Specification of Non-functional Requirements and Their Trade-offs in Service Contracts in the NGOSS Framework

The community of Operation Support Systems (OSS) for telecom applications defined a set of fundamental principles, processes, and architectures for developing the Next Generation OSS through the TeleManagement Forum TMF. At the heart of NGOSS lies the notion of a “Contract” which embodies the specification of services offered by an OSS component for quality management and product evaluation. However, TMF does not provide any method (or process) for specification of the non-functional part in the NGOSS contract specification. This chapter develops a systematic approach for specifying non-functional requirements of telecom OSS applications for contracts in the NGOSS framework for quality management and evaluation. Specifically, two categories of non-functional specification techniques are explored: qualitative and quantitative. Furthermore, two quantitative non-functional requirements specification methods are introduced: crisp and elastic to expand the capability of the current NGOSS contract specification method since only qualitative non-functional specification is currently available from TMF. In addition, a technique is developed for specification of trade-offs between non-functional requirements.