Telecom OSS and BSS are the two sets of software that a mobile or broadband operator uses to run its network as a business. BSS stands for business support systems. This is the software that faces the subscriber: it signs you up, charges you for what you use and sends you a bill. OSS stands for operations support systems. This is the software that faces the network: it plans the network, watches it and manages the traffic on it.
The towers of the radio access network and the packet core carry your calls and data. But they do not know your plan or your balance. That information is kept in the BSS, and the core asks the BSS before it lets your data through.
Imagine you buy a new prepaid SIM at a mobile shop in Guwahati and recharge it for ₹349. The shop's SIM activation app checks your identity, a step called KYC (know your customer), and switches the SIM on. From then on, telecom billing and real-time charging deducts every megabyte you use from your balance. If you later travel abroad, roaming and settlement lets a foreign operator serve you, and later works out what your operator owes it. Revenue assurance and fraud management checks that no call or recharge was left out of billing, and looks for fraud.
On the OSS side, deep packet inspection (DPI) recognises what kind of traffic is passing, such as a video stream or a voice call. Network planning software works out where the next tower or fibre route should go. IoT connectivity management runs the SIM cards inside machines, such as electricity meters and vehicle trackers.
Some products in this zone serve the government or add services. Lawful interception lets agencies, with a legal order, receive copies of one number's calls. Emergency location and public alerts finds a person who dials 112, and warns every phone in an area before a cyclone. Operator-branded cloud storage is photo and file storage that the operator offers under its own name.
Brands that sell mobile plans on another operator's network are called MVNOs. They own no towers, but they still need their own BSS, so many of them rent it from a software company.