It is generally observed throughout the world that in the last two decades, while the average speed of computers has almost doubled in a span of around eighteen months, the average speed of the network has doubled merely in a span of just eight months! In order to improve the performance, more and more researchers are focusing their research in the field of computers and its related technologies. World Wide Web (WWW) is one of the services provided by the Internet medium for sharing of information. As a result, millions of applications run on the Internet and cause increased network traffic and put a great demand on the available network infrastructure. With the increase in the number of Internet users, it is necessary to enhance the speed. This paper addresses the above issues and proposes a novel integrated approach by reviewing the works related to Web caching and Web pre-fetching.
TopIntroduction
Web caching is an intermediate storage between client and server and used to store the Web objects that are likely to be accessed in the near future.
Web pre-fetching is used to load webpages into the cache before the actual request arrives. When combined, these can complement each other where Web caching technique makes use of temporal locality, whereas Web pre-fetching technique use spatial locality of Web objects (Teng et al., 2005).
Web caching plays a predominant role in improving the performance of the Web today, due to the following reasons (Sathiyamoorthi, 2016):
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More and more Web users
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High cost of bandwidth
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Broken bandwidth and latencies
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Ever-increasing network distances
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Bandwidth demands continue to amplify
Therefore, Web caching reduces the bandwidth utilization as well as the server load by temporarily storing the Web objects nearer to the client. This provides the benefits such as reducing the cost of connection to the Internet, the latency of WWW and server workload and network traffic (Kumar & Norris, 2008).
There are many aspects which affect the performance of Web today, including discrepancies in network connectivity, real-world distances and overcrowding in networks or servers due to unforeseen demand (Sathiyamoorthi & Murali Baskaran, 2010b).
Some of the methodologies addressed here that help to increase the performance are Web caching, Web pre-fetching and integration of Web caching and Web pre-fetching.
Web caching can be positioned at different locations that are client side, server side and proxy side (Chen et al., 2003). In these, proxy-based Web caching is widely used to reduce the latency problem of today’s Webpages as it resides in between client and server. It plays a major role in dropping the response time and saves the bandwidth. The main element of Web caching is its page replacement policy (Chen et al., 2007). When a new document arrives and if the cache is full, then the replacement policy has to make critical decision in replacing an existing Webpage from the cache. The subsequent sections examine some of the existing Web caching policies and Web pre-fetching techniques. It also summarizes the various Web pre-fetching approaches with its pros and cons.
TopResarch Progress In Web Caching
The traditional cache policies are not appropriate for Web atmosphere since they concentrate on any one parameter (age, frequency, cost recentness and so on) and ignore other factors that have an impact on the Web caching (Koskela et al., 2003; Cobb & ElAarag, 2008; Ayani et al., 2003). Moreover, traditional policies are best suited for memory caching since it involves fixed page size whereas, Web caching involve pages of varying sizes. Also the authors have discussed that the popular objects will have innumerable requests from the users, while other objects which are present in the cache, are never accessed again. It is observed that many researchers have proposed various methods for improving the performance of Web caching (Kumar & Norris, 2008; Chiang et al., 2007).