Software-defined networking, otherwise known as SDN, is a new approach to networking that has come to be favored by technology professionals, and with good reason. Overall, it raises the technology to a new level, offering greater speed, flexibility, and security.
The basics of traditional networking
In traditional networking, there are routers and switches that allow for the movement of device traffic, getting network traffic from point A to point B. Routing protocols are the rules that routers use to determine the best path for moving traffic.
Some of the common routing protocols used for traffic inside an organization include Open Shortest Path First, otherwise known as OSPF, or intermediate systems to intermediate systems, or IS-IS.
Routing protocols that are used to connect with external organizations utilize what are known as exterior gateway protocols. The most common of these is Border Gateway Protocol, otherwise known as BGP.
Depending on the specific network need, routers will communicate with each other using one or more of these protocols to determine the best route for the current network traffic. Generally speaking, all of these protocols do a good job of managing traffic, but software-defined networking does a better job.
Introducing “the eye in the sky”
Software-defined networking separates the control of the data that is moving on the network from the routing and switching hardware. With traditional networking, the routing protocol acts as the control plane, determining the flow of traffic by sending it out through the forwarding planes in the routers to the various network interfaces.
You can think of software-defined networking as an eye in the sky that is constantly observing the network and its traffic to identify areas where there is congestion and determine the most optimal routes. This is accomplished through separating the control plane, which orchestrates the movement, from the forwarding plane, which is the router itself.
Enhancements delivered by software-defined networking
In effect, software-defined networking gives the control plane a new vantage point from which it can see the entire internet. It can see what is going on and identify congestion points, then provide direction for the traffic to the routers from a software-based controller.
The GPS navigation devices that are used to map traffic routes provide a good illustration of how software-defined networking works. Using satellite information, the GPS guides drivers, directing them to turn right or turn left to avoid traffic congestion and get to a destination as quickly and safely as possible.
With traditional networking, the control plane and the forwarding plane are both on the same device. Its efficiency is good, but not nearly as good as software-defined networking because it has less information to work with regarding the state of the network’s traffic.
The increased visibility that software-defined networks bring also provides for a higher level of security. Just as traffic can be seen with greater clarity, security threats are also easier to detect. Once a threat is detected, the network controller can be used to contain it by quarantining affected areas.
Finally, software-defined networking enhances network capabilities by providing a customizable infrastructure. Administrators working through a software-defined network have the ability to configure the services provided by the network in real time from a centralized location. Network infrastructure can be updated and virtual resources can be allocated much easier than with traditional networking.
Networks that are built on software-defined networking are able to accomplish greater control, greater speed, and much more agility. They allow for the customization of network infrastructure, making it perform better at a lower cost. Because of these features, it is truly the future of networking.