Deployment Guide

Table Of Contents
Data Center Bridging in a Traffic Flow
The following figure shows how DCB handles a traffic flow on an interface.
Figure 31. DCB PFC and ETS Traffic Handling
Enabling Data Center Bridging
DCB is automatically configured when you configure FCoE or iSCSI optimization.
Data center bridging supports converged enhanced Ethernet (CEE) in a data center network. DCB is disabled by default. It must
be enabled to support CEE.
Priority-based flow control
Enhanced transmission selection
Data center bridging exchange protocol
FCoE initialization protocol (FIP) snooping
DCB processes virtual local area network (VLAN)-tagged packets and dot1p priority values. Untagged packets are treated with a
dot1p priority of 0.
For DCB to operate effectively, you can classify ingress traffic according to its dot1p priority so that it maps to different data
queues. The dot1p-queue assignments used are shown in the following table.
To enable DCB, enable either the iSCSI optimization configuration or the FCoE configuration.
To enable DCB with PFC buffers on a switch, enter the following commands, save the configuration, and reboot the system to
allow the changes to take effect.
1. Enable DCB.
CONFIGURATION mode
dcb enable
2. Set PFC buffering on the DCB stack unit.
CONFIGURATION mode
DellEMC(conf)#dcb enable pfc-queues
NOTE: To save the pfc buffering configuration changes, save the configuration and reboot the system.
NOTE: Dell EMC Networking OS Behavior: DCB is not supported if you enable link-level flow control on one or more
interfaces. For more information, refer to Ethernet Pause Frames.
Data Center Bridging (DCB) 241