Business support systems (BSS) are the components that a telecommunications service provider (or telco) uses to run its business operations towards customers.
Together with operations support systems (OSS), they are used to support various end-to-end telecommunication services (e.g., telephone services). BSS and OSS have their own data and service responsibilities. The two systems together are abbreviated in various ways, such as OSS/BSS, BSS/OSS, B/OSS, BSSOSS, OSSBSS or BOSS. Some commentators and analysts take a network-up approach to these systems (hence OSS/BSS) and others take a business-down approach (hence BSS/OSS).
The initialism BSS is also used in a singular form to refer to all the business support systems viewed as a whole system.