Users Guide

DCB INPUT POLICY mode

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 32 characters.

6 Exit DCB input policy conguration mode.

DCB INPUT POLICY mode

exit

7 Enter interface conguration mode.

CONFIGURATION mode

interface type slot/port

8 Apply the input policy with the PFC conguration 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 trac service.

Dell Networking OS 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 congurations that are received in TLVs from peer devices.

By applying a DCB input policy with PFC enabled, you enable PFC operation on ingress port trac. To achieve complete lossless handling

of trac, also enable PFC on all DCB egress ports or congure the dot1p priority-queue assignment of PFC priorities to lossless queues.

To remove a DCB input policy, including the PFC conguration it contains, use the no dcb-input policy-name command in

INTERFACE Conguration mode. To disable PFC operation on an interface, use the

no pfc mode on command in DCB Input Policy

Conguration 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 trac is mapped are lossless by default. Trac may

be interrupted due to an interface ap (going down and coming up) when you recongure 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 congured priority trac (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 ow control on the interface. To delete the input policy, rst disable link-level ow control. PFC is then

automatically enabled on the interface because an interface is by default PFC-enabled.

• PFC still allows you to congure lossless queues on a port to ensure no-drop handling of lossless trac.

NOTE

: You cannot enable PFC and link-level ow 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 ow control is already enabled. You cannot be enable PFC and link-level ow control at the same time on an interface.

Data Center Bridging (DCB)