How do I configure a port breakout using a QSFP28 100GbE port on the QNAP switch?

Applicable Products

• QNAP M7308R-4X
• QSS

Overview

Port breakout enables you to split a high-speed QSFP port into multiple lower-speed interfaces, increasing flexibility and port utilization on your QNAP switch. The most common use case is breaking out a QSFP28 100GbE port into four independent 25GbE interfaces using a breakout cable and compatible SFP28 modules.

The QNAP M7308R-4X also supports breaking out a QSFP+ 40GbE port into four 10GbE interfaces with SFP+ modules and the appropriate breakout cable.
Note: A breakout cable is a special cable that allows a single high-speed port to function as several independent, lower-speed ports, often called "sub-interfaces."

Important: Configuring or changing breakout modes may interrupt data traffic. If your switch is in production use, consider performing these operations during scheduled downtime.

Procedure: Configuring 100GbE to 4x25GbE breakout

1. Log in to the switch management interface.
2. Go to System > Port Management > Port Breakout Configuration.
3. Select the QSFP28 100GbE port you want to break out.
4. Enable breakout mode and select 4x25GbE as the breakout option.
   
5. Go to System > Port Management > Port Configuration.
6. Confirm that the system has created four sub-interfaces (virtual ports) for the selected port, each operating at 25GbE.
   
7. Install compatible SFP28 modules and connect the 100GbE-to-4x25GbE breakout cable to the QSFP28 port.
8. Apply and save the configuration.

Each breakout port will now function as an independent 25GbE interface. Make sure all connected devices, cables, and modules support 25GbE operation.

Procedure: Configuring 40GbE to 4x10GbE breakout or switching from 100GbE to 40GbE breakout

1. Physically disconnect any existing 100GbE breakout cable and SFP28 modules from the QSFP28 port. (if any)
2. Install a compatible QSFP+ 40GbE breakout cable and SFP+ modules for each intended 10GbE sub-interface.
3. In the switch management interface, go to System > Port Management > Port Breakout Configuration.
4. Select the same QSFP port (now using a 40GbE cable and modules).
5. Enable breakout mode.
   
6. Go to System > Port Management > Port Configuration.
7. Confirm that the system has created four sub-interfaces (virtual ports) for the selected port, each operating at 10GbE.
   
8. Apply and save the configuration.

When switching from a 100GbE to 40GbE breakout, always physically replace the cables and modules before reconfiguring in the management interface.
Tip: Verify that all connected devices support 10GbE speeds.