How Network Operators are Implementing Steering of Roaming Solutions

As mobility increases, customers expect high-quality connectivity wherever they go. This puts pressure on telecom operators to provide stable roaming services and effectively manage roaming traffic. Steering of Roaming (SoR) enables operators to direct outbound roamers to preferred visited networks (VPLMNs). This solution helps telecom businesses meet commercial commitments, improve roaming quality of service (QoS) and control wholesale costs.

There are different ways to integrate SoR into telecom services. Read this article to explore recommended methods for implementing steering of roaming in operator networks.

SS7 and Diameter signalling steering

In legacy (2G/3G) and LTE networks, registration is driven by control‑plane signalling. SoR works by rejecting specific registration procedures so that the user equipment (UE) retries and eventually selects a preferred public land mobile network (PLMN).

In 2G and 3G (SS7/MAP-based) networks, steering is done primarily based on MAP UpdateLocation and MAP UpdateGPRSLocation messages. A SoR platform, based on its business logic and provided configuration, makes an autonomous decision on how to handle each registration request by either allowing it to proceed further or rejecting it with an appropriate network error code.

The method used in 4G/LTE (Diameter-based) networks is nearly identical. In this set-up, a SoR system receives Diameter Update-Location-Request messages and controls their flow by rejecting them to force a connection with the preferred network.

Other messages

Although location update requests are sufficient to implement active steering, it is often beneficial to include support of other messages in the system. They can either support steering, increasing its accuracy, or become the basis for developing value-added services like additional reporting or SMS Welcome triggering.

Over-the-Air (OTA) steering

While active (signalling) SoR provides bulletproof accuracy and immediate policy execution, passive, OTA-based steering enables steering functionalities without any negative impact on customer experience. This method is based on sending lists of preferred VPLMNs to SIM cards. When searching for a new network, a phone or other UE will compare results from the radio search with the list on the SIM cards and prioritize networks from that list. This way, mobile operators can connect roamers to their preferred networks without any signalling rejections. This allows for seamless network registration and reduces signalling load.

One drawback to this method is the lack of enforceability. This might result in lower steering accuracy (especially in roaming destinations with a low number of roamers) and increased risk of roamers getting into barred networks.

Implementing CSFB and OTA for better SoR consistency

The best results can be achieved by utilizing steering across multiple technologies. For example, Amplitiv’s Hybrid Steering approach merges 2G, 3G, 4G, 5G and OTA-based steering into one holistic platform where a single policy input results in automatically employing tools on all these layers.

Building a tool that will be able to steer all of that traffic together provides a great advantage but also comes with additional technical challenges that need to be addressed.

Combined attach registrations

On the signalling steering level, it is very important to ensure that combined attach registrations are permitted and not interrupted by the SoR platform. The SoR system needs to pro-actively monitor for potential combined attach cases and have a built-in logic for handling them from the start. The spread of VoLTE roaming diminishes the need for Circuit Switched Fallback (CSFB) but it’s unlikely that CSFB will disappear completely from the roaming environment anytime soon. That’s why maintaining its support remains fundamental.

Automated OTA roaming management

Some legacy roaming tools used by telecom operators are still dependent on manual management of OTA-preferred operator lists. This approach is not only inefficient but also prone to errors related to policy mismatch between active and passive steering as it requires manually aligning both policies upon any changes – either in policy or in roamer distribution.

As such, this method introduces a major vulnerability in steering accuracy as well as overall roaming continuity and stability.

It can be avoided by implementing modern steering solutions that fully automate policy adjustments as well as roamer distribution and the management of traffic spikes. A SoR system like that should be able to operate on a single set of business goals with capability to enforce them coherently across various technologies, including passive, OTA steering.

5G SA steering

5G SA roaming is still scarce today but when implementing a new SoR platform, covering 5G SA support is very important as part of the strategy to future-proof your systems and avoid costs of having to prematurely migrate to a newer system down the road when 5G SA roaming usage increases.

In terms of 5G steering implementation, the biggest technical question to answer is your steering method choice. 5G still supports the legacy approach to steering that is based on rejecting network registration requests. But it also introduces a new method, based on sending lists of preferred operators to the UE. Although the concept is similar to OTA-based steering discussed earlier, the difference here is that the list can be provisioned during the registration process itself and, more importantly, it is easily enforceable. SIM cards are programmed to expect this list and they’re obliged to follow the provided ruleset.

Effective steering of roaming implementation

Steering of roaming is an essential element of providing roaming services that meet customer expectations and demand for instant access, while limiting costs and ensuring service continuity. There are various methods of implementing steering – the strategy you choose will depend on the systems you use in your telecom business.

However, it’s important to keep in mind that telecom technologies continue to evolve. Your SoR solution should be able not only to address your current needs but also to accommodate future traffic to make your investment worthwhile. Traffic management, automation and monitoring capabilities are also useful features that will help you detect issues and ensure high service quality.

If you want to integrate SoR seamlessly, proven solutions like Amplitiv’s roaming offering can help you ensure the steering system fully meets your needs, technical requirements and industry standards. To get in touch with our telecom software experts, fill in this form. We’ll contact you to discuss how you can effectively implement steering of roaming in your company.

FAQ

How does implementing a steering of roaming solution benefit telecom operators?

SoR platforms enable mobile operators to move outbound roaming traffic to preferred networks. This improves quality of service and supports wholesale cost management.

How does Diameter signalling steering work?

In 4G/LTE (Diameter-based) networks, a SoR platform controls the flow of received Diameter Update-Location-Request messages by rejecting them, which forces a connection with the preferred network.

How does OTA steering work?

OTA-based steering is based on sending lists of preferred VPLMNs to SIM cards. When looking for a new network, a user device compares found results with the list on its SIM card and prioritizes networks from that list.