interface-type: Specifies an interface type. If you do not specify an interface type, the command displays the PFC information for all Ethernet interfaces.

interface-number: Specifies an interface number. If you do not specify an interface number, the command displays the PFC information for all Ethernet interfaces of the specified type.

Examples

# Display the PFC information for all Ethernet interfaces.

<Sysname> display priority-flow-control interface

Conf -- Configured mode Ne -- Negotiated mode P -- Priority

Interface Conf Ne Dot1pList P Recv Sent Inpps Outpps

XGE1/0/1 Auto On 0,2-3,5-6 0 178 43 12 15

Table 1 Command output

Field	Description
Conf -- Configured mode	Locally configured PFC status.
Ne -- Negotiated mode	Negotiated PFC status.
P -- Priority	802.1p priority value for which PFC is enabled.
Interface	Abbreviated name of the interface.
Conf	Locally configured PFC status: · Auto—The interface is configured to autonegotiate the PFC status with the remote end. · Off—PFC is disabled for the interface. · On—PFC is enabled for the interface.
Ne	Negotiated PFC status: · Off—PFC is disabled. · On—PFC is enabled.
Dot1pList	802.1p priorities that are enabled with PFC. 802.1p priority values 0 through 7 are available.
P	An 802.1p priority is displayed only when the 802.1p priority is enabled with PFC and the interface has received or sent packets with the 802.1p priority.
Recv	Number of received PFC pause frames.
Sent	Number of sent PFC pause frames.
Inpps	Incoming PFC frame rate in pps for the 802.1p priority.
Outpps	Outgoing PFC frame rate in pps for the 802.1p priority.

‌

Related commands

priority-flow-control

priority-flow-control no-drop dot1p

priority-flow-control (Ethernet interface view)

Use priority-flow-control to enable PFC on an Ethernet interface.

Use undo priority-flow-control to disable PFC.

Syntax

priority-flow-control { auto | enable }

undo priority-flow-control

Default

PFC is disabled on Ethernet interfaces.

Views

Ethernet interface view

Predefined user roles

network-admin

Parameters

auto: Specifies PFC in auto mode. In this mode, the local end automatically negotiates the PFC status with the remote end.

enable: Forcibly enables PFC.

Usage guidelines

The local device notifies the remote end to stop sending packets carrying the specified 802.1p priority if all of the following conditions exist:

· Both the local end and the remote end have PFC enabled.

· Both the local end and the remote end have the priority-flow-control no-drop dot1p dot1p-list command configured.

· The specified 802.1p priority is in the 802.1p priority list specified by the dot1p-list argument.

· The local end receives packets carrying the specified 802.1p priority, and the received packets cause congestion.

When congestion is eliminated, the local end notifies the remote end to continue to send packets carrying the specified 802.1p priority. In this way, the local device can forward packets carrying 802.1p priorities in the specified 802.1p priority list without packet drops.

If you execute this command in system view and Ethernet interface view multiple times, the most recent configuration takes effect.

Examples

# Enable PFC on Ten-GigabitEthernet 1/0/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 1/0/1

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control enable

Related commands

display priority-flow-control

priority-flow-control (system view)

priority-flow-control no-drop dot1p

priority-flow-control (system view)

Use priority-flow-control to enable PFC on all Ethernet interfaces.

Use undo priority-flow-control to disable PFC on all Ethernet interfaces.

Syntax

priority-flow-control { auto | enable }

undo priority-flow-control

Default

PFC is disabled on Ethernet interfaces.

Views

System view

Predefined user roles

network-admin

Parameters

auto: Specifies PFC in auto mode. In this mode, the local end automatically negotiates the PFC status with the remote end.

enable: Forcibly enables PFC.

Usage guidelines

The local device notifies the remote end to stop sending packets carrying the specified 802.1p priority if all of the following conditions exist:

· Both the local end and the remote end have PFC enabled.

· Both the local end and the remote end have the priority-flow-control no-drop dot1p command configured.

· The specified 802.1p priority is in the 802.1p priority list specified by the dot1p-list argument.

· The local end receives packets carrying the specified 802.1p priority, and the received packets cause congestion.

If you execute this command in system view and Ethernet interface view multiple times, the most recent configuration takes effect.

Examples

# Enable PFC on all Ethernet interfaces.

<Sysname> system-view

[Sysname] priority-flow-control enable

Related commands

display priority-flow-control

priority-flow-control (Ethernet interface view)

priority-flow-control no-drop dot1p

priority-flow-control deadlock auto-recover action

Use priority-flow-control deadlock auto-recover action to configure the action to take on packets during the delay timer period for PFC deadlock detection automatic recovery.

