Conference Paper

A Cost Effective Cache Consistency Method for Mobile Clients in Wireless Environment

Department of Computer Science and Engineering, Sogang University, Sŏul, Seoul, South Korea
DOI: 10.1007/978-3-540-24571-1_79 Conference: Database Systems for Advances Applications, 9th International Conference, DASFAA 2004, Jeju Island, Korea, March 17-19, 2004, Proceedings
Source: DBLP


When a mobile client disconnects for a prolonged time which exceeds the window size of the server’s invalidation reports ,
the mobile client’s cache is discarded even if most of data are still valid. In this paper, we propose an efficient cache
consistency method called CCI(Cost-based Cache Invalidation) for mobile clients, which takes into account not only the disconnection
time but also the update frequencies at a server.

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Available from: Sungwon Jung, Apr 12, 2014
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    • "On receiving a validation request, the server checks the update list for each data item in the list to determine whether the update timestamp is later than LastTS. More details on how the server maintains the update list can be found in [17]. "
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    ABSTRACT: Data broadcasting is an efficient data dissemination method in a wireless client–server system. A data server broadcasts data items periodically, and mobile clients cache data items to save communication bandwidth, resource usage, and data access time. The server also broadcasts invalidation reports (IRs) to maintain the consistency between server data and the clients’ cached data. Most existing cache invalidation policies in a wireless environment based on IRs simply purge the entire cache after a client has been disconnected long enough to miss a certain number (window size) of IRs. We present a cache invalidation scheme that provides better cache reusability and better data access time after a long disconnection. Our scheme attempts to increase cache reusability by respecting update rates at a server, broadcast intervals, the communication bandwidth, and data sizes, as well as disconnection time. Simulation results show that the increased cache reusability of our scheme can improve the data access time after a long disconnection.
    Full-text · Article · Nov 2007 · Data & Knowledge Engineering
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    • "Hence it generates larger query latency. Song et al proposed Cost -based Cache Invalidation (CCI) to deals with MNs disconnection time and the update frequency on source side [14]. A traditional pull-based strategy accomplishes less query latency at the cost of higher traffic, whereas push-based strategy accomplishes lower traffic at the cost of larger query latency. "
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    ABSTRACT: Data Caching improves data availability among the mobile nodes (MNs) that are connected together through unreliable wireless links. The MNs are often updating the cached data due to its dynamism. The query access rate of cached data is varied based on neighbor nodes requirements. The caching nodes must ensure the staleness of data with source. This paper proposes the novel Cluster Based Update (CBU) algorithm to avoid the stale data in caching nodes. The network is partitioning into non overlapping clusters and Cluster Head (CH) is selected based on weighting factor. The CH maintains Global Cache Index (GCI) that consist information about its cluster members and neighbor CHs. The CH maintains the query access entry for cached data in its cluster members. The source also sends data update rate to CH. Thus consistency is maintained based on data update and its query access rate through CHs. The simulation results shown that proposed algorithm reduces the latency, overhead than existing approach by increasing nodes and speed respectively.
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    ABSTRACT: In [1], we proposed a cost-based cache invalidation method for mobile clients. However, our previous work did not concern a remarkable difference of data transfer rate between download and upload links. In this paper, we present an enhanced cost-effective cache validation scheme with a new cost function. We prove that our proposed scheme greatly increases the cache reusability and the uplink message overhead does not lead to serious performance degradation through experiments.
    No preview · Conference Paper · Aug 2004
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