A UK-based voice carrier needed a way to rapidly protect its margins from surcharges based on invalid A-numbers. As significant increases in surcharges came to the UK, it had to find a solution for validating A-numbers in weeks, not months. The carrier was forced to quickly adapt to surcharges being deployed on both fixed and mobile calls or face maximum charges being applied to their UK voice traffic.

It needed a simple and efficient voice and management solution that pre-validated A- and B-numbers, saving on costs in surcharges and helping it to maximise its margins. While Origin Based Rating (OBR) and other surcharges have been common in markets like Germany and Spain, the UK has emerged as the latest destination to see surcharges grow significantly. Unanticipated surcharges can be as much as 10x the cost of a call, with some even reaching 500x the standard termination rate.

The carrier selected XConnect’s Global Number Range (GNR) data to seamlessly validate A-numbers and ensure it has predictable margins. It worked with XConnect’s expert team and was able to begin validating numbers in days.

The Challenge

A fixed line carrier in the UK notified local carriers that it would begin to apply a maximum surcharge on any voice traffic with an invalid A-number. The result of this would mean losses of margin in an already challenging market, or the blocking of traffic to the UK. Either way, the carrier would be losing out on opportunities to deliver traffic in the UK profitably.

It needed a way to pre-validate A-Numbers and proactively block invalid traffic with precision. The business could not tolerate false positives or risk relationships with its customers or partners. It needed a way to deliver traffic in the UK with confidence and limit its exposure to surcharges.

The challenge was to roll this out within a week and ensure that it was delivering pre-validated traffic to its UK carrier partner with no disruption to its business. It needed a solution that wouldn’t take a lot of development internally or require large integrations with existing platforms. For the solution to match its needs, it had to be effective and simple to deploy.

The Solution

It chose XConnect’s GNR data delivered via SIP API. The API-based solution enabled the carrier to rapidly expand its use of number intelligence and pre-validate phone numbers via a simple SIP invite sent to XConnect. This enabled the carrier to leverage XConnect’s numbering data, which has been refined over decades and is used by some of the largest and most innovative carriers in the world.

No software development or large-scale integrations were required, meaning that the solution could be deployed quickly and immediately deliver return on investment. The carrier can pre-validate all of its voice traffic to both UK fixed and mobile users and ensure that it does not face the new surcharges. It has also reduced the chances of disputes with its local partners, while preparing for similar surcharges to be rolled out in other countries.

XConnect’s GNR data and SIP API are carrier-grade and scalable to support billions of minutes per month. It has a track record of successfully delivering 99.999% accuracy when returning queries to its database.


  • Predictable Margins

The carrier limits its exposure to surcharges and removes the potential for bill shock when delivering UK traffic.

  • Increased Profitability

The carrier no longer has to block potentially valid traffic and risk losing out on legitimate business.

  • New Visibility

The carrier gains control over the traffic it carriers and has visibility into the legitimacy of the traffic that is being sent to it by partners or customers.

  • Fewer Disputes

The carrier can avoid costly and time-consuming disputes with customers and partners and focus on its core business.

  •  Rapid Deployment

The carrier was able to solve an immediate challenge and threat to its business in days instead of weeks, with an API-based approach.

  • Expert Support

The carrier gains a long-term partner that can advise on mitigating losses from surcharges in the UK as well as markets across the globe.

“The UK is an example of just how fast surcharges can be implemented and the rules of the game changed. Pre-validating A-Numbers has become essential for delivering voice traffic on both fixed and mobile networks and ensuring margins are protected. Organisations that take action now will see the benefits in the UK over the coming months, but they’ll also be ready for other surcharges to be implemented in markets across the globe.”

Eli Katz, Founder and CEO, XConnect

Find out more

You can work directly with XConnect or with one of our platform partners who integrate and utilise XConnect’s GNR data for number validation and surcharge control and mitigation.