Priority-Based Flow Control (Pfc); Pfc Overview; Pfc Configuration - Dell PowerConnect 8024 User Manual

Priority-based Flow Control (PFC)

PFC Overview

The Priority-based Flow Control feature allows the user to pause (inhibit transmission) of individual
priorities within a single physical link. By configuring PFC to independently pause congested priorities,
protocols that are highly loss sensitive can share the same link with traffic with different loss tolerances.
Priorities are differentiated by the priority field of the 802.1Q VLAN header.
CAUTION: All ports may be briefly shutdown when modifying either Flow Control (FC) or PFC settings.
PFC uses a control packet defined in 802.1Qbb and is not compatible with 802.3x FC.
NOTE: An interface that is configured for PFC is automatically disabled for 802.3x Flow Control.
When PFC is disabled on an interface, the FC configuration for the interface becomes active. FC frames
received on a PFC configured interface are ignored.
Each priority is configured as either drop or no-drop. When a priority that is designated as no-drop
becomes congested, the priority is paused. Drop priorities do not participate in pause.
PFC is disabled by default (there are no priority classifications configured).

PFC Configuration

Use the PFC Configuration page to configure the PFC settings on the switch.
To display the PFC Configuration page, click Switching → PFC → PFC Configuration in the navigation
menu.
Figure 7-131. PFC Configuration
Configuring Switching Information
451