The Push Toward 400G Data Center Networking: Technologies, Market Drivers, and Future Outlook

Data center operators and the data center supply chain are steadfastly pursuing 400 G Ethernet, driven by higher Ethernet speeds, cloud computing, IoT, and virtual data centers that demand more from network infrastructure.

Large‑scale operators are accelerating the adoption of 100 G links and modules, while 400 G form‑factor and optical modules have entered a critical launch phase expected to roll out throughout 2019, potentially doubling QSFP28 module density and tripling bandwidth with lower power consumption compared to four 100 G modules.

56 G PAM‑4 ASICs for network switches, developed by companies such as Broadcom, Innovium, Nephos, and Barefoot Networks, are becoming increasingly powerful, fueling demand for next‑generation optical interconnect systems.

These ASICs can deliver 12.8 Tbps, enabling switches with 32 × 400 Gbps ports or, in gearbox mode, 128 × 100 Gbps ports; OEMs like Cisco and Arista, as well as white‑box manufacturers, are already shipping higher‑speed switches.

Key Drivers of 400 G

IDC forecasts indicate data center storage demand grows over 50 % annually, reaching 40 ZB by 2020 and 163 ZB by 2025, propelled by cloud storage, open systems, edge computing, machine learning, deep learning, and AI.

Emerging technologies such as virtual reality and autonomous vehicles will further stress data center infrastructure.

Ultra‑large data centers typically upgrade their network architecture every two years, making component retirement inevitable.

The supply chain is accelerating the development of more powerful, energy‑efficient, scalable solutions; 100 G remains the fastest Ethernet link today, but 400 G will eventually dominate as the preferred speed for switches and network platforms.

Staying Ahead on the Development Curve

Future data center solutions will leverage both copper and fiber to achieve high signal integrity, reduced latency, and optimal efficiency, density, and speed.

Existing copper DACs can already reach 400 G, and 400 G optical transceivers are nearing full market release, with 100 G Lambda and 400 G modules in beta testing and expected to ship later in 2019.

Long‑reach 100 G CWDM4 transceivers will continue to be deployed, while 100 G PSM4 demand declines; low‑cost 100 G Lambda products will capture the CWDM4 market and interoperate directly with 400 G transceivers in branch topologies.

As bandwidth shifts upward, 10 G and 40 G technologies will be phased out, replaced by optical transceivers, DACs, and AOCs supporting 100 G, 200 G, 400 G, and beyond; QSFP‑DD will play a crucial role in this evolution.

Evolution of Optical Transceiver Form Factors

QSFP‑DD transceivers feature an eight‑channel electrical interface with 50 G per channel, delivering up to 20 W and, with advanced heat‑sink designs, achieving 400 G performance over various distances.

OSFP offers a wider, deeper form factor for 400 G and is fully backward compatible with QSFP+ and QSFP28; 56 G PAM‑4 is key to both QSFP‑DD and OSFP implementations, and integrated platforms are emerging to support 400 G Ethernet in cloud environments.

Without considering form factor, 400 G optical transceivers rely on DSP “gearboxes” that combine eight 50 G lanes into four 100 G optical channels, a critical supply‑chain component that will require advanced 7‑nm DSPs.

Companies like Molex demonstrate 100 G Lambda‑compliant QSFP28 and 400 G DR4 QSFP‑DD products; the ecosystem is moving toward 112 G PAM‑4 to underpin 400 G solutions, with MSA specifications highlighting challenges in optical interface design and multi‑vendor interoperability.

Beyond 400 G

ASIC vendors have announced mass‑production of 56 G PAM‑4 12.8 Tbps chips and are developing 112 G PAM‑4 25.6 Tbps ASICs that could enable 32‑port switches supporting 800 Gbps per port, raising new challenges in signal integrity, thermal management, power, and loss.

Collaboration between data center operators and capable suppliers will optimize the design and deployment of 100 G and 400 G infrastructure, ensuring efficient, risk‑mitigated scaling for future dynamic demands.