Can anyone briefly summarize when queueing theory is appropriate as a technique for modelling, as opposed to simulation and operation analysis? Thanks, Mat -- Matej Pfajfar St John's College, University of Cambridge, UK GPG Public Keys @ http://matejpfajfar.co.uk/keys WARNING: THIS E-MAIL ACCOUNT WILL BE DELETED ON 15/07/2002. PLEASE USE mp@cantab.net.