556 | Stackingw w w . d e l l . c o m | s u p p o r t . d e l l . c o mConverting 4x10GbE Ports to 40GbE for StackingStacking is supported only on 40GbE links by connecting 40GbE ports on the base module or a 2-PortQSFP+ module. However, on a 2-Port 40GbE QSFP+ module, the ports operate by default in 4x10GbE(quad) mode with breakout cables as eight 10GbE ports.To change a port from 4x10GbE to 40GbE mode of operation for stacking, use the no stack-unit portportmode quad command (Figure 31-7). After you convert the 4x10GbE ports to 40GbE, you must save theconfiguration and reload the stack for the change to take effect.Figure 31-7. no stack-unit port portmode quad Command ExampleFTOS(conf)# no stack-unit unit-number port port-number portmode quadWhere:stack-unit unit-number is the unit ID number in the stack unit. Valid values: 0 to 5. To display the stack-unitnumber, use the show system brief command.port port-number specifies the port number of the QSFP+ port to be converted to 40GbE mode. Validvalues are: base-module ports: 33 or 37; slot 0: 41 or 45; slot 1: 49 or 53 (refer to Figure 31-5).portmode quad identifies the port as a split 10GbE SFP+ port.Removing a Port from the Stacking ModeTo remove a 40GbE port from the stack, use the no form of the stack-unit unit-number stack-group numbercommand. After entering the command, save the configuration and reload the stack for the change to takeeffect.FTOS Behavior: Stacking configuration is handled as follows on an MXL 10/40GbE Switch:• If a stack unit goes down and is removed from the stack, the logical provisioning configured for thestack-unit number is saved on the master and standby switches.• When you add a new unit to the stack and the stack already has an existing member unit with thesame stack-unit number, the new unit is assigned the smallest available unit number (0 to 5). Aconfiguration mismatch between the newly added unit and a logically provisioned unit occurs inthe following situations:• The logical provisioning for the unit number configures FlexIO module ports for4x10GbE operation and the added unit has FlexIO Module ports operating in 40GbEmode.• 'The logical provisioning for the unit number and the added unit have different stackgroups configured.When a configuration mismatch occurs, the newly added switch enters into a Card-Problem stateand is disabled. A syslog error message is generated. To restore a stacked switch in aCard-Problem state, refer to Stack Unit in Card-Problem State Due to Configuration Mismatch.• A stack unit can also enter a Card-Problem state after a split-stack reload in which a unit that waspreviously neither the master nor standby is elected as the new master and has logical stack-unitprovisioning configured for a stack-unit number that creates a mismatch with the stack-unit num-bering on other units.
