This article explains how to manage the four QSFP, 40 Gigabit (Gb), ports on a standalone or on a stacked Force10 S4810 switch, including the following:
1. Splitting a QSFP port into 4 x 10Gb SFP+ ports
2. Verifying the 1 x 40Gb or 4 x 10Gb ports are available
3. Setting the 4 x 10Gb split ports to a 1 x 40Gb QSFP port, the default setting.
When changing from one mode to another, a switch reboot is required. Consider updating the firmware.

A supported breakout cable must be used. Please refer to the Installation Guide or the Release Notes for a list of supported cables. Also, split ports are not available as a stack-link to stack a S4810 system.

The fixed QSFP ports are named Fo 0/48, Fo 0/52, Fo 0/56 and Fo 0/60 in 40-gigabit mode and respectively, Te 0/48-51, Te 0/52-55, Te 0/56-59 and Te 0/60-63 in 10-gigabit mode.

The ports you choose will need to be in a default configuration before beginning the process. You will receive an error "Quad mode cannot be changed on a port which has a non-default configuration." Use the default interface command to return the selected interfaces to default configuration. Dell(conf)#default interface te 0/1
To split a 1 x 40Gb QSFP port on a Force10 S4810 switch into 4 x 10Gb SFP+ ports, do the following:
1. Verify the switch unit number to have split ports is the default, stack-unit 0.
F10-S4810>en
F10-S4810#show system brief
2. Verify the QSFP port has a default configuration before splitting it into 4x10Gb ports, quad mode.
Please contact ProSupport for default configuration assistance if needed.
F10-S4810>en
F10-S4810-1#show running-config interface fortyGigE <port number>
3. Configure the QSFP port to be broken out.
F10-S4810>enable
F10-S4810#configure
F10-S4810(config)#stack-unit 0 port <number> portmode quad
Please save and reset unit 0 for the changes to take effect.
4. Save the configuration change and reboot the switch to transition the port into 4x10Gb mode.
F10-S4810>enable
F10-S4810#write memory
F10-S4810#reload
Proceed with reload [confirm yes/no]: Yes
5. Verify the 4 x 10Gb ports are available. Four Additional TenGigabit ports are available and one less FourtyGigabit port is available.
F10-S4810>enable
F10-S4810#show interfaces status

To configure the opposite, set the QSFP as a 1 x 40Gb port, use the no stack-unit 0 port portmode quad command, and complete steps 4 and 5.