Use undo priority-flow-control deadlock auto-recover action to restore the default.

Syntax

priority-flow-control deadlock auto-recover action { discard | forwarding }

undo priority-flow-control deadlock auto-recover action

Default

The device forwards the received data packets during the delay timer period for PFC deadlock detection automatic recovery.

Views

System view

Predefined user roles

network-admin

Parameters

discard: Drops the received data packets.

forwarding: Forwards the received data packets.

Usage guidelines

When the device enters the PFC deadlock state, you can use this command to configure the device to drop or forward received data packets during the delay timer period for PFC deadlock detection automatic recovery.

Examples

# Configure the device to drop received data packets during the delay timer period for PFC deadlock detection automatic recovery.

<Sysname> system-view

[Sysname] priority-flow-control deadlock auto-recover action discard

Related commands

priority-flow-control deadlock cos

priority-flow-control deadlock enable

priority-flow-control deadlock auto-recover cos

Use priority-flow-control deadlock auto-recover cos to configure the delay timer for PFC deadlock detection automatic recovery.

Use undo priority-flow-control deadlock auto-recover cos to delete the delay timer for PFC deadlock detection automatic recovery.

Syntax

priority-flow-control deadlock auto-recover cos cos-value delay delay-interval

undo priority-flow-control deadlock auto-recover cos [ cos-value ]

Default

The delay timer for PFC deadlock detection automatic recovery is not configured.

Views

System view

Predefined user roles

network-admin

Parameters

cos cos-value: Specifies the CoS value of packets, in the range of 0 to 7. Different CoS values correspond to different 802.1p priority values. To see the CoS-to-802.1p mapping, execute the display qos map-table dot1p-lp command.

delay delay-interval: Specifies the delay timer for PFC deadlock detection automatic recovery, in the range of 1 to 15.

Usage guidelines

PFC deadlock detection periodically detects whether deadlock occurs to packets carrying the specified CoS value. If the device enters the PFC deadlock state and PFC deadlock detection is recovered in automatic mode, the device automatically recovers PFC deadlock detection after the delay timer expires. The delay timer is determined by this command and the PFC deadlock detection timer precision.

This command takes effect only in automatic recovery mode.

The specified CoS value must be within the 802.1p priority values configured by using the priority-flow-control no-drop dot1p command.

You can set the same delay timer for different CoS values.

If you execute this command multiple times for the same CoS value, the most recent configuration takes effect.

Examples

# Set the delay timer for PFC deadlock detection automatic recovery to 5 for packets carrying CoS value 7.

<Sysname> system-view

[Sysname] priority-flow-control deadlock auto-recover cos 7 delay 5

Related commands

display qos map-table dot1p-lp (ACL and QoS Command Reference)

priority-flow-control deadlock precision

priority-flow-control no-drop dot1p

priority-flow-control deadlock cos

Use priority-flow-control deadlock cos to set the PFC deadlock detection interval for the specified CoS value.

Use undo priority-flow-control deadlock cos to delete the PFC deadlock detection interval for the specified CoS value or all CoS values.

Syntax

priority-flow-control deadlock cos cos-value interval interval

undo priority-flow-control deadlock cos [ cos-value ]

Default

The PFC deadlock detection interval for a CoS value is not set.

Views

System view

Predefined user roles

network-admin

Parameters

cos cos-value: Specifies the CoS value of packets, in the range of 0 to 7.

interval interval: Specifies the PFC deadlock detection interval in the range of 1 to 15.

If you do not specify this keyword, the PFC feature and PFC deadlock detection feature are automatically recovered on an interface when the detection interval expires, no matter whether the interface receives PFC pause frames.

Usage guidelines

The PFC deadlock detection feature periodically detects whether deadlock occurs to packets that carry the specified CoS value. To obtain the length of time for the detection interval, multiply the detection interval by the precision of the PFC deadlock detection timer.

The specified CoS value must be within the 802.1p priority list specified by using the priority-flow-control no-drop dot1p command. To view the 802.1p priority for each CoS value, execute the display qos map-table dot1p-lp command.

You can set the same detection interval for different CoS values.

If you execute this command for the same CoS value multiple times, the most recent configuration takes effect.

