The complexity of software defined network (SDN) is daunting.

The basic concept behind OpenFlow and SDN is that as long as SDN-friendly switches emerge, the Controller and application environment will flourish ". In addition to SDN-friendly switches, SDN has more obstacles to overcome-complexity.

One of the goals of SDN is to decouple the control panel and centralize its decisions to the Controller to simplify the complexity of network management. This means that, for example, a unified policy can be promoted to various network device groups.

The F5 blog blogger Lori MacVittie pointed out in his blog this week that the other main goal of SDN is to achieve network programmability, which has never been a simple task. With SDN programmability, engineers can accelerate multiple virtual networks on an underlying physical infrastructure, and then use SDN controllers to implement QoS service quality for each network segment ). This will bring more flexibility to virtualization and cloud networks. However, as MacVittie points out, this requires a lot of code and is very complicated.

"Many people understand that higher complexity means higher risks," she wrote. This is not only an intuitive understanding of the mass influx of code into the data center architecture, but also has been proved by research ."

While we are waiting for the release of SDN-friendly switches, companies such as Big Switch are using network coverage technology to allow engineers to build SDN on any underlying physical infrastructure through tunnelling. This means that you do not need to wait for the OpenFlow switch of the switch supplier to create SDN. This also means that network engineers will need to manage multiple networks, including physical infrastructure and each SDN built on the physical infrastructure, instead of managing a network.

In the report on the Big Switch network coverage application, Shamus McGillicuddy, the news director of SearchNetworking, raised a key question to Kyle Forster, one of the Big Switch founders: "Is it worth the trouble to manage two networks?" Forster replied: "This depends on the number of virtual machines that an enterprise must support. In other words, this complexity is worthwhile if an enterprise needs enough virtual networks ."

Forster's answer also illustrates the current situation of SDN. To introduce programmability, Is it worthwhile to use complex code that may make the network unstable? This depends entirely on the extent to which enterprises need this programmability.

For cloud providers, they urgently need programmable virtual networks for interconnected data centers. This is not the case for typical enterprise data centers. But this does not mean that enterprises do not want to use SDN. They are trying to use SDN to manage network components, such as campus LAN intrusion defense ). Through those methods, SDN can indeed simplify management. However, over time, start-ups and traditional network providers are bound to solve the Code complexity issues related to SDN and network virtualization.