session 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

This command takes effect only on static BFD sessions after you configure the process-interface-status command.

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

If you execute the command on the local end, the BFD session for detecting the local interface state fails to be established when the following conditions exist:

· The command is not executed on the remote end.

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

Examples

# Configure the timer that delays reporting the first BFD session establishment failure as 100 seconds.

<Sysname> system-view

[Sysname] bfd static abc peer-ip default-ip interface vlan-interface 11 source-ip 10.1.1.1 discriminator local 1 remote 1

[Sysname-bfd-static-session-1] first-fail-timer 100

Related commands

bfd static

display interface (Interface Command Reference)

processing-interface-status

process-interface-status

Use process-interface-status to associate the interface state with a static BFD session.

Use undo process-interface-status to restore the default.

Syntax

process-interface-status

undo process-interface-status

Default

The state of a static BFD session does not affect the state of the data link layer of the interface.

Views

Static BFD session view

Predefined user roles

network-admin

Usage guidelines

This command enables a static BFD session with peer address 224.0.0.184 to set the link layer protocol of the interface to DOWN(BFD) when detecting a link failure. To display information about the link layer protocol state, use the display interface command.

Examples

# Associate the state of VLAN-interface 11 with static BFD session abc.

<Sysname> system-view

[Sysname] bfd static abc peer-ip default-ip interface vlan-interface 11 source-ip 10.1.1.1 discriminator local 1 remote 1

[Sysname-bfd-static-session-abc] process-interface-status

Related commands

bfd static

display interface

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

special-processing

Use special-processing to enable special processing for a static BFD session used to detect data link layer connectivity.

Use undo special-processing to disable special processing for the static BFD session.

Syntax

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

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

Default

All types of special processing are disabled for a static BFD session used to detect data link layer connectivity.

Views

Static BFD session view

Predefined user roles

network-admin

Parameters

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

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

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

Usage guidelines

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

When the authentication mode for BFD packets is M-MD5, M-SHA1, HMAC-MMD5, or HMAC-MSHA1, configuring the 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 special-processing session-up command on both of the local and remote ends.

Examples

# Enable all types of special processing for a static BFD session whose outgoing interface is VLAN-interface 10.

<Sysname> system-view

[Sysname] bfd static abc peer-ip default-ip interface vlan-interface 10 source-ip 10.1.1.1 discriminator local 1 remote 1

[Sysname-bfd-static-session-1] special-processing

Related commands

bfd static

process-interface-status

17-High Availability Command Reference

BFD commands

bfd multi-hop destination-port

Application scenarios

Operating mechanism

Recommended configuration

Restrictions and guidelines

reset bfd session statistics

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