Modelling and Performance Evaluation of a Manual Logon System for Electronic Fee Collection

摘要

In this paper we model a toll-station terminal logon process of an electronic fee collection system as used in the German toll collection system. Currently, approximately 734,000 vehicles participate in this electronic fee collection (EFC) system and up to nine million users are estimated to use a future Europe-wide solution. Thus, a clear view on traffic characteristics and performance of this large-scale, distributed telematics system are paramount for the overall architecture, parameterisation, and operation. Especially, reactions to downtime and recovery conditions must not result in an overload situation which could eventually lead to a total failure of the system. We describe the German toll collection system, detail the manual logon process, and, present a detailed system model. Then, we evaluate by simulation the process of delivering booking data records, which are stored in the terminals during a downtime of the central data centre, after system recovery. Finally, we compare different algorithms for sending data records during this phase regarding the time needed to deliver all queued records as well as regarding the load on the servers in the data centre. Index Terms—telematic system, electronic fee collection, backoff algorithm, manual logon, terminal, queueing network.