What Is a Network Controller?

Developed as software to orchestrate network functions, a network controller serves as an intermediary between the business and the network infrastructure. When an organization enters their desired business objectives into the controller, it sets-up the network to deliver on those objectives.

How network controllers work

A network controller is a software that orchestrates network functions. It serves as an intermediary between the business and the network infrastructure. The organization enters their desired business objectives into the controller which in turn sets up the network to deliver on those objectives. Network controllers do their jobs by:

  • Maintaining an inventory of devices in the network and their status
  • Automating device operations such as configurations and image updates
  • Analyzing network operations, identifying potential issues, and suggesting remediations
  • Providing a platform for integration with other applications such as reporting systems

Why now for network controllers?

The network is the lifeblood of a modern organization. The network not only provides basic connectivity but also security, enhanced collaboration, quality and continuity of service, etc. The architecture, infrastructure, and management of the network are therefore vital and increasingly tied to the success of the business.

A network controller manages and orchestrates all aspects of a network making sure that it is operating flawlessly and delivering on business objectives. To better understand the role of such controllers, consider how network management has evolved.

How network controllers evolved

Element management systems (EMSs) were one of the early tools for network device control. They aided and monitored certain aspects of specific groups of network devices, and it wasn't unusual to find more than one EMS in a large network. While they were useful, they couldn't control a network holistically.

EMSs eventually incorporated more functions, usually referred to as fault, configuration, accounting, performance, and security (FCAPS), and started to use northbound APIs to integrate with higher-level applications. Still, they were proprietary and worked only on small groups of devices, limiting their usefulness.

Software-defined networking (SDN) controllers fill a different need. These controllers are driven by applications that bring automation and agility to the devices they control. SDN controllers do not, however, provide the many other functions essential to build a truly responsive network.

Network controllers combine and expand on the functions of EMSs and SDN controllers. They help IT teams achieve more simplified, centralized, and agile operations, and they provide much-needed automation, performance analysis, fault detection and correction, and therefore, help achieve desired business outcomes.

How network controllers solve today’s IT challenges

Reduce operating costs

One of the biggest issues before IT today is the increasing cost of operations. These costs are a result of providing services to increasing number of users and devices who connect to the network from offices, homes, coffee shops, airports, etc., and applications that are distributed in private data centers and public clouds. This growth is outpacing IT capabilities and manual management efforts. Network Controllers automate operations that result in better scaling, reducing time, eliminating errors, and cutting costs.

Increase availability

A network controller collects and analyzes network traffic to proactively detect any potential issues before they become real problems. It can perform root-cause analysis and alert IT operations who can take corrective and preventive steps to ensure network services always remain available.

Improve agility

A network controller makes networks agile and responsive to business needs. It implements required changes on all network devices consistently and universally without the time-consuming need for device-by-device configurations.

Enhance security

A network controller’s thorough analysis of network traffic may reveal potential security threats. The controller can then act to isolate the threat and prevent its spread.

Accelerate adoption of intent-based networking

Organizations are taking steps to make their networks agile and responsive, to keep pace with evolving business needs. They're rearchitecting their networks to align with intent-based networking (IBN) principles. A network controller plays a foundational role in the evolution of legacy networks to IBN.

What is a network controller's role in intent-based networking?

An intent-based networking (IBN) architecture builds on SDN and provides the building blocks that transform a hardware-centric, manual network into a software-driven network that continuously captures business intent, translates it into policies, and applies them consistently across the network.

A network controller acts as a central control point for network activity in an intent-based network.


A network controller uses automation extensively for configuring, managing, testing, deploying, and operating physical and virtual devices in a network.


A network controller translates business intent into policies that network devices can implement to help produce desired outcomes. For example, if there's an intent for your finance department to receive uninterrupted service at month's end, corresponding policies would place finance users and applications on a secure segment that gets the highest-priority service.


A network controller distributes desired policies across the physical and virtual network infrastructure, using networkwide automation.


A network controller collects and analyzes telemetry data from network devices to help them operate smoothly and to spot any irregularities or potential issues. Some controllers are equipped to apply artificial intelligence (AI) and machine learning (ML) techniques to ascertain whether issues they notice will affect performance or security, to pinpoint the cause, and to provide guidance for resolving them.


A network controller can help ensure that security measures are built into the network, compared with reliance on security applications to secure only the perimeter. It can automatically determine what's new, what's important, and what's unusual, everywhere across the distributed network.


A network controller provides a central point for network orchestration, abstract individual devices, and expose a higher level of functionality through open-standard APIs. Such APIs can be used to write custom applications that serve specific business needs, interwork with IT processes such as service management, and integrate with controllers in the organization’s other networks.