SIP reseller: porting a customer’s numbers is easy, getting the right name to show is not

A migration that looked finished

A small SIP trunk reseller moved about forty numbers for a customer from one upstream carrier to another. Porting went through, test calls connected, and the customer’s billing started on the new route. From the reseller’s side the job was done.

Two weeks later the customer rang up, irritated. Their outbound calls were arriving with no name at all on some networks, and with the previous carrier’s generic label on others. The business had spent years building recognition for its name on its customers’ screens, and it had silently gone.

Why it happens

The name shown on a call comes from a caller name database, and every carrier reads from its own copy. When numbers move, the old record can linger in one place, the new one can lag in another, and nobody gets an alert either way. The only way to find out what a recipient sees is to look at a recipient’s phone.

Making the check part of the handover

The reseller added a step to its porting checklist. After a number moves, it runs a CNAM lookup on each one and compares the result with the registered name. Anything that doesn’t match goes onto a list for the carrier to correct, with the output attached.

• Mismatches are caught in days, not when a customer complains.
• Carrier tickets arrive with evidence, which gets them handled sooner.
• The customer gets a short report on handover showing exactly how each number displays.

The owner says the report has become a small selling point on its own: other resellers hand over numbers, theirs hands over proof that the numbers look right.

Industry: telecom reseller · Use case: CNAM verification after number porting · Team: provisioning and support

If this is your team

Porting moves the number; it does not move the name. CNAM is looked up by the terminating carrier against its own database, so a customer’s business name that displayed correctly on the old carrier can show blank, stale or as the previous owner after the port. Run a free caller ID check on a sample of each ported range from handsets on the big terminating networks before you hand the batch back, and keep the screenshots with the port order.

Resellers who do this routinely add the check to the port completion checklist and rerun it a week later, because some CNAM databases refresh on a lag. If a customer also dials internationally, test from a handset in that country: routes into India and Nigeria rewrite the presented number more often than most teams expect, and that failure looks identical to a CNAM problem from the dialler side. See how the airline rebooking desk traced that kind of mismatch.