The software system is designed so as to provide an easy access to the data base coritaning information on a network structured object (such as real telecommunication networks).  Both the system and the data base are original products.  The main feature of the system is that it is capable of flexible graphical representation of the data.  More specifically, any desired part of the network structure (or the whole network) can be drown on the geographical map according to its physical location.  Important administrative information on the territory depicted is also supplied and can be visualized.  Technical capabilities of particular fragments of the network (such as paths, subpaths, or nodes) are reflected by means of standard sets of pictograms and colors.  All the standard data base control functions (such as searching for a subset of elements according to a specified key) are available.  The system may be supplemented with different optimization algorithms.  On the system background there was constructed the program package to solve the routine problem.  The program was used in practical work with the real telecommunication network structure of the former Soviet Union.  The suggested methods permit to solve large-scale network synthesis problems.  The decision support system will be helpful for statement and solution of new scientific and practical problems concerning investigation of multicommodity networks, their vulnerability and vitality, recovering and development strategies, uncertainty in abonent requirements.