An Approach to Select a Best Suitable Video Server

Today, many institutions begin to employ services to distribute multimedia content to their customers. Especially in the areas of tele-learning and tele-medicine, the requirements on the availability and the achieved transmission quality are very high. Therefore, multiple video servers for a particular service are distributed over the internet in order to allow the clients to choose the ’best’ one. The term ’best’ can be defined in various manners. Typically, the client uses a try-and-error based selection mechanism to choose a best fitting server. Additionally, methods have been developed to choose an optimum server based on its current load. The presented approach goes a little further. Quality of service (QoS) based mechanisms are employed for the selection process. In order to find the server which fits best for a particular service a quick check is started before the connection to the selected server is set up. This check includes the test of the availability of the server and the particular service as well as the measurement of the currently available quality of service from the server towards the client. This is done by initiating a packet stream for testing reasons only. The client analyzes the stream to calculate values such as the delay, the delay variation (the jitter), and the packet loss ratio. Based on the results of these measurements the ’best’ server can be chosen.