一种最优化期望时延的容迟网络副本分发协议

Optimal expected delay copy dissemination protocol in delay tolerant networks

多副本路由协议能有效降低容迟网络消息交付时延。目前的工作仅将节点间的当前质量作为分发依据,忽视了容迟网络固有的大延迟交付特性。提出了分发跳数约束的最优化消息期望时延的路由协议ODCD(optimal expected delay copy dis-semination),能在整个分发时间维度内选择最佳中继节点以优化期望时延。ODCD利用最佳停止规则进行建模,设计了综合性的动态分发尺度和相应的分发规则,并提出了一个用于计算该尺度的反向递归算法。在真实接触数据集上的仿真表明,相比同类算法,ODCD以少量发送成功率上的损失获得了在消息端到端时延和路由代价上的明显优势。

In delay tolerant networks, multi-copy routing protocol can reduce the message delivery delay efficiently. However, today most efforts take current quality of node pairs as the dissemination metric and neglect the nature of the inherent large delivery delay characteristic in delay tolerant networks. This paper proposes an optimal expected delay copy dissemination （ODCD） protocol with constrained remaining hop-count for each message. ODCD algorithm disseminates the copies to the best relay nodes to optimize the expected delay of each message within whole dissemination time dimensionality. ODCD algorithm employs the optimal stopping rule to model the copy dissemination; designs the comprehensive dynamic dissemination metric and dissemination rule. A backward recursive algorithm is proposed to calculate the dissemination metric. Simulation results based on the real contact data set indicate that the 0DCD algorithm show prominent superiority in end-to-end delay and routing cost with acceptable degradation in delivery success rate.