priority-flow-control no-drop dot1p

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

Use undo priority-flow-control no-drop dot1p to restore the default.

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.

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.

Usage guidelines

You can enable PFC for certain 802.1p priorities at the two ends of a link. When network congestion occurs, the local device checks the PFC status for the 802.1p priority carried in each arriving packet. The device processes the packet depending on the PFC status as follows:

If PFC is enabled for the 802.1p priority, the local device accepts the packet and sends a PFC pause frame to the peer. The peer stops sending packets carrying this 802.1p priority for an interval as specified in the PFC pause frame. This process is repeated until the congestion is removed.
If PFC is disabled for the 802.1p priority, the local port drops the packet.

The relationship between the PFC function and the generic flow control function is shown in Table 8.

Table 8: The relationship between the PFC function and the generic flow control function

flow-control	priority-flow-control enable	priority-flow-control no-drop dot1p	Remarks
Unconfigurable	Configured	Configured	You cannot enable flow control by using the flow-control command on a port where PFC is enabled and PFC is enabled for the specified 802.1p priority values.
Configured	Configurable	Unconfigurable	On a port configured with the flow-control command, you can enable PFC, but you cannot enable PFC for specific 802.1p priorities. Enabling both generic flow control and PFC on a port disables the port from sending common or PFC pause frames to inform the peer of congestion conditions. However, the port can still handle common and PFC pause frames from the peer.

When you configure PFC, follow these guidelines:

As a best practice to ensure correct operations of IRF and other protocols, do not enable PFC for 802.1p priorities 0, 6, and 7.
Perform the same PFC configuration on all ports that traffic travels through.

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

Examples

# Configure Ten-GigabitEthernet 1/0/1 to automatically negotiate with the peer port to enable PFC, 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

priority-flow-control

flow-control

flow-control receive enable

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