What is software-defined networking security?

Software-defined networking (SDN) has evolved as a significant improvement vs. traditional networks. A centralized approach to network management, SDN eliminates the reliance on hardware such as routers and switches. Instead, this approach uses software-based controllers, or application programming interfaces (APIs), to control network traffic and connect data to the underlying hardware infrastructure. This dynamic and efficient network configuration uses an application on a centralized SDN server to separate the data plane from the control plane. The architecture gives SDN security an advantage of controllability compared to traditional network security.

How does software-defined networking work?

SDN is software-based, forming a virtualized architecture rather than a physical architecture. SDN does this by separating the control plane — where the data is sent — from the data plane which handles the actual transport of the data. The three basic components of SDN architecture are:

• Applications that handle resource requests and provide an interface and network information to the administrator
• Software-based controllers that serve as the brain of SDN architecture and execute all complex functions
• Networking devices that receive commands from the controllers to move data between the controller and the destination of the data

While these components can be located in different physical locations, they are fully integrated through virtualization.

Software-defined networking benefits

SDN greatly simplifies the process of moving data across a network. Its software-based controls centralize the execution of policies. It uses a well-defined application programming interface to effectively separate the data and control functions. SDNs deliver numerous benefits vs. traditional network architecture.

• SDNs are massively scalable, connecting distributed locations with speed and flexibility.
• Multiple switches can be combined into a single intelligent switch to enhance scalability.
• It creates speed advantages as data packet switching is software-based, avoiding hardware latency.
• SDNs foster flexibility, supporting emerging technology with real-time programmability.
• The components’ processes are viewed and managed as a whole by the administrator.
• In SDN, the entire network is controllable vs. traditional networks’ management on a device-by-device basis.

SDN is a network virtualization architecture where the entire network is visible and security threats can be addressed holistically and in real time. This enables a granular approach to SDN security administration, allowing for:

• Selective blocking of malicious traffic
• Diversion of specific data flows to intrusion detection systems
• Configurability of separate zones and security levels for classes of devices
• Isolation of infected devices so that they cannot compromise the network

Software-defined networking and cloud computing

This integrated architecture creates distinct advantages of SDN over traditional networks, especially for cloud computing. The cloud demands dynamic connections, enhanced management capabilities through virtualization, and dynamic and scalable capacity to address fluctuating traffic levels. Among the chief benefits:

• Software-defined networking and cloud computing have developed together since the switch speed of SDNs is much greater than that of traditional network infrastructure.
• The platform offers a common suite of tools that is conducive to the elastic scaling of cloud-based resources and self-service provisioning.
• SDNs provide essential energy efficiency to data centers as bandwidth and parallel processing requirements of cloud computing services have increased.

SDN security features

The centralized nature of software-defined networks creates security risks similar to traditional networks, but with a few distinctions.

• A compromised SDN controller can be used to manipulate the entire network.
• Distributed denial of service (DDoS) attacks can occur on both the control and data plane layers.
• The interface between control plane and data plane layers is vulnerable to man-in-the-middle (MITM) attacks. This is where an attacker positions themselves in the middle of communications between two parties to eavesdrop on, or steal or alter data.
• Due to its inherent programmability, hacking the software defined networking security application can achieve control over the entire network.

While many of the SDN security challenges are familiar, the flexible and programmable SDN platform delivers robust security response capabilities. Specific measures to consider when deploying an SDN include:

• Harden the operating system on the SDN server to resist attacks and attempts to compromise.
• Foster redundancy by using several physical SDN servers with a master server to control switching.
• Address DDoS threats through rule aggregation and proactive rule caching.
• Decrease switch-to-controller delays and increase switch buffering capability.
• Require encryption of the messages between the control and data layers to enhance switch integrity.

Lumen software-defined network solutions are secure, high-performance virtual networks ideal for public and private clouds. The dynamic SDN-based controls at the heart of Lumen® Cloud Connect solutions enable businesses of any size to experience network functionality matched to the performance level and seamlessness of the cloud.

To meet today’s hybrid cloud requirements, choose the dynamic network controls and enhanced visibility of agile Lumen SDN solutions.

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