Administrator Guide

• Discovery of DCB capabilities on peer-device connections.
• Determination of possible mismatch in DCB conguration on a peer link.
• Conguration of a peer device over a DCB link.
DCBx requires the link layer discovery protocol (LLDP) to provide the path to exchange DCB parameters with peer devices.
Exchanged parameters are sent in organizationally specic TLVs in LLDP data units. For more information, refer to Link Layer
Discovery Protocol (LLDP). The following LLDP TLVs are supported for DCB parameter exchange:
PFC parameters PFC Conguration TLV and Application Priority Conguration TLV.
ETS parameters ETS Conguration TLV and ETS Recommendation TLV.
Data Center Bridging in a Trac Flow
The following gure shows how DCB handles a trac ow on an interface.
Figure 29. DCB PFC and ETS
Trac Handling
Enabling Data Center Bridging
Data center bridging is enabled by default on an MXL 10/40GbE Switch to support converged enhanced Ethernet (CEE) in a data
center network.
A prerequisite for conguring DCB:
• Priority-based ow 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 eectively, you can classify ingress trac according to its dot1p priority so that it maps to dierent data queues.
The dot1p-queue assignments used are shown in the following table.
Data Center Bridging (DCB)
217