An emulator for evaluating DQDB performance

This paper presents the design and implementation of a DQDB network emulator, developed at Lancaster University. The emulator uses standard Unix processes and System V named pipes to create a model of a Distributed Queue Dual Bus subnetwork of a Metropolitan Area Network. Apart from gaining insights into the DQDB protocol implementation based on a finite state machine model, the goals of the work reported in this paper included the performance evaluation of DQDB networks and the provisioning of a suitable platform to investigate various isochronous service management issues. The paper provides results on the operations of the distributed queue state machines and on the performance evaluation of DQDB networks. Finally, future developments of the emulator are identified.