Users Guide

Data Center Bridging in a Traffic Flow

The following figure shows how DCB handles a traffic flow on an interface.

Figure 3. 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. For

information to configure iSCSI optimization, refer to iSCSI Optimization. For information to configure

FCoE, refer to Fibre Channel over Ethernet.

Data Center Bridging (DCB)