An SNMP set to enable CoS will automatically enable per-port dot1p examination and diffserv replacement controls as needed for the functionality of CoS. Diffserv replacement is enabled for a QoS profile on all ports if the corresponding tosValue for CoS index 0-7 is configured. Otherwise, diffserv replacement is disabled for the corresponding QoS profile on all ports. Dot1p replacement is disabled for all QoS profiles on all ports. In addition, all QoS profiles are created and the dot1p examination to QoS profile mapping are fixed to match the TXQ reference mapping for CoS indexes 0-7. The internal CoS state is used to warn the user in the CLI in the event that the controls setup by CoS are modified. A subsequent SNMP set to disable CoS disables the internal CoS state. This turns off the warning messages in the CLI; however, it does not restore the configuration to its original state before the global enable action occurred.
When the internal CoS state is enabled, the global enable action is performed on any new switch that is inserted into the stack.