Trends in Bandwidth Increase: From 40G/100G to 400G Networks

The development of high-definition video, VR, the Internet of Things, and cloud computing has accelerated the upgrade requirements of network bandwidth. The average annual growth rate of Internet traffic remains at a high level, which is also the main reason for promoting data centers to upgrade from 40G/100G to 400G networks. Compared with the 10G/25G network, the 40G/100G network still has certain advantages in capacity and performance. However, with the development of technology, the cost-effectiveness brought by the 400G network is gradually gaining popularity.

Trends for 40/100G Network to 400G Network

As of 2022, the market shares for 40G/100G and 400G networks are relatively balanced. However, the growth in the application of 400G technology is setting the stage for its dominance in the future.

Market Trends

The rapid evolution of applications and technologies such as Big Data, Cloud Computing, AI, and ML has led to exponential growth in data traffic, prompting enterprises to upgrade from 100G to 400G networks.

The data graph of the number of Ethernet port devices and DWDM shows that the competition between 100G and 400G networks is still going on. In the future, 200G/400G networks will occupy a large part.

According to Dell'Oro, telecommunications service providers are widely adopting 400 Gbps technology, and network operators are continuously deploying 400 Gbps ports using infrastructure such as modules and adapters to provide 400G connectivity. Sameh Boujelbene, Vice President of Dell'Oro Group, stated that 400G technology currently dominates the data center switch market. Also, other market reports indicate that the 400G optical module market is projected to grow at a CAGR of 6.2% during the forecast period (2024 - 2031).

40G/100G to 400G Network Technology Trends

The technical application of the 400G network improves data transmission efficiency and supports the connection scheme of branch cables. The development of optical chips in the 400G network is also becoming more mature, making the 400G network more cost-effective.

PAM4: PAM4 is a more advanced signal coding technology than NRZ. It uses 4 channels for data transmission, transmits two-digit logic information within the clock cycle, and the code rate of the signal is twice that of NRZ. Due to its high transmission and low costs, the use of PAM4 in 400G transceivers can greatly improve data transmission efficiency, which will adapt to the development of 5G networks, in line with the trend of high-bandwidth networks, and promote the next generation of high-speed signal interconnection.

8-Channel Solution: Traditional parallel transmission uses 12 or 16 optical fibers for network connections, increasing power consumption. 400G branch link solutions, such as 4x100G and 8x50G, improve transmission efficiency while reducing cabling complexity, enabling smooth upgrades of 100G network equipment to 400G networks.

Optical Chip: The 100G transceivers are primarily based on a 25Gbaud/s chip, use DML and VCSEL modulated lasers, and use NRZ signals to implement 100G networks. The 400G optical chip uses a DML laser and supports 56Gbaud rates for higher performance

400G Coherent Technology: The coherence technology adopted by 400G coherent transceivers on long-distance transmission networks is mature, and data transmission over 80 kilometers can be achieved through WDM (wavelength division multiplexing). At the same time, the 400G network also improves the transmission bandwidth and distance of OTN (optical transmission network), enabling OTN networks to achieve large bandwidth and long-distance transmission without the need for relays, which has an important role in supporting OTN networks in 5G commercial use.

Difference Between 40G/100G Network and 400G Network

40G/100G networks are primarily used in small to medium-sized enterprise networks and traditional data centers and are suitable for moderate-scale data transmission needs. The 40G network supports up to 400m with multimode fiber, while the 100G network offers higher capacity, lower latency, and better performance. 10G and 40G WDM have limitations in LAN services due to ODU container sizes. 100G WDM technology solves these issues, supports various Ethernet rates with unified mapping, and facilitates smooth upgrades of low-speed networks like 4x25G and 2x50G.

The capacity and transmission efficiency of 400G networks surpass those of 40G and 100G. Due to its higher bandwidth and support for 4 or 8 fiber transmissions, 400G modules and DAC/AOC cables make cabling much easier to manage. Simultaneously, a single 400G port costs less than a 4 x 100G port connection, which reduces power consumption. The 400G network not only increases network capacity but also optimizes total cost of ownership (TCO) by simplifying cabling and reducing power consumption. So it is suitable for large-scale data centers and backbone networks, meeting the high-speed data transmission demands of emerging technologies such as 5G, cloud computing, big data, and AI.

Considerations of Upgrading from 40G/100G Network to 400G Network

In the process of upgrading from a 40G/100G to a 400G network, the branch port and rate configuration need to be reconsidered. 400G transceivers usually need to use the corresponding fiber jumpers for 16x25G, 8x50G, or 4x100G channel data transmission. Hence, the above case should be considered when using existing 100G switches and optical modules. Corresponding fiber jumpers can be selected, like the 8 core MTP fiber patch cables that can achieve 100% utilization of 8x50G.

The 400G network uses PAM4 modulation technology. When upgrading from a 100G network to a 400G network, it is necessary to use 100G and 400G modules with PAM4 modulation. 100G QSFP28 transceivers that support PAM4 can be used to connect 400G transceivers, achieving 100G to 400G network migration. In addition, 400G QSFP-DD transceivers are backward compatible with QSFP+, and QSFP28 transceivers, enabling the rapid upgrade of 40G/100G networks.

Conclusion

The increasing demand for existing Internet traffic has promoted the continuous upgrading of the network. As the mainstream trend of the previous generation, the 100G network has gradually entered a mature and stable stage. The 400G network has exerted great advantages in data center networking, metropolitan area networks, and data center interconnection, and technology development will continue to expand the cost-effectiveness, which is why 400G networks will be the new mainstream trend after 100G network.