PRIMUS IT Limited.
PRIMUS IT Limited.

400G Optical Module Solution Case For Metropolitan Area Network

Background: New services drive traffic growth in the 5G era

The emergence of 100GE technology in 2013 marked a technological turning point in the industry. Because 100GE ports cannot meet the increasing transmission demand brought about by traffic bursts. If multiple 100G links are bundled together, fiber resources will lag behind the growth of bandwidth resources, and load imbalance may occur. Therefore, high-performance ports with higher bandwidth capabilities are required. Therefore, as more and more networks use coherent transmission technologies with higher speeds, 100G ports for remote transmission also need to be upgraded.

By 2021, about 70% of data center east-west traffic will remain in the data center, and the growth rate is expected to be much higher than the north-south traffic and the traffic between the data centers.

The penetration of cloud computing has led to the replacement of traditional data centers by cloud data centers, greatly increasing the demand for high-speed optical modules.

Traditional data centers use 10G low-speed optical modules, while cloud data centers mainly use 100G high-speed optical modules.

Traditional data centers mainly transmit north-south traffic, while cloud data centers mainly transmit east-west traffic, which drives a large number of east-west connections and significantly increases the utilization rate of optical modules on a single server. Therefore, services that mainly rely on east-west traffic (such as machine learning and artificial intelligence) require more computing and storage capabilities.

Currently, cloud computing data centers have completely adopted 25G/100G optical interconnect solutions. However, in the second half of 2018, large OTT customers in North America led to the switch to 50G/400G optical interconnect solutions. At the same time, existing companies plan to start deploying 400G solutions in 2020. Starting in the first half of 2019, Chinese OTT customers have also started 400G research and initiated the first 400G test involving multiple 400G optical module suppliers in China

With the rapid development of 5G, new services including 4K VR, Internet of Things, ultra-high-definition video, VR, augmented reality (AR) and Internet of Vehicles (IoV) put forward the following new requirements on the bearer network: ultra-high bandwidth, multiple Connection channel, ultra-low latency and high reliability. Because the 100GE port of the metropolitan area network cannot support the convergence layer and the core layer that require ultra-broadband, a 400GE-based optical interconnection solution is necessary.

5G bearer network architecture

Feature.1  5G bearer network architecture

Take the 5G bearer network as an example. According to the bandwidth evaluation of the Next Generation Mobile Network (NGMN) Alliance, during the large-scale 5G commercialization of metropolitan area networks, the bandwidth of the access layer will be developed to 50GE, and the bandwidth of the core layer will be developed to 200GE/400GE.

Network layer project

Metropolitan Area Access Network

Metropolitan Convergence Network

Urban Core Network

5G Front-haul

5G Middle


5G Back haul+DCI

5G Back haul+DCI






Optical modules

10G/25G grey optical modules

Nx25G WDM Color optical modules

25G/50G grey optical modules

Nx25G/50G WDM Color optical modules

100G/200G gray optical modules

Nx100G WDM Color optical modules

200G/400G gray optical modules

Nx100G/200G/400G WDM Color optical modules

Feature.2  5G bearer network optical module bandwidth requirements

Data center interconnection

Feature.3  Data center interconnection