Dell Broadcom NetXtreme Family of Adapters User Manual page 140

Using Data Center Bridging (DCB): Broadcom NetXtreme II Network Adapter User Guide
switch acknowledges the C-NIC's willingness, then the switch will send the C-NIC the recommended ETS and PFC parameter
settings. The DCBX protocol uses the Link Level Discovery Protocol (LLDP) to exchange PFC and ETS configurations between
link partners.
Configuring DCB
By default, DCB is enabled on Broadcom NetXtreme II DCB-compatible C-NICs. DCB configuration is rarely required, as the
default configuration should satisfy most scenarios. DCB parameters can be configured through BACS. See
Advanced Control Suite
DCB Conditions
The following is a list of conditions that allow DCB technology to function on the network.
If DCB is enabled on the interface, DCBX is automatically enabled and carried out automatically once a link is
established.
If DCBX fails to synchronize with a compatible peer, the adapter will automatically fall back to default NIC behavior (no
priority tagging, no PFC, no ETS).
By default, the port will advertise itself as willing, and as such, will accept all DCB settings as advertised by the switch.
If PFC is operational, PFC settings supersede link level flow control settings. If PFC is not operational, link level flow
control settings prevail
In NIC Partitioned enabled configurations, ETS (if operational) overrides the Bandwidth Weights assigned to each
function. Transmission selection weights are per protocol per ETS settings instead. Maximum bandwidths per function
are still honored in the presence of ETS.
In the absence of an iSCSI or FCoE application TLV advertised through the DCBX peer, the adapter will use the settings
taken from the local Admin MIB.
Please read all Restrictions and
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for more information on BACS.
Disclaimers.
Using Broadcom