How a Software-Defined Network Puts You Back in Control

By: Larry Loeb| - Leave a comment


Changing the way your network is set up is costly for many reasons. It’s not just the cost of hardware and accessories that come into play; the cost of the disruption to your business operations during such a change should also be considered in your planning.

As budgets are developed for the year ahead, let’s outline the software-defined network technologies that can improve your network flow today and allow for more seamless growth tomorrow.

Software-defined networking (SDN) is an approach that allows a network administrator to manage overall network services through the abstraction of the higher-level functionalities involved. The method involves decoupling the system that makes decisions about where traffic is sent, called the control plane, from the underlying systems that forward traffic to the selected destination, called the data plane.

Components of a Software-Defined Network

SDNs are made up of a few basic components:

  • SDN applications are the programs that directly communicate the network requirements as well as the desired network behavior to the SDN controller. This is completed with what is called northbound interface (NBI). These are the highest-level programs in the system, and net admins control them.
  • SDN controllers are composed of one or more NBI agents, the SDN control logic and the control to data-plane interface (CDPI) driver. They translate the requirements given by the SDN application layer down to the SDN datapaths while also providing the SDN application with an abstract view of the network.
  • SDN datapath is a network device that has uncontended (from other devices in its network) control over forwarding and data processing capabilities. This is what moves the bits down the wire, no matter what form the wire takes.
  • SDN CDPI devices sit between an SDN controller and an SDN datapath. They control forwarding operations and also issue notifications and advertise what they can do to other network elements.

NBIs and CDPIs are usually implemented in open, vendor-neutral ways.

SDN Usage

A software-defined network enables infrastructure-as-a-service (IaaS) by providing elastic methods for elements connected in a network to communicate together. This elasticity is the key attribute of a software-defined network. It can be controlled automatically as well as dynamically through the use of pre-established rules that decode the notifications sent by network elements between the layers.

This allows the overall capacity of a network (and implicitly, the devices connected to it) to be reconfigured on the fly to meet dynamic demands. Resources can be used in different ways depending on the issue that must be solved.

SDNs can control both on-site and off-site networking, which means the on-site data center can benefit from SDN techniques, and organizations outsourcing data storage to keep information in the cloud can take advantage, as well. Overall utilization of resources can only improve in such a flexible setup.

Software-defined networking assures that a network can adapt to the future needs of a business, and this shift can be made without the downtime disruption that a static-only network can cause. SDN provides control over how a network is allocated in real time — not just at upgrade time.

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