SDN: Software Defined Networking

SDN or Software Defined Networking are the natural evolution of the traditional network as we know them now. After view how was computation virtualized, the next logic step is the lower level layer virtualization, this is the virtualization of our CPD network.

SDN is based on capability to define and configure network only with software, starting on static physical topology. That permits to change logical topology and configuration in a very quickly and flexible way, so it would be easily adaptable to the moment requirements. SDN also permits to do a very scalable design thanks to its versatility and integration.

SDN allow network administrators to increment an abstraction grade on network management, separating the control plane and the forwarding plane. In this way only would be needed to modify the control plane for change the whole network.

The main advantages of SDN are:

• Simplicity
• Agility
• Automation

Specifying a little bit more, their characteristics are:

• The control plane are programmable directly
• Dissociate the control and forwarding permits a very quickly network adjusting
• Logic are centralized by SDN controller
• Is possible to create applications to automatize configurations, because the programming software are not proprietary
• The implementations use open standards and for that is easy to make compatible the different vendors devices

The rising of this technology comes from the traditional model problems, which are the following:

• Currently, for each network modification, its necessary to manually reconfigure all the involved network devices.
• Is needed to have a very accurate knowledge of devices, protocols and processes which intervene on network.
• Is not possible automatize reconfiguration processes.
• Difficult to scale
• Very dependent on vendor systems.

To manage the SDN and communicate control plane and forwarding plane it could be use OpenFlow, which is the first standard defined to manage SDN.

SDN are a new technology which strongly rises in the networking world, with very good future perspectives, because facilitates the network development and therefore, the business associate, and permits reduce costs and provide huge flexibility.