Proxy Caching Research Articles

Optimizing Caching in a Patch Streaming Multimedia-on-Demand System

In on-demand multimedia streaming systems, streaming techniques are usually combined with proxy caching to obtain better performance. The patch streaming technique has no start-up latency inherent to it, but requires extra bandwidth to deliver the media data in patch streams. This paper proposes a proxy caching technique which aims at reducing the bandwidth cost of the patch streaming technique. The proposed approach determines media prefixes with high patching cost and caches the appropriate media prefix at the proxy/local server. Herein the scheme is evaluated using a synthetically generated media access workload and its performance is compared with that of the popularity and prefix-aware interval caching scheme (the prefix part) and with that of patch streaming with no caching. The bandwidth saving, hit ratio and concurrent number of clients are used to compare the performance, and the proposed scheme is found to perform better for different caching capacities of the proxy server.

An Alpha Cut (α-cut) Filter-Based Proxy Caching Control for Wireless Coverage Streaming Services

Unfair media object processing in the proxy cache leads to traffic overload at the local buffer, increases delay and energy power, and requires retransmission. To fully support high quality media streaming service in IEEE 802.11-based wireless multimedia applications, this paper proposes a novel alpha cut (?-cut) filter-based proxy caching (AFPC) mechanism for wireless coverage streaming services. The AFPC consists of burst referenced caching strategy (BRCS) and capacity referenced caching strategy (CRCS) to acquire the optimal streaming quality for continuous objects and non-continuous objects. The BRCS controls the streaming congestion, by considering the encoding rate and channel bandwidth; the CRCS scheme reduces the caching congestion by scheduling different types of stream packets, based on the restricted caching resource, and media characteristics. Then, the AFPC mechanism monitors the traffic flow to guarantee an exact and fast streaming service during buffer caching. We perform a simulation to prove the efficiency of the proposed mechanism, and our simulation results show that the proposed AFPC mechanism has better performance than the S-caching, I-caching, and C-caching mechanisms.

Analysis of Application-Layer Filtering Policies With Application to HTTP

Application firewalls are increasingly used to inspect upper-layer protocols (as HTTP) that are the target or vehicle of several attacks and are not properly addressed by network firewalls. Like other security controls, application firewalls need to be carefully configured, as errors have a significant impact on service security and availability. However, currently no technique is available to analyze their configuration for correctness and consistency. This paper extends a previous model for analysis of packet filters to the policy anomaly analysis in application firewalls. Both rule-pair and multirule anomalies are detected, hence reducing the likelihood of conflicting and suboptimal configurations. The expressiveness of this model has been successfully tested against the features of Squid, a popular Web caching proxy offering various access control capabilities. The tool implementing this model has been tested on various scenarios and exhibits good performance.

Improving the Performance of a Proxy Cache Using Tree Augmented Naive Bayes Classifier

In this paper, we attempt to improve the performance of Web proxy cache replacement policies such as LRU and GDSF by adapting a semi naïve Bayesian learning technique. In the first part, Tree Augmented Naive Bayes classifier (TANB) to classify the web log data and predict the classes of web objects to be revisited again future or not. In the second part, a Tree Augmented Naïve Bayes classifier is incorporated with proxy caching policies to form novel approaches known as TANB-LRU and TANB-GDSF. This proposed approach improves the performances of LRU and GDSF in terms of hit and byte hit ratio respectively.

Intelligent Dynamic Aging Approaches in Web Proxy Cache Replacement

One of commonly used approach to enhance the Web performance is Web proxy caching technique. In Web proxy caching, Least-Frequently-Used-Dynamic-Aging (LFU-DA) is one of the common proxy cache replacement methods, which is widely used in Web proxy cache management. LFU-DA accomplishes a superior byte hit ratio compared to other Web proxy cache replacement algorithms. However, LFU-DA may suffer in hit ratio measure. Therefore, in this paper, LFU-DA is enhanced using popular supervised machine learning techniques such as a support vector machine (SVM), a naive Bayes classifier (NB) and a decision tree (C4.5). SVM, NB and C4.5 are trained from Web proxy logs files and then intelligently incorporated with LFU-DA to form Intelligent Dynamic- Aging (DA) approaches. The simulation results revealed that the proposed intelligent Dynamic- Aging approaches considerably improved the performances in terms of hit and byte hit ratio of the conventional LFU-DA on a range of real datasets.

