Analysis of the controller based wireless LAN concept considering time critical applications and QoS

The focus of this dissertation is to achieve a critical analysis of the centralised Wireless LAN deployment concerning Voice over IP and Quality of Service. In today's enterprises Wireless LAN has become an important network infrastructure providing required services as well as flexibility for employees, customers and guests. Flexibility is provided through mobile offices and guest services including wireless mobile applications and web access. These services include data transmission for time critical applications like voice and video over IP. Therefore distributed and centralised WLAN deployments handle multiple kinds of data and time critical traffic (voice and video). The centralised approach provides all the required logic represented in form of a wireless controller and only a minimum of intelligence in the access point itself instead of using a distributed approach where the logic is placed into the access point. As wireless infrastructures become more and more important supporting mobility in an enterprise the infrastructure needs to be extended and improved to fulfil changing requirements related to security, mobility, speed and size. The change of hardware and support of time critical traffic lead enterprises to evolve their infrastructure to the centralised approach. One important factor for today's enterprises is to improve their voice infrastructure using VoIP. Voice over WLAN has become an important service and therefore QoS needs to be considered. Evolving from the autonomous to the centralized wireless LAN design involves additional overhead that needs to be analysed considering time critical applications (VoIP). Therefore the centralized architecture will be analysed considering Voice over IP.