The reliance on computer networking is increasing; therefore managing and controlling it effectively is very important. Network traffic could be separated based on its aim and purpose. Network architecture consists of three parts: management-, control- and data planes.
The control plane carries control information; creates and maintains network topology map; and also path calculation and routing protocols run on it.
Usually IP network elements can be logically separated based on these planes. This means that the control- and data planes are already separated in the switches internally. The gist of the “split network architecture” is to separate these already detached functions physically as well. Thus the control plane of the switches could be moved into a physically separated device.
There are multiple standards based on this physical separation; for example the “Forwarding and Control Element Separation” (ForCES) framework. The IETF has already accepted its protocols.
The OpenFlow Consortium is developing a standard similar in functionality to ForCES; it is called the “OpenFlow Switch Specification”. Besides moving out the control plane from the switches this specification also centralizes it. The OpenFlow capable switches connect to one or more controller computer and they communicate using the specification’s proprietary secured channel.
NOX is a network controller which uses the OpenFlow Switch Specification. Besides it is open source it provides a high level application programming interface (API).
In this bachelor’s thesis I have defined a test network of switches with one NOX controller application. Instead of configuring hundreds of physical equipments emulated networks have been created by software. Measurements were intended to examine CPU, memory and network utilization of the controller.