Traditional vs Controller-based Networking

There are two types of networking environments: traditional and controller-based. This tutorial compares both and explains their main differences.

Traditional networking environments

In traditional networking environments, you individually configure and manage each network device. For example, if you have 10 routers in your network, you need to configure and manage them separately. Configuring and managing each network device is a tedious task. Since you configure each device manually by entering commands, there is also a possibility of mistakes. With traditional networking environments, you take the following actions for each network device over the lifetime of the device:

• You install the network device (such as a router or a switch) into the network.
• You make the initial configuration of the device. The initial configuration allows the device to perform its functions in the network.
• You monitor the overall performance of the device and the events that occur on it. For this, you can use network management protocols such as SNMP (Simple Network Management Protocol) and NetFlow.
• Over time, you modify and update the configuration as per the requirements of the network.
• You upgrade the operating system on the device as needed.

At first glance, the above-listed tasks may not seem like a lot of work. But if you have to repeat these tasks with each device on the network, it becomes overwhelming. For example, if you want to update the IOS, you have to take the following steps.

• Back up the running configuration and the old IOS
• Add the new IOS and configure the device to use the new IOS to boot
• Restore the running configuration from the backup

To update the IOS on all routers, you have to perform the above-listed tasks 30 times (3 steps x 10 routers). For each configuration change you want to make, you need to log into the router. Logging into the router is not as easy as logging into the PC. To log in to a router, you need to access the router through a console connection or remote protocols like Telnet and SSH. After making changes, you must disconnect the device. You have to repeat this process on each device whenever you want to make changes.

Key points:-

• You manage all devices independently. To manage them, you have to establish a new connection each time. You also have to terminate the connection after making the changes.
• You manually make all changes. Manual configuration is prone to configuration errors.
• It uses the blacklisting security model. In this model, everything is allowed unless you disallow it.

Controller-based networking environments

Controller-based networking uses automation technologies to apply configuration changes to multiple devices at the same time. It uses the controller software or device to automate configuration changes on the network and manage their deployment to multiple devices simultaneously. It actively monitors the network for changes. When you add a new device to the network, it automatically applies the initial configuration without needing your intervention. You can use automation for many tasks. For example, you can use it to manage IOS images on devices. Once configured, it actively checks the developer's site for new versions. If a new version is available, it automatically backs up the existing version on the device and replaces it with the latest version. All this process is done automatically without your intervention. You also do not need to visit the devices. Another use of automation is task scheduling. You can schedule specific tasks or operations on the device and automate troubleshooting procedures if there is a problem.

Key points: -

• You manage all devices collectively. To manage them, you use the controller software or appliance.
• You only need to configure the controller software or appliance. The controller software or appliance manages all devices automatically based on their configuration.
• Since the controller configures all devices, the chances of configuration errors are zero unless you misconfigure the controller device.
• It uses the whitelisting security model. This model blocks everything unless you allow it. It enhances the network's security.
• It reduces network costs. Since the controller software or appliance performs the maximum work, a company needs only one or two administrators to manage the controllers, reducing the need for additional staff.
• It saves time. With traditional networking, you manually need to configure all devices, which is too time-consuming.
• It provides consistency in configurations. You create the script and then instruct the controller to deploy it to the devices. This way, all devices receive the same configuration.

Conclusion

Shifting from traditional networking environments to controller-based networking represents a significant advancement in network management. Traditional networking requires manual configuration and management of each device, which can be tedious and error-prone. This approach poses challenges in scalability, consistency, and efficiency, particularly as networks grow in size. In contrast, controller-based networking leverages automation technologies to streamline network management. Managing devices collectively through a centralized controller minimizes the risk of configuration errors and enhances security. Additionally, it offers significant time savings, reduces labor costs, and ensures consistent configurations across all devices. Ultimately, adopting a controller-based networking environment can lead to a more efficient, reliable, and secure network infrastructure, making it a preferred choice for modern organizations aiming to meet the demands of today's dynamic technological landscape.