Study on Overlay Mechanisms of Supporting Real-Time Multimedia Applications in Internet
支持Internet实时多媒体应用的Overlay技术研究

Recently, large-scale multimedia applications put a challenge on traditional Internet. Due to many drawbacks in implementing reliability and QoS control, as well as requirements in upgrating infrastructure components, IP multicast has more difficulties to be widely deployed in Internet. However, circumventting these problems via overlay networking increasingly attracts many interesting of researchers. This paper models some measures of relaibility, QoS and scalability relating to large-scale real time multimedia applications. Furthermore, overlay networking protocols especially overlay multicast protocols have been analyzed referring to these issues. Comparing to IP multicast, overlay mul- ticast may induce some delay penalty, but this shortcoming is insignificant by virtues of proper protocol design. Overlay multicast can employ upper-layer functionalities in where, thus make it feasibly and efficiently to achieve E2E reliability and QoS based on hop-by-hop. Besides, scalability as well as TCP-frienliness is guaranteed efficiently in overlay multicast. Moreover, no infrastructure support is needed, thus paving the way for widely deployment in Internet. Advantages above have made overlay multicast to be a promising techniques for large-scale real time multimedia applications in Interact.