Concept Guide

pfc no-drop queuesqueue-range
Data Center Bridging Exchange Protocol (DCBx)
DCBx allows a switch to automatically discover DCB-enabled peers and exchange conguration information. PFC and ETS use DCBx to
exchange and negotiate parameters with peer devices. DCBx capabilities include:
• 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 141. DCB PFC and ETS Trac 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 conguring DCB:
• Priority-based ow control
• Enhanced transmission selection
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FC Flex IO Modules