15-05-2012, 06:51 PM
John. I
CSE - IV
we need a ppt for conditional shortest path routing in DTN as a supportive material for doing our review.
15-05-2012, 06:51 PM
John. I CSE - IV we need a ppt for conditional shortest path routing in DTN as a supportive material for doing our review.
16-05-2012, 10:23 AM
to get information about the topic "conditional shortest path routing in delay tolerant networks " full report ppt and related topic refer the link bwellow https://seminarproject.net/Thread-condit...t-networks
07-07-2012, 04:04 PM
CONDITIONAL SHORTEST PATH ROUTING IN DELAY TOLERANT NETWORKS CONDITIONAL SHORTEST.docx (Size: 97.57 KB / Downloads: 38) ABSTRACT: Delay tolerant networks are characterized by the sporadic connectivity between their nodes and therefore the lack of stable end-to-end paths from source to destination. Since the future node connections are mostly unknown in these networks, opportunistic forwarding is used to deliver messages. However, making effective forwarding decisions using only the network characteristics (i.e. average intermeeting time between nodes) extracted from contact history is a challenging problem. Based on the observations about human mobility traces and the findings of previous work, we introduce a new metric called conditional intermeeting time, which computes the average intermeeting time between two nodes relative to a meeting with a third node using only the local knowledge of the past contacts. We then look at the effects of the proposed metric on the shortest path based routing designed for delay tolerant networks. We propose Conditional Shortest Path Routing (CSPR) protocol that routes the messages over conditional shortest paths in which the cost of links between nodes is defined by conditional intermeeting times rather than the conventional intermeeting times. Through trace-driven simulations, we demonstrate that CSPR achieves higher delivery rate and lower end-to-end delay compared to the shortest path based routing protocols that use the conventional intermeeting time as the link metric. INTRODUCTION: Routing in delay tolerant networks (DTN) is a challenging problem because at any given time instance, the probability that there is an end-to-end path from a source to a destination is low. Since the routing algorithms for conventional networks assume that the links between nodes are stable most of the time and do not fail frequently, they do not generally work in DTN’s. Therefore, the routing problem is still an active research area in DTN’s. Routing algorithms in DTN’s utilize a paradigm called store-carry-and-forward. When a node receives a message from one of its contacts, it stores the message in its buffer and carries the message until it encounters another node which is at least as useful (in terms of the delivery) as itself. Then the message is forwarded to it based on this paradigm, several routing algorithms with different objectives (high delivery rate etc.) and different routing techniques. SYSTEM ANALYSIS: EXISTING SYSTEM: Message delivery in sparse Mobile Ad hoc Networks (MANETs) is difficult due to the fact that the network graph is rarely (if ever) connected. A key challenge is to find a route that can provide good delivery performance and low end-to-end delay in a disconnected network graph where nodes may move freely. Some bridge nodes are identified based on their centrality characteristics, i.e., on their capability to broker information exchange among otherwise disconnected nodes. Due to the complexity of the centrality metrics in populated networks the concept of ego networks is exploited where nodes are not required to exchange information about the entire network topology, but only locally available information is considered. Then SimBet Routing is proposed which exploits the exchange of pre-estimated "between’s' centrality metrics and locally determined social "similarity' to the destination node. We present simulations using real trace data to demonstrate that SimBet Routing results in delivery performance close to Epidemic Routing but with significantly reduced overhead. Additionally, we show that SimBet Routing outperforms PRoPHET Routing, particularly when the sending and receiving nodes have low connectivity. PROPOSED SYSTEM: We propose Conditional Shortest Path Routing (CSPR) protocol that routes the messages over conditional shortest paths in which the cost of links between nodes is defined by conditional intermeeting times rather than the conventional intermeeting times. Through trace-driven simulations, we demonstrate that CSPR achieves higher delivery rate and lower end-to-end delay compared to the shortest path based routing protocols that use the conventional intermeeting time as the link metric. CONCLUSION: In this paper, we introduced a new metric called conditional intermeeting time inspired by the results of the recent studies showing that nodes’ intermeeting times are not memory less and that motion patterns of mobile nodes are frequently repetitive. Then, we looked at the effects of this metric on shortest path based routing in DTN’s. For this purpose, we updated the shortest path based routing algorithms using conditional intermeeting times and proposed to route the messages over conditional shortest paths. Finally, we ran simulations to evaluate the proposed algorithm and demonstrated the superiority of CSPR protocol. These results show that the conditional intermeeting time represents link cost better than the standard intermeeting time. |
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