Cache Invalidation Scheme Research Articles

A Cache Invalidation Strategy Based on Publish/Subscribe for Named Data Networking

Named Data Networking (NDN) aims to improve the efficiency of data delivery for the Internet. One of the typical characteristics of NDN is ubiquitous caching, that is to say, each network participant in NDN is capable of caching contents. This caching feature is beneficial for enhancing the data availability but also raises a problem of cache consistency. In this paper, we propose a novel strategy of cache invalidation, called PIOR (Proactive Invalidation with Optional Renewing), to provide strong consistency for NDN. PIOR is based on a lightweight publish/subscribe model, actively publishing the updated contents to the router nodes to guarantee the copy validity. We also conceive customized publish/subscribe rules to relieve the unbearable burden on the server imposed by the excessive publishing traffic. The advantage of PIOR lies in simple deployment and compatibility, since the invalidation process of PIOR is independent of the inherent process of NDN. We conduct extensive simulations over a real topology to evaluate the achievable performance of PIOR. The simulation results show that PIOR is able to achieve a high hit ratio and low server load at the low cost of network management.

Fructifying the Network Performance of iVANET thru a Rectified Associative Service Mechanism: An Algorithmic Proposal

Internet based Vehicular (iVANET) ad-hoc networks are meticulously especial case of normal VANET. It is basically made of a combined wired Internet as well as vehicular ad hoc network for developing a new baby-boom of omnipresent and ubiquitous computing. The Internet connectivity is usually extended to V2I (vehicle to infrastructure) communication whilst ad-hoc networks are used in vehicle to vehicle (V2V) communication. The latency is one of the main matters of concern in VANET. By minimizing distance between data source and the remote vehicle through rectified caching technique along with redefined cache lookup mechanism, the latency can be shortened by a significant factor in iVANET environment. In this paper various cache invalidation schemes are studied and analyzed. Exploring the possibilities of caching schemes which can be hybridized or mutated, paper introduces an algorithmic proposal along with redefined services mechanism for cache lookup and invalidation, which strives for achieving low latency with reduced negative acknowledgement (NACK) in the network. This paper introduces a rectified algorithm for guaranteed delivery of the queried data and efficiently invalidating cache contents at different levels of hierarchy. The proposed work is anticipated to fructify the network performance minimizing the cost and bandwidth utilization during cache invalidation and hence guarantees improved quality of service (QoS).

Invalidation Method for Wireless Mobile Network to Maintain Consistency

This paper is proposed for the distributed cache invalidation mechanism (DCIM), it is a client-based cache consistency scheme which is implemented on the top of a previously proposed architecture for the caching data items in mobile ad hoc networks (MANETs), namely COACS, where special nodes cache the queries and the addresses of the nodes that store the responses to these queries. Caching frequently accessed data items on the client side is an effective technique for improving performance in a mobile environment. The classical cache invalidation strategies are not suitable for the mobile environments due to frequent disconnections and mobility of the clients. The huge amount of demand has been created due to trend toward wireless communications and advances in mobile technologies are which increasing the consumer demands for ubiquitous access to Internet-based information and services. DCIM can be implemented using ns2, and compared against the client-based and server-based schemes to assess its performance experimentally. Hear introduce DCIM that is totally client-based. DCIM is a pull- based algorithm that implements adaptive time to live (TTL), piggybacking, and pre-fetching, and provides near strong consistency capabilities. Keywordsdata caching, pull-based, TTL, shared data.

Minimizing Query Delay Using Co-operation in IVANET

Abstract Internet-based vehicular ad hoc (IVANET) network is a exponentially growing technique that is a combination of wired and wireless components while a Vehicular Ad hoc Network (VANET) is for ubiquitous communication. Cache the frequently accessed data items in a local cache of vehicles is an optimization approach as vehicles are not limited with resources. So important research issue is to invalidate the cache on update of data on server. For Moving vehicles access to valid data should be fast.In this paper, we have propose a Cooperative Gateway Cache Invalidation scheme and it is a modification of Cooperative Cache Invalidation (CCI) technique.It takes the advantage of cooperation of Gateways in different regions along with the underlying location management scheme to reduce the number of broadcast operations and the corresponding query delay. We developed an analytical model for technique for cost of query communication. We evaluated the performance of our cache invalidation schemes through simulations using customized NS2.35 by varying query arrival rate. Our simulation results indicate that the proposed schemes can reduce the query delay.

