Users Guide

Enabling DCB on Next Reload To configure the Aggregator so that all interfaces come up with DCB

enabled and flow control disabled, use the dcb enable on-next-reload command. Internal PFC buffers

are automatically configured.

Task Command Command Mode

Globally enable DCB on all

interfaces after next switch

reload.

dcb enable on-next-reload CONFIGURATION

To reconfigure the Aggregator so that all interfaces come up with DCB disabled and link-level flow

control enabled, use the no dcb enable on-next-reload command. PFC buffer memory is

automatically freed.

Enabling Auto-DCB-Enable Mode on Next Reload To configure the Aggregator so that all interfaces

come up in auto-DCB-enable mode with DCB disabled and flow control enabled, use the dcb enable

aut-detect on-next-reload

command.

Task Command Command Mode

Globally enable auto-detection

of DCBx and auto-enabling of

DCB on all interfaces after switch

reload.

dcb enable auto-detect on-next-

reload

CONFIGURATION

Enabling DCB To configure the Aggregator so that all interfaces are DCB enabled and flow control

disabled, use the dcb enable command.

Disabling DCB To configure the Aggregator so that all interfaces are DCB disabled and flow control

enabled, use the no dcb enable command.

dcb enable auto-detect on-next-reload Command Example

Dell#dcb enable auto-detect on-next-reload

Configuring Priority-Based Flow Control

PFC provides a flow control mechanism based on the 802.1p priorities in converged Ethernet traffic

received on an interface and is enabled by default when you enable DCB.

As an enhancement to the existing Ethernet pause mechanism, PFC stops traffic transmission for

specified priorities (Class of Service (CoS) values) without impacting other priority classes. Different traffic

types are assigned to different priority classes.

When traffic congestion occurs, PFC sends a pause frame to a peer device with the CoS priority values of

the traffic that is to be stopped. Data Center Bridging Exchange protocol (DCBx) provides the link-level

exchange of PFC parameters between peer devices. PFC allows network administrators to create zero-

loss links for Storage Area Network (SAN) traffic that requires no-drop service, while retaining packet-

drop congestion management for Local Area Network (LAN) traffic.

To ensure complete no-drop service, apply the same DCB input policy with the same pause time and

dot1p priorities on all PFC-enabled peer interfaces.

Data Center Bridging (DCB)