Reference Guide

Data Center Bridging | 463

Data Center Bridging

Overview

Data center bridging (DCB) refers to a set of IEEE Ethernet enhancements that provide data centers

with a single, robust, converged network to support multiple traffic types, including LAN, server, and

storage traffic.

DCB and Switch Stacking Caveats for the S4820T

The following is a list of behaviors and limitations regarding the use of DCB over S4820T ports

involved in switch stacking:

• You can enable DCB only on 40 Gig (QSPF+) ports.

• DCB is not supported over any of the 48 RJ-45 10 Gig ports while they are configured in stacking

mode.

• You cannot configure stacking on any of the 48 RJ-45 10 Gig ports, if DCB is enabled on any of

the 40 Gig stacking ports.

• If DCB is enabled, it will disable the ability to use any of the 48 10 Gig ports for stacking.

The Dell Force10 operating software (FTOS) commands for data center bridging features include

802.1Qbb

priority-based flow control (PFC), 802.1Qaz enhanced transmission selection (ETS), and the

Data Center Bridging Exchange (DCBX) protocol. CLI commands for individual DCB features are as

follows:

DCB Command

• dcb-enable

PFC Commands

• clear pfc counters

• dcb-input

• dcb-policy input

• dcb-policy input stack-unit stack-ports all

• dcb stack-unit pfc-buffering pfc-port pfc-queues

• description

• pfc link-delay

• pfc mode on

• pfc priority