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Core routers lead the 400GE ultra-high-speed era

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We are entering a golden age of services. Traffic on the backbone network continues to grow dramatically due to services such as 4K, VR/AR, cloud computing, and Internet of Things (IoT).

According to the IEEE bandwidth evaluation report, 1 million minutes of video content passes through the network every second. Bandwidth on the network especially that on the backbone network, doubles every 18 months. The global IP traffic is predicted to reach 2.3ZB by the end of 2020.

To cope with the overwhelming growth of traffic, the interface capacity of network devices is continuously increased from 100M, GE, 10GE, to the mainstream 100GE. However, this also causes problems such as mass optical fibres, complex configuration, and heavy maintenance workload. Leading operators have considered the introduction of next-generation interface technology to support backbone network evolution. Telecom networks are at a new intersection of backbone network upgrades. Industry opinion indicates that 2019 will be the 400GE commercialisation year, and 400GE technology will be the optimal choice for core routers over the next ten years.

The use of single-port 400GE technology significantly improves the interface integration of boards. That is, one 400GE interface equals to four 100GE interfaces. In this manner, both the user-side optical fiber resources and the interface configuration workload are reduced by 75%. For single backbone nodes that typically carry over 30Tbps traffic, single-port 400GE reduces the interface quantity on a router from 30,000 100GE interfaces to 7500 400GE interfaces. In addition, interface aggregation addresses the imbalanced load of 100GE links.

400GE commercialisation following the release of the 400GE standard

Objectively, a standard must be finalised before any new technology can be seen as being ready for widespread commercial use. Back in 1985, IEEE released the 10Mbps 802.3 Ethernet standard. In 2010, IEEE officially approved the 802.3ba standard, marking the beginning of 40G/100G commercialisation. In early 2013, the industry started to discuss standardising 100GE interfaces in IEEE 802.3, and 400GE standardisation being added to the agenda.

Due to the complexity of Ethernet standards, 400GE standardisation faces the following challenges:

1. The logical-layer architecture, the core of the 400GE standard, needs to be oriented towards the backbone IP network to support wide interconnection, high reliability, and high compatibility; and

2. Technical challenges, such as the limitations of physical-layer optical link bandwidth, the number of optical lanes, the line-rate data of super-high-speed signals, and packet processing, need to be addressed.

As a major participant in global Ethernet standardization, Huawei works together with other parties in the industry to tackle technical issues in 400GE standardisation. Huawei actively contributed to the IEEE 802.3 400GE standard proposal by submitting more than 50 technical documents and holding key positions, such as the chairperson of the 400GE 2/10 km standard working group and 400GE 40km standard working group and the editor of the optical layer standard.

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As early as 2011, Huawei started to research basic 400GE technologies. This was even before IEEE 802.3 started to research a successor to 100GE. Since then, Huawei has been at the forefront of researching the technical solution of the Ethernet logical-layer architecture, data processing at a 400 Gbps rate, and FEC algorithm and adaptation. These basic technologies have been included in the published 400GE standard.

In 2012, Huawei began research and development on high-speed signal transmission technology at the 400GE physical layer. Huawei took the lead in researching and developing the 8 x 50Gbps 4 pulse amplitude modulation (PAM4) physical-layer optical transceiver system to support 10/40km long-distance transmission and high reliability transmission, fully meeting the strict requirements of IEEE 802.3 on technical feasibility and cost feasibility, thereby achieving low-cost and commercially available 400GE.

In 2016, Huawei and China Telecom set up a 400GE joint innovation team. The team implements R&D based on the system architecture model, algorithms and software, and hardware platforms to ensure the commercial use of 400GE products.

On December 6, 2017, IEEE 802.3 Ethernet working group officially approved the IEEE 802.3bs Ethernet definition, which included the 200GE and 400GE Ethernet standards. This marks that the 400GE standard is mature to effectively support future commercial deployment.

400GE, ready for commercial use

During the 400GE standardisation process, Huawei's core routers made continuous improvements in response to the ever-increasing interface rate. Huawei is collaborating with upstream and downstream partners to promote the 400GE industry and accelerate the 400GE commercialisation.

In September 2012, Huawei released the industry's first 480Gbps routing line card, which was half a year ahead of the industry. In April 2013, Huawei released the 1Tbps routing line card, which was more than one year ahead of the industry. In October 2017, China Telecom Guangzhou Research Institute and Huawei collaborated to conduct the world's first 400GE test. Testing was performed in China Telecom's network and terminal key laboratory using test cases designed based on real-world network applications. Huawei's Tbps backbone router line cards were used to verify a variety of 400GE port functions, such as line-rate forwarding, multi-service overlay, and fault reporting. The success of this test shows that 400GE, the next-generation large-capacity port technology, is ready for commercial use.

The 400GE optical module is also being rapidly promoted. As the core technology of 400GE high-speed optical modules, PAM4 signaling uses four different levels to transmit signals. In high-speed signal interconnection scenarios, PAM4 doubles the transmission efficiency given the same baud rate. This means that the 400GE optical module can achieve the 400GE transmission efficiency without increasing the optical component bandwidth, which accelerate 400GE commercialisation. Currently, the PAM4-based optical modules developed by mainstream vendors are all ready for commercialisation and delivery at scale.

In the 400GE communication testing domain, mainstream vendors have provided the corresponding 400GE test solutions to support 400GE commercialisation.

The combined use of 400GE routers and 400G optical transport devices allows Huawei to provide the industry's first E2E 400GE solution and help operators around the world to build E2E 400GE networks.

With the advent of the 400GE commercialisation era, Huawei will continuously work with upstream and downstream partners in the industry to promote the development of backbone networks and build leading backbone networks for sustainable evolution.

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