Carefully designed and managed services are essential for quality-demanding traffic, especially in large-scale IP networks where the aggregation of flows and the variety of traffic types are extensive. Although individual mechanisms have been widely investigated, not much related work exists on integrated approaches to QoS provisioning that are also feasible to implement. This work presents a thorough approach to the design, dimensioning and provisioning of a high priority service for high-quality demanding traffic over an IP network. Our approach employs efficient scheduling and a dynamic admission control scheme while demonstrating novel characteristics in terms of the quality offered to IP flows.

The implementation of successful assured forwarding (AF) services according to the DiffServ framework remains a challenging problem today, despite the numerous proposals for AF PHB mechanisms and AF-based service implementations. In this work, we propose two modules, the TCP-window aware marker (TWAM) and the dynamic WRED (DWRED) mechanism for implementing the DiffServ AF PHB. We provide analytical models and an experimental evaluation in order to demonstrate how they succeed in enhancing the quality, increasing fairness, improving the performance and easing the deployment of a production- level AF-based service.

The increased need for quality of service (QoS) in today's networks has concentrated a lot of research and implementation efforts. Particular interest exists for the exploitation of the DiffServ framework towards the provision of qualitative services in MAN and WAN worldwide. Although individual mechanisms have been widely investigated, not many references to studies combining all levels of priority and QoS provisioning exist. This work aims at presenting a thorough and unified approach to the dimensioning and provisioning of a high priority service for high-quality demanding traffic over a MAN/WAN environment. Our approach anticipates for bounds in specific quality metrics and is demonstrated by the experimental case-study of a high-priority service over a MAN topology.

A lot of research work has recently focused on the exploitation of the DiffServ framework towards building reliable networking services that provide deterministic quality guarantees. In this work we are attempting to devise a DiffServ-based service model for relative differentiation of traffic in a network serving aggregated traffic. The service model proposed aims at providing a minimum capacity during congestion and a bounded average end-to-end delay to profile-conforming traffic, obtaining thus a relatively better performance when compared to the best-effort service. We provide the framework on which the proposed service model is based and we present results from its deployment in a simulation environment.

The use of Internet services has become part of everyday life. The need for more advanced applications is increasing and solutions have to be provided in order to meet it. Multimedia information is becoming more popular. The connection bandwidth is not yet ready to cope with rising expectations for applications such as video on demand (VoD). We propose a way to implement such a service over a limited bandwidth/best effort Internet based network. Our proposal consists of the implementation of algorithms and the introduction of quality of service features on a network such as the Internet that inherently does not support such features. We propose two techniques for the implementation of an Internet based video on demand service. The first deals with the distribution of video titles on several video servers and is called the Disk Manipulation Algorithm (DMA). The second gives a dynamic nature to the service, imposes a virtual routing procedure to the system and is called the Virtual Routing Algorithm (VRA).

The exceptional advent and dominance of interactive multimedia applications in our days has led to the need for their exploitation for educational, among many other, purposes. In this work, we present the design and implementation of a multimedia annotation environment for young children using the Java 2 Platform. This environment was developed to provide children of ages 4 to 8 with the opportunity to reflect upon and annotate episodes from their everyday life.