Software Defined Networking (SDN) represents a modern approach to network infrastructure, enabling centralized control of network traffic and resources through software. This approach brings higher flexibility, automation, and efficiency in network management. Linux servers offer an excellent platform for implementing SDN due to their openness, flexibility, and wide support for various tools and technologies. In this article, we'll explore how to set up and use SDN on Linux servers.

Prerequisites

Before we begin, it's important to have:

• A Linux server with a suitable distribution (e.g., Ubuntu, CentOS) with root access.
• Basic knowledge of working in the Linux terminal.
• Internet connectivity for downloading necessary packages.

Installation and Configuration of SDN Controller

The first step is to install an SDN controller, which will serve as the central point for managing the network infrastructure. OpenDaylight is a popular open-source SDN controller that supports a wide range of network protocols and features.

1. Installation of Java Runtime Environment (JRE): OpenDaylight requires JRE for its operation. You can install JRE using the command line:

   sudo apt-get update
   sudo apt-get install default-jre
   

2. Downloading and Installing OpenDaylight:

   • Go to the official OpenDaylight website and download the latest stable version.
   • Unpack the downloaded archive and navigate to the OpenDaylight directory:

     tar xvf opendaylight.tar.gz
     cd opendaylight
     ​

3. Running OpenDaylight:

   • Use the bin/start script to run OpenDaylight.
   • Verify the controller's operation using bin/status.

Configuration of Network Devices

SDN allows the management of network devices (e.g., switches, routers) through the controller. To integrate these devices into SDN, they need to be configured to communicate with the controller.

1. Connecting Network Devices:

   • Configuring network devices varies depending on the manufacturer and model. Generally, it's necessary to set up the network device to use the OpenFlow protocol or another supported protocol for communication with the SDN controller.

2. OpenFlow Configuration:

   • On the respective network device, enable OpenFlow and set the IP address and port of the SDN controller.

Management and Monitoring of SDN

After setting up the controller and configuring network devices, you can access the SDN controller interface for network management and monitoring.

1. Accessing the User Interface:

   • OpenDaylight and other SDN controllers typically offer a web interface for easy network management. Log in to the interface using a web browser.

2. Creating and Managing Network Policies:

   • Through the user interface, you can define and enforce network policies, such as routing rules, security policies, and QoS policies.

3. Network Monitoring and Analysis:

   • SDN controllers provide tools for monitoring the network, including visualization of network topology, performance of network devices, and detection of network anomalies.

Implementing SDN on Linux servers allows for efficient management of network infrastructure with high levels of automation and flexibility. With open-source tools like OpenDaylight, organizations can easily transition to software-defined networks and harness their full potential for improving network performance and security.