Reference Guide

Data Center Bridging (DCB) | 293
Configuring DCBx Operation
The data center bridging exchange protocol (DCBx) is used by DCB devices to exchange configuration
information with directly connected peers using the link layer discovery protocol (LLDP) protocol. DCBx
can detect the mis-configuration of a peer DCB device, and optionally, configure peer DCB devices with
DCB feature settings to ensure consistent operation in a data center network.
DCBx is a prerequisite for using DCB features, such as priority-based flow control and enhanced traffic
selection, to exchange link-level configurations in a converged Ethernet environment.
DCBx is also deployed in topologies that support lossless operation for FCoE or iSCSI traffic. In these
scenarios, all network devices are DCBx-enabled (DCBx is enabled end-to-end). For more information
about how to configure and use FCoE and iSCSI features, refer to:
• FCoE Transit
• iSCSI Optimization
DCBx requires LLDP to be enabled on all DCB devices.
Supported DCBx Versions
The following DCBx versions are supported on the S5000 switch:
• Converged Enhanced Ethernet Data Center Bridging Exchange (CEE-DCBX) protocol
• Cisco, Intel, Nuova Data Center Bridging Exchange (CIN-DCBX) protocol
• IEEE 802.1Qaz (Draft 2.5) protocol
DCBx Operation
DCBx performs the following operations:
• Discovers DCB configuration (such as PFC and ETS) in a peer device.
• Detects DCB mis-configuration in a peer device; that is, when DCB features are not compatibly
configured on a peer device and the local switch. Mis-configuration detection is feature-specific
because some DCB features support asymmetric configuration.
• Reconfigures a peer device with the DCB configuration from its configuration source if the peer
device is willing to accept configuration.
• Accepts the DCB configuration from a peer if a DCBx port is in “willing” mode to accept a peer’s
DCB settings and then internally propagates the received DCB configuration to its peer ports.