User-defined consistency sensitive cache invalidation strategies for wireless data access

In order to fulfill users’ insatiable interests in accessing Internet services and information wirelessly, one of the key optimization techniques is caching frequently accessed data items in a local cache. A strong consistency is implicitly assumed in most caching schemes but it may cause a long query delay. In this paper, we propose a consistency-sensitive cache invalidation scheme, called ConSens, based on the existing Invalidation Report (IR) and Updated IR (UIR) based cache invalidation frameworks. In the ConSens scheme, each user is able to set its own consistency level with a server independently. This user-defined cache consistency can support diverse consistency requirements of applications. We also propose both lazy request and opportunistic data access techniques to effectively balance the data accessibility and query delay. In addition, we enhance the IR-based cache invalidation mechanism and propose a multiple data transmission scheme, called MDT, to further reduce the query delay. Extensive performance evaluation studies show that the proposed strategies can effectively balance the data accessibility, reduce the query delay, and significantly increase the number of opportunistic accesses according to the user-defined consistencies.

Rule-Based Data Mining Cache Replacement Strategy

Caching in mobile environments is used for improving bandwidth usage and reducing query delays among resource constrained devices. It is used in multitudes of approaches. Some rely on the server occasionally broadcasting reports to inform clients of updated data while others permit clients to access data whenever they need it. Caching can be constrained by size and bandwidth; thus, coming up with a good invalidation scheme is critical in improving cache consistency solutions. In this work, the authors propose a new hybrid cache invalidation scheme that makes use of data mining concepts. They also compare their scheme with other related strategies.

Flexible Data Dissemination Strategy For Effective Cache Consistency In Mobile Wireless Communication Networks

In mobile wireless communication network, caching data items at the mobile clients is important to reduce the data access delay. However, efficient cache invalidation strategies are used to ensure the consistency between the data in the cache of mobile clients and at the database server. Servers use invalidation reports (IRs) to inform the mobile clients about data item updates. This paper proposes and implements a multicast based strategy to maintain cache consistency in mobile environment using AVI as the cache invalidation scheme. The proposed algorithm is outlined as follows – To resolve a query, the mobile client searches its cache to check if its data is valid. If yes, then query is answered, otherwise the client queries the DTA (Dynamic Transmitting Agent) for latest updates and the query is answered. If DTA doesn’t have the latest updates, it gets it from the server. So, the main idea here is that DTA will be multicasting updates to the clients and hence the clients need not uplink to the server individually, thus preserving the network bandwidth. The scenario of simulation is developed in Java. The results demonstrate that the traffic generated in the proposed multicast model is simplified and it also retains cache consistency when compared to the existing methods that used broadcast strategy.

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.

A Cache Invalidation scheme through Data Classification in IVANET

Every one spends 10 to 40 % time in vehicles a day that’s why it is necessary to be updated with knowledge in vehicles. Vehicular Ad hoc Network (VANET) is a technology that establishes communication among vehicles through road side infrastructure. Internet Vehicular Ad hoc Network (IVANET) is a combination of wired internet and VANET technology. IVANET caches frequently access data items in a local storage of vehicles which have not storage problem. Due to high mobility of vehicles, a critical design issue is how to invalidate them when data items are updated and which data should be invalidated first. We have proposed an algorithm for data cache invalidation in IVANET as well as decide priority of data invalidation. In this scheme we classify invalidating data in to three categories queried data, emergency data and fixed data.

Efficient cache invalidation schemes for mobile data accesses

This paper presents two cache invalidation schemes to maintain data consistency between the server and clients in a mobile environment. Designed according to real situations like MANET, the Adaptive Data Dividing ( ADD) scheme divides data into groups of different utilization ratios and varies group broadcast intervals to reduce data access time and bandwidth consumption. The Data Validity Defining ( DVD) scheme aims to solve the validity problem of cached data items, which usually happens after clients disconnect from the server. Experimental evaluations and performance analyses exhibit that the two schemes outperform most existing cache invalidation schemes in terms of data access time, cache miss ratios, query uplink ratios and bandwidth consumption.

