Introduction

Today we live in a world where information is available at the touch of a button and the Internet has become the backbone of sharing information from anywhere in the world. As the technology grows, it requires more and more resources and depends heavily upon the Internet. As a result of this bottlenecks within Internet and other networks occur. This is where the caching concept comes in.

A web cache is a mechanism which monitors the requests sent to a web server and keeps a copy of the response. A cache consists of a set of files which can contain images, HTML Files, Scripts, etc. When a request is sent to a URL which was previously visited and the cache contains copy of the response, the response is loaded from the cache instead of the actual web server and thus reducing the network usage and possible occurrence of bottleneck. A web cache can be implemented at browser level, within proxy server or gateway device as per requirement of the User, Network administrator or Web Master. Such centralized caching systems will reduce bandwidth and help expand the network.


Even though a Centralized caching system is able to reduce the network bandwidth, there is the risk of personal information being stored in an unsecured location. An implementation of a centralized cache may not be possible in instances where there is no proxy server available. A decentralized cache is an alternative to avert this issue. Decentralized caching eliminates the requirement of a common shared storage space for a cache.

Instead, the cache is implemented within the devices and the requests are sent to neighboring devices and the response is sent. Since the response is handled as close to the host as possible, the latency and network usage is less than a centralized caching system. iCache is a system designed on the concept of decentralized caching. It is mainly targeted towards mobile and wireless networks. iCache system will be implemented on the Linux platform for PCs as well as the Android platform for Mobile hand-held devices while maintaining cross-platform connectivity. The caching mechanism of iCache will be implemented on Wi-Fi Technology. The reason for using wireless technology is to reduce the cost of infrastructure when building a wired network and since deploying proxy servers may not be practical for all situations.

Several research projects have been done in this aspect. Squirrel is a web based peer-to-peer caching system which is implemented for wired networks. But the main disadvantage of Squirrel is that it requires a structured network and all the requests are forwarded to one node (Home Node) within the network which contains a directory of all the objects held by the rest of the nodes. In case if the home node drops out of the network the whole caching system will fail and thus the concept of decentralization is limited to the local network.