A Comprehensive Guide to 400G OSFP Ethernet Optical Transceivers

As data center infrastructures continue to scale and AI, HPC, and other high-performance computing scenarios develop rapidly, network requirements for bandwidth, latency, and stability are becoming increasingly stringent. 400G Ethernet has emerged as one of the mainstream solutions for intra-data-center interconnection and high-performance networks, and has already achieved large-scale deployment in real-world environments.

Among the various 400G optical transceiver form factors, OSFP stands out as a next-generation form factor specifically designed for high-speed Ethernet, offering clear advantages. This article introduces the fundamental concept and key characteristics of 400G OSFP Ethernet optical transceivers, and analyzes their practical value in data center and high-speed networking scenarios, with reference to NADDOD’s 400G OSFP product portfolio.

What Is the OSFP Form Factor?

OSFP (Octal Small Form-factor Pluggable) is an optical transceiver form factor designed for ultra-high-speed Ethernet and data center interconnect applications. Compared with earlier form factors such as QSFP28 and QSFP-DD, OSFP represents a systematic upgrade in mechanical structure, thermal performance, and electrical interface bandwidth, and is primarily intended to support 400G and higher data rates in Ethernet and high-performance computing networks.

From a physical perspective, OSFP modules are slightly larger than QSFP-DD modules. However, this increase in size is not arbitrary — it is purpose-built to accommodate higher power consumption and higher signal rates. The OSFP standard was originally defined around 400G and 800G transmission requirements, enabling a single module to integrate eight high-speed electrical lanes (8 × 50G PAM4 or higher). This design provides a robust and scalable interface foundation for next-generation switch ASICs and network architectures.

Key Characteristics of OSFP Transceivers

OSFP transceivers offer several features that make them particularly well-suited for high-speed networking environments. Designed from the outset with 400G and beyond in mind, the OSFP form factor is capable of reliably supporting 400G Ethernet transmission, making it an ideal choice for high-bandwidth data communication scenarios.

OSFP transceivers feature a larger package size and optimized thermal architecture, resulting in more efficient heat dissipation. OSFP offers two main thermal solutions: OSFP IHS (Integrated Heatsink) and OSFP RHS (Ride-on Heatsink).

• OSFP IHS (Integrated Heat Sink): The module features built-in fins or grooves on the top surface, leveraging convective cooling to effectively transfer heat generated by internal components to the surrounding environment.
• OSFP RHS (Riding Heat Sink): This solution relies on close surface contact and maximized contact area to achieve efficient heat dissipation.

In terms of port density, OSFP makes efficient use of front-panel space while maintaining strong thermal and electrical performance. This allows network equipment to deploy a higher number of high-speed ports within a limited footprint — an important advantage for data centers pursuing high-density architectures.

NADDOD 400G OSFP Ethernet Transceiver Product Options

NADDOD offers a comprehensive range of 400G Ethernet optical transceivers based on the OSFP form factor, covering different transmission media and application requirements. These products are designed for modern data center and high-performance computing environments.

All NADDOD 400G OSFP transceivers undergo rigorous compatibility and reliability testing and are fully interoperable with leading platforms from NVIDIA, Arista, Cisco, and other major vendors. This ensures high reliability and seamless operation, even in complex RoCE-based networking environments.

NADDOD currently offers the following 400G OSFP Ethernet modules:

NADDOD 400G OSFP Ethernet Transceiver Applications

OSFP transceivers are widely deployed in 400G Ethernet and high-performance computing (HPC) networks. Typical application scenarios include high-speed interconnections between switches, as well as between switches and network interface cards (NICs).

400G OSFP SR4 Ethernet Transceiver Application

The 400G OSFP SR4 Ethernet transceiver uses an MTP/MPO-12 connector. It supports transmission distances of up to 60 meters over OM3 multimode fiber and up to 100 meters over OM4 multimode fiber.

Use Cases

• 800G Switch to 400G OSFP NIC：On the switch side, an OSFP 800G 2×SR4 transceiver connects to two OSFP 400G SR4 transceivers on the NIC side using two MTP/MPO-12 APC multimode fiber cables.

• 800G Switch to 200G OSFP NIC：The OSFP 800G 2×SR4 transceiver on the switch side connects to four OSFP 400G SR4 transceivers on the NIC side through two 1:2 fiber splitters.

400G OSFP 2×SR4 Ethernet Transceiver Application

The OSFP 400G 2×SR4 Ethernet transceiver is an eight-lane parallel pluggable OSFP module designed for 400G Ethernet applications. It integrates eight data lanes in each direction, with each lane operating at 26.5625 Gbd. The module supports transmission distances of up to 100 meters over OM4 multimode fiber. NADDOD OSFP 400G 2×SR4 transceivers support flexible link configurations, enabling diverse interconnection scenarios.

Use Cases

• 800G Switch to 200G QSFP56 Switch：The OSFP 400G 2×SR4 module is connected using two direct-attach optical fiber links. Each MTP-12 APC fiber jumper connects to one 200G SR4 QSFP56 transceiver, enabling efficient interconnection between an 800G Ethernet switch and a 200G QSFP56 switch.

• 800G Switch to 2×200G QSFP56/QSFP112 NIC：The OSFP 400G 2×SR4 module is deployed on the OSFP switch port and connects to 200G QSFP56 or QSFP112 NICs via 12-fiber multimode MPO jumpers, enabling interconnection between an 800G OSFP switch and 200G NICs.

