Group communication, be it one-to-many (such as TV broadcasting) or many-to-many (such as teleconferencing) is becoming increasingly important because it enables the widespread dissemination of information (such as in today's Word Wide Web) and the collaboration between remote groups. This kind of communication can be supported efficiently in digital networks through multicasting, a technique of non-redundant simultaneous data transmission from a sender to a set of receivers. Multicast applications such as voice and video require Quality of Service guarantees (such as maximum packet delay, packet loss probability), which can be provided by reserving network resources. In this dissertation we propose solutions to several critical problems of multicasting in heterogeneous environments: differences in network resource availability, differences in receiver Quality of Service requirements, differences in network resource availability and differences in resource reservation protocols. In the first part of the dissertation we consider the problem of resource reservation for multicast sessions in the context of both network and receiver heterogeneity. We develop centralized and distributed algorithms that accommodate this heterogeneity by performing a differentiated per-link resource reservation. We apply these algorithms in the context of packetized voice and MPEG video multicast connections over wide area networks. We find that our algorithms enable a network to carry as much as a 50% more traffic compared to the case where the network does not accommodate heterogeneity. In the second part of the dissertation we present algorithms for local (link) admission control and resource reservation at an Earliest Deadline First packet scheduler that provides heterogeneous packet delay guarantees at a link. When the data transmission is characterized by piecewise linear traffic envelopes, we show that the algorithms have very low computational complexity and thus, practical applicability. In the third part of the dissertation we focus on resource reservation protocols in the heterogeneous environment of IP over ATM networks. We describe a method for establishing reservations in the ATM network for IP flows (named ATM shortcutting). This method provides better performance to IP flows by avoiding the IP processing of IP packets, and better utilization of ATM network resources. In the last part of the dissertation we quantify the improvement in utilization of IP/ATM network when using ATM shortcutting. We present methods to evaluate this benefit given an IP/ATM network topology, link capacities and traffic patterns. We use this methods in simulation experiments using random networks. These experiments indicate that in many cases ATM shortcutting brings benefits in network utilization when it decreases the average length of network routes.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-3092 |
| Date | 01 January 1998 |
| Creators | Firoiu, Victor |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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