Reference Guide

pfc mode on
The default is PFC mode is on.
5. (Optional) Enter a text description of the input policy.
DCB INPUT POLICY mode
description text
The maximum is 80 characters.
6. Exit DCB input policy configuration mode.
DCB INPUT POLICY mode
exit
7. Enter interface configuration mode.
CONFIGURATION mode
interface type slot/port
8. Apply the input policy with the PFC configuration to an ingress interface.
INTERFACE mode
dcb-policy input policy-name
9. Repeat Steps 1 to 8 on all PFC-enabled peer interfaces to ensure lossless traffic service.
FTOS Behavior: As soon as you apply a DCB policy with PFC enabled on an interface, DCBx starts exchanging
information with PFC-enabled peers. The IEEE802.1Qbb, CEE, and CIN versions of PFC Type, Length, Value (TLV) are
supported. DCBx also validates PFC configurations that are received in TLVs from peer devices.
By applying a DCB input policy with PFC enabled, you enable PFC operation on ingress port traffic. To achieve complete
lossless handling of traffic, also enable PFC on all DCB egress ports or configure the dot1p priority-queue assignment of
PFC priorities to lossless queues (refer to Configuring Lossless Queues).
To remove a DCB input policy, including the PFC configuration it contains, use the no dcb-input policy-name
command in INTERFACE Configuration mode. To disable PFC operation on an interface, use the no pfc mode on
command in DCB Input Policy Configuration mode. PFC is enabled and disabled as the global DCB operation is enabled
(dcb enable) or disabled (no dcb enable).
You can enable any number of 802.1p priorities for PFC. Queues to which PFC priority traffic is mapped are lossless by
default. Traffic may be interrupted due to an interface flap (going down and coming up) when you reconfigure the
lossless queues for no-drop priorities in a PFC input policy and reapply the policy to an interface.
To apply PFC, a PFC peer must support the configured priority traffic (as detected by DCBx).
To honor a PFC pause frame multiplied by the number of PFC-enabled ingress ports, the minimum link delay must be
greater than the round-trip transmission time the peer requres.
If you apply an input policy with PFC disabled (no pfc mode on):
• You can enable link-level flow control on the interface (refer to Ethernet Pause Frames). 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 (refer to
Configuring Lossless Queues).
NOTE: You cannot enable PFC and link-level flow control at the same time on an interface.
When you apply an input policy to an interface, an error message displays if:
• The PFC dot1p priorities result in more than two lossless port queues globally on the switch.
• Link-level flow control is already enabled. You cannot be enable PFC and link-level flow control at the same time
on an interface.
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