Reference Guide

DCBX uses LLDP to mediate the automatic negotiation and exchange of device settings, such as PFC and ETS. DCBX uses LLDP TLVs to
perform DCB parameter exchange:
• PFC conguration and application priority conguration
• ETS conguration and ETS recommendation
This sample DCBX topology shows two 40GbE ports on a switch that are congured as DCBX auto-upstream ports and used as uplinks to
top-of-rack (ToR) switches. The top-of-rack (ToR) switches are part of a bre channel storage network.
DCBX conguration notes
• To exchange link-level congurations in a converged network, DCBX is a prerequisite for using DCB features, such as PFC and ETS.
DCBX is also deployed in topologies that support lossless operation for FCoE or iSCSI trac. In these scenarios, all network devices
must be DCBX-enabled so that DCBX is enabled end-to-end.
• DCBX uses LLDP to advertise and automatically negotiate the administrative state and PFC/ETS conguration with directly connected
DCB peers. If you disable LLDP on an interface, DCBX cannot run. Enable LLDP on all DCBX ports,
• DCBX is disabled at a global level by default. Enable DCBX globally on a switch to activate the exchange of DCBX TLV messages with
PFC, ETS, and iSCSI congurations.
• DCBX is enabled by default on OS10 interfaces. You can manually recongure DCBX settings on a per-interface basis. For example, you
can disable DCBX on an interface (no lldp tlv-select dcbxp command) or change the DCBX version (dcbx version
command).
• For DCBX to be operational, DCBX must be enabled at both the global and interface levels. If the show lldp dcbx interface
command returns the message DCBX feature not enabled, DCBX is not enabled at both levels.
• OS10 supports DCBX versions: CEE and IEEE2.5.
• By default, DCBX advertises all TLVs—PFC, ETS Recommendation, ETS Conguration, DCBXP, and basic TLVs.
• A DCBX-enabled port operates in a manual role by default. The port operates only with user-congured settings and does not auto-
congure with DCB settings received from a DCBX peer. When you enable DCBX, the port advertises its PFC and ETS congurations
to peer devices but does not accept external, or propagate internal, DCB congurations.
• DCBX detects misconguration on a peer device when DCB features are not compatibly congured with the local switch.
Misconguration detection is feature-specic because some DCB features support asymmetric (non-identical) congurations.
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