Local number portability (LNP) is the ability to keep an existing phone number when moving service from one phone provider to another, as long as the new provider can serve that number’s area. In practice, “porting” is the process: the new provider submits a request, the old provider validates and releases the number, and the network’s routing records are updated so calls to that number reach the new provider. For businesses, porting is what makes it practical to change carriers, phone systems or UCaaS providers without reprinting every number customers know.
At a glance
- LNP lets you keep your phone numbers when you switch providers, within the limits of where the new provider can serve them.
- The new (gaining) provider manages the port; the old (losing) provider validates the request and releases the numbers.
- Most delays come from mismatched account details, so the request should match the old provider’s records exactly.
- Keep the old service active until the port completes; cancelling first can lose the numbers.
- Toll-free and international numbers follow their own processes, and rules differ by country.
What problem it solves
Phone numbers are part of a business’s identity: they are on websites, invoices, signage, directories and customers’ contact lists. If changing providers meant changing numbers, few businesses would switch, and providers would have little reason to compete on price or service. Number portability removes that lock-in.
In the US, portability between local providers has been required for many years, and regulators in many other countries have adopted their own versions. For buyers, it is the reason a move to SIP trunking, a hosted PBX or UCaaS can keep the same main number and direct inward dialing (DID) numbers.
How it works
Authorization. You sign a letter of authorization (LOA) allowing the new provider to request the port on your behalf. The request lists the numbers, the current provider, the account number, the authorized name and the service address, plus a port-out PIN or passcode where the old provider uses one.
Validation. The old provider compares the request with its customer service record (CSR). Any mismatch, such as a different suite number or business name, can lead to a rejection and resubmission. Requesting the CSR before submitting saves time.
Firm order and scheduling. Once accepted, the port is given a confirmed date and time. For large or multi-site ports, many providers schedule a coordinated cutover, sometimes outside business hours.
Activation. On the port date, routing databases are updated so the network sends calls for those numbers to the new provider. In North America this relies on shared number portability databases that carriers query to route calls correctly. Inbound calls may briefly reach either provider while changes take effect, so both services should be ready.
Simple and complex ports. Single lines without special features are usually simple. Ports involving many numbers, several locations, number ranges used by a PBX, or lines with special services are complex and take longer.
Wireless and fraud protection. Mobile carriers often require port-out PINs or allow port freezes to reduce fraudulent ports, and some regulators have added protections against this kind of fraud. Business mobile accounts may need an account administrator to approve a port.
When it matters for buyers
- When changing carriers, phone systems or UCaaS providers, since porting is often the longest lead-time item.
- When consolidating several providers onto one, with different account details at each.
- When a provider exits a market or is acquired, and numbers need to move.
- When numbers are tied to old accounts or former employees, which complicates authorization.
- When a CLEC or reseller holds your numbers through an arrangement you don’t fully know.
Questions to ask vendors
- Can you serve every number we want to port, including toll-free, fax and any numbers in other countries?
- Who prepares the LOA, and will you review our customer service record before submitting?
- What intervals do you expect for our simple and complex ports, and how do you handle rejections?
- Will you schedule a coordinated cutover, and who is available on cutover day?
- How do we test inbound and outbound calls and 911 on ported numbers before and after the port?
- If we leave you later, how do we port our numbers out, and are there any fees or restrictions?
- How will our emergency calling location records be updated for ported numbers?
How it differs from toll-free number porting
LNP covers geographic numbers that are tied to a local area. Toll-free numbers in the US and Canada are managed through a separate central registry, and moving one means changing the organization that manages it in that registry, often called a RespOrg change, rather than a local port. The paperwork looks similar, but the process, timing and rejection reasons differ.
If you are changing voice providers and want help sequencing number moves, see our SIP trunking solution page.