How Much Do You Know About 400G OSFP Transceiver?

Data centers support the IT infrastructure needed to run data-intensive applications and their ever-growing demand for storage. From remote work and streaming entertainment to decentralized finance and the connected devices that make up the Internet of Things, the need for 400G technology is here and the leap to 800G will be realized with small form factor pluggables such as OSFP.

What Is 400G OSFP Transceiver Optics?

The Octal Small Form Factor Pluggable (OSFP) module is an optical transceiver designed to provide high speed 400G/800G data communications for data centers and networking systems. A typical 400G OSFP module features 8 electrical lanes, each capable of transmitting 50Gb/s using PAM4 modulation, resulting in an aggregated bandwidth of 400Gb/s.

FS 400G OSFP Transceivers

The following table shows the 400G OSFP optical modules provided by FS. Engineered for Ethernet and InfiniBand (IB), these OSFP 400G transceivers feature built-in advanced DSP chips for low power consumption and ultra-fast speeds. FS's 400G OSFP modules exhibit exceptional stability and dependability after extensive testing for interoperability with leading brands like NVIDIA.

Product

Technology

Max. Power Consumption

Max Cable Distance

Modulation(Electrical)

Modulation (Optical)

Connector

Application

OSFP-SR4-400G-FL	InfiniBand	8.5W	30m@OM3/50m@OM4 or OM5	4x100G-PAM4	4x100G-PAM4	MPO-12/APC	Flat-top OSFP for ConnectX-7 Adapter
OSFP-DR4-400G-FL	InfiniBand	10W	500m	4x100G-PAM4	4x100G-PAM4	MPO-12/APC	Flat-top OSFP for ConnectX-7 Adapter
OSFP-SR8-400G	Ethernet	10W	100m@OM4	8x50G-PAM4	8x50G-PAM4	MPO-16/APC	Finned Top, Data Center, 400G to 8x50G Breakout
OSFP-DR4-400G-Si	Ethernet	10W	500m	8x50G-PAM4	4x100G-PAM4	MPO-12/APC	Finned Top, Data Center, 400G to 8x50G Breakout

It can be found that OSFP packaging is also divided into flat top and finned top. Finned top modules are used only in NVIDIA Quantum-2 NDR InfiniBand and Spectrum-4 SN5600 400GbE Ethernet air-cooled switches, while flat top modules are primarily used in network adapters and GPU servers, like ConnectX-7 adapter cards, DGX H100 Cedar7 GPU links, and liquid-cooled systems. Please read the article Understanding 400G and 800G OSFP Transceivers: Finned-Top vs. Flat-Top for more details.

400G OSFP Transceivers Connectivity Scenarios

Here, we explore five key connection types: direct connections, 800G to 2x 400G links using multimode fiber, 800G to 2x 400G links using single-mode fiber, 100G-to-400G upgrades, and 50G-to-400G migrations.

Note: The models mentioned (e.g., specific OSFP modules) are used as examples to illustrate each scenario. Each scenario may employ different types of fiber cables and breakout configurations depending on the network’s design, whether multimode or single-mode is used.

400G Connectivity with Direct Connect Cabling

Taking the OSFP-SR8-400G module as an example, using an MPO-16/APC OM4 fiber cable, two 400G switches can be directly connected, with a maximum transmission distance of 100m.

800G-to-two 400G links to ConnectX-7 - Up to 50m

Using two MPO-12/APC OM4 multimode fibers, two OSFP-SR4-400G-FL multimode modules can be connected to the twin-port OSFP-SR8-800G module based on 100G PAM4 technology. This setup enables the connection between 800G switch and two combinations of 400G ConnectX-7 and/or BlueField-3, with a maximum reach of 50-meters.

800G-to-two 400G links to ConnectX-7 - Up to 500m

With two OS2 single mode fiber cables, two OSFP-DR4-400G-FL single mode modules can be connected to the twin-port OSFP-DR8-800G module, allowing the 800G switch to communicate with two combinations of 400G ConnectX-7 and/or BlueField-3 up to 500m.

100G to 400G Migration

The OSFP-DR4-400G-Si supports 4x100G Breakout to QSFP-DR-100G modules and simplifies fiber cables to upgrade 100G networks to 400G, optimizing cost-effectiveness.

50G to 400G Migration

The OSFP-SR8-400G module utilizes 8x50G PAM4 modulation and can facilitate connections between 50G and 400G switch ports. Use an MTP-16 to 8x LC Duplex OM4 conversion cable to connect the 400G SR8 module with 8x SFP-50GSR-85 modules, enabling a cost-effective migration from 50G to 400G networks.

FAQ about 400G OSFP Transceiver

Q1: How does the OSFP address the thermal need?

A: The OSFP includes an integrated heatsink, which increases thermal efficiency and allows modules with up to 15W of power to be installed in a switch chassis with conventional airflow.

Q2: What about OSFP backward compatibility?

A: Because the OSFP is somewhat broader and deeper than the QSFP, an adapter that supports current 100G QSFP optical modules in an OSFP cage may be built. Backward compatibility is provided via an OSFP to QSFP adaptor.

Q3: What does "SR8", "DR4", "XDR4", "FR4", and "LR4" mean?

A: "SR" refers to short range, and "8" implies there are 8 optical channels. "DR" refers to 500m reach using single-mode fiber, and "4" implies there are 4 optical channels. "XDR4" is short for "eXtended reach DR4". And "LR" refers to 10km reach using single-mode fiber.

Q4: Can I plug an OSFP transceiver module into a QSFP-DD port?

A: No. QSFP-DD and OSFP are totally different form factors. For more information about QSFP-DD transceivers, you can refer to 400G QSFP-DD Transceiver Types Overview. You can use only one kind of form factor in the corresponding system. E.g., if you have an OSFP system, OSFP transceivers and cables must be used.

Q5: Can I plug a 100G QSFP28 module into an OSFP port?

A: Yes. A QSFP28 module can be inserted into an OSFP port but with an adapter. When using a QSFP28 module in an OSFP port, the OSFP port must be configured for a data rate of 100G instead of 400G.

Q6: What other breakout options are possible apart from using OSFP modules mentioned above?

A: OSFP 400G DACs & AOCs are possible for breakout 400G connections. See 400G Direct Attach Cables (DAC & AOC) Overview for more information about 400G DACs & AOCs.

Conclusion

400G OSFP transceiver provides a good solution for 400Gbps optical deployments in data centers and broadband access connectivity. More and more 400G OSFP transceivers are continuously introduced to the market, and mass production is gradually realized. It will meet rapidly growing customer demand for analytics, machine learning, and content delivery applications.