Examples

# Set the PFC deadlock detection interval to 5 for packets carrying CoS value 7.

<Sysname> system-view

[Sysname] priority-flow-control deadlock cos 7 interval 5

Related commands

display qos map-table dot1p-lp (ACL and QoS Command Reference)

priority-flow-control deadlock precision

priority-flow-control no-drop dot1p

priority-flow-control deadlock enable

Use priority-flow-control deadlock enable to enable PFC deadlock detection on an interface.

Use undo priority-flow-control deadlock enable to disable PFC deadlock detection on an interface.

Syntax

priority-flow-control deadlock enable

undo priority-flow-control deadlock enable

Default

PFC deadlock detection is disabled on an interface.

Views

Ethernet interface view

Predefined user roles

network-admin

Usage guidelines

The device enters the PFC deadlock state if the following conditions exist on an interface:

· PFC for 802.1p priorities is enabled by using the priority-flow-control and priority-flow-control no-drop dot1p commands.

· Packets carrying the specified 802.1p priority are transmitted in a loop.

· No packets in the data buffer can be forwarded.

This command enables periodically detecting whether the device is in PFC deadlock state.

Examples

# Enable PFC deadlock detection on Ten-GigabitEthernet 1/0/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 1/0/1

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control deadlock enable

Related commands

priority-flow-control

priority-flow-control deadlock cos

priority-flow-control no-drop dot1p

priority-flow-control deadlock precision

Use priority-flow-control deadlock precision to set the precision for the PFC deadlock detection timer.

Use undo priority-flow-control deadlock precision to restore the default.

Syntax

priority-flow-control deadlock precision { high | low | normal }

undo priority-flow-control deadlock precision

Default

The PFC deadlock detection timer uses normal precision.

Views

System view

Predefined user roles

network-admin

Parameters

high: Specifies the high precision for the PFC deadlock detection timer.

low: Specifies the low precision for the PFC deadlock detection timer.

normal: Specifies the normal precision for the PFC deadlock detection timer.

slot slot-number: Specifies an IRF member device by its member ID.

Usage guidelines

Use this command to adjust the precision for the PFC deadlock detection timer and change the PFC deadlock detection interval.

If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Set the high precision for the PFC deadlock detection timer.

<Sysname> system-view

[Sysname] priority-flow-control deadlock precision high

priority-flow-control deadlock recover

Use priority-flow-control deadlock recover to recover PFC deadlock detection on an interface.

Syntax

priority-flow-control deadlock recover

Views

Ethernet interface view

Predefined user roles

network-admin

Usage guidelines

The device can automatically release the deadlock state, but both the PFC deadlock detection and PFC features are disabled on the interface at the same time. To manually recover PFC deadlock detection on the interface, execute this command after setting the manual recovery mode for PFC deadlock detection on the interface. The PFC feature is also enabled again when you execute this command.

Examples

# Recover PFC deadlock detection on Ten-GigabitEthernet 1/0/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 1/0/1

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control deadlock recover

Related commands

priority-flow-control deadlock recover-mode

Use priority-flow-control deadlock recover-mode to set the recovery mode for PFC deadlock detection on an interface.

Use undo priority-flow-control deadlock recover-mode to restore the default.

Syntax

priority-flow-control deadlock recover-mode { auto | manual }

undo priority-flow-control deadlock recover-mode

Default

PFC deadlock detection recovers in automatic mode on an interface.

Views

Ethernet interface view

Predefined user roles

network-admin

Parameters

auto: Specifies the automatic recovery mode.

manual: Specifies the manual recovery mode.

Usage guidelines

When the PFC deadlock state is detected and PFC deadlock detection is recovered in automatic mode, the device automatically releases the deadlock state and recovers PFC and PFC deadlock detection after the delay timer expires. Within the delay timer period, the device disables PFC and PFC deadlock detection on the interface, so that packets can be forwarded properly. PFC deadlock detection can be recovered in automatic or manual mode on the interface. Recovering this feature enables the PFC feature again at the same time. Use the automatic recovery mode when no serious failures occur.

When a packet loop cannot be resolved and the device enters the PFC deadlock state frequently, manually recover PFC deadlock detection on the interface as follows:

1. Perform troubleshooting and set the manual recovery mode for PFC deadlock detection.

2. Execute the priority-flow-control deadlock recover command to recover the PFC deadlock detection and PFC features.

Examples

# Set the manual recovery mode for PFC deadlock detection on Ten-GigabitEthernet 1/0/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 1/0/1

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control deadlock recover-mode manual

Related commands

priority-flow-control deadlock recover

priority-flow-control deadlock threshold

Use priority-flow-control deadlock threshold to configure the upper threshold for PFC deadlock times within the specified period.

