With the rapid advancement of mobile devices, people have become more attached to them than ever. This rapid growth combined with millions of applications (apps) make smartphones a favourite means of communication among users. In general, the available contents on smartphones, apps and the web, come into two versions: (i) free contents that are monetized via advertisements (ads), and (ii) paid ones that are monetized by user subscription fees. However, the resources (energy, bandwidth, processing power) on-board are limited, and the existence of ads in either websites or free apps can adversely impact these resources. These issues brought the need for good understanding of the mobile advertising eco-system and how such limited resources can be efficiently used. This thesis focuses on mobile web browsing. Surfing web-pages on smatphones is one of the most commonly used task among smartphone users. However, web-page complexity is increasing, especially when designed for desktop computers. On one hand, the existence of ads in web-pages is essential for publishers' monetization strategy. On the other hand, their existence in webpages leads to even higher complexity of the webpages. This complexity in the smartphone environment, where the battery and bandwidth resources are limited, is reflected in longer loading time, more energy consumed, and more bytes transferred. With this view, quantifying the energy consumption due to web ads in smartphones is essential for publishers to optimize their webpages, and for system designers to develop an energy-aware applications (browsers) and protocols. Apart from their energy impact, ads consume network bandwidth as well. Therefore, quantifying the bandwidth consumption due to downloading web ads is crucial to creating more energy and bandwidth aware applications. This thesis first classifies web content into: (i) core information, and (ii) forced ``unwanted" information, namely ads. Then, describes an approach that enables the separation of web content in a number of a websites. Having done so, the energy cost due to downloading, rendering, and displaying web ads over Wi-Fi and 3G networks is evaluated. That is, how much energy web ads contribute to the total consumed energy when a user accesses the web. Furthermore, the bandwidth consumed by web ads in a number of well-known websites is also evaluated. Motivated by our findings about ads' impact on the energy and bandwidth, the thesis proposes and implements a novel web-browsing technique that adapts the webpages delivered to smartphones, based on a smartphone's current battery level and the network type. Webpages are adapted by controlling the amount of ads to be displayed. Validation tests confirm that the system, in some cases, can extend smartphone battery life by up to ~ 30\% and save wireless bandwidth up to ~ 44\%.

Web browsing has been one of the most popular activities on the internet. The increasing importance of the Web in everyday life calls for device-independent access to existing web sites. Although, there is full Web access available on mobile phones the user experience is often poor when compared to the Web user experience on Personal Computer (PC). Therfore, it is important for the Internet service provider to find the indications of user dissatisfaction from the network. While using the mobile Web, user can normally abort the transfer by pressing the stop or reset buttons in the browsers, leaving the page being downloaded by following a bookmark or can close the connection. Such events can be observed through the TCP reset (RST) flag from traffic on network level. In this thesis we have investigated the possible causes of TCP RST flags mobile Web session is interrupted. We further analyze up to what extent we can rely on TCP RST flags for being an indication of user dissatisfaction in mobile web browsing. Therefore, an experiment testbed is developed to capture the TCP packet traces during controlled active tests. Results are gathered using mobile devices with four popular mobile operating systems (OS). The trace files captured are analyzed using perl script to dicern the flow and focusing on the TCP RST flag during the flow. Further, TSTAT tool is used to validate our trace files. / 0760-882089

User perceived latency is the most prominent performance issue influencing the World Wide Web (www) presently. Hyper-Text Transfer Protocol(HTTP) and Transmission Control Protocol (TCP) have been the backbone of web transport for decades, thus received a lot of attention recently due to end-to-end performance degradation in mobile environments. Inefficiencies of HTTP and TCP strongly affect web response time mainly in resource limited devices. HTTP compression reduces some of the burden imposed by TCP slow start phase. However, compression is still an underutilized feature of the web today [1]. In order to fulfill the end user expectations, we can optimize HTTP to improve Page Load Time (PLT), low memory usage and better network utilization. SPDY, a web latency reducing protocol and HTTP pipelining are a recent proposal to provide faster information exchange over web. Through the course of this work, we present a comprehensive study of new approaches to reduce mobile web latency. At first, we measure the PLT after implementing SPDY, HTTP and HTTP pipelining. Secondly, we also analyze the performance of these protocols after tuning the network parameters like bandwidth and round-trip time (RTT). Finally, we compare the performance of HTTP and other latency reducing protocols. We have conducted all experiments over DummyNet under user-configured network conditions. We critically discuss the challenges of shifting from HTTP to these latency-reducing protocols.