How do you create a software defined network with open source tools?

1 Step 1: Choose a controller

The controller is the brain of the SDN, as it manages the network policies and communicates with the switches and routers. There are many open source controllers available, such as OpenDaylight, ONOS, Ryu, and Floodlight. Each one has its own features, benefits, and drawbacks, depending on your use case and requirements. For example, OpenDaylight is a modular and extensible platform that supports various protocols and applications, while ONOS is a distributed and high-performance controller that focuses on carrier-grade networks. You can compare and contrast different controllers and choose the one that suits your needs.

2 Step 2: Choose a switch

The switch is the device that connects the network nodes and forwards the packets according to the instructions from the controller. There are two types of switches in SDN: hardware and software. Hardware switches are physical devices that support SDN protocols, such as OpenFlow, while software switches are virtual devices that run on a host machine, such as Open vSwitch. Hardware switches offer better performance and reliability, but they are more expensive and less flexible than software switches. Software switches are cheaper and easier to deploy and configure, but they have lower throughput and higher latency than hardware switches. You can choose the type of switch that matches your budget and performance needs.

3 Step 3: Choose a protocol

The protocol is the language that the controller and the switch use to communicate and exchange information. The most common protocol in SDN is OpenFlow, which defines how the controller can manipulate the flow tables of the switch. OpenFlow is widely supported by many controllers and switches, and it offers a standard and interoperable way to implement SDN. However, there are also other protocols that can be used in SDN, such as NETCONF, P4, and gRPC. These protocols have different features and advantages, such as configuration management, programmable data planes, and remote procedure calls. You can choose the protocol that best fits your network architecture and functionality.

4 Step 4: Choose an application

The application is the software that runs on top of the controller and provides the network services and functions. There are many open source applications that can be used in SDN, such as network monitoring, load balancing, firewall, routing, and VPN. These applications can leverage the programmability and flexibility of SDN to achieve better performance, security, and efficiency. You can choose the application that meets your network objectives and requirements, or you can develop your own application using the APIs and frameworks provided by the controller.

By following these four steps, you can create a basic SDN with open source tools. Of course, this is not the only way to do it, as there are many variations and combinations of tools and technologies that can be used in SDN. The main idea is to understand the concepts and principles of SDN, and then experiment and explore the possibilities and potentials of open source tools.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?