Looking toward the future of computer networking, we see that the need for increased interconnectivity will require continual growth in speed and features. Today there are several successful LANs competing in the 100 Mbps arena. Now we are considering the next generation of network. Ideally, users need a solution that provides the necessary bandwidth and connectivity while preserving their investments in hardware and software. This paper will present an architecturally different design for a new more effective LAN. The new architecture will provide a convenient solution to the need for higher total network capacity by interconnecting multiple FDDI networks (and/or network segments). The underlying network architecture is based on the FDDI protocols, which is an attractive feature for those who have invested resources in FDDI. Scalability is a required feature for any future network design and is addressed in detail by this architecture. This alternative next-generation networking solution has been presented to the ANSI standards committee X3T12 as a possible FDDI follow-on standard (FFOL).

This paper explores the effects of locality on the performance of a FDDI-based multinetworking environment and compares this to a scaled FDDI approach. Both of these schemes have been presented to the Standards Committee for consideration in migrating the FDDI protocols to gigabit speeds. One is a simple linear scaling (10/spl times/) of the FDDI protocol to reach the gigabit speed, and the second, presented by these authors, is a hierarchical scheme which preserves the existing FDDI standards and defines an interconnection network that acts as a backbone to the underlying FDDI networks. An introduction to both network schemes is presented. The average network access delay in the hierarchical network scheme is affected by the locality of the data traffic since data traffic has to traverse two networks if it is not local. A numerical method is presented which allows access to delay results with various network configurations. In the scaled approach there is only one network, thus eliminating the effects of data locality on the performance of the network. The paper is concluded with a discussion of the pros and cons of the two schemes.

Simulators are valuable tools in helping us understand how complex systems will operate and perform, without actually having to build a physical model to test. It is best to write the simulator in a higher level programming language, in our case we use Mathematica and are able to obtain fast results with excellent graphing capabilities. The goal of our research is to find a method for obtaining an estimate of the average access delay for advanced token ring based networks such as FDDI (fiber distributed data interface) or FFOL (FDDI follow on LAN). We have developed a method that will generate exact results at low to medium loaded networks. As the load level increases, the error rate also increases, this however is monitored and can be used as a confidence measure for the results obtained. A symmetric multimedia environment is used as the model, with bimodal traffic consisting of short data packets and longer video packets. The method we developed to calculate the estimated average access time under a specific network configuration as a function of varied offered load. A full listing of the Mathematica code is included in the appendix and is referenced in the analysis section.

Local area networks (LANs) have emerged as the technology of choice for inter-computer communication. As computers get faster, so must the LAN environment that supports them. Today there are several successful competing LANs in the 100 Mbps arena, and we are now starting to look forward to the next generation of network to take over when the current generation cannot provide the necessary bandwidth and connectivity. The paper discusses some of the architectural trade-offs available to designers of the next generation LAN, and proposes an architecture which provides for convenient interconnection of multiple FDDI networks (and network segments). The underlying network architecture is based on FDDI protocols, an attractive feature for those who have invested into FDDI. Scaleability appears to be a required feature for any future network design and is addressed in detail. The ultimate goal of this research is to present an alternative next generation networking solution that could be adopted by ANSI as the FDDI follow on standard.>