XMission's Company Journal

The Rules of Local Number Portability


Local Number Portability (LNP): the process of taking your phone numbers with you when you go. Sounds simple enough. You move, or you get a new phone system, so you tell the new carrier what your numbers are,  they add them to the new system and you’re done. Right?

Well, no. Unfortunately, it’s almost never that simple. There are a series of often baffling and, on surface appearance, inconsistent rules and rapids that need to be carefully navigated in order to successfully port your numbers.

Why is it so difficult?
The truth is, some of these rules are here to protect you from your current carrier, who may not be thrilled that you are taking your service elsewhere. But there are also rules to protect the carriers from their customers, in case someone is trying to slip out of a contract or an unpaid bill.

But most of these rules exist to protect you and your phone number, and to verify your identity and authority to own and carry these numbers with you. These are federal regulations in place to protect the security of your phone calls.

Combined, porting rules can be confusing. But really, there are only a few standard errors that can stall your business’s LNP request. I’m going to tell you about a few and discuss how we get them fixed at XMission.

First, let’s define some acronyms, because no regulated service is complete without a small mountain of confusingly jumbled letters:

  • LNP Local Number Portability. This is the act of porting your numbers from one service provider, or carrier, to a new service provider or carrier.
  • BTN Business Telephone Number. This is essentially the account number of the business at the losing carrier. Often it is the same as the “main” number for the business, but not always. In some cases, you may not even know what it is.
  • LOA Letter of Authorization. This is the form you must fill out and sign that declares your intent to port the numbers from the current carrier to the new carrier. All the information on this form must exactly match the information on the old account.
  • CSRCustomer Service Record. This is the official billing record for your account at the old carrier, which includes the BTN, the account number, the service address, the numbers assigned to the account, and of course the account owner. All of this information must exactly match the information on the LOA for a new account to successfully port in your old numbers.
  • LSP Losing Service Provider, or the carrier from which you are porting out your numbers.

Now, let’s look at some of the errors often cited when LNP fails:

Address and Zip Code Mismatch
This is the most common rejection. But the name of this error doesn’t always reflect the underlying issue, which, rather simply, means that the address on the LOA you have submitted doesn’t match the address on the account with your current carrier.

  • How Do We Prevent it?
    XMission recommends that prior to filling out a new LNP form, you ask your current carrier for a CSR. If they will not provide a CSR (some do not or cannot), ask instead for the relevant porting data. Porting data is verified against this CSR data, so if the carrier reports it to you correctly, you should not have any porting problems.
  • So, How Do We Fix It?
    XMission will help you double check the address for mistakes. Is it possible the address the LSP is using is not current? Could the bill be going to a service location different than where the phones reside? Is the Zip Code incorrect? Check all of these things. If they appear to match, and no readily identifiable error exists, XMission will have you request a CSR from the LSP.

Incorrect BTN/ Porting Telephone Number Mismatch

This is the most common error, which means that the billing telephone number entered on the LOA form does not match the one on your account with the losing carrier. The BTN is often the same as the account number, and is often – but not always – the first, or “main” number on the account. Unfortunately, while this all sounds rather simple, it often is not. For example, here’s one critical issue: especially with VoIP carriers, it is increasingly common that your account may have more than one BTN, and in some cases your phone numbers may all have their own individual BTN.

  • How Do We Prevent it?As before, ask the LSP for a current customer service record and use that information to fill out your LOA. Optionally, inquire about the BTN information for all the numbers on your account.
  • So, How Do We Fix It?
    First, XMission will let you know if all or only some the numbers were rejected. Often we submit LNP orders for dozens of numbers, and just a few get rejected because they are actually under a different BTN. Once you know for sure what has been rejected, call the LSP and request either a full CSR or the BTN for those rejected numbers.Also, check internally. Sometimes business managers are unaware that they may have more than one telephone carrier providing services, which confuses the porting request process.

Partial Port
We see this error most commonly when the BTN of the existing account at the losing carrier is one of the numbers that is being ported away, but there are still remaining numbers on the account at that carrier. Let me explain that. For example, say you have a block of 20 numbers, and the first is the BTN on the current account. You decide to port your numbers away, but decide that you only need 15 of them, which includes current BTN. This would leave 5 numbers at the current carrier. But because you have requested to port away the BTN, the remaining service would have no BTN. The losing carrier will sometimes reject that port request until a new BTN has been established by the customer for the remaining service numbers.

  • How Do We Prevent it?Be aware. Are you intentionally leaving some numbers at the current carrier? If so, contact them first to ask if you need to make any changes to your account to support the LNP request. Optionally, you tell the winning service provider that you can request a termination of service for the remaining numbers at the time of port.
  • So, How Do We Fix It?XMission can resubmit the LNP forms and request termination of remaining services upon port if that is what you need. If other arrangements need to be in place, you will need to contact the LSP and follow their guidelines.

Pending Order on Account
Typically, this is just an “oops”. It can mean that an LNP request is already being processed at the losing carrier, which prevents any further orders. But it can also happen if an un-executed order exists at the losing carrier, such as a disconnect order or a feature change request.

  • How Do We Prevent it?Often this sort of rejection comes when more than one person at the business is working on the same thing and have placed conflicting orders. Also, XMission recommends that if you are leaving some service at the losing carrier, wait until the port is fully completed and verified, and only then shut off the remaining service at the LSP. This will prevent unexpected obstructions.
  • So, How Do We Fix It?Sometimes this rejection means that a recent order was canceled before completion, and the new order overlaps. The only way to know is to contact the losing carrier and ask what exists on your account that is preventing any new requests.

LSP Account Freeze

This happens more often than you would think. It means that the losing carrier has a hold on the account that prevents the customer from taking the service away until they are satisfied. There are many reasons they may and can do this, including but not limited to the threat of fraud or delinquency (you cannot port out numbers on an account that is not in good standing with the LSP). There are many less ethically challenged triggers as well.

  • How Do We Prevent it?XMission again recommends that you check with the LSP before you order an LNP request for new service.
  • So, How Do We Fix It?XMission can’t help on this one. This is a conflict between the customer and the losing carrier that must be resolved between the two. You will need to contact that carrier to identify the barrier and have it removed.


  1. Make sure you current voice account is in good standing with the losing carrier.
  2. Obtain a Customer Service Record from your current provider, or if one is unavailable, request “porting data”.
  3. Pay attention to the numbers! Be aware of your current BTN and how that may affect the order.
  4. Ask you XMission account representative for help. That’s what we’re here for!

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2 thoughts on “The Rules of Local Number Portability

  • Jesse Harris says:

    Number portability is restricted in other ways too. You cannot move a VoIP number to a landline (as I found when switching from Vonage to Comcast). Some providers in rural markets (such as Frontier Communications in Tremonton) are not obligated to honor portability requests.

  • Rich says:

    One of the reasons I’m still paying $25/month for XMission Voice is due to the fact I cannot port my home number straight over to Google Voice. I would have to port twice (once over to a mobile buerner number then over to Google Voice). Wish XMission would offer a slightly lower price point other than the $25/month for VoIP since Google Voice currently offers their service for free!