Shulou(Shulou.com)06/02 Report--

Software defined Network (SDN) is one of the two pillars of network transformation in the past decade. At the beginning of its birth, many people regarded SDN as a way for the network to get rid of traditional routing, but this goal has not been achieved so far. Although SDN has a place in the data center, there is still relatively little SDN in WAN.

The forwarding control based on OpenFlow proposed by the Open Network Foundation (ONF) is one of the models that most enterprises consider when evaluating SDN. In data centers, especially in cloud data centers, virtual local area networks must be deployed to build multi-tenant services and applications. The SDN deployment model proposed by ONF has been widely adopted, which only proves the effectiveness of this model, but not its scalability.

Scalability has always been the biggest challenge for SDN applications in the wide area network. Every network operator is skeptical that SDN can be used to build the Internet. For the SDN model proposed by ONF, the IP network is too large to work, which is a problem encountered by SDN in the wide area network.

5G and other network changes focusing on metropolitan area networks provide the ground for SDN applications outside the data center. The implementation of specific functions of 5G, such as network slicing, promotes the deployment of SDN. The combination of 5G, network function virtualization, edge hosting, content delivery and streaming media makes the deployment of SDN in man more and more demanding. The new manageable man deployment is an ideal place to introduce new technologies, which makes WAN more and more open to SDN.

Application of SDN in 5G

Mobile network has become a combination of mobile management and content delivery functions. The emerging 5G network puts forward the demand for network virtualization, while network slicing solves the need for multi-tenant mobile devices and hosting additional functions. To achieve virtualization within the network slice. This provides two ways for SDN applications in 5G metropolitan area networks: using SDN for data center interconnection (DCI) and mobility and content management.

Both 5G and mobile content are drivers of reliable edge hosting because service capabilities and content cache nodes need to be close to applications that use the service. Edge hosting means that network operators will use micro data centers, which are less efficient in handling variable loads, so we can use them to create virtual resource pools of edge managed nodes and deploy DCI on a larger scale. If the high broadband connection uses the SDN edge data center, SDN in 5G technology will extend across DCI links to establish a resource pool at the data center boundary, thus promoting the application and expansion of SDN in the WAN.

If mobility management functions in a mobile network, such as EPC in 5G, rely on SDN-connected data center hosting capabilities, it is easy to understand how SDN implements these functions. EPC technology is based on the implementation of tunneling after mobile users roam the site, SDN forwarding can achieve the same function, and the same SDN device can provide a direct connection between mobile content consumers and their cache nodes. SDN can support reconstructed mobility and content delivery based on white-box devices rather than customized devices.

Will SDN be extended to other areas?

The use of SDN in 5G technology may promote the explosive development of metropolitan area networks, which is the focus of investment for operators to deploy 5G in at least the next five years. This trend is mainly affected by two risk factors, the results of which could be very different, which could result in SDN being locked in the data center.

The first risk factor that may lock SDN in the data center is the speed and integrity of 5G adoption. Operators expect the full implementation of 5G to take more than four years, and it is not clear to what extent it can be implemented. The 5G standard used to create hybrid 5G and 4G LTE wireless networks is the first step towards 5G, but some people think it may be the only measure that needs to be taken for a long time, unless new sources of service revenue growth can be found to drive the 5G revolution.

The second risk factor is the emergence of network node operating systems such as AT&T 's DANOS and ONF's Stratum, which can be used to support SDN, but can also host open traditional routing and switching software. AT&T decided to deploy 60, 000 DANOS white-box devices in base stations to host traditional routing software, indicating that these open white-box devices may be a major risk for SDN in wide area networks and 5G networks.

ONF's Stratum may bring double risks to the deployment of SDN in the WAN. ONF once introduced the standard mode of SDN deployment, but now ONF advocates an open operating system choice, which can provide an alternative to SDN. Many early SDN supporters now doubt the attractiveness of SDN, especially the use of SDN in WAN.

Operators say the biggest problem with their application of SDN in WAN and metropolitan expansion is the lack of mature and widely accepted standards between the east-west direction of the SDN controller and the controller API. As network operators deploy 5G, the Internet of things, and other edge hosting-intensive services, new infrastructure investment will become a new opportunity.

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