Use undo priority-flow-control deadlock threshold to restore the default.

Syntax

priority-flow-control deadlock threshold cos cos-value period period count count [ error-down ]

undo priority-flow-control deadlock threshold cos [ cos-value ]

Default

The upper threshold for PFC deadlock times within the specified period is not configured.

Views

System view

Predefined user roles

network-admin

Parameters

period period: Specifies the period for detecting PFC deadlock times, in the range of 1 to 60 seconds.

count count: Specifies the upper threshold for PFC deadlock times within the specified period, in the range of 1 to 500.

error-down: Shuts down an interface when the number of PFC deadlock times within the detection period reaches the upper threshold. If you do not specify this keyword, PFC will be disabled for the corresponding 802.1p priority when the number of PFC deadlock times within the detection period reaches the upper threshold.

slot slot-number: Specifies an IRF member device by its member ID.

Usage guidelines

With this command executed, when the PFC deadlock times within the specified period exceed the upper threshold on an interface, the device disables PFC for the corresponding 802.1p priority on the interface. To recover the PFC feature on the interface in this case, execute the undo priority-flow-control deadlock threshold command.

The detection period specified in this command must be longer than the PFC deadlock detection interval configured by using the priority-flow-control deadlock cos command, so that you can determine whether the device frequently enters the PFC deadlock state.

When the device is in the PFC deadlock state, you cannot execute this command.

The specified CoS value must be within the 802.1p priority values configured by using the priority-flow-control no-drop dot1p command.

You can set the same detection period for different CoS values.

If you execute this command multiple times for the same CoS value, the most recent configuration takes effect.

Examples

# Set the upper threshold for PFC deadlock times to 100 within the period of 5 seconds.

<Sysname> system-view

[Sysname] priority-flow-control deadlock threshold cos 7 period 5 count 100

Related commands

priority-flow-control deadlock cos

priority-flow-control no-drop dot1p

priority-flow-control early-warning inpps

Use priority-flow-control early-warning inpps to configure the early warning threshold for incoming PFC packets.

Use undo priority-flow-control early-warning inpps to delete the early warning threshold for incoming PFC packets.

Syntax

priority-flow-control early-warning dot1p dot1p-list inpps pps-value

undo priority-flow-control early-warning [ dot1p dot1p-list ] inpps

Default

No early warning threshold is configured for incoming PFC packets.

Views

Ethernet interface view

Predefined user roles

network-admin

Parameters

dot1p-list: Specifies an 802.1p priority (or dot1p priority) list to identify flows that are subject to PFC (for example: 1,3-5). A hyphen (-) connects two numeric values, which together indicate a continuous value range. Different values or value ranges are separated with commas (,). You can configure up to 16 characters for this argument.

inpps pps-value: Specifies the number of PFC frames that an interface can receive in pps, in the range of 1 to 159783010.

Usage guidelines

You can configure the early warning threshold for incoming or outgoing PFC packets of an interface as needed. The early warning threshold notifies a situation where the PFC packet transmission rate is still within a normal range but needs attention.

When the rate of PFC packets that an interface sends or receives reaches the early warning threshold, the system generates traps and logs to notify the user. According to the traps and logs, the user can discover some exceptions in the network, for example:

· The NIC of the peer device fails and continuously sends PFC packets at a high speed. In this case, you can set the early warning threshold for incoming PFC packets.

· The device fails and continuously sends PFC frames. In this case, you can set the early warning threshold for outgoing PFC packets.

To monitor bidirectional PFC packets, you can set the early warning thresholds for incoming packets and outgoing packets separately.

The number of PFC pause frames that an interface receives is counted and the early warning threshold configuration takes effect only when PFC is enabled.

If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Set the early warning threshold to 80 pps for incoming PFC packets with 802.1p priority value 7 on Ten-GigabitEthernet 1/0/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 1/0/1

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control early-warning dot1p 7 inpps 80

priority-flow-control early-warning outpps

Use priority-flow-control early-warning outpps to configure the early warning threshold for outgoing PFC packets.

Use undo priority-flow-control early-warning outpps to delete the early warning threshold for outgoing PFC packets.

Syntax

priority-flow-control early-warning dot1p dot1p-list outpps pps-value

undo priority-flow-control early-warning [ dot1p dot1p-list ] outpps

Default

No early warning threshold is configured for outgoing PFC packets.

