Cache Placement Strategy Research Articles

Benefit based cache data placement and update for mobile peer to peer networks

Mobile Peer to Peer (MP2P) networks provide decentralization, self-organization, scalability characters, but suffer from high latency and link break problems. In this paper, we study the cache/replication placement and cache update problems arising in such kind of networks. While researchers have proposed various replication placement algorithms to place data across the network to address the problem, it was proven as NP-hard. As a result, many heuristic algorithms have been brought forward for solving the problem. In this article, we propose an effective and low cost cache placement strategy combined with an update scheme which can be easily implemented in a decentralized way. The contribution of this paper is the adaptive and flexible cache placement and update algorithms designed for real MP2P network usage. The combination of MP2P cache placement and update is the novelty of this article. Extensive experiments are conducted to demonstrate the efficiency of the cache placement and update scheme.

A hybrid cache placement scheme for multi-hop wireless service network

In this paper, a hybrid cache placement scheme for multihop wireless service networks is proposed. In this scheme, hot nodes in data transferring path are mined up by means of routing navigation graph, and whole network is covered with network clustering scheme. A hot node has been chosen for cache placement in each cluster, and the nodes within a cluster access cache data with no more than two hops. The cache placement scheme reduces data access latency and workload of the server node. It also reduces the average length of data transferring, which means that fewer nodes are involved. The network system energy consumption decreased as involved relay nodes reduced. The performance analysis shows that the scheme achieves significant system performance improvement in network environment, with a large number of nodes.

Analysis and performance study for coordinated hierarchical cache placement strategies

Data caching has been shown to be efficient in reducing network bandwidth consumption and accelerating information access. In a caching system, an important issue is coordinating data placement to achieve optimal system performance. This paper studies cache placement strategies and their performance in cooperative hierarchical caching environments. A theoretical model is introduced to analyze the access cost of placing a set of object copies in the routing path. Using this model, the object placement problem can be formulated as an optimization problem. It is proved that the problem can be divided into subproblems, thus optimal solutions can be obtained by using dynamic programming. It is further proved that if some nodes are known to be in the optimal solution, the calculation cost of the dynamic programming algorithms can be reduced. A heuristic greedy algorithm is also presented for efficient implementation. Performance of these strategies are evaluated using simulations under both synthetic workload traces and real workload traces. It is shown that both the optimal and the heuristic strategies perform well in cooperative hierarchical caching systems.

Efficient cache placement scheme for clustered time-shifted TV servers

A cost-effective approach for enhancing availability of clustered system is to cache popular data across the memories of servers so as to alleviate disk I/O bandwidth bottleneck. The cache placement problem is complicated for the fact that video popularity changes over time. Moreover, as a new multimedia streaming service, time-shifted TV introduces new challenges to the problem. In this article, we investigate the crucial problem of the clustered time-shifted TV system. We formulate it as a multi-objective optimization problem based on the time-based popularity model. We propose a classification replication algorithm and a novel cache placement algorithm, named as cost-aware least load proportion first (CALLF). The algorithms focus on the time-varying nature of time-shifted TV, and explore previous stored information to reduce the cost of redeploying. We also present a dual-threshold reconfigure scheme to further balance the load of servers dynamically. Simulation reveals that the proposed algorithms are efficient on improving the performance of time-shifted TV system in terms of total outgoing bandwidth requirement.

Efficient Cache Placement in Multi-Hop Wireless Networks

In this paper, we address the problem of efficient cache placement in multi-hop wireless networks. We consider a network comprising a server with an interface to the wired network, and other nodes requiring access to the information stored at the server. In order to reduce access latency in such a communication environment, an effective strategy is caching the server information at some of the nodes distributed across the network. Caching, however, can imply a considerable overhead cost; for instance, disseminating information incurs additional energy as well as bandwidth burden. Since wireless systems are plagued by scarcity of available energy and bandwidth, we need to design caching strategies that optimally trade-off between overhead cost and access latency. We pose our problem as an integer linear program. We show that this problem is the same as a special case of the connected facility location problem, which is known to be NP-hard. We devise a polynomial time algorithm which provides a suboptimal solution. The proposed algorithm applies to any arbitrary network topology and can be implemented in a distributed and asynchronous manner. In the case of a tree topology, our algorithm gives the optimal solution. In the case of an arbitrary topology, it finds a feasible solution with an objective function value within a factor of 6 of the optimal value. This performance is very close to the best approximate solution known today, which is obtained in a centralized manner. We compare the performance of our algorithm against three candidate cache placement schemes, and show via extensive simulation that our algorithm consistently outperforms these alternative schemes.

Hierarchical Binary Set Partitioning in Cache Memories

In this paper, a new cache placement scheme is proposed to achieve higher hit ratios with respect to the two conventional schemes namely set-associative and direct mapping. Similar to set-associative, in this scheme, cache space is divided into sets of different sizes. Hence, the length of tag fields associated to each set is also variable and depends on the partition it is in. The proposed mapping function has been simulated with some standard trace files and statistics are gathered and analyzed for different cache configurations. The results reveal that the proposed scheme exhibits a higher hit ratio compared to the two well-known mapping schemes, namely set-associative and direct mapping, using LRU replacement policy.