What technical support is needed to build a fixed network architecture based on SDN/NFV?

As of the end of October 2016, the number of China Mobile's wired broadband users was 75.51 million, and the number of China Unicom's wired broadband users was 75.472 million. China Mobile's fixed-line broadband users exceeded China Unicom's by a huge margin. China Telecom still ranked first among the three major operators with more than 120 million fixed-line broadband users. From the user data, we can see that the competition in the domestic fixed-line market is becoming increasingly fierce.

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China Mobile's network architecture faces three major challenges

China Mobile has not been developing wired broadband for a long time. How did it achieve such remarkable results in such a short period of time? Li Zhenqiang, project manager of the Network Technology Research Institute of China Mobile Research Institute, said that this is due to China Mobile's development of a "high starting point" wired broadband business - mainly 50M, with 100M showing its advantages, and vigorously developing FTTH access.

Although China Mobile's wired broadband business has achieved great results, and China Mobile's backbone network has completed interconnection with other domestic operators and the international Internet, from the perspective of the overall network architecture, China Mobile's network architecture still faces three major challenges. At the backbone network level, the main problem is traffic imbalance; at the edge of the metropolitan area network, BRAS equipment faces problems such as low utilization, complex operation and maintenance, and slow launch of new services; and in terms of CPE at the edge of the network, the main problems are insufficient intelligence and difficulty in service upgrades.

When talking about how to solve the current problems of China Mobile's fixed network, Li Zhenqiang believes that China Mobile should establish a fixed network architecture based on SDN/NFV.

Li Zhenqiang pointed out that the establishment of a fixed network architecture based on SDN/NFV involves four key technologies: first, establishing a network architecture based on TIC; second, SDN traffic scheduling at the CMNet level; third, using vBRAS with control separation at the BRAS level; and fourth, using smart gateways and s-CPE at the CPE level.

Establishing a fixed network architecture based on SDN/NFV

First, the network architecture based on TIC has evolved from a voice-centric to a content- and traffic-centric new network architecture. A new data center is built with TIC to form a telecom cloud and realize control and media cloudification. There are three major principles in this: first, centralized control, where control functions are centrally deployed in the core TIC to achieve more flexible network scheduling; second, media sinking, where the media plane is flexibly sunk to the edge TIC; third, optimizing traffic and user experience, improving network sales, and developing multiple means and technologies on demand at the access layer to meet capacity and coverage requirements.

At the same time, TIC should be built based on the collaboration of SDN and NFV. In the process of SDN and NFV collaboration, the controller is a core component. Therefore, China Mobile independently developed an SDN controller - Aero, which is based on ODL mobile self-development, oriented to data center scenarios, focusing on solving the performance problems of native solutions, and breaking the SDN solution single-vendor binding through standardized interfaces. Currently, Aero can support OpenStack I version and K version, and also communicate with equipment from manufacturers such as H3C, Cisco, and Ruijie through standard interfaces.

The second is SDN traffic scheduling. Based on the SDN architecture, a backbone network traffic optimization platform is developed to adjust the traffic forwarding path and optimize network utilization through intelligent calculation. Recently, China Mobile has adopted the model of network visualization and local traffic optimization, and will adopt the centralized scheduling of the entire network traffic in the long term.

The second is the separation of BRAS control and forwarding. With the rapid increase in the number of broadband users, the development of new services such as 4K high-definition and the Internet of Things, traditional BRAS, as the edge of the CMNet network and the gateway for user access, faces huge challenges. China Mobile has made great improvements in the centralization of the control plane and the localization of the forwarding plane in the deployment of BRAS with separation of control and forwarding. At present, China Mobile cooperates with the mainstream manufacturers in the industry, such as Huawei, ZTE, H3C, FiberHome, and Alcatel-Lucent, to lead the design of the structure and interface of BRAS with separation of control and forwarding, and promote the maturity of the industrial chain; China Mobile is also leading the product testing, and it is expected to complete the formulation of equipment specifications and test specifications by the end of this year, conduct tests and pilots in 2017, and commercialize it in 2018.

*** is the smart home gateway and sCPE. China Mobile needs to introduce the vCPE technology architecture to build a new network, adopt virtualization, and support new functions and value-added services. Among them, pCPE locally provides home entrance and service flow classification, and sCPE cloud realizes centralized control and flexible deployment of services.