MACOM - A Tool for Evaluating Communication Systems

MACOM (Markovian Analysis of Communication Systems) is a software tool for the model based performance evaluation of (parts of) communication systems. Models are speciied by graphical interactive means, model solution is performed by using numerical techniques for Markovian models. Compared to purely analytic approaches, this approach allows for a considerably enhanced model world. Concepts covered by the model world of MACOM are nite or restricted resources, adaptive strategies, simultaneous resource occupation, peaky traac, and bulk arrivals. Stationary analysis is possible for models of size up to hundreds of thousands of states, depending on the available hardware. MACOM contains a complete modelling environment with a graphical model editor, experiment run control, management of model and result data, and an option for graphical result presentation. Versions of MACOM currently exist on Sun workstations using SunView or the X Window System. 1 Models in MACOM The model world of MACOM is derived from queueing networks and wait-loss-systems 1, 2]. A MACOM model is a network of sources, sinks, and elements for service or control of load units. In case a requested resource is currently not available a load unit may utilize an alternative resource, may wait, or get lost. Load units (e.g., calls, packets, jobs) enter the system at sources. To describe the load of modern communication systems, arrival patterns are modelled via Markovian arrival processes (MAP, MMPP, IPP) or simpler distributions with exponential phases. Batch arrivals, ssion and fusion of load units are possible. The resources of the net are called stations. Stations for modelling time consumption are loss systems with a limited capacity for load units. Queueing may occur depending on the strategy of the station. Besides innnitive server and processor sharing , also random selection, priority and polling strategies are selectable in diierent variants. Routing is realized via conex elements, where stochastic or state dependent routing can be speciied. Sync stations, containing a generalized semaphore concept, can