协作缓存在移动自组织网络中得到了充分的应用和部署.提出了一种基于簇的一致性维护策略CCS(cluster-based consistency scheme).在CCS中,相邻的节点组成一个簇.每个簇中挑选一个能量较高、较稳定的节点作为簇头,而簇中的其他节点与簇头节点最多相距两跳.簇头节点利用基于DHT(distfibuted Hash table,分布式哈希表)的Chord协议作为组管理协议,即簇头节点组成一个Chord环.通过动态地在Chord环上建立更新树传播更新内容.这样,更新数据在不同的簇之间是通过更新树传播的,而在簇内是通过MAC层的广播传播的.仿真实验结果表明,与基于流言传播的缓存一致性维护策略相比,CCS具有开销小、成功率高和传播快的特点.
Cooperative caching has been adequately addressed in MANETs for QoS and cooperative computing. This paper presents a Cluster-based Consistency Scheme, CCS. In CCS, the close nodes in locality are organized into a cluster, where a more stable and powerful node is selected as header in each cluster and the others are at most 2 hops away from the header as the members of the cluster. All header nodes form a ring with Chord as group management protocol. An updating tree is built dynamically on top of the Chord ring to propagate the updated data items. In this way, the updated data item is broadcasted within cluster at MAC layer and transmitted among the header nodes along the updating tree. The simulation results demonstrate CCS outperforms the Gossip scheme for consistency of cooperative caching with less workload, higher success rate and less updating time.