Dcb Policies In A Switch Stack; Dcbx Operation - Dell PowerEdge M IO Aggregator Command Reference Manual

DCB Policies in a Switch Stack

A DCB input policy with PFC and ETS configuration is applied to all stacked ports in a switch stack or on
a stacked switch.

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 misconfiguration 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 (PFC) and enhanced
traffic selection (ETS), 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).
The following versions of DCBX are supported on an Aggregator: CIN, CEE, and IEEE2.5.
DCBX requires the LLDP to be enabled on all DCB devices.
DCBX Operation
DCBX performs the following operations:
• Discovers DCB configuration (such as PFC and ETS) in a peer device.
• Detects DCB misconfiguration in a peer device; that is, when DCB features are not compatibly
configured on a peer device and the local switch. Misconfiguration 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.
Data Center Bridging (DCB) | 63