OSS stands for Operations Support Systems,, i.e. an IT system for a telecommunications network. OSS software are dedicated specifically to providers of telecommunications services. The processes supported by OSS systems include service management and maintenance of the network inventory (modules: Service Inventory Management and Network Inventory Management), configuration of particular network components as well as fault management.
The term OSS is often associated with BSS (Business Support System), i.e. business systems which focus on handling customer-related processes such as billing, payments etc. Sometimes one can come across the two terms joined as B/OSS. From the historical point of view, OSS comprises BSS, since initially OSS referred to all systems for the management of operations and processes, including business systems.