Multimedia services have been popping up at tremendous speed in recent years. A large number of these multimedia streaming systems are introduced to the consumer market. Internet Service Providers, Telecommunications Operators, Service/Content Providers, and end users are interested in the mechanisms they use, the Quality-of-Experience they provide (e.g. video/audio quality, audio-video synchronization, communication delay, start-up time, etc.), the resources they need, the system stability, and the service availability. The multimedia streaming systems analyzed in this thesis include IP layer multicast TV (IPTV), Peer-to-Peer TV (P2PTV), Content Delivery Networking (CDN), Peer-to-Peer Video-on-Demand (P2PVoD), Server-to-Client Video Conferencing (IPVC) and Peer-to-Peer Video Conferencing (P2PVC). This thesis aims to study various kinds of popular streaming systems, through analytical models, measurement experiments, and simulations, to reveal their characteristics and performance in different aspects. Based on this research, we can not only better understand the behavior and limitations of existing systems and find out the key parameters that affect their performance, but also investigate the potential problems and predict the system performance for future cases. By comparing the two general streaming content delivery methods (Server-Client and Peer-to-Peer), we gain in-depth insights on “which is better” and “what determines better” for different services and in different scenarios.