Purpose and area of application

This software is designed for analytic performance evaluation and capacity planning of various telecommunication networks and their segments where the flows of information are heterogeneous and versatile (what is typical, e.g., for ISDN, ATM networks) and the transmission processes are correlated. The impact of repeated attempts is considered what creates the possibility to investigate mobile cellular networks, local and metropolitan area networks with CSMA/CD-like protocols, etc.

The real flows in a network are assumed to be described in terms of the BMAP (Batch Markovian Arrival Process), MMPP (Markov Modulated Poisson Process) in particular. The service (transmission) process is described in terms of semi-Markovian process allowing dependence of successive service times. Using this software, the user has an opportunity to calculate, compare and optimize the main performance measures of computer network segments (under different fixed network topologies, hardware, flows routing, multiple access protocols, information transmission protocols on different layers, etc.), on conditions that their operation can be modelled in framework of queueing systems.

The list of available queueing systems (single or multi-server) includes the models where the package who meet the server being busy at arrival epoch moves to the infinite or finite buffer and enters the service according to some fixed access protocol, models where the package is lost forever if it meets all servers being busy, retrial queueing models where the package who meet the server busy leaves the system (goes to the orbit) and tries his luck after some random time interval (queues with repeated attempts). Different strategies of retrials (centralized and decentralized management by active stations, stationary or fluctuating individual retrial rates, etc.) are allowed.

Some models deal with the systems having several available operation modes, which differ by the behaviour of the input flow, service and retrial processes. The cases when the switching of the operation modes is controlled by some decision-maker depending on the current traffic in the system and when the switching of the modes occurs due to some random reasons (e.g., total or partial breakdown of the link or the server, bursty traffic increasing, changing the access protocols, etc.) are handled. The systems subject to temporal crashes (e.g., due to virus of hacker attacks) are dealt with as well.

Technical characteristics

This software is suitable for performance evaluation and capacity planning of any other real-life systems whose operation is described in terms of queues with correlated input flow, service and retrial processes.

Software is developed in C++. Operating systems Windows 9x/NT/2000/XP. It has an user-friendly Windows standard interface (multidocument capability, contextual help, pop-up menu, hot-keys, toolbar, etc.). CASE - tool Visual C++ from Microsoft were used when developing the mathematical part, and Delphi, - when creating the user interface for Windows. Microsoft Foundation Classes Library (MFC), Visual Component Library (VLC) were used in the project.