hardDesignCase StudySeniorStaffLead
Where does OSS end and BSS begin, and how would you break up a monolithic BSS without stopping the business?
OSS vs BSS architecture separates commercial systems such as catalogue, ordering, charging and billing from network systems such as inventory, activation and assurance. The boundary works because commercial products and network capabilities change at different rates.
6 min readUpdated 2026-08-15
Answer
Short answer
In telecom, BSS owns the commercial view: customer, product catalogue, orders, charging, billing and settlement. OSS owns the network view: inventory, activation, assurance, faults and workforce. The handoff is usually a service order, and decomposition should proceed by data ownership and customer cohort so live orders and bill cycles are not split.
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Likely follow-ups
- Which domain would you extract first, and what makes it a safer first cut than billing?
- How do you run old and new rating side by side without double-charging anyone?
- What do you do about the reports that read directly from the monolith's tables?
- When is the decomposition finished, and how would you know rather than assume?
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