SDN

Stands for "Software-Defined Networking."

SDN is a networking architecture that separates the responsibilities for routing and forwarding network data packets. A central server takes over all routing decisions for the network, instead of leaving those decisions up to each individual node. An administrator can configure and manage a network through software running on the server, instead of managing each device separately. Data centers, enterprise networks, and campuses often use SDN to manage large, complex networks.

Each function of a router or switch is conceptually part of one of three planes:

  • The data plane (or forwarding plane) is responsible for the physical forwarding of data packets to the next node toward its destination.
  • The control plane determines the routing of those data packets, creating a path of nodes for the packet to move along.
  • The management plane configures the control plane by giving the network administrator access to a command-line interface or control panel.

In a traditional network infrastructure, each device is responsible for all three planes. In a software-defined network, each switch or node is only responsible for the data plane; the central server takes over the control and management planes.

The SDN's central server handles routing decisions for all the nodes on the network
The SDN's central server handles routing decisions for all the nodes on the network

An administrator of a traditional network must configure each switch (or other type of node) on that network separately. A large network may have dozens or even hundreds of switches, which leads to a lot of duplicate work when updating configuration settings on each one. Software-defined networking centralizes the control and management of the entire network into a single dedicated device. An SDN server instructs the switches and other nodes how to forward data packets using a network protocol like OpenFlow.

In addition to being easier to manage, software-defined networks can move data more efficiently. Individual switches making routing decisions on their own may not choose the most efficient route, since they have limited knowledge of the conditions across the entire network. An SDN server, however, can monitor and control the entire network to optimize traffic for specific applications while bypassing congestion.

Updated May 8, 2023 by Brian P.

quizTest Your Knowledge

What is the purpose of a service-oriented architecture (SOA)?

A
To improve customer service
0%
B
To reduce service costs
0%
C
To make it easy for a business to add new services
0%
D
To provide service as quickly as possible
0%
Correct! Incorrect!     View the SOA definition.
More Quizzes →

The Tech Terms Computer Dictionary

The definition of SDN on this page is an original definition written by the TechTerms.com team. If you would like to reference this page or cite this definition, please use the green citation links above.

The goal of TechTerms.com is to explain computer terminology in a way that is easy to understand. We strive for simplicity and accuracy with every definition we publish. If you have feedback about this definition or would like to suggest a new technical term, please contact us.

Sign up for the free TechTerms Newsletter

How often would you like to receive an email?

You can unsubscribe or change your frequency setting at any time using the links available in each email.

Questions? Please contact us.