It is evident that both ATM and Ethernet networks will comprise the "network of the future". Ethernet networks are rapidly transitioning from half-duplex CSMA/CD to full-duplex switched operation. While much of the current research in ATM networks is relevant to both types of networks, there are significant remaining problems in the area of Ethernet networks that urgently need to be addressed. These problems include: 1. The traffic characteristics of future gigabit applications have not yet been predicted. Current traffic models may not be applicable for gigabit applications. Therefore, better knowledge of traffic from expected gigabit applications is needed to be able to predict network performance. 2. For high-speed networks, memory speed limits output buffered and shared memory switch architectures to low port densities. For this reason, scheduling algorithms which achieve high throughputs for input buffered only ATM switches have been the subject of recent research. Yet, there do not exist scheduling algorithms or switch architectures which accommodate variable length packets and Quality of Service (QoS) in input buffered only switches and full-duplex repeaters. 3. While switched operation will likely be predominant in future networks, inefficiencies in gigabit half-duplex CSMA/CD Ethernet still remain and need to be addressed. The objective of this four year CAREER program is to address these problems. Existing traffic models are largely based on time series analysis of traffic traces resulting in a limited understanding of the causes of observed traffic characteristics. New knowledge will be gained by instrumenting application and protocol implementations to study the user behavior, source data objects, and application and protocol behaviors of expected gigabit applications. Using the resulting traffic models as input to performance models that will be developed, methods for highly scalable, input buffered only switches to provide high throughput and efficient support for bursty, best-effort data traffic and guaranteed-service traffic streams will be advanced. The hypothesis is that by using traffic shaping at each input port, the scheduling algorithm can be made simple and scalable. The applicability of packet bursting and spacing, priority queueing, and selective PAUSE flow control will be studied. To support CSMA/CD on large span, half-duplex Gigabit Ethernet networks with high-data rates, the current minimum 64-byte packet size must effectively be increased to 512 bytes to allow for correct collision detection. The IEEE 802.3 Gigabit Ethernet standard uses packet bursting to transmit small packets. A more efficient and interoperable method of operation whereby late collisions are permitted, can be detected, and handled correctly will be studied. A systems and experimental approach will be used to tackle the problems. A laboratory of Gigabit Ethernet attached personal computers and servers will be built. This laboratory will be used for direct perimentation, as a facility for parallel execution of simulation models, and for related educational activities at both the graduate and undergraduate levels. A tool for parallel independent replications of simulation models will be developed and made generally available. Much more significantly, new ideas in traffic modeling, new knowledge in switch scheduling for variable length packets with support for QoS, and new methods for using CSMA/CD in large span, half-duplex Ethernet networks will be presented in appropriate conferences and journals, and to standards bodies. To solicit input and generate external participation, a WWW site with a bulletin board will be established for researchers and developers from academia and industry to share software tools, new ideas, and findings. In addition, a workshop will be held. New ideas will thus be seeded into the research community. Education Plan The College of Engineering at the University of South Florida currently has a new undergraduate degree track in Information Systems . A graduate track in Information Systems is under consideration. This CAREER program will advance a strong networking and performance modeling focus for this Information Systems degree track. New courses and curricula will be developed and research results will be brought into the classroom. The emphasis will be on experimental and hands-on projects where students will work in teams to solve real world problems using cutting-edge knowledge. The educational materials developed as a result of this project will be used as a contribution to ongoing ACM and IEEE-CS efforts to develop curriculum guidelines for Information Systems programs. To encourage undergraduate students to pursue graduate education in engineering, portions of this CAREER program have been explicitly identified for undergraduate student research involvement.
