Administrator Guide
Data Center Bridging in a Traffic Flow
The following figure shows how DCB handles a traffic flow on an interface.
Figure 132. DCB PFC and ETS Traffic Handling
Enabling Data Center Bridging
Data center bridging is enabled by default on an FN IOM to support converged enhanced Ethernet (CEE) in a
data center network.
A prerequisite for configuring DCB:
• 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.
On the FN IOM Switch, by default, DCB is enabled and MMU buffers are reserved to achieve no-drop traffic
handling for PFC. Disabling DCB does not release the buffers reserved by default. To utilize reserved buffers
for non-DCB applications, you have to explicitly release the buffers (Refer to
Configuring the PFC Buffer in a Switch Stack).
FC Flex IO Modules 1062