Software-Defined Networking (SDN) Definition

What is SDN? The physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices.

SDN Definition

Software-Defined Networking (SDN) is an emerging architecture that is dynamic, manageable, cost-effective, and adaptable, making it ideal for the high-bandwidth, dynamic nature of today’s applications. This architecture decouples the network control and forwarding functions enabling the network control to become directly programmable and the

underlying infrastructure to be abstracted for applications and network services. The OpenFlow® protocol is a foundational element for building SDN solutions. For an in-depth understanding of SDN-based networking and use cases, check out the open source micro-book, “Software-Defined Networks: A Systems Approach”.

The SDN Architecture is:


Network control is directly programmable because it is decoupled from forwarding functions.


Abstracting control from forwarding lets administrators dynamically adjust network-wide traffic flow to meet changing needs.


Network intelligence is (logically) centralized in software-based SDN controllers that maintain a global view of the network, which appears to applications and policy engines as a single, logical switch.


SDN lets network managers configure, manage, secure, and optimize network resources very quickly via dynamic, automated SDN programs, which they can write themselves because the programs do not depend on proprietary software.


When implemented through open standards, SDN simplifies network design and operation because instructions are provided by SDN controllers instead of multiple, vendor-specific devices and protocols.

SDN Architecture

SDN Revolution Started It All

The ONF, which started the SDN movement, has had a number of notable successes.

CORD leverages the previous work of SDN, OpenFlow and ONOS, and blends in Cloud and NFV technologies to create what is now the leading solution for transforming operator edge networks


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Movement to decouple control and forwarding planes to enable innovation


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First standard interface for separating the network control and data planes

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Leading Open Source SDN Controller for Operators

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‘Edge Cloud’ solution, with 70% of operators planning to deploy CORD to transform their networks

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