Date of Award

Spring 1997

Document Type


Degree Name

Doctor of Philosophy (PhD)


Computer Science

Committee Director

Kurt J. Maly

Committee Member

C. Michael Overstreet

Committee Member

David E. Keyes

Committee Member

Wayne H. Bryant


As new computer network technologies emerge, the application designers and the application users expect an increasing level of quality of service from them. Hence, it is a common practice in the newer technologies to provide more Quality of Service (QoS) components. Until now, these QoS solutions have been both network-technology specific and network-oriented solutions. In this thesis, we present an application-oriented approach to design a high quality network which is independent of the underlying communication technology. In this thesis, we propose a QoS architecture to "provide predictable performance to the end-to-end application users in a high quality networking environment." In our architecture, QUANTA (Quality of Service Architecture for Native TCP/IP over ATM networks), we integrate different application requirements and different existing native QoS architectures into a single end-to-end architecture.

Through experimentation we identify the architectural issues and the different QoS components required. We propose solutions which include isolation of the applications and managing the knowledge of the applications. The issue of isolating an application is subdivided into classification and identification of the applications. In addressing these issues we propose a ripple-through classification mechanism and a Generic Soft State (GSS) identification mechanism. To manage the knowledge of the applications we propose different QoS components, such as a GSS negotiation mechanism, a GSS communication mechanism and a GSS monitoring mechanism (such as GSS Relays and GSS Agents).

QUANTA's overhead is measured by running applications with different life-times and QoS requirements with and without QUANTA. For a transaction-oriented applications, the overhead induced by using QUANTA is larger than the benefit of using QUANTA. In high data rate applications and in long life time applications, a predictable performance to the applications is achieved with very low overhead by QUANTA. We demonstrate that QUANTA can manage and maintain Quality of Service for different classes of applications under varying host and network load conditions transparent to the application user. Using QUANTA, we can reach nearly 80% of the channel utilization under loaded conditions, whereas without QUANTA, the load on the network can reduce the channel utilization to 40%. Quanta has reduced a 350 msec delay under loaded conditions to less than a 10 msec delay. With the exception of short transition periods, QUANTA can sustain throughput to within the bounds of the specification of the user. We identify the limitations of QUANTA as currently proposed and discuss possible enhancements to it and other such architectures to remedy these limitations.


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