节点状态感知的机会网络分布式协作缓存机制

Node Status Aware Distributed Cooperative Caching Mechanism for Opportunistic Networks

合理利用节点间的协作关系及相邻节点的缓存资源可有效提高机会网络中节点缓存的利用率与消息的投递率。该文提出一种节点状态感知的分布式协作缓存机制,通过感知消息扩散程度动态估计消息的重要程度,确定消息在缓存操作中的优先级。进而根据节点的活跃度及相对粘度获知给定消息与其目标节点的相遇概率,并针对消息源节点的差异设计分区协作缓存方法,同时在本地缓存处于存满状态时动态选取协作节点,实现本地消息到相邻节点的转移,以达到高效利用缓存资源的目的。结果表明,所提出的协作缓存机制能够有效地利用节点有限的缓存资源,并大幅度地改善消息投递率及节点缓存利用率。

By reasonably exploiting the collaborative relationships between nodes and the limited cache resources of neighbor nodes, the cache utilization rate and the message delivery probability of opportunistic networks can be effectively improved. A node status aware distributed cooperative cache management mechanism is proposed in the paper, where the importance degree of a given message can be dynamically estimated by perceiving its spreading degree to determine the caching priority. Furthermore, according to the active degree and the relative viscosity, the encounter probability of a given message to its destination node can be obtained for the design of adaptive cooperative cache management strategies for messages in each cache area respectively. When the cache is fully occupied, the collaboration node within the transmission range is dynamically selected, thus the message transferring to the collaboration node and the efficient utilization of caching resources can be ideally achieved. The results show that the proposed caching mechanism can fully exploit the limited cache resources and greatly improve the message delivery rate and the buffer utilization rate.