保证高可靠度和低传输开销的DTN拓扑控制

由于时延容忍网络中复杂的环境可能导致网络节点失效或链路故障，再加上节点的持续移动和链路的间歇连通，都给网络可靠拓扑控制带来挑战．为解决这些问题，基于时空图提出了有效的可靠拓扑控制方案．该方案适用于节点周期性运动的卫星网络、星际网络等时延容忍网络．首先将网络拓扑转化为时空图；然后定义了网络的可靠拓扑控制问题，拓扑控制保证在网络连通的条件下，寻找网络中任意节点对的最可靠路径，并最小化网络的传输开销；最后提出了两个算法来解决此问题．仿真验证了提出的方法既能保证网络的可靠性，还能降低网络的传输开销，从而说明提出的拓扑控制方案适用于拓扑周期性可预测的时延容忍网络．

Topology control with a high reliability and low transmission overhead in DTN

Complex environment in delay tolerant networks may lead to node or link failure. In addition, the continuous movement of nodes and intermittent connectivity of the links also bring challenges to the reliable topology control. Effective reliable topology control schemes based on time-space graph are proposed in this paper, which are suitable for delay tolerant networks where nodes periodically move, such as satellite networks, interplanetary networks, other space network, etc. First, the network topology is transformed into a space-time graph. Then, the reliable topology control problem is defined. In the case that the network is connected, the topology control aims at finding the most reliable path for any pair of nodes and minimizing the transmission overhead. Simulation shows that the proposed methods can guarantee the reliability and reduce the transmission overhead. So the proposed topology control schemes are applicable to delay tolerant networks with predictable periodic topology.