04-05-2012, 03:56 PM
Consistency Management Strategies for Data Replication in
Mobile Ad Hoc Networks
109. PPT.ppt (Size: 36.5 KB / Downloads: 43)
Existing system
We assume that replicas of a data item become invalid after the host holding the original updates it and the consistency of data operations on replicas is kept in the entire network. However, since network partitioning frequently occurs in a MANET, this strong consistency management scheme heavily deteriorates the data availability.
Moreover, many applications in MANETs do not require such a strong consistency. For instance, consider a situation where members of a rescue service that constructs a MANET in the disaster area are divided into several groups each of which is responsible of a certain region and the members in each group share various kinds of information such as that on the extent of damages. In this situation, the consistency of data operations to data items that are used locally in each group must be strictly kept in the same group and is not required to be maintained strictly in different groups.
Proposed system
We discuss different consistency conditions of data operations on replicas in MANETs. First, we classify consistency levels according to application requirements. Next, we propose protocols to achieve them and, then, discuss the impact of replica allocation for the system performance when the memory space of mobile hosts is limited
MANET’S Partition
We assume an environment where each mobile host accesses data items held by other mobile hosts in a MANET and allocates replicas of the data items on its memory space. We also assume that the area in which mobile hosts can move around is divided into several regions and the consistency of data operations on replicas is managed based on the regions.