Improving the Performance of a Proxy Cache Using Very Fast Decision Tree Classifier

Abstract In this paper, we improved the performance of Web proxy cache replacement policies such as LRU and GDSF by adapting a Very Fast Decision Tree learning technique. In the first part, a sliding window method integrated with Very Fast Decision tree classifier (VFDT) to classify the web log data and predict the classes of web objects to be revisited again in future or not. In the second part, a Very Fast Decision Tree classifier is incorporated with proxy caching policies to form novel approaches known as VFDT-LRU and VFDT-GDSF. This proposed approach improves the performances of LRU and GDSF in terms of hit and byte hit ratio respectively.

MSC: a multi-version shared caching for multi-bitrate VoD services

Recently, many Video-on-Demand (VoD) service providers try to attract as many users as possible by offering multi-bitrate video streaming services with differentiated qualities. Many researches focus on video layered coding (e.g., scalable video coding, SVC). However, SVC is not widely used in VoD industry. Another solution, multi-version videos, can be classified into online transcoding and pre-stored multi-version videos. Online transcoding is a CPU-intensive and costly task, so it is not suitable for large-scale VoD applications. In this paper, we study how to improve caching efficiency based on pre-stored multi-version videos. We leverage the sharing probability among different versions of the same video and propose a multi-version shared caching (MSC) method to maximize the benefit of caching proxy. If the desired version is not in the cache while the higher neighbor version is in, MSC transmits the higher version streaming to user temporarily. In this case, MSC can make full use of the caching resources to improve the cache hit ratio and decrease users' average waiting time. Simulation results show that MSC outperforms the others in the cache hit ratio and the average waiting time.

Pre-eminence of Combined Web Pre-fetching and Web Caching Based on Machine Learning Technique

It is always wise to keep the frequently used information by various users in the cache memory. This makes the users feel that their needed information is available almost immediately. Apart from experiencing less access delay, caching process also helps in better bandwidth utilization and load reduction in the origin server. Pre-fetching is the process of fetching few of the Web pages in advance by assuming that those pages will be needed by the user in the near future. Combining pre-fetching and caching techniques results in experiencing much less access delay and much better bandwidth utilization. Many works have been reported in the literature, separately for Web caching techniques and pre-fetching of Web pages. In this paper, pre-fetching technique that uses clustering is combined with SVM (support vector machine)–LRU algorithm, a machine learning method for Web proxy caching. By using real-time data, it is demonstrated that the latter approach will be advantageous than clustering-based pre-fetching technique using traditional LRU-based caching policy. The efficiency of our proposed method is also compared with caching using Bayesian networks and neuro-fuzzy system.

Segment-Based Proxy Caching for Streaming Media Delivery

At present the majority of streaming media files is large and it requires a lot of network bandwidth and disk bandwidth. We propose an adaptive segment-based method, the cache replacement method and the multi technologies combined optimized transmission policy. Simulation results indicate that they are highly efficient methods for use of caching proxy server resources, reducing the startup latency and save of bandwidth of backbone network.

