What is 400G?

400G is the next generation of cloud infrastructure. With a fourfold increase in maximum data transfer speed over 100G, 400G addresses the massive bandwidth demands being placed on network infrastructure providers. Open systems, artificial intelligence (AI), machine learning, and cloud storage all contribute to exponential traffic growth. As large data centers transition to faster, more scalable infrastructures, high-capacity connectivity is essential to keep pace with the ever-expanding number of users, devices, and applications.

To fully understand what’s driving the need for 400G, it’s important to distinguish the various ways 400G can be defined and used in data center networking conversations.

• 400G most commonly refers to a solution that offers 400G of capacity on one 400G wavelength. It’s interchangeable with 400GbE and 400Gb/s depending on the context.
• 400GbE refers to the next capacity rate in Ethernet interfaces that can travel through a single link. It’s based on the approved IEEE 802.3bs standard that 400GbE physical layers, management parameters, and Media Access Control (MAC) parameters must meet.
• 400Gb/s refers to the speed at which data is transferred. In this case, 400 billion bits of information travel through a single optical wavelength every second.

What Problems Does 400G Solve?

Traffic demands will continue to push data center servers to their capacity limits. 400G-capable solutions are ideal for high-volume telco providers, large data centers, and enterprises grappling with unrelenting traffic growth. In addition, 400G promises the power, efficiency, and density required for 5G and emerging applications such as augmented and virtual reality and 4k video streaming.

The IEEE 400GbE standard achieves data transfer speeds that are 4x faster than 100Gb/s and provides far greater efficiency as larger pipes are easier to manage and transmit bits at a lower power percentage. A single 400G port on a router, along with optics, will cost less than four individual ports of 100G (4 x 100G) with their own set of 100G optics. And the same is true for power: A single 400G port consumes less power than the aggregate power consumed by four individual 100G ports.

Additionally, 400Gb/s speeds allow for scale-up and scale-out architectures optimized for enhanced resilience and reduced blast radius.

Emerging 400G equipment, such as optical transport products, compact connectors, high-speed optical transceivers, and fiber management, supports 400GbE scale-up and scale-out networks with significantly low cost-per-bit, high density, and reliable throughput.

How Does 400G Work?

400GbE technology requires the ability to process more symbols per second and advanced modulation formats to support more bits per symbol. Combined, these abilities enable the transport capacity of 400Gb/s per wavelength to be delivered at the optimum cost per bit with a smaller form factor, fewer points of failure and interfaces, and lower power and heating—all with 4x the capacity of 100Gb/s.