Mobile voice VPN – past, present and future

Mobile Voice VPN – past, present and future

Mobile voice VPN is where things really got going for our team, way back in the 1990s. And, it turns out, it’s a key part of our future – and yours. What is mobile voice VPN and why does it still matter?

What is mobile voice VPN?

A mobile voice VPN - or virtual private network – is itself a derivative of an old concept, the Closed User Group, or CUG. CUGs have long been used in voice services, because they allow a group to be created and for interaction to be enabled within the group. Members can reach each other via the use of special short codes, bypassing the normal routing procedures and allowing the use of more memorable numbers.

When mobile networks came along, the concept was transferred to GSM systems, but of course, the mobile dimension had to be considered, as group members might be connected to any of the available cells. As a result, CUGs morphed into an IN-based supplementary service, which allows the group to use the same features, but in a mobile environment.

From this, it was a short hop to full mobile voice VPNs. These were typically offered to companies, enabling them to use internal dialling schemes over public networks. Companies that had adopted in-house PBX systems could easily extend the internal call plan to include what were then mobile devices. The beauty of a true mobile voice VPN solution was that it worked over 2G, so there was never any need for a dedicated data connection. The control was handled by servers in the network and users could be members of multiple groups and sub-groups, all controlled by the service logic.

Gintel was an early pioneer of such systems, ensuring full compatibility with the required number plans, backed by the flexibility to customise solutions for different environments.

Why does mobile voice VPN remain so important?

Today, fewer and fewer companies use in-house PBX systems, but even though many have moved these to the cloud, they still use mobile voice VPN solutions to ensure that mobiles can be reached within corporate networks. We have millions of active mobile voice VPN users, which we support through our operator customers.

It’s surprising to many that such an apparently basic service endures, but it does because:

  • It’s extremely useful to companies, particularly with today’s suddenly distributed workforce
  • That’s because it works, on any generation of mobile network – so even if a company does adopt a cloud IP-based PBX solution, they can still ensure that mobiles are included in numbering plans and remain part of the corporate voice network, without the need for a data path to a mobile.
  • Even though LTE is widespread, mobiles can be reached on 3G or even 2G, if there are coverage gaps
  • It generates revenue for mobile operators

Of course, even if in principle it is simple, in practice, almost every mobile voice VPN is different. That’s where the flexibility of our solution comes in handy, because we can customise each solution we deliver to the specific needs of each operator. This has been particularly important when we replace legacy platforms, because the service must continue, seamlessly. No-one really wants to change services that have been delivering for years.

A mobile voice VPN is also a core functional component of a more sophisticated system, such as a mobile PBX, because the same principles are used to create teams and groups within an organisation, and to activate other terminating or originating call features. So, they continue to be highly relevant.

Will mobile voice VPN be relevant in the 5G era?

But, what does the future hold for mobile voice VPN, as we race towards the 5G era? Well, this is a topic in which we investing considerable research, in conjunction with institutions such as NTNU and our operator partners. It turns out that, the ability to configure groups and to coordinate calling within the group and to external, non-members, is likely to become fundamental to many new services in 5G, particularly when we consider network slicing.

A network slice is essentially a private network. While a slice may be offered for a specific suite of functions – wireless process automation on an oil rig, for example – but clearly, once such a slice has been established, there is the potential to provide more capabilities. One such is voice, with a dedicated corporate network within the slice. As we’ve written before, what happens when a user moves outside of the slice domain and into a region that is not covered? This is where mobile voice VPN, backed by roaming procedures for moving from non-public networks (NPNs) to public networks (PLMNs) has a role to play.

Mobile voice VPN to serve new segments and new opportunities

Similarly, the creation of dedicated telemedicine and healthcare services will also demand functionality that is enabled through the deployment of – perhaps specialised, but none-the-less recognisable – mobile voice VPN functionality. One relevant and current example that could evolve in a 5G context is found in a country served by one of our operator customers.

Here, there is a special access code to enable cardiac specialists to be reached. The service allows authorised users (it’s not a public service) to contact any member of the group, but they will be routed to the closest available member. This combines mobile voice VPN with location services to ensure constant access to specialist help across that country’s health service. The current solution is based on fallback to 2G or 3G procedures, but we’re upgrading it so that it can function in VoLTE (there being no specific equivalent VoLTE service, so we’re making it so). It’s easy to conceive of this working on 5G, within the specific slice allocated to one hospital, but with breakout to slices in others.

So, we think mobile voice VPN, while a venerable service, has a lot more mileage in the tank. Not only does it remain a key standalone offer, it has a strong role to play as a component or enabler in other services, which will need new orchestration and coordination techniques. If you’d like to know more about how we are enabling operators to evolve their mobile voice VPN offers and how we can help you transition to the next generation, please get in touch.

VoLTE, Voice VPN, PBX, 2G, Voice Virtual Private Network, 5G

Want to learn more about Gintel?