Cache Invalidation Technique Research Articles

An adaptive cache invalidation technique for wireless environments

With an evolution of Internet and related technologies such as 4G, and 5G, there is a need of fast response time for various queries raised by intermediate nodes and mobile terminals from infra structured-based/less networks. Although there has been many efforts in the past to address this issue by using an invalidation report (IR)-based cache management schemes which reduce the bandwidth requirements, and battery consumptions, but when the update rate of data at the server is high, then most of the existing approaches have long query latency due to large and fixed size of IRs, and broadcast time (BT) interval. To address these issues, in this paper, an adaptive cache invalidation technique (ACIT) is proposed. In comparison to the previous approaches, the proposed scheme uses different thresholds update rates for adaptive IR, and BT intervals. In the proposed scheme, only hot data updates in IR are recorded which results a less query delay, and bandwidth consumption. The performance of the proposed scheme was studied by extensive simulations by comparing it with the other state-of-the-art schemes using various metrics. The proposed scheme yields 1.5 times enhancement in query response time with a reduction in IR size to 25 % in comparison to other existing techniques. Moreover, there is a reduction of 119.89 % in broadcast time interval using the proposed scheme.

Cache invalidation strategies for Internet-based vehicular ad hoc networks

Internet-based vehicular ad hoc network ( Ivanet) is an emerging technique that combines a wired Internet and a vehicular ad hoc network ( Vanet) for developing an ubiquitous communication infrastructure and improving universal information and service accessibility. A key design optimization technique in Ivanets is to cache the frequently accessed data items in a local storage of vehicles. Since vehicles are not critically limited by the storage/memory space and power consumption, selecting proper data items for caching is not very critical. Rather, an important design issue is how to keep the cached copies valid when the original data items are updated. This is essential to provide fast access to valid data for fast moving vehicles. In this paper, we propose a cooperative cache invalidation (CCI) scheme and its enhancement (ECCI) that take advantage of the underlying location management scheme to reduce the number of broadcast operations and the corresponding query delay. We develop an analytical model for CCI and ECCI techniques for fasthand estimate of performance trends and critical design parameters. Then, we modify two prior cache invalidation techniques to work in Ivanets: a poll-each-read (PER) scheme, and an extended asynchronous (EAS) scheme. We compare the performance of four cache invalidation schemes as a function of query interval, cache update interval, and data size through extensive simulation. Our simulation results indicate that the proposed schemes can reduce the query delay up to 69% and increase the cache hit rate up to 57%, and have the lowest communication overhead compared to the prior PER and EAS schemes.

Cache Management for Concurrent Transaction Execution in Mobile Wireless Environment

Problem statement: Improvement in mobile communication technology and increased capability of mobile devices has made transaction processing possible with mobile devices. Transactions access services provided by the data server connected to the packet data network. Direct data access may overload the network and server. Data items are cached to improve data availability. The cache should be managed and maintained effectively to support concurrent transaction execution in mobile wireless environment. This study proposes a cache management strategy that includes cache invalidation and replacement. Approach: The contents of the cache are invalidated based on the predicted life time of the data item and the cache contents are replaced based on the degree of sharing. The count of dependent transactions determines the degree of sharing of the data item. Results: The experimental results ensure reduced stale hit probability and restart probability of the proposed PLP based cache invalidation technique. The proposed cache replacement policy improves the cache hit ratio at least by 20% when compared to the existing replacement policies. Conclusion: The proposed cache invalidation strategy and replacement policy suit well for concurrent transaction execution environment where the degree of data sharing and the dynamism in data update need to be considered.

A Hybrid Cache Invalidation Technique for Data Consistency in MANET

Recent advances in computer and wireless communication technologies have led to an increasing interest in ad hoc networks, which are temporarily constructed by only mobile hosts. Data accessibility in ad hoc networks is lower than that in the conventional fixed networks.. Caching the frequently accessed data items on the client side is an effective technique for improving the performance in a mobile environment. This form of data caching significantly improves the efficiency of information access in a wireless ad hoc network which in turn reduces the access latency and bandwidth usage. The main objective is to avoid the stale data using invalidation policy based on TTL. This paper introduces an Extended Adaptive TTL (Ex-ATTL) algorithm, in which 1-hop distance nodes to data cache node maintain a hash table for cache invalidation. Data item name is used as key and TTL is used as its value. The network is simulated using NS-2 to evaluate the performance of the proposed algorithm, also it is compared with fixed TTL and Adaptive TTL schemes. The simulation results shows that Ex-ATTL algorithm can cut the query delay by a factor of 3 and double the throughput compared to the Adaptive TTL.

