Contents

PFC commands· 1

display priority-flow-control 1

priority-flow-control (Ethernet interface view) 2

priority-flow-control (system view) 3

priority-flow-control early-warning inpps· 4

priority-flow-control early-warning outpps· 5

priority-flow-control no-drop dot1p (Ethernet interface view) 6

priority-flow-control no-drop dot1p (system view) 7

priority-flow-control poolID headroom·· 8

 

 

PFC commands

display priority-flow-control

Use display priority-flow-control to display the PFC information for an interface.

Syntax

display priority-flow-control interface [ interface-type [ interface-number ] ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

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

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

HGE1/0/1      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 on an Ethernet interface.

Syntax

priority-flow-control { auto | enable }

undo priority-flow-control

Default

PFC is disabled on an Ethernet interface.

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 command executed.

·     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 HundredGigE 1/0/1.

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] priority-flow-control enable

Related commands

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.

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 all Ethernet interfaces.

<Sysname> system-view

[Sysname] priority-flow-control enable

Related commands

priority-flow-control (Ethernet interface view)

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 HundredGigE 1/0/1.

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] 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

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.

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

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 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 HundredGigE 1/0/1.

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] 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 and set PFC thresholds for the specified 802.1p priorities.

Use undo priority-flow-control no-drop dot1p to disable PFC for the specified 802.1p priorities.

Syntax

priority-flow-control no-drop dot1p dot1p-list [ pause-threshold { threshold-value | ratio threshold-ratio } [ headroom cell-count | pause-threshold-offset offset-value | reserved-buffer reserved-value ] * ]

undo priority-flow-control no-drop [ dot1p dot1p-list ]

Default

PFC is disabled for all 802.1p priorities.

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. If you do not specify an 802.1p priority when executing the undo form of this command, this command disables PFC for all 802.1p priority values.

pause-threshold: Specifies the back pressure frame triggering threshold. If you do not specify this keyword, all PFC thresholds use their defaults.

threshold-value: Specifies the back pressure frame triggering threshold in absolute value in the range of 1024 to 200000000.

ratio threshold-ratio: Specifies the back pressure frame triggering threshold in percentage in the range of 1 to 90.

headroom headroom-value Specifies the maximum number of cell resources that can be used in the headroom storage space for queues, in the range of 256 to 1000000.

pause-threshold-offset offset-value: Specifies the offset between the back pressure frame stopping threshold and triggering threshold in the range of 256 to 1000000.

reserved-buffer reserved-value: Specifies the PFC reserved threshold for queues, in the range of 256 to 1000000.

Usage guidelines

	CAUTION: After PFC for 802.1p priorities is enabled, each PFC threshold mentioned above uses a default value, which is adequate in typical network environments. As a practice, do not change the default value.

 

Setting PFC thresholds enables flexible control over PFC and can make good use of the storage spaces. The device supports the following PFC thresholds:

·     Headroom buffer threshold—Maximum cell resources that can be used by packets with the specified 802.1p priority values in a headroom storage space. An interface drops received packets once this threshold is reached.

·     Back pressure frame triggering threshold—Maximum cell resources that can be used by packets with the specified 802.1p priority values in a shared storage space. PFC is triggered once this threshold is reached. The back pressure frame triggering threshold can be configured in the following methods:

¡     Absolute value—Maximum cell resources set in absolute value (static back pressure frame triggering threshold).

¡     Percentage—Maximum cell resources set in percentage (dynamic back pressure frame triggering threshold).

·     Offset between the back pressure frame stopping threshold and triggering threshold—When the number of cell resources used by packets with a specific 802.1p priority value decreases by this offset after PFC is triggered, PFC will be stopped.

·     PFC reserved threshold—Number of cell resources reserved for packets with the specified 802.1p priority values in a guaranteed storage space.

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

Examples

# Enable PFC on HundredGigE 1/0/1, and enable PFC for 802.1p priority 5.

<Sysname> system-view

[Sysname] interface hundredgige 1/0/1

[Sysname-HundredGigE1/0/1] priority-flow-control enable

[Sysname-HundredGigE1/0/1] priority-flow-control no-drop dot1p 5

Related commands

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

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

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.

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.

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. For more information about the 802.1p priority, see ACL and QoS Configuration Guide.

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

display priority-flow-control

priority-flow-control

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

priority-flow-control poolID headroom

Use priority-flow-control poolid headroom to set the maximum number of cell resources that can be used in a headroom storage space.

Use undo priority-flow-control poolid headroom to restore the default.

Syntax

priority-flow-control poolid pool-number headroom headroom-number

undo priority-flow-control poolid pool-number headroom

Default

The maximum number of cell resources that can be used in a headroom storage space is not set.

Views

System view

Predefined user roles

network-admin

Parameters

pool-number: Specifies a headroom storage space by its number, which is fixed at 0.

headroom-number: Specifies the maximum number of cell resources, in the range of 256 to 30000000.

Examples

# Set the headroom buffer threshold to 1000 for headroom storage space 0.

<sysname> system-view

[Sysname] priority-flow-control poolID 0 headroom 1000