Overview
Wholesale voice termination is the business of carrying telephone calls from one network and delivering, or terminating, them on another. When a call needs to reach a destination a provider does not serve directly, it hands the call to a wholesale carrier that does. That carrier either terminates the call on its own interconnects or passes it to another partner, repeating until the call lands.
Termination is sold on an A-Z basis, meaning rates are published for every destination prefix in the world. Providers buy the routes they need and resell or use them to complete their own traffic.
How routing works
A call arrives at the carrier with a destination number. A routing engine decides which of several possible routes to use for that prefix, balancing price against quality in real time.
- Least-cost routing chooses the cheapest viable route for each destination.
- Quality-based routing prioritises answer rate, call duration and caller ID integrity.
- Most carriers blend the two, with automatic failover to the next best route if one degrades.
What makes a good route
Price is only half the story. The metrics that separate a premium route from a cheap one are measurable and worth watching.
- ASR (Answer-Seizure Ratio): the percentage of calls that connect.
- ACD (Average Call Duration): short durations can signal poor audio or fraud.
- PDD (Post-Dial Delay): the wait between dialling and ringing.
- CLI integrity: whether the caller ID is preserved end to end.
A cheap route with low ASR or stripped CLI often costs more in failed calls and lost trust than a premium route that simply works.
Choosing a wholesale partner
Look for transparent, real-time reporting on the metrics above, weekly rate decks so pricing stays current, fraud controls that protect both sides, and support from people who understand routing rather than a ticket queue.