FCoE Cookbook for HP Virtual Connect Version 4.20 Firmware Enhancements May 2014

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Virtual Connect Troubleshooting
Troubleshooting DCBX issues
The Data Center Bridging eXchange protocol (DCBX) is a discovery and capability exchange protocol to discover and
exchange DCB configuration information between link partners, it provides the following functions:
 Discovers the peer devices' capabilities and determines whether devices at both ends support these
capabilities.
 Detects configuration errors on peer devices.
 Remotely configures the peer device if the peer device accepts the configuration.
Note: Virtual Connect supports only the remote configuration function.
These DCB capabilities include the number of priority and traffic classes supported, the priority to traffic class maps, the
scheduling algorithms for traffic classes and their parameters like the ETS bandwidth for each ETS enabled traffic class,
the indication of which priorities have PFC enabled, the willingness to accept the recommendations (CNA).
DCBX is designed as an extension of the Logical Link Discovery Protocol (LLDP), and provides new Type, Length, Value
(TLV) definitions.
DCBX information is essential when troubleshooting FCoE issues. It is necessary to verify that DCBX negotiation has
successfully gone through between Virtual Connect and the DCB peer.
DCBX information available in VCM
DCBX information is provided under the Virtual Connect GUI and CLI. The UI provides the overall status of DCBX protocol
exchange with peer entity, the status of the Application protocol, the Priority Flow Control and the Priority Group feature
exchanges.
Note: The DCBX information is only available for physical uplink and downlink ports. It is not available for Flex-10
subports.