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.

Probabilistic Broadcast-Based Cache Invalidation Scheme for Location Dependent Data in Mobile Environments

Probabilistic Broadcast-Based Cache Invalidation Scheme for Location Dependent Data in Mobile Environments

A cache invalidation strategy for mobile networks

The diversity of services delivered over wireless channels has increased people's desire in ubiquitously accessing these services from their mobile devices. However, a ubiquitous mobile computing environment faces several challenges such as scarce bandwidth, limited energy resources, and frequent disconnection of the server and mobile devices. Caching frequently accessed data is an effective technique to improve the network performance because it reduces the network congestion, the query delay, and the power consumption. When caching is used, maintaining cache consistency becomes a major challenge since data items that are updated on the server should be also updated in the cache of the mobile devices. In this paper we propose a new cache invalidation scheme called Selective Adaptive Sorted ( SAS) cache invalidation strategy that overcomes the false invalidation problem that exists in most of the invalidation strategies found in the literature. The performance of the proposed strategy is evaluated and compared with the selective cache invalidation strategy and the updated invalidation report startegy found in the literature. Results showed that a significant cost reduction can be obtained with the proposed strategy when measuring performance metrics such as delay, bandwidth, and energy.

모바일 애드혹 네트워크에서 캐쉬 접근 시간 향상을 위한 시간보증 기반의 캐쉬무효화 기법

모바일 장치의 증가와 무선 네트워크 기술의 발전으로 인해 새롭게 모바일 애드혹 네트워크에 대한 관심이 증가하고 있다. 최근까지의 연구는 데이터 접근성(Accessibility) 향상을 위해 데이터 복사본 활용이 효율적임을 증명하였다. 그러나, 데이터 복사본이 모바일 애드혹 네트워크에서 활용되기 위해서는 원본과 복사본 사이에 일관성(Consistency)이 확보되어야만 한다. 기존의 연구에서 사용되고 있는 일관성 확보 기법은 원본을 가진 노드에게 복사본 사용 노드들이 매번 일관성을 가지는지 확인하는 기법이 활용되었다. 그러나, 시간제약을 가지는 응용의 경우 원본을 가진 노드에게 확인하는 기법은 효율적이지 못하거나 때로는 심각한 문제를 일으킬 수도 있다. 본 논문에서는 시간제약응용을 위한 캐쉬 무효화 기법을 제안하고 있다. 제안하는 기법을 통해 기존의 일관성 확인 기법에서 일어나는 ‘롤백(Rollback)’ 문제를 해결할 수 있었으며, 접근시간(Access time) 측면에서 성능향상을 얻을 수 있었다. 또한 본 논문에서는 임계값 기반의 보완 기법을 제안한다. 우리는 실험 결과를 통해 제안하는 기법이 약간의 현재성(Currency) 손해는 있지만, 접근시간 측면에서 효율적임을 증명하여 준다. Due to the popularity of mobile devices and advances in wireless communication technologies, a mobile ad hoc network has received a lot of attention. In the existing data replication management research, the use of a replica has been shown to be an efficient technique for improving data accessibility. However, to use a replica in ad hoc networks, the data consistency between the original data and the replica should be guaranteed. In the traditional research, a mobile node should check an original data whether the data is updated or not. However, It may be costly or sometimes impossible to check the original data. In the case of the time constraint applications, the checking cost can cause more serious problem. In this paper, we propose the time-guarantee based cache invalidation schemes for time constraint applications and the threshold based compensation method to enhance the time-guarantee based scheme. The proposed schemes can remove the "rollback" problem. Simulation results show that our schemes outperform the previous ones in terms of access time with little loss of data currency.

XIR: Efficient Cache Invalidation Strategies for XML Data in Wireless Environments

With the growth of wireless computing and the popularity of eXtensible Markup Language (XML), wireless XML data management is emerging as an important research area. In this paper, cache invalidation methodology with XML update is addressed in wireless computing environments. A family of XML cache invalidation strategies, called S-XIR, D-XIR and E-XIR, is suggested. Using S-XIR and D-XIR, the unchanged part of XML data, only its structure changes, can be effectively reused in client caching. E-XIR, which uses prefetching, can further improve access time. Simulations are carried out to evaluate the proposed methodology; they show that the proposed strategies improve both tuning time and access time significantly. In particular, the proposed strategies are on average about 4 to 12 times better than the previous approach in terms of tuning time.

