Measuring End-to-End Ajax Performance in Broadband Satellite Networks.

摘要

Ajax-enabled web applications represent a new breed of rich and interactive websites. Ajax prevents the reloading of entire web pages by transmitting small amounts of asynchronous data in the background, thereby allowing users to interact directly with a website without waiting for page reloads. This method masks the round trip and transmission latency of network connections. In response, attempts have been made to identify those factors that are associated with Ajax performance.;Past research has studied Ajax performance and found varying degrees of performance improvement when compared with the traditional HTML request-response model. Current approaches measure the relative performance of Ajax applications against an equivalent non-Ajax application based on response size, service times, traffic patterns, response times, total byte size, and latency. Notable limitations with current approaches include the lack of a general measurement framework and empirical research examining end-to-end Ajax performance over high-delay bandwidth networks.;As the use of Ajax increases, the development of a general framework for measuring end-to-end Ajax performance is warranted to better understand Ajax performance in high-delay bandwidth networks. This dissertation improves upon previous work in this field by introducing a measurement framework to facilitate the end-to-end measurement of Ajax performance in a satellite environment. This investigation's artifacts include the framework design and a proof of concept designed to validate the framework by using it to measure response time using application-level traces of actual HTTP request-response and XHR calls.;This research included the development of a prototype used in conjunction with an active probing measurement tool to measure and compare overall response time of XHR and HTTP calls. The prototype was used in the proof of concept to evaluate the HTTP and XHR calls across an emulated satellite network. Subsequently, a statistical analysis was performed on the dataset collected from the proof of concept. The conclusion supported by a paired t-test indicated that Ajax performs better than HTML in two loss rates. In particular, use of DOM-based updates coupled with the XHR call in an Ajax application results in both lower mean response/request size, and lower mean user experience time. Recommendations for future research include the utilization of the framework to explore and compare additional Ajax components and/or explore the impacts of the existing work in different satellite environments.