QoS optimization in congested multimedia networks

In multimedia networks, maintaining the agreed QoS (Quality of Service) level is fundamental. VoIP (Voice over IP) and other multimedia applications such as video conferencing, video-on-demand, media streaming, data traffic etc. impose strict requirements and arise various factors that may alter the QoS in the network. The QoS may easily be affected by delaying or dropping packets, as a consequence of parameters such as latency, jitter, bandwidth and packet loss. The wide range of multimedia applications on the current market, impose various and strict requirements for multimedia networks to deal with. For better managing such requirements and improving the service process, it is worth classifying traffic with respect to the bit rate. According to the service requirements of source applications and to the arrival characteristics, the traffic on high-performance networks can be divided into four categories: Constant Bit Rate, Variable Bit Rate, Available Bit Rate and Unspecified Bit Rate. The paper presents the results of a performance evaluation experiment conducted within our Competence Center for Network Management. The performance measurements involve several scenarios which combine different traffic types, queuing mechanisms and resource reservation protocols. The goal of the experiment is to identify the most suitable scenario to provide qualitative services and to efficiently utilize resource given the conditions imposed by each traffic type.