What Is QSFP-DD?_
QSFP-DD (Quad Small Form-factor Pluggable Double Density) is a transceiver form factor supporting 400G and 800G Ethernet connections. It is backwards compatible with QSFP+ and QSFP28, making it suitable for networks upgrading incrementally. QSFP-DD is the most widely deployed 400G connector in NVIDIA GPU cluster Ethernet fabrics.
Technical Details
QSFP-DD doubles the electrical lane count of QSFP28 from 4 to 8, enabling 400G (8x50G) and emerging 800G (8x100G) capacities. The form factor maintains backwards compatibility with QSFP+ and QSFP28 modules, allowing mixed-speed deployments during network upgrades. QSFP-DD modules have a maximum power consumption of approximately 12–14W for 400G and higher for 800G variants. Thermal management in switches is a consideration at high port densities. The module uses a 2x4 electrical contact arrangement with dual-row connectors. For GPU cluster deployments, QSFP-DD is the standard form factor for 400GbE Ethernet switches and network adapters.
How Leviathan Systems Works with QSFP-DD
Leviathan Systems deploys QSFP-DD-based connectivity as the standard for 400GbE GPU cluster networks, ensuring proper cable type selection and transceiver configuration for each connection.