QSFP28 Optical Switch Installation Solution Inventory

QSFP28 transceivers are hot-swappable modules that require proper installation, FEC configuration, and inventory verification to ensure seamless 100G network operation.

Overview of QSFP28

QSFP28 (Quad Small Form-factor Pluggable 28) modules provide four lanes of 25G, enabling 100G Ethernet connectivity. They support multiple optical technologies, including SR4, LR4, ER4, BIDI, and DR, and can be used in both data center and metro networks. QSFP28 modules are compatible with CAUI-4 electrical interfaces and can be broken out into four 25G connections if needed .

Installation Procedure

1. Safety and Tools: Ensure ESD protection and use appropriate tools for handling optical modules .
2. Hot-Swappable Installation: Insert the QSFP28 module into the switch port until it clicks. Modules are hot-swappable, so the switch does not need to be powered down .
3. Fiber Connection: Connect fiber-optic cables matching the module type and wavelength. Ensure cable lengths do not exceed specifications to maintain signal integrity .
4. FEC Configuration: For certain modules like BIDI or DR, disable RS-FEC on the port before installation to prevent transceiver type mismatch and port down status .
5. Module Verification: Use switch commands to verify module recognition. For example, show controllers optics location R/S/I/P displays PID, serial number, and module status .

Inventory Troubleshooting

• If a QSFP28 module does not appear in the inventory (show inventory), it may be due to software defects or unsupported optics .
• Workarounds include performing a warm reload of the module using hw-module location 0/0 reload warm to refresh inventory recognition .
• Ensure that only certified modules from the switch vendor or compatible third-party modules are used to avoid detection issues .

Module Selection Considerations

• Short-range (SR4): Multimode fiber, cost-effective for data center interconnects.
• Long-range (LR4/ER4): Single-mode fiber, suitable for metro or regional networks.
• BIDI: Requires paired modules, supports bidirectional transmission over a single fiber.
• DR: High-performance 100G modules, not suitable for stack connections .
• Coherent vs PAM4: Coherent QSFP28 offers extended reach and wavelength tunability, while PAM4 is optimized for short-range, low-power deployments .

Best Practices

• Always match module type and wavelength with the remote end of the fiber link.
• Use vendor-certified modules to ensure proper inventory detection and network stability.
• Document serial numbers and port locations for inventory management.
• Monitor port status after installation to confirm link integrity and correct FEC settings. By following these steps, QSFP28 modules can be installed efficiently, recognized correctly in switch inventory, and integrated into high-speed 100G networks with minimal downtime .