Improving Hit Ratio and Byte Hit Ratio Using Combined Pre-Fetching and Web Caching

Combined caching and pre-fetching of web pages help to enhance bandwidth utilization, reduce access delay and also reduce the load on the server. Pre-fetching is the technique of fetching Web pages in advance that will be assumed to be needed or browsed in near future by the user and the caching process stores them in the memory. In the literature, number of works has been reported separately for caching and pre-fetching of Web pages. In this paper clustering based pre-fetching technique is combined with machine learning technique-SVM (Support Vector Machine)-LRU algorithm for Web proxy caching. With the help of real dataset it is demonstrated that the latter approach will be better than Clustering based pre-fetching technique with traditional caching policy like LRU in terms of bandwidth utilization and access latency.

WINDOWS WEB PROXY CACHING SIMULATION: A TOOL FOR SIMULATING WEB PROXY CACHING UNDER WINDOWS OPERATING SYSTEMS

Web caching plays a key role in improving the performance of the web by reducing the latency of delivering web objects to the users. On the other hand, a simulation tool plays a key role in studying the behavior of any network such as studying the effects of web caching on the performance of the network. The aim of this work is to present a tool for simulating a web proxy caching for windows operating systems since there is no existing well-compatible simulation tool for windows operating systems that can simulate Hit Ratio (HR) and Byte Hit Ratio (BHR) for traditional caching policies. The proposed simulation tool is called Windows Web Proxy Caching Simulation (WWPCS). The results show the performance of traditional web caching policies for different cache’s sizes. Moreover, in order to show the efficiency of WWPCS, the results of running WWPCS are compared to the results of running a Unix-based tool.

Security in the CernVM File System and the Frontier Distributed Database Caching System

Both the CernVM File System (CVMFS) and the Frontier Distributed Database Caching System (Frontier) distribute centrally updated data worldwide for LHC experiments using http proxy caches. Neither system provides privacy or access control on reading the data, but both control access to updates of the data and can guarantee the authenticity and integrity of the data transferred to clients over the internet. CVMFS has since its early days required digital signatures and secure hashes on all distributed data, and recently Frontier has added X.509-based authenticity and integrity checking. In this paper we detail and compare the security models of CVMFS and Frontier.

Research of Proxy Cache Algorithm in Multi-media Education System

Multi-media education system is more and more widely used in all levels of education. In order to decrease cost of multi-media system and keep efficiency with increasing multi-media materials, proxy cache algorithm has been widely studied. Based on analysis of existing research of proxy cache results, an improved proxy coaching strategy of prefix cache and postfix merging is proposed. The strategy can dynamically adjust prefix cache size with the object access change. A more effective method of steaming merging has been proposed with multicast used in postfix portion. The results show that the improved strategy can effectively utilize proxy cache resource, shorten time delay and save band width.

Proxy Caching Algorithm based on Segment Group Popularity for Streaming Media

Multi-media is more and more popular in all levels of education for its vivid picture and video. Due to the increasing number of videos and pictures in school server, how terminal computers in classrooms access multimedia at low cost is an important problem to solve. A novel dynamic scheduling algorithm of PCASGP (Proxy caching algorithm based on segment group popularity for streaming media). Based on the popularity of the segment group, content of proxy caching would be replaced and data size would in proportion of segment popularity. The cache window size would be updated dynamically with the access time based on the algorithm. Results of simulation shows that the algorithm is quite adaptable and can gain more average number of streaming media objects with less delayed access ratio.

A Cross Layer Collaborating Cache Scheme to Improve Performance of HTTP Clients in MANETs

This paper proposes a novel cross layer collaborating cache scheme for HTTP clients. It is designed to accelerate the process that an HTTP client retrieves Web content in mobile ad hoc network environment. Unlike other techniques to exploit Web proxy caching or to build P2P protocol overlay to improve HTTP, our scheme incorporates collaboratively working capability into the HTTP client response cache, and thus there is no impact on the compatibility of upper level applications. In addition, as the sharing file information is diffused with routing information, there is no redundant traffic to maintain the cooperating cache mechanism. Using this scheme, cacheable Web content can be distributed among local peers and retrieved later by a client if needed. In our simulation results, this novel cache scheme significantly decreases the latency experienced by a client to download Web content.

