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Research Of Routing Protocol For Delay Tolerant Network

Posted on:2012-09-08Degree:MasterType:Thesis
Country:ChinaCandidate:J X WuFull Text:PDF
GTID:2178330332467341Subject:Computer applications
Abstract/Summary:PDF Full Text Request
Internet is currently the world's largest and most widely used computer network, which is based on TCP/IP communication protocol. It connects the network of different countries, and different personal computers, constituting the world's largest Internet system structure. However, the Internet mainly depends on the cable networks and Internet architecture has some basic assumptions:physical layer needs long-time and consistent connection; application layer does not need to consider the lower layer's communication; There must exist an end-to-end route; network delay between any two nodes can not be too much; symmetrical bi-directional data transfer rate; end-to-end packet loss rate should be relatively small and so on. With the emergence of microelectronics technology and military and other areas'needs, a new type of network appeared. The host in such network has the character of large random mobility and the router is no longer fixed; energy and storage resources are relatively limited; link is frequently broken; delay is relatively long; packet loss rate increases; delivery rate decreased rapidly. Such network is known as "Delay Tolerant Network". DTN currently has many applications, such as land mobile network, external media networks, and military wireless ad hoc networks and sensor networks and so on.Researchers have already carried out studies on DTN's network model, architecture, routing algorithm as well as security control. As the DTN network has the character of long delay, high packet loss rate and low energy of the node, then the routing strategies occupy a key position in DTN research. Existing routing algorithms can be divided into two categories: single message routing and message copies-based routing. This paper sorted these two categories further and analyzed the advantages and disadvantages of these algorithms, besides, the adaptation network environment of different algorithms were described.Based on the analysis of major DTN routing algorithms, this paper focuses on an algorithms named RACS, which is a message copies-based routing. RACS's main features are as follows:when two nodes meet, they will record their node's centrality and then send or receive message copies according their centrality proportion, which result the nodes that have big centrality can gain relatively more message copies and cause the increasing of delivery rate. This paper proposed a new algorithm called A_RACS which is based on the improving of RACS. In A_RACS, there are two kinds of node, they are "special nodes" and "common nodes". When a node with a message meets a common node, they send or receive message according their centrality proportion, but when meets a special node, the special node will receive the message while define the message copies as initial value, so that message can be diffused more widely. Moreover, in A_RACS, when a message arrives its destination, it will create a response so that the message can be erased in time and the buffer can be released so that other nodes have more buffers for other message transfer. And in chapter four, this paper simulated A_RACS algorithm and other related algorithms with ONE simulation tools. From the results, we can found that the performance of A_RACS routing is much better than others.Finally, I summarized the research work and gave some suggestions about further studying of DTN routing protocol.
Keywords/Search Tags:DTN, routing algorithm, node centrality, message copy control, Response ACK
PDF Full Text Request
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