Original scientific paperDiscrete-time multiserver queues have been successfully used in the performance evaluation of computer and communication systems in various contexts such as TDM, voice-data integration, deflection routing and more recently, ATM-switching technology. In digital communication systems, buffers are used for the temporary storage of digital information awaiting transmission via some communication channel(s). Usually, information presents itself in the form of fixed-size packets, and synchronous (slotted) transmission is used so that the buffers can be modelled as discrete-time queuing systems. In this article, performance analysis of space division output buffered switches operating in an ATM multimedia environment is presented. Fixed size packets arrive onto the switch inputs in each time slot. The switch is modelled as a discrete-time, batch arrival, multiserver queuing system, with infinite buffer and geometric service times. The main contribution of this work is using multiserver case and geometric service time. Many performance measures such as System occupancy, Queuing time, Unfinished work and Waiting time are analysed. Probability Generating Functions (PGFs) and expectations for the corresponding random variables are derived. The results of the analysis have been verified in many ways. First, they have been used to generate the results of some previous analyses as special cases. Second, they obviously seem to preserve classical queuing relations (e.g. the famous Little's formula). Last, they have been shown to generate intuitively acceptable graphs, when translated into numerical values.Key words: Data Communications, Performance Analysis, Output Buffered Switches, System Occupancy, Multiserver queues Procjena učinkovitosti prospajanja komutatora. Diskretni višeserverski redovi uspješno su korišteni kod analize učinkovitosti računalnih i komunikacijskih sustava u različitim okolnostima poput TDM-a, glasovnopodatkovne integracije, ATM komutatora. U sustavima digitalnih komunikacija bufferi se koriste za privremeno pohranjivanje digitalnih informacija koječekaju na prijenos preko komunikacijskih kanala. Uobičajeno se informacije prikazuju u formi paketa fiksne veličine, a sinkronizirani prijenos koristi se kako bi bufferi mogli biti modelirani kao diskretni sustav sčekanjem. U ovomečlanku prikazana je analiza učinkovitosti komutatora u ATM multimedijskom okruženju. Paketi fiksne veličine stižu na ulaze preklopnika u svakom vremenskom okviru. Preklopnik je modeliran kao diskretni višeserverski sustav s batch dolascima, s beskonačnim bufferom i geometrijskom razdiobom vremena servisa. Glavni doprinos ovog rada je korištenje višeserverskog slučaja i geometrijske razdiobe vremena servisa. Analizirane su mnoge mjere učinkovitosti kao što je zauzetost sustava, vrijemečekanja, nezavršen posao. Izvedena je funkcija izvodnica i očekivanje za odgovarajuće slučajne varijable. Rezultati analize provjereni su na mnoge načine. Prvo su korišteni za generiranje rezultata nekih prethodnih analiza kao po...