Program Of Energy Conservation And Congestion Control In DTNs

Today, many popular applications on the Internet mostly based on the assumption that accessible and timely of end to end:send a message to an endpoint or a support server, and then get a feedback message immediately. However, these assumptions that applicable for most Internet communications are deficiencies sometimes:some private network such as space communications, traffic conditions monitoring network communications. Since most of these communication networks with the use of radio waves as a carrier, the node moves around, and communication environment is poor and limited the ability of the node, we proposed the concept of DTN to describe the networks in recent years.Different with the traditional networks, DTN is an abstract network model. In this network, the network topology is unstable, conditions of communication between nodes are poor and there is a big delay in the network. In the packet transmission process, there is no advance pathes from the source node to-end for connections between nodes, this feature makes the routing issue has become the core issue of DTN.Because of the special nature of the environment for the DTN, much of the relevant routing protocols are raised continually. Some of the more influential such as Epidemic, Spray and Wait, Prophet, MaxProp and so on. These routing protocols are divided into single-copy and multiple copy algorithms, which rely on whether to allow data packets in the network is several-fold increase. In a single copy scenario, there is only one relay node in the network to submit messages to the destination node. For example, the copies of data can be forwarded based on a maximum value of the utility function at each node encountered. In a multi-copy program, copies were distributed to the network by several conditions. For example, all nodes exchange their copies simply when they met each other in the Epidemic.In a variety of literature, for each of the performance of DTN routing algorithm studies have followed the impact of environmental characteristics, such as the area size of network and node density. However, the node itself is rarely taken into account the impact of factors on the routing algorithm. This is mainly the node's own energy, the size of the cache capacity and the importance of the copies, etc.In this paper, we first analyze and summarize the concepts of DTN, its architecture, and a variety of common routing algorithms, then, in response to these problems, we propose the following programs:1. Give full consideration to the node capacity factor, combined with the TTL of Message to improve the routing protocols. When the node energy is insufficient, according to a threshold of TTL to forwarding data packets. It has been explored for three well-known routing algorithms proposed for DTN. Simulation results show that a threshold can be found to achieve a good purpose of saving network energy and the damage of delivery rate is not obviously.2. Proposed the Congestion Control Scheme of Epidemic in DTN based on the TTL of Message. When congestion occurs, discard the node cache packets by the TTL Threshold of Message. The simulation results show that the program has improved the delivery performance of Epidemic.3. We have built Simulation System for DTN to simulat the improved programs, and give the results.