ENHANCE PERFORMANCE OF WEB PROXY CACHE CLUSTER USING CLOUD COMPUTING

Web caching is a crucial technology in Internet because it represents an effective means for reducing bandwidth demands, improving web server availability and reducing network latencies. However, Web cache cluster, which is a potent solution to enhance web cache system’s capability, still, has limited capacity and cannot handle tremendous high workload. Maximizing resource utilization and system capability is a very important problem in Web cache cluster. This problem cannot be solved efficiently by merely using load balancing strategies. Thus, along with the advent of cloud computing, we can use cloud based proxies to achieve outstanding performance and higher resource efficiency, compared to traditional Web proxy cache clusters. In this paper, we propose an architecture for cloud based Web proxy cache cluster (CBWPCC) and test the effectiveness of the proposed architecture, compared with traditional one in term of response time ,resource utilization using CloudSim tool.

A Proposed Model for Web Proxy Caching Techniques to Improve Computer Networks Performance

one of the most important techniques for improving the performance of web based applications is web proxy caching Technique. It is used for several purposes such as reduce network traffic, server load, and user perceived retrieval delays by replicating popular content on proxy caches that are strategically placed within the network. The use of web proxy caching is important and useful in the government organizations that provides services to citizens and has many branches all over the country where it is beneficial to improve the efficiency of the computer networks performance, especially remote areas which suffer from the problem of poor network communication. Using of proxy caches provides all users in the government computer networks by reducing the amount of redundant traffic that circulates through the network. It also provides them by getting quicker access to documents that are cached. In addition, there are a lot of benefits we can obtain from the using of proxy caches but we will address them later. In this research, we will use web proxy caching to provide all of the above benefits that we are mentioned above and to overcome on the problem of poor network communication in ENR (Egyptian National Railways). We are going to use a scheme to achieve the integration of forward web proxy caching and reverse proxy caching.

Cache Optimization on Hot-Point Proxy Caching Using Weighted-Rank Cache Replacemnt Policy

The development of proxy caching is essential in the area of video-on-demand (VoD) to meet users' expectations. VoD requires high bandwidth and creates high traffic due to the nature of media. Many researchers have developed proxy caching models to reduce bandwidth consumption and traffic. Proxy caching keeps part of a media object to meet the viewing expectations of users without delay and provides interactive playback. If the caching is done continuously, the entire cache space will be exhausted at one stage. Hence, the proxy server must apply cache replacement policies to replace existing objects and allocate the cache space for the incoming objects. Researchers have developed many cache replacement policies by considering several parameters, such as recency, access frequency, cost of retrieval, and size of the object. In this paper, the Weighted-Rank Cache replacement Policy (WRCP) is proposed. This policy uses such parameters as access frequency, aging, and mean access gap ratio and such functions as size and cost of retrieval. The WRCP applies our previously developed proxy caching model, Hot-Point Proxy, at four levels of replacement, depending on the cache requirement. Simulation results show that the WRCP outperforms our earlier model, the Dual Cache Replacement Policy.

Coordination Algorithm Design of the Load Sharing Proxy Servers for Streaming Media

With the rapid development of streaming media applications, clustered streaming media proxy servers have become the mainstream of high-end streaming media proxy. To increase the IO throughput capacity of streaming media proxy servers, the most effective method is middle-ware technology in which several servers are bridged together to form a proxy cache server cluster, and the key is the coordination of individual proxy servers. The decision problem of the user request dispatch actually belongs to NP-complete. This article proposes an online coordination algorithm for the load sharing streaming media proxy servers, and discusses the relative deviation of the online algorithm from the optimal solution, to serve as a reference to the specific applications of clustered streaming media proxy servers.

Enhancing the Performance of Proxy Cache Management through Browsing Behavior-based Learning Mechanism

Enhancing the Performance of Proxy Cache Management through Browsing Behavior-based Learning Mechanism