Dell MX5108n OS10 Enterprise Edition User Guide for PowerEdge MX IO Modules Re - Page 655

Data center bridging eXchange DCBX allows a switch to automatically discover and set up DCBX-enabled peers configured with compatible settings. In a converged data center network, DCBX provides plug-and-play capability for server, storage, and networking devices in an end-to-end solution. 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 configuration and application priority configuration • ETS configuration and ETS recommendation This sample DCBX topology shows two 40GbE ports on a switch that are configured 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 fibre channel storage network. DCBX configuration notes • To exchange link-level configurations 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 traffic. 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 configuration 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 configurations. • DCBX is enabled by default on OS10 interfaces. You can manually reconfigure 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 Configuration, DCBXP, and basic TLVs. • A DCBX-enabled port operates in a manual role by default. The port operates only with user-configured settings and does not auto- configure with DCB settings received from a DCBX peer. When you enable DCBX, the port advertises its PFC and ETS configurations to peer devices but does not accept external, or propagate internal, DCB configurations. Converged data center services 655