Testing of switch node with Call Generator software module

In the last decade most of the development and research in telecommunications moved from hardware design to software applications. Nowadays, most of the new features and services are introduced through software development. Due to strong competition on the telecommunication market telecommunication companies are forced to develop their products in the shortest possible time. The verification of software code still takes a lot of time and effort. If we want to spare some of that time, we have to enable developers to verify functionality of their code while it is still in development. Usually developers are verifying their code on the test configurations of switch nodes. The verification can be done by external devices (black box approach) or with a software package. A weakness of external testing devices (external call generators) is their high price and complicated usage. The paper will present a Call Generator software test module written in SDL (Specification and Description Language). SDL is a standard formal language for the specification and description of systems [1]. It has been developed and standardized by the CCITT [2, 3, 4]. It is largely used for the development of telecommunication systems. After an introduction of the problem we describe practical realization of the Call Generator software module for analog subscriber lines that we developed for the biggest Slovenian telecommunications company IskraTEL and its SI2000 switch node family [5, 6, 7]. The software approach is much cheaper compared to expensive external call generators. It also provides accessibility to all developers all the time because it is located inside every switch node. A user of Call Generator can test a switch node with any desired load even with the biggest configurations. The test follows a prescribed scenario which is located in the switch node’s database. Every developer can prepare test scenarios for his current development work and test its functionality. It can be used from the developer’s working place. Software Call Generator has been developed for easy and thorough testing of the software developer’s program code. The software module does not limit its user in any way. Scenarios can simulate any user action and test the switch node’s response. One of the main development objectives was geographical independence of the Call Generator user. It can be used from any place in the world if you have Internet access to the switch node that you want