Reference Guide

Configuration
source
The port is configured to serve as a source of configuration information on the switch. Peer
DCB configurations received on the port are propagated to other DCBx auto-configured ports.
If the peer configuration is compatible with a port configuration, DCBx is enabled on the port.
On a configuration-source port, the link with a DCBx peer is enabled when the port receives a
DCB configuration that can be internally propagated to other auto-configured ports. The
configuration received from a DCBx peer is not stored in the switch’s running configuration. On
a DCBx port that is the configuration source, all PFC and application priority TLVs are enabled.
ETS recommend TLVs are disabled and ETS configuration TLVs are enabled.
Manual The port is configured to operate only with administrator-configured settings and does not
auto-configure with DCB settings received from a DCBx peer or from an internally propagated
configuration from the configuration source. If you enable DCBx, ports in Manual mode
advertise their configurations to peer devices but do not accept or propagate internal or
external configurations. Unlike other user-configured ports, the configuration of DCBx ports in
Manual mode is saved in the running configuration.
On a DCBx port in a manual role, all PFC, application priority, ETS recommend, and ETS
configuration TLVs are enabled.
When making a configuration change to a DCBx port in a Manual role, Dell Networking
recommends shutting down the interface using the shutdown command, change the
configuration, then re-activate the interface using the
no shutdown command.
The default for the DCBx port role is manual.
NOTE: On a DCBx port, application priority TLV advertisements are handled as follows:
• The application priority TLV is transmitted only if the priorities in the advertisement match the configured
PFC priorities on the port.
• On auto-upstream and auto-downstream ports:
– If a configuration source is elected, the ports send an application priority TLV based on the
application priority TLV received on the configuration-source port. When an application priority
TLV is received on the configuration-source port, the auto-upstream and auto-downstream ports
use the internally propagated PFC priorities to match against the received application priority.
Otherwise, these ports use their locally configured PFC priorities in application priority TLVs.
– If no configuration source is configured, auto-upstream and auto-downstream ports check to see
that the locally configured PFC priorities match the priorities in a received application priority TLV.
• On manual ports, an application priority TLV is advertised only if the priorities in the TLV match the PFC
priorities configured on the port.
DCB Configuration Exchange
The DCBx protocol supports the exchange and propagation of configuration information for the enhanced transmission
selection (ETS) and priority-based flow control (PFC) DCB features.
DCBx uses the following methods to exchange DCB configuration parameters:
Asymmetric DCB parameters are exchanged between a DCBx-enabled port and a peer port without
requiring that a peer port and the local port use the same configured values for the
configurations to be compatible. For example, ETS uses an asymmetric exchange of
parameters between DCBx peers.
Symmetric DCB parameters are exchanged between a DCBx-enabled port and a peer port but requires
that each configured parameter value be the same for the configurations in order to be
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