Reference Guide

Defaults none
Command Modes INTERFACE
Command History
This guide is platform-specific. For command information about other platforms, refer to the
relevant FTOS Command Line Reference Guide .
The following is a list of the FTOS version history for this command.
Version 8.3.19.0 Introduced on the S4820T.
Version 8.3.12.0 Introduced on the S4810.
Version 8.3.16.0 Introduced on the MXL 10/40GbE Switch IO Module.
Usage
Information
If you apply an input policy with PFC disabled (no pfc mode on):
• You can enable link-level flow control on the interface. To delete the input policy, first
disable link-level flow control. PFC is then automatically enabled on the interface
because an interface is by default PFC-enabled.
• PFC still allows you to configure lossless queues on a port to ensure no-drop handling
of lossless traffic.
When you apply an input policy to an interface, an error message is displayed if:
• The PFC dot1p priorities result in more than two lossless port queues globally on the
switch.
• You already enabled link-level flow control. PFC and link-level flow control cannot be
enabled at the same time on an interface.
In a switch stack, configure all stacked ports with the same PFC configuration.
A DCB input policy for PFC applied to an interface may become invalid if you reconfigure the
dot1p-queue mapping. This situation occurs when the new dot1p-queue assignment exceeds
the maximum number (2) of lossless queues supported globally on the switch. In this case, all
PFC configurations received from PFC-enabled peers are removed and resynchronized with the
peer devices.
Traffic may be interrupted when you reconfigure PFC no-drop priorities in an input policy or
reapply the policy to an interface.
If the priority group to QoS policy mapping configurations in the DCB output profile are not
complete (for example, no priorities are mapped or only some of the priorities are mapped), all
eight priorities map to a single priority group with a PGID of 0 for DCBx negotiations.
Related
Commands
dcb-input — creates a DCB input policy.
dcb-policy input stack-unit stack-ports all
Apply the specified DCB input policy on all ports of the switch stack or a single stacked switch.
S4820T
Syntax
dcb-policy input stack-unit {all | stack-unit-id} stack-ports
all dcb-input-policy-name
To remove all DCB input policies applied to the stacked ports and rest the PFC to its default
settings, use the no dcb-policy input stack-unit all command.
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