Software-defined networking (SDN) has emerged as a solution that provides companies with more flexibility in how their network is controlled by separating a network’s control and forwarding planes from one another to promote network virtualization, allowing for greater network automation through software rather than physical infrastructure. SDN brings with it easier provisioning and management of network resources while providing a network infrastructure that is more responsive to organizational needs. There are numerous advantages to SDN, such as network scalability, flexibility, and adaptability, among others. However, with these advantages come a variety of valid concerns over SDN.
The centralized nature of SDN can be a security advantage, as it becomes easier to manage an entire network. However, this centralization can also make the SDN controller a target for threats. In addition, any glitches between the control and data planes can open vulnerabilities that attackers can more readily take advantage of. Furthermore, if a threat is introduced into a network, SDN’s centralization increases the potential that the threat can spread more easily throughout the entire network. Another similar SDN advantage with the potential to turn harmful is the segmented nature of SDN. On one hand, this means that certain segments of a network can have higher or lower security settings to better protect sensitive data. However, this segmentation also means that individual risks can threaten each different segment, requiring similarly individualized security requirements.
As SDN makes networks more flexible and automated, it has the potential to threaten network reliability, which is one of the primary concerns with SDN technology. A report on SDN and network function virtualization by Cartesian found that 90% of survey respondents believe that SDN must be as reliable as traditional networks, making issues of reliability and stability the biggest concern that they had about SDN technology. This issue of reliability ties in closely with latency issues.
Because SDN virtualizes a network and separates the control and data planes so that they are managed independently, latency can become an issue. Despite being separate, these two planes still must coordinate with one another. If they become out of sync when transferring data, the network may face increased latency. This has repercussions for workflow efficiency and performance.
With the greater virtualization that SDN provides, there is also a certain loss of visibility in terms of network traffic and performance. As networks become more automated through SDN, network traffic visibility can become more limited. This can have adverse effects on the network, as disruptions in the network flow that go unaddressed can weaken performance and security. It’s critical, therefore, that networks retain a high degree of visibility when using SDN in order to monitor the network and applications and limit their susceptibility to security threats. Fortunately, there are ways to promote enhanced visibility in an SDN environment through solutions like visibility fabric and others.
Not all of the concerns with SDN relate to technical considerations. One major concern is on the human capital side of the SDN equation. Since SDN is still a new technology, there is a limited pool of individuals with the requisite knowledge and expertise to manage SDN. The supply of individuals with adequate skills for deploying SDN hasn’t been able to keep up with the demand. This requires companies looking to transition to SDN to invest in either extensive recruitment efforts or substantial SDN training for current staff. Depending on the company, this lack of readily available SDN expertise can complicate plans to make the transition to SDN.
There are clearly multiple concerns that companies must contend with in regard to SDN. However, even with these concerns, there are also clear benefits to SDN. Whether they are considering making the switch to SDN or already have, companies should carefully consider how they will address these concerns to make sure their network runs as optimally as possible.