Performance analysis derived from a formal specification of a multimedia protocol provides important information on the performance characteristics of a multimedia system before implementation; this information includes time-dependent functional behaviours, and statistical traffic characteristics. We have developed an extended Estelle, called Time-Estelle, suitable for specifying time-dependent performance characteristic of a multimedia system, and a method based on GSPN (Generalized Stochastic Petri Net) for analysing the performance of a protocol specified in Time-Estelle. This paper describes an application of this method to analyse the performance of an industrial multimedia protocol, the Resource ReSerVation Protocol (RSVP) specified in Time-Estelle; it also presents the performance analysis results which are expressed in terms of blocking probability, packet dropping probability, channel utilisation and packet delay, with variations in time intervals.