Caching for transcoding-enabled proxies

Abstract

This thesis is focused on the subjects of caching, transcoding, and the combination thereof in a network proxy. The motivation for exploring this field of study is twofold. First there is the rapid increase in bandwidth consumption that is caused by the popularity of the Internet. Second is the advent of ubiquitous computing, in the form of an exponential proliferation of end user computing devices, causing the user space to become heterogeneous and diverse. To cater to each of these users, who have their own specific hardware specifications and bandwidth capacity, is a challenging task. A modern web site or online application makes use of rich multimedia content to make the user experience enjoyable, such as high resolution images, motion video and audio. This is very strenuous for the average Internet connection, let alone the low speed access that a mobile phone or personal digital assistant has to offer. Also the hardware of the device might not always be suitable for such intensive media content, simply because of a small display screen, and as such there is a dire need for per-user customization of the content. One way to approach this obstacle is by employing a caching and transcoding proxy, which merits are that it takes care of the media adaptation in a transparent way, without requiring any changes on either the client or the server platform. It also stores frequently visited resources to speed up future requests. This thesis gives a detailed summary of the current state of affairs on the topics of caching, transcoding, and the integration of those two technologies. After having performed this literature study, a practical implementation was realized, which offers the previously described functionality. To accompany that software project a series of tests and measurements were performed that show once more the importance and benefits of employing such technology. It is concluded that this is a valuable subject, that deserves its share of research, for its use has become paramount (indispensable) in this world of bandwidth consuming Internet applications and ever evolving client device heterogeneity.