Command Line Interface Guide

888 Data Center Bridging Commands
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, all auto-upstream ports other than
the configuration source are marked as willing disabled.
In order to reduce flapping of configuration information, if the configuration
source port is disabled, disconnected or loses LLDP connectivity, the system
clears the selection of configuration source port (if not manually selected)
and enables the willing bit on all auto-upstream ports. The configuration on
the auto-configuration ports is not cleared (configuration holdover). If the
user wishes to clear the configuration on the system in this scenario, the user
can put the configuration source port into manual mode.
2CSPC4.X8100-SWUM100.book Page 888 Wednesday, August 29, 2012 6:23 PM