What's the Current and Future Trend of 400G Ethernet?

Updated on Jan 14, 2022 by

400G represents the future of cloud infrastructure by quadrupling the peak data transfer rate compared to its predecessor, 100G. This enhancement is crucial to meet the burgeoning demands for bandwidth from network infrastructure vendors. The integration of open systems, advancements in artificial intelligence (AI), deeper learning algorithms, and the proliferation of cloud storage solutions are driving a traffic surge like never before. Major data centers are shifting towards more efficient and expandable architectures to support the growing ecosystem of internet users, an array of devices, and burgeoning applications, making high-capacity network links more vital than ever.

According to the leading Cloud Service Providers (CSPs) and various networking forecast reports, 400G Ethernet will emerge as the leading technology since 2020. IDC (International Data Corporation) and Cignal Ai have also proved the similar situation. In short, 400G Ethernet will replace 100G and 200G deployments in a faster way than 100G did to the previous Ethernet.

New Technology Adoption Rates.jpg

Faster 400G Ethernet Trend Than Previous Ethernet.jpg


The Rise of 400G Ethernet

The factors affecting the development of 400G are mainly application-driven and technology-driven. The application drivers include 5G high-speed transmission, market requirements for data centers, cloud computing, and high-definition video transmission. Technology drivers include development of technologies in the market and product standardization.

Application-Driven Factors

  • 5G Accelerates 400G Ethernet:5G technology requires edge computing architecture to bring cloud resources such as computing, storage and networks closer to applications, devices and users. With the bandwidth provided by 400G technology, 5G can support more devices and applications within a limited range.

Items 4G LTE 5G
Average Data Rate 25 Mb/s 100 Mb/s
Peak Data Rate 150 Mb/s 10,000 Mb/s
Latency 50 ms 1 ms
Connection Density 2,000 Per Square Kilometer 100,000 Per Square Kilometer


  • Data Center & Cloud Computing Requirements: A research from Cisco indicates that cloud-based data centers will take over 92% of the next-generation data center workload while the traditional data centers will take over less than 8% after 2021. These objective requirements for higher data rates drive 400G development greatly. It is estimated that 400G will be the prevailing speed in switch chips and network platforms in the coming years.

  • High-Definition Video Transmission Needs: Basically all forms of Internet applications are moving towards video. It is estimated that more than 80% of the traffic is video. Video is a very important platform for everyone to interact in the future, especially real-time video streaming, such as multi-party video conferences. High-definition videos (such as 4K videos) need more bandwidth and less latency compared with the previous normal ones featuring lower definition.

Technology-Driven Factors

To achieve the 400G milestone based on a 50 Gbps lane rate, a pivotal shift in the signal-encoding strategy was imperative. Traditionally, Ethernet standards have relied on the straightforward 2-level Non-Return-to-Zero (NRZ) technique to encode binary data streams into transmissible electrical signals. However, to boost lane data rates, the adoption of a 4-Level Pulse Amplitude Modulation (PAM4) encoding scheme became necessary. This scheme effectively doubles the data transmission rate within the same temporal span. The IEEE completed its 802.3bs standard (IEEE Std 802.3bs-2017) for 200G and 400G Ethernet by implementing a combination of PAM4 encoding and multiple parallel lanes.

For more information about PMA4 technology, check out: PAM4 in 400G Ethernet application and solutions.

Influences of 400G Ethernet

400G Optics Promotes 25G and 100G Markets While Reduces 200G Market Share

Compared to the 10G Ethernet, 25G Ethernet gains more popularity in the whole optical transmission industry because 25Gbps and 50Gbps per channel technology provide the basic standards for existing 100G (4x 25Gbps), the coming 400G (8x 50Gbps) and the future 800G network. Therefore, the rapid development of 400G Ethernet will promote the 25G and 100G markets to a certain extent in turn. Similarly, the quick appearance of 400G applications implicates that 200G is a flash in the pan.

400G Technology Is Expected to Reduce Overall Network Operation and Maintenance Costs

  • For access, metro, and data center interconnection scenarios, where short transmission distance and higher bandwidth are required, fiber resources are relatively scarce. The single-carrier 400G technology can provide the largest transmission bandwidth and the highest spectral efficiency with the simplest configuration, which effectively reduces transmission costs.

  • In the backbone and some more complex metropolitan area networks, where the transmission distance is longer with more network nodes, the requirements for transmission performance are more stringent. Under such circumstances, dual-carrier technology (2x 200G) and an optimized algorithm could work together to compress the channel spacing. This can not only improve the spectral efficiency by 30% (close to the level of a single-carrier 400G technology), but also extend the transmission distance of 400G Ethernet to several thousand kilometers, helping operators quickly deploy 400G backbone networks with minimum bandwidth resources.

  • 400G solution can also increase the single fiber capacity by 40% and reduce power consumption by 40%, thereby greatly improving network performance and reducing network operation and maintenance costs.

Opportunities for 400G Ethernet Vendors and Users

Many suppliers hype their 400G products to get ahead of the curve. Actually, few vendors have the real supply capacity and the quality of most 400G products supplied can't be assured. To win from the fierce market competition, vendors should pay more attention to improving product quality and strong supply capability. And this is indubitably beneficial to users, who can get better products and services with relatively lower prices.

Impact of 400G Optics on Cabling and Connectivity

In the multimode installed base, the biggest difference between 100G and 400G modules is the increase in total number of fibers. For single mode transmission system, most of the duplex LC and MPO-based architecture that is deployed at 100G should serve for 400G. For parallel or multi-fiber transmission, transceivers like 400GBASE-SR4.2 operating with short wavelength division multiplexing (SWDM) at four wavelengths provide longer distances over OM5 fiber than OM4 or OM3. FS 400GBASE-SR4.2 module with MTP/MPO-12 connectors and compatibility with parallel OM5 multi-mode fiber, it delivers blazing speeds of up to 150m. The OM5 wideband multimode fiber (WBMMF) will allow use of SWDM technology to transmit multiple signals (wavelengths) on one fiber. This indicates that OM5 fiber and SWDM technologies will continue to offer improved support on 400G Ethernet.

Data Rate Transceiver Pairs Rated Reach
40G 40G-BiDi 1 OM3: 100m
OM4: 150m
OM5: 200m
40G-SWDM4 1 OM3: 240m
OM4: 350m
OM5: 440m
100G 100G-BiDi 1 OM3: 70m
OM4: 100m
OM5: 150m
100G-SWDM4 1 OM3: 75m
OM4: 100m
OM5: 150m
400G 40GBASE-SR4.2 4 OM3: 70m
OM4: 100m
OM5: 150m

Are You Ready for 400G Ethernet?

Driven by the increasing demands of cloud data centers, the evolution of Ethernet standards has rapidly reached an incredible data rate of 400G. Using new encoding schemes and higher signaling rates, the 400G Ethernet standard marks a significant break from past standards and sets a path towards even faster speeds in the future.

As a somewhat mature 400G optical product supplier on the market, FS has been committed to promoting the development of 400G Ethernet and applications. We not only provide high-quality 400G Ethernet modules and switches, but also provide customers with customized solutions to cope with increasingly complex network environments. As 400G Ethernet accelerates its development toward standardization, commercialization, and scale, the 400G product system will soon be gradually improved, and more 400G products will appear.

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