400G OSFP VR4 Ethernet Transceiver Application

The 400G OSFP VR4 Ethernet transceiver is a four-lane parallel pluggable OSFP module. It integrates four data lanes in each direction, with each lane operating at 53.125 Gbd. This transceiver supports transmission distances of up to 60 meters over OM3 multimode fiber and up to 50 meters over OM4 multimode fiber, making it suitable for short-reach data communication and interconnection scenarios.

Use Cases

• 800G Switch to 400G OSFP NIC：An OSFP 800G 2×VR4 transceiver on the switch side connects to an OSFP 400G VR4 transceiver on the NIC side using MTP/MPO-12 APC multimode fiber. This configuration enables connectivity between an 800G OSFP switch and two 400G ConnectX-7 NICs.

• 800G Switch to 200G OSFP NIC：Using two 1:2 fiber splitters, the OSFP 800G 2×VR4 transceiver on the switch side connects to four OSFP 400G VR4 transceivers on 200G ConnectX-7 NICs.

400G OSFP SR8 Ethernet Transceiver Application

The 400G OSFP SR8 (OSFP-RHS) Ethernet transceiver uses an MTP/MPO-16 APC connector and supports transmission distances of up to 100 meters over multimode fiber (MMF). This transceiver is primarily used for NIC testing, providing a cost-effective solution for NIC-to-switch connectivity.

Use Cases

• 400G Switch to 400G NIC：Using multimode MPO/MTP 16 APC patch cords, the QSFP-DD 400G SR8 on the 400G QSFP-DD switch side can interconnect with the OSFP 400G SR8 on the network card side.

400G OSFP DR4 Ethernet Transceiver Application

The OSFP 400G DR4 Ethernet transceiver is designed for high-speed 400G data transmission. It uses an MTP/MPO-12 connector and supports transmission distances of up to 500 meters over single-mode fiber (SMF).

Use Cases

• 800G Switch to 2×400G NIC：Two OSFP 400G DR4 transceivers connect to one OSFP 800G 2×DR4 transceiver using two single-mode MPO-12 APC fiber jumpers, enabling seamless connectivity between an 800G OSFP switch and 400G ConnectX-7 NICs.

• 800G Switch to 200G OSFP NIC：An OSFP 800G 2×DR4 transceiver on the switch side connects to four OSFP 400G DR4 transceivers on 200G NICs using two 1:2 single-mode fiber splitters (S2MPOA2×4F), enabling interconnection between an 800G switch and 200G NICs.

Why Choose NADDOD 400G OSFP Ethernet Transceivers?

• Stable Compatibility and Reliability

NADDOD 400G OSFP Ethernet transceivers undergo systematic testing to ensure stable compatibility with mainstream platforms from vendors such as NVIDIA, Arista, and Cisco. At the signal processing level, the modules leverage digital signal processing (DSP) technology combined with algorithm optimization, achieving pre-FEC bit error rates (BER) in the range of 1E-8 to 1E-10. After FEC correction, the BER approaches zero, ensuring high interoperability, reliability, and consistent network performance in complex RoCE environments.

• Reliable Product Quality and Delivery Assurance

NADDOD operates advanced manufacturing facilities and implements strict quality control systems to ensure high consistency across production batches, effectively reducing compatibility risks and potential service interruptions. In addition, mature production capacity and sufficient inventory enable rapid response to the high-reliability optical interconnection demands of AI and machine learning clusters, supporting on-schedule project delivery.

• End-to-End RoCE Solutions

Beyond 400G OSFP Ethernet transceivers, NADDOD provides comprehensive RoCE solutions, including network architecture planning, cabling recommendations, and on-site commissioning. NADDOD’s RoCE solutions have been validated in large-scale deployments and demonstrate reliable performance and strong compatibility in multi-vendor environments.

• Comprehensive Product Portfolio

In addition to 400G OSFP Ethernet transceivers, NADDOD offers a full range of 1.6T, 800G, 400G, 200G, and 100G optical modules, as well as DAC/AOC cables, fiber jumpers, and switches. This comprehensive product portfolio enables customers to complete network hardware selection and procurement within a unified supply framework, simplifying supply chain management and deployment processes.

Frequently Asked Questions About OSFP Transceivers

Q: Can I insert an OSFP transceiver into a QSFP-DD port?

A: OSFP and QSFP-DD are completely different form factors. Therefore, OSFP transceivers cannot be used in QSFP-DD ports.

Q: Can modules with different form factors (QSFP-DD, OSFP, QSFP112) interoperate?

A: OSFP, QSFP-DD, and QSFP112 differ only in physical form factor. As long as both ends use the same optical interface type, such as 400G VR4 or 400G DR4, interconnection is supported.

Q: Can 400G OSFP modules be used in 800G OSFP ports?

A: Yes. As long as the physical form factor is compatible, 800G OSFP ports are backward compatible with 400G OSFP modules.

Q: Are there other breakout options besides the 400G OSFP Ethernet transceivers mentioned above?

A: OSFP 400G DAC and AOC cables can be used for 400G breakout connections. For more information, please refer to How to choose 400G DAC & 400G AOC? 。

Conclusion

As data center networks continue to evolve toward higher bandwidth, lower latency, and greater reliability, 400G Ethernet has become a critical component of modern infrastructure. OSFP, as a transceiver form factor designed for high-speed applications, demonstrates clear advantages in thermal performance and long-term scalability.