Comparing Ucn with Fddi and Dqdb Using a Realistic Workload Model

The token ring FDDI and the slotted bus DQDB are the two currently most important standards for high speed networks. Each of these networks has its own specific advantages and disadvantages, and its own specific type of load for which it petforms best. We propose a new network design, called Universal Channel Network (UCN). UCN is adaptive and can be made to behave either like a token ring, a slotted ring, or anything in between. The aim is to get a network that combines the advantages of both the token ring and the slotted ring. In this paper UCN is explained and its pelformance is compared with that of DQDB and FDDI. The workload model used is a detailed representation of today's traffic, extrapolated into the future. performance adaptive. In Section 4 we discuss the workload model used to derive the simulation results presented in Section 5. In Section 6 we draw some conclusions and list some ongoing work concerning UCN. 2 Comparing slotted rings and token rings In this section the difference between slotted rings and token rings will be examined. It will be shown in both a qualitative and a quantitative way what the difference is between them, how this influences performance, and how token ring and slotted ring can be combined. In the sequel we will repeatedly use the term message with the meaning of a Data Link Layer Service Data Unit (DLL SDU).