11 March 2025
# How real-time OLI verification lets you decide the level of wholesale voice risk YOU want to accept
We can’t really frame the conversation without defining some basics. When a call is made, it contains, as signals, vital information: for our purposes, we’re most interested in the stuff that identifies:
- **who’s calling** the OLI (Originating Line Identity) which can also be labelled the CLI, Calling Line Identity, or the A-number, or even calling number delivery (CND), calling number identification (CNID), calling line identification presentation (CLIP), and call display
- **who’s being called** which can also be referred to as the B-number or the TLI, the Terminating Line Identity.
Now, not so surprisingly, to protect consumers in many countries, surcharging is applied if the OLI is invalid – which has a direct impact on your bottom line. You want to protect your reputation as a reliable, reputable supplier and avoid unforeseen costs in the form of those surcharges.
But there are various definitions of what number invalidity actually is! The problem is compounded by the fact that most telcos obtain new numbers either from blocks that have been reserved for them by the regulator, or, historically, by appending extra digits to older, shorter ones—so you can’t know if an OLI is valid unless you can ‘see’ the number block and so do a straightforward “prefix plus length” lookup.
So, you just must have that detailed number block data. But here it gets even messier; because it’s as important to identify a given number as *invalid* as it is confirming it is *valid*, most numbering data sets out there—rather than positively identifying a number as invalid—default to fitting a number into the closest matching block.
This requires a different approach to numbering intelligence. All this is made even more complicated by the fact that, as stated, different countries have different or slightly different rules on network and presentation numbers and how they must be handled in the signalling validity rules.
In the UK, for instance, all numbers have to be in the National Numbering Scheme and shown to be valid in the National Telephone Numbering Plan (see [here](https://niccstandards.org.uk/wp-content/uploads/2019/09/ND1016-v4.2.1.pdf)), and no matter how suspect it might be OLI-wise all attempts to contact Emergency Services must be put through. In the US, you have to be compliant with the [Federal Do-Not-Call Registry](https://www.federalregister.gov/documents/2003/07/25/03-18766/rules-and-regulations-implementing-the-telephone-consumer-protection-act-tcpa-of-1991), and so on.
There are many rules regarding network and presentation numbers and how they must be handled in the signalling, not all of which is your problem; the ultimate responsibility for checking the OLI rests with the originating service provider. But anyone else involved in the handling—like the voice wholesaler--must check the validity of the information provided.
The way the industry has dealt with that is to try and work with as much data as you can get from the phone companies or regulators about valid number block ranges. But obviously, there will be gaps, and you may well have to do that for multiple countries and regions; numbering intelligence in many platforms is just cumbersome, typically requiring an extra call to a third-party service and routing manipulation based on clearing cause.
That’s very far from what you really want-- real-time OLI verification so you can just get on with either connecting or blocking calls. But Digitalk voice customers can now do that automatically, thanks to our strategic alliance with, after extensive research of the market, the genuine world leader at all this: a specialist in number validation called [XConnect](https://www.xconnect.net/solutions/traffic-validation-and-optimisation).
## The XConnect approach to real-time OLI verification
We’ve been working together since the Summer (though we [only formally announced our tie-up in September](https://www.digitalk.com/blog/digitalk-carrier-cloud-integrates-xconnects-global-number-range-service)) to embed its software into Carrier Cloud—work which has now been completed. And what’s clever about the XConnect’s solution to the scattered data problem has been serious work and investment in compiling a global, aggregated number intelligence dataset.
The benefits are obvious. Take your OBR business: if you can confirm CLIs are valid, you don’t have to worry about unplanned OBR penalty surcharges; if you can analyse A- and B-numbers in flight, you can by the same token correctly assign OBR surcharge rules for voice rating and routing. And if you can now identify and block calls with invalid CLIs before they become a problem.
When it comes to fraud, you can now reject all invalid numbers, so not just spoofer ones but ones from unallocated or non-dialable ranges, or incorrect digit length; block or accept traffic based on potentially fraudulent CPN/CLI modification; build advanced risk scores based on origin, destination and call agent privileges, and much more (as is now the case is [Digitalk 6.3](https://www.digitalk.com/carrier-cloud/carrier-cloud-resources/articles/carrier-cloud-release-6-3-brochure)).
How does this tie into risk management? As Digitalk Carrier Cloud uses this data set to perform real-time OLI verification as standard now, this means that wholesale carriers like you can determine the level of risk on which you want to operate your business.
Do you want to pass on all cleared calls, reject them, or automatically flag that a number is incomplete or invalid in the rating records? Whatever you choose, you can rate or route calls differently and do things like charge more for invalid records, for example, or test the presentation identity and fall back to network identity if necessary—and much more.
And as all this is now incorporated directly into Carrier Cloud’s Interconnect configuration, you can use Carrier Cloud to perform a validity check and block unwanted traffic as a single configuration option when managing an interconnect – in real-time.
Lots of good things drop out from that; because we have checked against the integrated XConnect database (which we automatically update), we can also report automatically on origination, protect sensitive customers by checking the reputation of suppliers (or building your own score, e.g., how many invalid numbers do they send to you? OK, charge them more!). Or help your partners: Are too many invalid numbers being sent to them by this carrier? No problem, offer them a more reliable source of traffic.
You can also enhance your own reputation as a carrier by rejecting invalid numbers, etc. Real-time OLI verification really does open both safety for you and genuine revenue opportunities; to find out more, [contact us today](https://www.digitalk.com/contact) to see how.
## FAQ
- What is OLI verification in wholesale voice?OLI (Originating Line Identity) verification is the process of checking whether the calling number on a voice call is valid, dialable, and from an allocated number range. It helps wholesale carriers identify and block invalid or fraudulent calls before they cause problems.
- Why does invalid OLI matter for wholesale voice carriers?If a call carries an invalid OLI, surcharges can be applied in many countries, directly hitting a carrier's bottom line. It can also damage your reputation as a reliable supplier if invalid traffic is passed on to partners or customers.
- How does Digitalk handle real-time OLI verification?Digitalk Carrier Cloud integrates directly with XConnect's global number intelligence dataset to perform OLI verification in real time as part of standard interconnect configuration — no extra calls to third-party services or manual routing manipulation required.
- What can wholesale carriers do with real-time OLI data?Carriers can choose to block, pass, or flag invalid calls; charge differently based on validity; build custom risk scores by supplier; protect downstream customers from bad traffic; and report automatically on call origination — all within Carrier Cloud.
- How does OLI verification help with fraud prevention?It allows carriers to reject calls from unallocated, non-dialable, or incorrect-length number ranges, block suspicious OLI/CLI modifications, and build advanced risk scoring based on origin, destination, and call agent behaviour.
- What countries and regulations does this cover?The XConnect dataset covers global numbering intelligence, including country-specific rules such as the UK National Telephone Numbering Plan and the US Federal Do-Not-Call Registry, helping carriers stay compliant across multiple regions.
---
**Share this post**
[  ](https://www.digitalk.com/javascript:copyToClipboard();)
[  ](https://www.digitalk.com/javascript:window.open("https://twitter.com/intent/tweet?url="%20+%20document.location.href))
[  ](https://www.digitalk.com/javascript:window.open("https://www.facebook.com/sharer/sharer.php?u="%20+%20window.location.href))
[  ](https://www.digitalk.com/javascript:window.open("https://www.linkedin.com/sharing/share-offsite/?url="%20+%20document.location.href))