AN AGENT BASED TRANSACTION PROCESSING SCHEME FOR DISCONNECTED MOBILE NODES

We present a mobile transaction framework in which mobile users can share data which is stored in the cache of a mobile agent. This mobile agent is a special mobile node which coordinates the sharing process. The proposed framework allows mobile affiliation work groups to be formed dynamically with a mobile agent and mobile hosts. Using short range wireless communication technology, mobile users can simultaneously access the data from the cache of the mobile agent. The data Access Manager module at the mobile agent enforces concurrency control using cache invalidation technique. This model supports disconnected mobile computing allowing mobile agent to move along with the Mobile Hosts. The proposed Transaction frame work has been simulated in Java 2 and performance of this scheme is compared with existing frame works.

An Efficient Cache Invalidation Method in Mobile Client/Server Environment

In mobile computing environments, cache invalidation techiniques are widely used. However, theses techniques require a large-sized invalidation report and show low cache utilization under high server update rate. In this paper, we propose a new cache-level cache invalidation technique called TTCI (Timestamp Tree-based Cache Invalidation technique) to overcome the above two problems. TTCI also supports selective tuning for a cache-level cache invalidation. We show in our experiment that our technique requires much smaller size of cache invalidation report and improves cache utilization.

An analytical study of cache invalidation algorithms in mobile environments

Caching is commonly used to improve the performance of mobile computers. Due to the limitations of wireless networks (e.g. low bandwidth, intermittent connectivity), ensuring the consistency of cached data becomes a difficult issue. Existing research have shown that broadcast‐based cache invalidation techniques can effectively maintain cache consistency for mobile applications. However, most existing performance analysis of cache invalidation algorithms were carried out through simulation. Therefore, an analytical study is important to provide a deeper understanding of broadcast‐based invalidation techniques. In this paper, we present detailed analytical models of the major existing cache invalidation schemes. The models provide a basis to highlight the strengths and weaknesses of the different schemes and facilitate further investigation into cache invalidation for mobile environments. Extensive simulation has also been performed, and verifies the accuracy of the models developed.

Scalable cache invalidation algorithms for mobile data access

In this paper, we address the problem of cache invalidation in mobile and wireless client/server environments. We present cache invalidation techniques that can scale not only to a large number of mobile clients, but also to a large number of data items that can be cached in the mobile clients. We propose two scalable algorithms: the Multidimensional Bit-Sequence (MD-BS) algorithm and the Multilevel Bit-Sequence (ML-BS) algorithm. Both algorithms are based on our prior work on the Basic Bit-Sequences (BS) algorithm. Our study shows that the proposed algorithms are effective for a large number of cached data items with low update rates. The study also illustrates that the algorithms ran be used with other complementary techniques to address the problem of cache invalidation for data items with varied update and access rates.

A scalable low-latency cache invalidation strategy for mobile environments

Caching frequently accessed data items on the client side is an effective technique for improving performance in a mobile environment. Classical cache invalidation strategies are not suitable for mobile environments due to frequent disconnections and mobility of the clients. One attractive cache invalidation technique is based on invalidation reports (IRs). However, the IR-based cache invalidation solution has two major drawbacks, which have not been addressed in previous research. First, there is a long query latency associated with this solution since a client cannot answer the query until the next IR interval. Second, when the server updates a hot data item, all clients have to query the server and get the data from the server separately, which wastes a large amount of bandwidth. In this paper, we propose an IR-based cache invalidation algorithm, which can significantly reduce the query latency and efficiently utilize the broadcast bandwidth. Detailed analytical analysis and simulation experiments are carried out to evaluate the proposed methodology. Compared to previous IR-based schemes, our scheme can significantly improve the throughput and reduce the query latency, the number of uplink request, and the broadcast bandwidth requirements.