延迟/中断可容忍网络研究进展

Delay/Disruption-Tolerant Network Study

DTN网络是一类延迟/中断可容忍网络,具有长延时、某一时刻不存在端到端链路或者链路频繁中断、节点存储/计算能力低等特点,与现在的地面有线网有着根本的区别,所以现有网络协议,如TCP协议等无法满足DTN网络应用.在介绍DTN网络起源和特点的基础上,详细描述了DTN网络中几个典型的网络协议;比较了不同的DTN网络路由算法;对DTN网络在深空探测、野生动物研究、湖水质量检测、偏远地区通信等领域的应用作了介绍;最后对DTN网络未来的研究趋势进行了分析与展望.

Although often not explicitly stated, the existing Internet model is based on a number of assumptions, such as： an end-to-end path exists between the source and its destination at all time, the maximum delay is not excessive, and the packet drop probability is small. However, a class of challenged networks, which are called DTN （delay/disrupton-tolerant network）, emerge in many circumstances. DTN is greatly different from the traditional network model. It has long delay, frequent disruption, no end-to-end path simultaneously, and the network nodes have the capability of limited storage/processing. As a result, the present network protocols, such as Transfer Control Protocol （TCP）, can not satisfy the applications over DTN. Some recent advanced researches in DTN are reviewed in this paper. Firstly, the main organizations working on DTN topic and typical characteristics of DTN are introduced. Then several classical overlay protocols of DTN are presented, such as bundle protocol, and some routing algorithms, including single copy routing algorithms based on knowledge and multicopy routing algorithms, are compared. Moreover, DTN researches in deep space communication, ferine animal, water quality survey and remote village connecting with Internet are discussed as real examples of DTN. Finally , the open issues and challenges of DTN in near future are proposed.