Dcb Configuration Exchange - Dell PowerEdge M IO Aggregator Command Reference 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

On an Aggregator, the DCBX protocol supports the exchange and propagation of configuration
information for the following DCB features.
• Enhanced transmission selection (ETS)
• Priority-based flow control (PFC)
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 with the
requirement that each configured parameter value is the same for the configurations to be compatible.
For example, PFC uses an symmetric exchange of parameters between DCBX peers.
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