A cache invalidation scheme for continuous partial match queries in mobile computing environments

The continuous partial match query is a partial match query whose result remains consistently in the client's memory. Conventional cache invalidation methods for mobile clients are record ID-based. However, since the partial match query uses content-based retrieval, the conventional ID-based approaches cannot efficiently manage the cache consistency of mobile clients. In this paper, we propose a predicate-based cache invalidation scheme for continuous partial match queries in mobile computing environments. We represent the cache state of a mobile client as a predicate, and also construct a cache invalidation report (CIR), which the server broadcasts to clients for cache management, with predicates. In order to reduce the amount of information that is needed for cache management, we propose a set of methods for CIR construction (in the server) and identification of invalidated data (in the client). Through experiments, we show that the predicate-based approach is very effective for the cache management of mobile clients.

Increasing mobile clients' cache reusability in a wireless client‐server environment

AbstractIn a wireless client‐server environment, data broadcasting is an efficient data dissemination method and some of the broadcast data are often cached at each mobile client's cache. Data broadcasting and caching save communication bandwidth, resource usage, and data access time. A server also broadcasts invalidation reports (IRs) to maintain the consistency between server data and clients' cached data. Most existing cache invalidation policies 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 to increase the reusability of the data in mobile clients' caches after long disconnection. Instead of clearing the entire cache regardless of its consistency after long disconnection, a client estimates the relative cost of purging all data and the cost of a selective purge. If a selective purge is cheaper, the client sends server an uplink message to ask the validity of data whose update rate is low to salvage as many valid data as possible. Simulation results show that our scheme effectively increases cache reusability since our cost functions respect update rates at a server, broadcast intervals, the communication bandwidth, and data sizes as well as disconnection time. Copyright © 2007 John Wiley & Sons, Ltd.

Better mobile client’s cache reusability and data access time in a wireless broadcast environment

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.

Cache invalidation strategies for internet-based mobile ad hoc networks

Internet-based mobile ad hoc network ( Imanet) is an emerging technique that combines a mobile ad hoc network ( Manet) and the Internet to provide universal information accessibility. Although caching frequently accessed data items in mobile terminals (MTs) improves the communication performance in an Imanet, it brings a critical design issue when data updates. In this paper, we analyze several push and pull-based cache invalidation strategies for Imanets. A global positioning system (GPS) based connectivity estimation (GPSCE) scheme is first proposed to assess the connectivity of an MT for supporting cache invalidation mechanisms. Then, we propose a pull-based approach, called aggregate cache based on demand (ACOD) scheme that uses an efficient search algorithm for finding the queried data items. In addition, we modify two push-based cache invalidation strategies, proposed for cellular networks, to work in Imanets. They are called modified timestamp (MTS) scheme and MTS with updated invalidation report (MTS + UIR) scheme, respectively. We compare the performance of all these schemes as a function of query interval, cache update interval, and cache size through extensive simulation. Simulation results indicate that the ACOD scheme provides high throughput, low query latency, and low communication overhead, and thus, is a viable approach for implementation in Imanets.

Defending against cache consistency attacks in wireless ad hoc networks

Caching techniques can be used to reduce bandwidth consumption and data access delay in wireless ad hoc networks. When cache is used, the issue of cache consistency must be addressed, and maintaining strong cache consistency is desired in some strategic scenarios (e.g., battlefields). In these situations, the invalidation-based approach is preferred due to its low overhead. However, this approach may suffer from some security attacks. For example, malicious nodes (also called intruders) may drop, insert or modify invalidation messages to mislead receivers to use stale data or unnecessarily invalidate data that are still valid. In this paper, we first propose to employ the Invalidation Report (IR) based cache invalidation strategy to prevent intruders from dropping or modifying invalidation messages. Although digital signatures can be used to protect IRs, this has significantly high overhead in terms of computational and bandwidth overhead. To address this problem, we further propose a family of randomized grouping-based schemes for intrusion detection, damage recovery and intruder identification. Extensive analysis and simulations are performed to evaluate the proposed schemes. The results show that our solution can achieve a satisfactory level of security with low overhead.