Answers
How Does Wholesale Roaming Settlement Work Between Operators?
When a subscriber roams, the visited network carries their traffic and later charges the subscriber's home operator for it. The visited operator records the usage, prices it at the wholesale rates the two operators agreed, and sends the records to the home operator, traditionally as TAP files through a data clearing house. The home operator checks the records, bills its own subscriber, returns any it rejects, and pays the visited operator. Payments between operators are usually netted through a financial clearing house, so each pair of operators settles one balance rather than every invoice separately.
GSMA's newer Billing and Charging Evolution (BCE) standard is changing this model, moving from record-by-record exchange to settlement on aggregated data. Most operators run both today.
The parties involved
Operators can exchange files directly, but most use clearing houses because each operator has hundreds of roaming partners.
| Party | Role |
|---|---|
| Home operator (HPMN) | Owns the subscriber. Receives the charges, bills the subscriber, pays the visited operator |
| Visited operator (VPMN) | Carries the roaming traffic. Records and prices it, invoices the home operator |
| Data clearing house (DCH) | Receives, validates, converts and forwards usage records between operators |
| Financial clearing house (FCH) | Nets amounts owed in both directions and handles invoicing and payment |
TAP settlement, step by step
Alongside this, operators exchange near real-time roaming data for fraud control, because TAP files can arrive too late to stop a compromised SIM running up large charges.
- Usage recorded. The visited network produces records for the roamer's calls, SMS and data sessions.
- Wholesale pricing. The visited operator prices each record at the agreed inter-operator tariff.
- TAP file created. Priced records are packed into a TAP file, the GSMA format for exchanging roaming usage between operators.
- Clearing. The data clearing house validates the file and delivers it to the home operator.
- Validation and billing. The home operator checks each record, rates it at the subscriber's retail roaming price, and bills the subscriber.
- Rejections. Records that fail validation, for example unknown subscriber, duplicate or late, are returned in a RAP file. The visited operator corrects them or accepts the loss.
- Financial settlement. Invoices are raised for the agreed period, amounts owed both ways are netted, and the balance is paid.
Discounts sit outside TAP
TAP records carry standard inter-operator tariffs. Most operator pairs also have discount agreements: volume tiers, commitments, or flat rates. Those are calculated and settled separately, often once per agreement period, by comparing the TAP-based totals against the agreed terms. Discount settlement is where large amounts get disputed, because it depends on both sides agreeing on the underlying volumes.
What BCE changes
BCE was introduced by GSMA as a replacement for TAP, built for 5G and IoT roaming. Instead of charging every roaming event separately, it settles on aggregated usage data.
The practical differences:
- Aggregated settlement. Operators exchange usage and charge reports rather than every individual record.
- Flexible periods. Operators can settle monthly, quarterly, annually or on bespoke terms, without rigid file exchange windows.
- Commercial models built in. Discounts and newer charging models are part of the process instead of sitting outside it.
- Structured reconciliation. A standard way to reconcile usage, charges, or both.
The migration is gradual
Because TAP is built into decades of legacy billing, operators have to keep supporting it for partners that have not moved, so the near future means running TAP and BCE side by side.
What this means for MVNOs
Most MVNOs are not direct parties to international roaming settlement. The host network holds the roaming agreements, settles with foreign operators, and charges the MVNO for its subscribers' roaming at the rates in the wholesale contract.
That still creates MVNO-specific work:
- Late usage. Roaming records can reach the host days after the usage, and the MVNO later still. Prepaid balances and usage alerts may lag behind real roaming usage.
- Invoice checks. The MVNO needs its own view of roaming usage to check the roaming lines on the host's invoice.
- IoT permanent roaming. IoT devices deployed abroad on a home-country profile roam permanently, which some visited networks restrict and price differently.
Related Pages
FAQs
What is the difference between TAP and RAP?
TAP files carry roaming usage from the visited operator to the home operator. RAP files go the other way, returning records the home operator rejected, with the reason.
Who sets wholesale roaming rates?
The operators, through bilateral roaming agreements. Some regions regulate them. In the EU, for example, wholesale roaming charges between operators are capped by regulation.
Why do operators use clearing houses?
Scale. An operator with hundreds of roaming partners would otherwise need hundreds of direct file exchanges, format checks and payment relationships. Clearing houses centralise validation, conversion and netting.