Dell Networking 2024 Reference Manual page 888

Configuration Source Port Selection Process
When an auto-upstream or auto-downstream port receives a configuration
from a peer, the DCBX client first checks if there is an active configuration
source. If there is a configuration source already selected, the received
configuration is checked against the local port operational values as received
from the configuration source, and if compatible, the client marks the port as
operationally enabled. If the configuration received from the peer is
determined to not be compatible, a message is logged, an error counter is
incremented and the DCBX clients become operationally disabled on the
port. The port continues to keep link up and exchanges DCBX packets. If a
compatible configuration is later received, the DCBX clients will become
operationally enabled.
If there is no configuration source, a port may elect itself as the configuration
source on a first-come, first-serve basis from the set of eligible ports. A port is
eligible to become the configuration source if:
• No other port is the configuration source.
• The port role is auto-upstream.
• The port is enabled with link up and DCBX enabled.
• The port has negotiated a DCBX relationship with the partner.
• The switch is capable of supporting the received configuration values,
either directly or by translating the values into an equivalent configuration
N.B. Whether or not the peer configuration is compatible with the
configured values is NOT considered.
The newly elected configuration source propagates DCBX client information
to the other ports and is internally marked as being the port over which
configuration has been received. Configuration changes received from the
peer over the configuration source port are propagated to the other auto-
configuration ports. Ports receiving auto-configuration information from the
configuration source ignore their current settings and utilize the
configuration source information.
When a configuration source is selected, local ETS and PFC configuration
for all auto-up, auto-down and config-source ports is overridden by the
configuration received from the configuration source.
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Data Center Bridging Commands