Demystifying SDN Network Architecture
Home Data Center Demystifying SDN Network Architecture

Demystifying SDN Network Architecture

Posted on by FS.COM

Networking has undergone monumental changes in the last few decades. Enabled by OpenFlow, SDN (software defined networking) is an emerging architecture that is dynamic, manageable, cost-effective, and adaptable, which is thought to be ideal for the high-bandwidth, dynamic nature of today’s applications. Everybody these days seems to be talking SDN and what it means for the future of data centers. How much do you know about SDN network architecture? What does it differ from traditional network? What benefits can really we get from it? Let’s get closer to SDN together in this blog.

Traditional Network Architecture Basis
Networking typically involves a collection of switches and routers that work together to achieve end to end communication. The key functions of these network elements can be segmented into layers of management, data plane and control plane. The traditional way of making these nodes work with each other is by implementing protocols running at each of these nodes to exchange information. This creates a distributed architecture, where every node across the network needs to be at a similar state to get the desired end result. In addition, these protocols are very rigid in what they can and cannot do. The result is a very static network architecture that is not adaptive to change.


Demystifying SDN Network Architecture
In a traditional network architecture, the data plane and control plane are coupled on the physical device. A traditional architecture not particularly fits to meet the needs of today’s end users since it makes the network too static and limits network designers. SDN decouples the control and data planes, abstracts the underlying network infrastructure from the applications, and logically centralizes the state and intelligence of the network. With SDN, the control functions of switches are offloaded to a central controller. So rather than configuring each switch to make its own control decisions, data center managers use software to configure the controller to make those decisions for multiple switches on the network.

SDN Network Architecture

Components of SDN Network Architecture
In order to further understand how SDN network works, six main components of SDN network architecture will be introduced in this part.
1. Network Devices
In a telecommunications network, network devices are the actual physical or virtual switches which define the forwarding plane of the network. A heterogeneous network may include wireless access points, computing resources, sensors, etc.

2. Southbound API (OpenFlow)
The network devices are connected to the SDN controller via an application programming interface (API). OpenFlow is the dominant source southbound API available for SDN, and other open source options are in development.

3. Controller
The SDN controller is the brain of the network which controls all underlying physical or virtual network devices (or both). OpenDayLight and ONOS are two of the most popular open source SDN controllers supported by many industry players.


4. Northbound API
This interface allows the applications and services to gain access and program the network devices via the controller. Currently, there is no open standard northbound API, although ONF and OpenDayLight have formed study groups to address this matter.

5. Applications and Services
This is the programmability layer and arguably the area with the greatest potential value. The most common services discussed in these environments are network virtualization, network monitoring & provisioning, data flow balancing and security services.

6. Automation and Orchestration
The ultimate goal of a programmable network such as SDN is to tie it into an automation or orchestration software stack to fully enable a cloud-like infrastructure. This may include open source cloud computing software such as OpenStack and the plug-ins available for the network.

From controlling traffic and handling high-bandwidth applications, to eliminating the need to continue purchasing expensive proprietary equipment, SDN network architecture promises to reduce capital and operating expenditure while improving overall reliability, manageability and scalability. FS.COM new introduced SDN switches have open API interfaces and Debian system to achieve SDN, which are cost-effective Ethernet access and aggregation platform to Enterprise, Data Center and Metro application. For more details, please visit or contact us via

Related Article: SDN vs NFV: the Future of Networking

Copyright © 2002-2018. All Rights Reserved.