S8HR – Faster Path to VoLTE Roaming, but not Without Challenges

With 46 operators having commercially launched VoLTE-HD voice services in 29 countries and more than 117 operators investing in VoLTE*, VoLTE roaming has become a major focus of mobile operators’ attention. Many are involved in discussions about Local Breakout (LBO) and S8 Home Routed (S8HR) roaming models that are ongoing within the GSMA and 3GPP standards and specifications communities.

S8HR, which uses the LTE S8 interface for transporting VoLTE traffic between the visited and home network as data traffic, has recently gained momentum. The main reason is that S8HR implementation is simpler to implement than LBO, resulting in faster time to market for global VoLTE roaming deployment. Unlike LBO, S8HR does not require IMS in the visited LTE network and therefore IMS interoperability testing is not required between the home network and each visited network. This significantly simplifies implementation. Although the GSMA continues to identify LBO as the default roaming model, many mobile operators eager to bring VoLTE roaming to market quickly are considering adopting S8HR first.

While S8HR does simplify VoLTE roaming implementation, it also presents many challenges resulting from several technical gaps that have been identified by the GSMA. For example, not all services normally provided by the visited network can continue to be provided with S8HR. As previously mentioned, the visited network in S8HR does not use IMS, therefore, the visited network is not service aware. As a result, it cannot support Lawful Interception and non-authenticated user emergency calling for visiting end users. In many countries Lawful Interception and emergency calling for visiting end users are required by local regulators.

Another challenge is end user experience in situations of 4G handover to legacy 2G/3G, enabled by SRVCC/eSRVCC. Because all visiting end user calls in S8HR go back to the home network for routing, the SRVCC/eSRVCC signaling to initiate the handover also goes back to the home network. This can result in significant handover delay and “dead air” time for the end user.

The technical gaps of S8HR, identified by the GSMA, are detailed in the GSMA’s S8 Home Routed VoLTE Roaming Technical Report, dated April 2015. These gaps, plus other technical and commercial gaps, are summarized in the tables at the end of this article.

As part of our standard VoLTE roaming offerings, iBasis supports both the S8HR and LBO roaming models. In addition to standard VoLTE offerings, iBasis has enhanced solutions that address challenges in both roaming and interworking. The GSMA is working on solutions to overcome the S8HR challenges they have identified. However, this effort could take a year or more. iBasis offers solutions today that allow mobile operators to address the challenges sooner rather than later. At iBasis, we understand the importance of time to market. Therefore, our goal is to provide solutions that enable mobile operators to quickly and confidently deploy S8HR and assist them on their path to global VoLTE roaming.



* Global mobile Supplier Association (GSA), January 25, 2016

** Not identified by GSMA in S8 Home Routed VoLTE Roaming Technical Report.

Back to the Future: Why an Industry Pioneer Decided to Bring Wholesale Voice Back into Focus

Why an Industry Pioneer Decided to Bring Wholesale Voice Back into Focus

The market has spoken: Wholesale is here to stay. In decline? Unquestionably. But with more than 30 billion minutes in 2015, making up 20% of the international voice market, those players who dare stay in the game will continue to reap the rewards of their perseverance.

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You Can’t Fix What You Can’t See.

Up to 50% of your subscribers are in possession of a 4G handset but do not have an LTE subscription or do not have access because of incorrect provisioning. But, you can’t fix it because you don’t know it. In fact, you can’t see it. Our new analytics monitoring solution, iBasis InVision, helps you turn this roaming challenge into active 4G roamers and additional roaming revenues.

“You can’t manage what you can’t see” is a popular axiom at the foundation of iBasis roaming management strategy: maximize visibility across all networks.

The InVision Opportunity Identifier, a new module within the InVision platform, enables you to quickly identify subscribers who own a 4G handset but either don’t have an accompanying LTE subscription or do have one, but were incorrectly provisioned in the system – depriving the user of LTE services for which he/she is paying and very possibly leading to an unhappy customer.

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RCS – Getting A Bigger Audience

61% of MNOs rated RCS combined with VoLTE as a top new opportunity, according to March 2015 Ovum survey. 87 operators in 32 countries are expected to have launched RCS by end of this year, according to GSMA.

RCS (Rich Communication Suite) is a GSMA initiative supported by leading service providers to accelerate the adoption of applications and services that provide an interoperable, convergent, rich communication experience based on the IMS core. The combination of RCS and VoLTE can bring new opportunities for mobile operators. It enables them to upgrade current service offerings to provide customers a richer experience.

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Reality Check: Managing GRX/LTE Migration Smoothly with Guided Execution Plan

At first sight mobile operators can be afraid of transitioning to the new LTE/IP core network and feel they don’t have time for adding such complex operations to their tight schedule. That’s why the iBasis engineering and operation teams have developed a migration guide to facilitate the transition of services and share with mobile customers their roaming & interworking knowledge to support them through the whole process.

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Surviving Summer Roaming Traffic Jams

Better yet, avoid traffic jams by staying up to date on traffic trends and planning in advance the summer “Black Saturdays” high peak roaming traffic in Europe and ensure service continuity.

During the summer, iBasis experienced 8 to 10 fold increase in the number of unique roamers and of LTE signaling traffic compared to last year especially we observed tremendous spikes in roaming traffic during the summer “Black Saturdays” – the weekends marking the highest travel periods in Europe.

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Don’t Miss the Keynote Address at Carriers World

Willem Offerhaus, iBasis CEO, will deliver the keynote address on Tuesday September 29th at 9:10 AM titled “Keep calm and carrier on: The journey of wholesale carriers”

Topics to be covered include:
• What’s Now — what are consumers and enterprises doing?
• What is the impact on international carriers and operators?
• What’s Next — the international carriers “To-do List”
• The evolving role of wholesale carriers in the global IP ecosystem


Be sure to attend the Carriers World Awards event on September 30, 2015. iBasis is pleased to be named a finalist in three of the award categories:

  • Best IPX Provider,
  • Best Security/Fraud Solution Provider, and
  • Best Messaging Solution.