What ERP Owns in a Telco
Last updated 12 Oct 2026
At a glance
An ERP is the system of record for the company’s money and physical goods: ledger, payables, fixed assets, build projects, purchasing and device stock. It does not own customers, offerings, orders, services, resources or usage. Most confusion about ERP in a telco comes from expecting it to do BSS work.
The picture
BSS and OSS own the customer side. ERP owns the company’s money and goods. They meet at a few crossings.
BSS / OSS: the customer
- Customer, account
- Product offering (catalog)
- Product, service and resource orders
- Services and network resources
- Usage, rating, invoices
Who they are, what they bought, what they owe
Crossings
BillingLedger
Summarised journals
CPQ, COMStock
Device stock and cost, reservation
Resource inventoryFixed assets
Reconciliation of the same network
The asset register and resource inventory drift: a fourth truth, finance truth
ERP: the company
- General ledger, close, consolidation
- Payables and procurement
- Fixed assets and build projects
- Stock of handsets, SIMs, CPE, spares
- Budgets, tax ledgers
Holds a debtor reference at most, never the customer master
How it works
Two different jobs
CRM, CPQ and Billing deal with the customer: who they are, what they bought and what they owe. An ERP deals with the company: its books, what it buys, what it holds in stock and what it owns. In a telco the two meet at a handful of points.
Twelve capability areas
The table uses Microsoft Dynamics 365 Finance and Supply Chain Management as the reference (now called the finance and operations apps). SAP S/4HANA and Oracle Fusion Cloud ERP cover the same ground under different names.
| Capability area | Role in a telco |
|---|---|
| General ledger, close, consolidation | System of record for the books of every legal entity in the group |
| Tax | Owns tax ledgers and returns; tax on the customer invoice is usually calculated by billing |
| Accounts payable | Supplier, dealer-commission and interconnect payables |
| Accounts receivable, credit, collections | A design choice; consumer receivables usually stay in billing (7.3) |
| Fixed assets and leases | The financial record of the network: towers, fibre, equipment |
| Project accounting | Network rollouts and builds (7.5) |
| Revenue recognition | The accounting view of revenue under IFRS 15 / ASC 606 (7.4) |
| Budgeting and cost accounting | Budgets, cost centres, overhead allocation |
| Procurement and sourcing | Suppliers and procure-to-pay |
| Inventory and warehouse | Stock of handsets, SIMs, CPE and spares, and its value |
| Transportation and landed cost | Device logistics and field spares only |
| Asset management (maintenance) | Overlaps OSS and field service for passive infrastructure such as towers and power |
The one path that faces the network
Of the twelve, only one has a substantial link to the network: network-build project → fixed asset → depreciation. The asset register records cost, book value and a depreciation profile. It does not hold topology or capacity; the working element lives in resource inventory. The two drift apart, which adds a fourth truth to the billing, service and network truths that already diverge: finance truth.
Who owns what
| Entity | System of Record | System of Engagement | System of Reference | Notes |
|---|---|---|---|---|
| Chart of accounts, ledgers | ERP | — | — | The books of each legal entity. |
| Suppliers, purchase orders | ERP | — | Field service, OSS projects | — |
| Stock of devices and spares | ERP (inventory and warehouse) | — | CPQ, COM | Quantity and value. The serial number of an assigned device also lives in resource inventory. |
| Fixed asset (financial view) | ERP | — | Resource Inventory | The network element itself is owned by resource inventory. |
| Customer | CRM / party management | — | ERP (debtor record, if any) | ERP holds a reference, never the master. |
| Invoice and usage | Billing | — | ERP (summarised journals) | — |
| Product offering, order, service | Catalog, COM, SOM | — | — | Not ERP data at all. |
In practice
Where BSS and OSS come from a different vendor to the ERP, the boundary is an integration to be designed. The capability list is the same across SAP, Oracle and Microsoft; what differs is how far a vendor reaches into billing and receivables (7.7).
The trade-off
What it solves
Drawing the line at money and goods gives finance one book per legal entity and keeps subscriber-scale work in the systems built for it.
What it does not solve
- Reconciliation. The asset register and resource inventory still describe the same network differently.
- Receivables. Both billing and ERP can hold them, and the choice still has to be made.
- Customer master. A debtor record in ERP still has to be kept in step with CRM.
What it adds
- A fourth truth, finance truth, beside billing, service and network truth.
- Interfaces across the boundary that no TM Forum Open API standardises in full.
Architecture decision
How far should ERP reach into the customer side?
ERP owns money and goods only
Choose when BSS already handles customers, invoices and receivables at subscriber scale, and finance needs balances rather than per-invoice detail.
ERP also owns receivables or invoicing
Choose when the operator runs an ERP-native high-volume subledger or convergent invoicing and wants receivables and ledger on one platform.
Breaks if ERP is treated as a second customer master. Two customer records drift, and invoices, credit decisions and collections stop agreeing.
Takeaways
Key Takeaways
- ERP owns the money and the physical goods: ledger, payables, fixed assets, projects, procurement, stock and warehouse
- It does not own customers, offerings, orders, services, resources or usage
- Its one real link to the network is the capital path from build project to fixed asset
- That asset register has to be reconciled with resource inventory, or finance truth drifts from network truth
Check yourself
A programme proposes making the ERP the customer master because it already holds debtor records. What do you say?Show answerHide
The customer is owned by CRM or party management. ERP may hold a debtor reference for finance, but making it the master puts subscriber-scale customer data in a system built for the company’s books and creates a second customer truth.
An auditor asks which network equipment sits behind a fixed asset. Which systems do you need, and why might the answer be slow?Show answerHide
ERP for the financial asset and resource inventory for the elements. They are kept by different teams at different granularity, so unless a shared asset reference exists and is reconciled, matching them is manual work.