Investigation Into Quality Of Service Issues With Transmission Of Multimedia Information Over A Connectionless Network

Muhimedia communications embraces a range of applications and networking infrastructures. The term multimedia is used to indicate that the information/data relating to an application may be composed of a number of different tj^es are text, images, speech, audio and video and some example applications are video telephony (speech and video), multimedia electronic mail (text, images and audio), interactive television (text, audio and video), electronic commerce (text, images, audio and video), Web TV (text, audio and video) and many others. The current hitemet, based on packet switched hitemet Protocol (IP), has been described as a "Best-Effort" delivery system, as it provides no guarantees for the delivery of packets from a source to the destination. The design philosophy, at that time, had been largely focused on only one media-type, i.e. text, and all the efforts were spent in providing an error-free, highly flexible means of communication. However with advances in technology, it has become evident that the Internet now needs to support other media types like audio and video. These new media types have certain real-time aspects for which the best-effort Intemet is not well-suited. With the Internet expansion, real-time transmission over Intemet is becoming a new promising application. Successfiil real-time communication over IP networks requires reasonably reliable, low delay, low loss date transport. Since hitemet is a nonsynchronous packet switching network, high load and lack of guarantees on data delivery make real-time communication such as Voice and Video over IP a challenging application to become realistic on the Intemet. IP networks are on a steep slope of iimovation that will make them the long-term carrier of all types of traffic, including multimedia. However, such networks are not designed to support real-time multimedia communication because their variable characteristics (e.g. due to delay, delay variation and packet loss) lead to deterioration 1 in multimedia quality. A major challenge in such networks is how to measure or predict multimedia quality accurately and efficiently for QoS monitoring and/or control purposes to ensure that technical and commercial requirements are met. Multimedia quality can be measured using either subjective or objective methods. Subjective measurement (e.g. SSCQE, DSIS) is the benchmark for objective methods, but it is slow, time consuming and expensive. Objective measurement (e.g. PSNE) is more accurate, but normally is unsuitable for monitoring live traffic because of the need for a reference data and to utilize the network. This makes other objective methods (e.g. MSE) more attractive for monitoring multimedia quality from IP network impairments. However, current objective methods rely on subjective tests to derive model parameters and as a result are limited and do not meet new and emerging applications. iiSchool of Computing, Communications and Electronic