Views

Ethernet interface view

Predefined user roles

network-admin

Parameters

outpps pps-value: Specifies the number of PFC frames that an interface can send in pps, in the range of 1 to 159783010.

Usage guidelines

· The NIC of the peer device fails and continuously sends PFC packets at a high speed. In this case, you can set the early warning threshold for incoming PFC packets.

· The device fails and continuously sends PFC frames. In this case, you can set the early warning threshold for outgoing PFC packets.

To monitor bidirectional PFC packets, you can set the early warning thresholds for incoming packets and outgoing packets separately.

The number of PFC pause frames that an interface sends is counted and the early warning threshold configuration takes effect only when PFC is enabled.

If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Set the early warning threshold to 50 pps for outgoing PFC packets with 802.1p priority value 1 on Ten-GigabitEthernet 1/0/1.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 1/0/1

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control early-warning dot1p 1 outpps 50

priority-flow-control no-drop dot1p (Ethernet interface view)

Use priority-flow-control no-drop dot1p to enable PFC.

Use undo priority-flow-control no-drop dot1p to disable PFC for 802.1p priorities on an Ethernet interface.

Syntax

priority-flow-control no-drop dot1p dot1p-list

undo priority-flow-control no-drop dot1p

Default

PFC is disabled for all 802.1p priorities on an Ethernet interface.

Views

Ethernet interface view

Predefined user roles

network-admin

Parameters

Usage guidelines

If you enable PFC and execute this command on both the local and peer devices, the local device will notify the peer device to stop transmitting packets with the specified 802.1p priority when congestion occurs. When congestion is removed, the local device notifies the peer device to transmitting the packets again. This prevents packet loss for traffic with the specified priority. For more information about 802.1p priority, see QoS configuration in ACL and QoS Configuration Guide.

This command is mutually exclusive with the flow-control command or the flow-control receive enable command.

If you execute this command multiple times in system view and interface view, the most recent configuration takes effect.

Examples

# Enable PFC in auto mode on Ten-GigabitEthernet 1/0/1, and enable PFC for 802.1p priority 5.

<Sysname> system-view

[Sysname] interface ten-gigabitethernet 1/0/1

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control auto

[Sysname-Ten-GigabitEthernet1/0/1] priority-flow-control no-drop dot1p 5

Related commands

display priority-flow-control

flow-control (Interface Command Reference)

flow-control receive enable (Interface Command Reference)

priority-flow-control

priority-flow-control no-drop dot1p (system view)

Use priority-flow-control no-drop dot1p to enable PFC for 802.1p priorities on all Ethernet interfaces.

Use undo priority-flow-control no-drop dot1p to disable PFC for 802.1p priorities on all Ethernet interfaces.

Syntax

priority-flow-control no-drop dot1p dot1p-list

undo priority-flow-control no-drop dot1p

Default

PFC is disabled for all 802.1p priorities on all Ethernet interfaces.

Views

System view

Predefined user roles

network-admin

Parameters

Usage guidelines

The local device notifies the remote end to stop sending packets carrying the specified 802.1p priority if all of the following conditions exist:

· Both the local end and the remote end have PFC enabled.

· Both the local end and the remote end have the priority-flow-control no-drop dot1p command configured.

· The specified 802.1p priority is in the 802.1p priority list specified by the dot1p-list argument.

· The local end receives packets carrying the specified 802.1p priority, and the received packets cause congestion.

If you execute this command in system view and Ethernet interface view multiple times, the most recent configuration takes effect.

Examples

# Enable PFC for 802.1p priority 5 globally.

<Sysname> system-view

[Sysname] priority-flow-control no-drop dot1p 5

Related commands

priority-flow-control no-drop dot1p (Ethernet interface view)

03-Layer 2—LAN Switching Command Reference

PFC commands

display priority-flow-control

priority-flow-control (Ethernet interface view)

priority-flow-control (system view)

priority-flow-control deadlock auto-recover action

priority-flow-control deadlock auto-recover cos

priority-flow-control deadlock cos

priority-flow-control deadlock enable

priority-flow-control deadlock precision

priority-flow-control deadlock recover

priority-flow-control deadlock recover-mode

priority-flow-control deadlock threshold

priority-flow-control early-warning inpps

priority-flow-control early-warning outpps

priority-flow-control no-drop dot1p (Ethernet interface view)

priority-flow-control no-drop dot1p (system view)

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