Of packets and people: a user-centered approach to quality of service

Abstract

Multimedia communication has gained increasing attention, both from the application side and the network provider side. While resource provisioning for QoS support in packet switched networks has lead to the design and development of sophisticated QoS architectures, notably ATM, IntServ or DiffServ, research has not exactly been user or application-context centered. In the cause of the evolution of QoS architectures, the integrated service network approach has lost momentum, and with it, the notion of QoS guarantees. Differentiation of QoS classes within the DiffServ framework is based on the definition of various per-hop behaviors. What is currently missing is a technique for specification and mapping of application and user QoS preferences onto evolving service profiles. In addition, adaptation of applications (and users) is becoming increasingly important in the face of dominating weak QoS-assurance paradigms, both in wireline and wireless environments. As a prerequisite, this paper investigates cognitive and perceptive conditioning of users and applications in a situated setting. The contribution of this paper is twofold: First, essential empirical results on user QoS preferences and QoS graduations are presented, and second, methodological foundations are laid for investigating user-centered QoS.

Case Study in Assessing Subjective QoS of a Mobile Multimedia Web Service in a Real Multi-access Network

“…Thus, it is the user application that leads the main role in determining the user's QoS requirements, although neither does it dictate them solely. The salience of different quality criteria is influenced also by the goal of the interaction, and the ideal QoS profile of an application consequently varies with the task performed [3]. Three general categories for user-level QoS requirements (defined in [6]) are discussed here: criticality, cost, and security.…”

“…The user study methods include, e.g. Mean Opinion Scores (MOS), continuous assessment, Task Performance Measures (TPMs), and qualitative methods [3]. Objective measurements, on the other hand, rely on measurement of some application quality metric(s) (e.g.…”

“…We chose to use MOS in our user study to collect the subjects' opinions of the experienced service quality. In short, MOS enables performing controlled assessment of subjective QoS with untrained subjects and controlled levels of quality [3]. The method employs a 5-point scale, according to which subjects judge the experienced quality after conducting a task.…”

Congestion pricing. Paying your way in communication networks

“…Studies of user responses to variable network conditions indicate, however, that users prefer stable QoS levels. 13 This implies that users might prefer a fixed-bandwidth flow, even if a variable amount provided more bandwidth on average.…”

The Dynamic User-oriented QoS Specification and Mapping for multimedia Differentiation Services

“…According to the definition of the DiffServ architecture, the network resources are graded into expedited forwarding (EF) and assured forwarding (AF) to provide diverse requirements of applications in order to increase the scalability of Integrated Service (IntServ). However, there are two critical problems arose in the DiffServ/IntServ QoS networks [2,6,7]. (i) The traditional way to differentiate services is based on the viewpoint of the network provider.…”