We are several years into the 5G era, and attention is focused on the significant benefits and new service opportunities 5G brings to Communication Service Providers (CSPs). These advances stem from standards organizations expanding mobile networks’ role beyond voice, text, and basic data.
5G introduces a new way of designing communication networks and enables services that require precise location, very low latency, ultra-reliability, and high bandwidth for consumer and enterprise applications. Network slicing makes it possible to create customized virtual “mini-networks” tailored to the needs of individual businesses. Achieving this required major changes to network architecture over many years, including a redesign of the network core.
Early communication networks relied on a single monolithic switching system to handle voice calls. Over successive technology generations, the trend has been to break the network into clearly defined, standardized network functions that interact via data messages using standardized protocols. As the number and variety of network functions grows, the messaging between them becomes increasingly important and critical for correct network operation. This system of message exchanges and protocols is referred to as signalling—it functions as the nervous system of the 5G core.
Signalling is central to a CSP’s business success. With the right signalling framework, CSPs can realize superior performance, high network reliability, and rapid business agility. The wrong approach can block new revenue opportunities, cause poor performance, or in the worst case trigger network-wide outages.
Signalling shouldn’t be an ‘add on’ in your 5G deployment
The key 5G network function that provides a robust signalling architecture is the Service Communication Proxy (SCP). Much like an Ethernet switch connects multiple devices, the SCP creates a hub-and-spoke topology for network functions, with the SCP serving as the hub. It supports the Service Based Architecture by managing interactions with the Network Repository Function (NRF), allowing a new network function to discover and connect to its environment instead of being manually provisioned.
A 5G network can be deployed without an SCP by manually provisioning direct connections between each network function and the others it needs to communicate with. While this mesh approach may work for very small deployments, it quickly becomes complex and costly to operate as the network grows. Most CSPs recognize they will need an SCP eventually to manage this complexity.
The strategic choice is whether to deploy the SCP at the start of a standalone 5G core implementation—accepting a higher initial cost—or delay deployment and pay more over time. In many cases, deploying the SCP up front lowers total cost of ownership (TCO) because it reduces integration, debugging, and ongoing operational burdens.
Integration costs: Every signalling link between two network functions requires integration by the services team. Differences in protocol implementations—especially across vendors—must be discovered and resolved. In a full mesh, the number of integrations grows rapidly with each type of network function, often resulting in hundreds of pairwise efforts. With an SCP in a hub-and-spoke topology, each function integrates only with the SCP, dramatically cutting deployment effort and cost.
Debugging effort: When issues arise during deployment, operators need visibility into signalling messages to diagnose problems. Since signalling links are typically encrypted, probes must be placed at endpoints to inspect traffic. Without an SCP, many probes are necessary; when an SCP is present, a single probe at the hub can expose signalling across the core, simplifying troubleshooting.
Message mediation: Even standardized protocols can be implemented with subtle differences. An SCP that can modify messages in transit provides a pragmatic way to reconcile mismatches without changing network functions themselves. This capability lowers integration costs and shortens deployment timeframes. In mesh deployments, the only alternatives are modifying individual network functions or requesting vendor patches, both of which are slower and more expensive.
These advantages continue through the operational life of the network. Integration remains simpler when introducing new functions or applying software updates, problems can be diagnosed quickly through centralized visibility, and message mediation helps operators fine-tune behavior without disruptive changes to network elements.
Delaying signalling strategy or treating it as an afterthought exposes CSPs to avoidable costs and risks. From a TCO perspective, investing in an SCP at the outset is typically the more cost-effective path.
Three fundamental signalling characteristics
If you include an SCP from the beginning, what should you look for? Network architecture always involves trade-offs, so it’s important to prioritize key requirements. When designing 5G signalling, CSPs should focus on three essentials: flexibility, performance, and cloud-native design.
Flexibility means the signalling layer must be able to observe, control, and adapt all parts of a 5G core in a vendor-agnostic way. Operators need the ability to fine-tune operations and resolve unexpected issues. Because no CSP can predict every problem in advance, the SCP needs a highly adaptable message filtering and policy system that can be updated as requirements evolve.
Performance requires low latency and high throughput across diverse service scenarios. Scalability—upward and downward—is essential to accommodate traffic changes and cloud elasticity. Message filtering and mediation must operate at line rates so they do not become bottlenecks for real-time signalling traffic.
A cloud-native design is vital in the era of web-scale infrastructure. Signalling should be software-based and architected to run on private, public, or hybrid clouds, leveraging cloud-native principles such as containerization, microservices, and orchestration. Because many 5G benefits depend on web-scale patterns like service-based architecture, a signalling system that is not cloud-native will struggle to deliver those advantages.
Start your 5G strategy the right way
No matter which network strategy a CSP adopts, implementing a signalling strategy at the outset of a 5G project delivers clear benefits: service-specific signalling controls, faster core integration, reduced risk of outages, simplified operations, and lower overall TCO.
Starting a 5G rollout with an upfront signalling plan helps CSPs avoid unexpected operational complexity and cost, enabling them to bring new 5G services to market faster and with higher quality.
(Photo by Tobias Cornille on Unsplash)
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