Chinese Journal of Computers   Full Text
Title	Forwarded History-Based Asynchronous Routing for Challenged Networks and Research of the Number of Relays
Authors	CHEN Hui1) FAN Xiu-Mei1) SHAN Zhi-Guang2)
Address	1)(Beijing Laboratory of Intelligent Information Technology, School of Computer Science, Beijing Institute of Technology, Beijing 100081) 2)(Department of Information Research, State Information Center, Beijing 100045)
Year	2008
Issue	No.10(1687—1694)
Abstract &   Background	Abstract For the reason of the mobility，fallibility of nodes, and the sparsity of Links, most of the time links in challenged networks are disconnected. Traditional synchronous routing methods are unsuitable for this circumstance, thus we should consider the routing problem of challenged networks in an asynchronous way. This paper proposes a totally asynchronous routing algorithm, which uses the forwarded history of the messages to make routing decision. This method could decrease network traffic caused by message flooding. In addition, the authors study of the influence of the number of relays on the performance. This paper elaborates the method and analyses the performance of the method by comparing the simulation result with some other methods. Keywords routing； challenged networks; contact; delay tolerant network Background This article is mainly study of the asynchronous routing algorithm for intermittent networks. There are many type of challenged networks, and in each of them the wireless nodes have different mobility pattern. Even though a message-switched architecture for asynchronous communication has already been proposed, there is not an efficient routing algorithm that suitable for most of the circumstances. Some scholars use network knowledge to accurately decide when and using which relay to forward a message, this method only suitable for networks that nodes have a regular mobility pattern. Some other scholars proposed some method which based on message replication to improve the delivery ratio of messages. These methods generate too much network traffic. Other people consider the routing as a resource problem, and this method has better performance. In this article, the authors propose an asynchronous routing method which does not need any network knowledge; also this method could decrease the network traffic and has a better performance. This subject is part of the 863 project "New-style Ad-hoc Routing to Hold out Intermittently Connect". This project is aimed to propose an advanced routing protocol which could be used in networks characterized by long delay, frequent interruption, and intermittently connectivity. The significance of this article is to study of the asynchronous routing technology of Ad-hoc Networks, and to promote the enacting of the standard of our country.