and TMForum is given below. E. Luoma (X) Department of Computer Science and IS, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland e-mail: Eetu.Luoma@jyu.fr P. Tyrväinen and O. Mazhelis (eds.), Vertical Software Industry Evolution, Contributions to Management Science, DOI 10.1007/978-3-7908-2352-3_5, C Springer-Verlag Berlin Heidelberg 2009 E. Luoma et al. The ITU is the United Nations agency for information and communication tech- nologies. In the domain of telecommunications management, their central concept, denoting management activities of CSP, is the telecommunications management network (TMN). It is an architecture encompassing processes and atomic tasks for planning, provisioning, installation, maintenance, operation and administration of telecommunications equipment, networks and services. The architecture is divided into layers including business, customer, service, network and element manage- ment layers (ITU-T 2000). The telecommunications management is therefore concerned with operational, that is, day-to-day processes for service fulfilment, service assurance and billing as well as infrastructure development processes. Operations support systems (OSS), business support systems (BSS), network management systems, and element management systems corresponding to the TMN layers constitute the CSPs system environment. The main subject of this book is the software systems supporting the processes specific to this vertical industry, namely the OSS and BSS. The term Operations Support System (OSS) refers to software systems supporting network management processes such as maintaining network inventory, provisioning services, configuring network com- ponents, collecting and mediating usage information and managing faults. The term Business Support Systems (BSS) typically refers to software systems supporting customer management processes including taking orders, providing customer service, processing bills, and collecting payments (Terplan 2001). 2 TM Forum The TM Forum (also TeleManagement Forum, 