SEPP, SCP and IWF: The Building Blocks of 5G SA Roaming

3GPP specifies that high-performance 5G SA roaming services require Security Edge Protection Proxy (SEPP) and Service Communication Proxy (SCP) components. Additionally, an Interworking Function (IWF) provides a critical transitional component, bridging older network generations and modern 5G SA cores.

Global adoption of 5G Standalone (5G SA) has not been slow. Currently, there are 1.7 billion 5G SA connections. Six years after 4G’s launch, only 15% (1 billion) of all connections were 4G.

Arguably, the deployment of 5G SA by big operators is putting pressure on competitors to follow suit. For example, Reliance Jio’s 5G SA core deployment covers over 7,700 towns and cities in India. Unless competitors adapt, they risk being labelled as outdated and unable to offer the revenue-generating opportunities of 5G SA.

As GSMA’s Mobile Economy Report 2026 outlined, simply having a 5G Standalone core isn’t enough. True value will come from capabilities, which raises the need for 5G SA roaming.

So, why are SEPPs, SCPs and IWFs fundamental to 5G SA roaming?

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SEPP: Security for 5G SA Roaming

A Security Edge Protection Proxy (SEPP) provides an initial trust boundary for roaming partners to establish secure 5G SA roaming connectivity. Inter-network communications are secured by the SEPP’s:

Mutual authentication.
End-to-end encryption.
Protocol compliance
Topology hiding.
Message filtering and normalisation.
Overload protection

SCP: 5G SA signalling management

A Service Communication Proxy (SCP) centralises signalling management and routing in the 5G core, enabling:

Streamlining complex routing.
Load balancing, throttling and filtering.
Message manipulation.

By centralising signalling management, an SCP reduces operational complexity and improves network efficiency and scalability. As network technologies like IoT and AI drive up network traffic, SCPs will become increasingly important.

5G IWF: Seamless Multi-Generation Network Roaming

The SVI-IWF HTTP-2 Interworking Function enables HTTP/2, Diameter, LTE and SS7 network interconnections. The 5G IWF provides comprehensive forward and backward compatibility, allowing:

Implementation of new revenue streams.
Extension of existing infrastructure lifespan.
Seamless multi-generation network connectivity.
Continuous billing across network generations.

“As network traffic surges, operators face increasing pressure balancing escalating infrastructure needs against consumer AI and IoT demands. Embracing 5G SA solutions seems inevitable. Identifying the best solutions to increase revenue and ensure network reliability and efficiency is the tricky part.”

Douglas Bryce, Marketing Communications Specialist at Squire Technologies

Find out more about Squire Technologies’ 5G signalling solutions here.