Evolution of MNP Routing in Hybrid Networks
The development of 5G Standalone networks and cloud architectures is forcing telecom operators to modernize their mobile number portability (MNP) routing mechanisms. Traditional monolithic BSS/OSS systems are being replaced by modular, API-driven solutions to eliminate call setup delays and reduce signaling load.
In global practice, there are two main routing methods:
- Indirect Routing: the call first goes to the donor operator, which redirects the traffic to the recipient operator, creating additional load on the channels.
- Direct Routing: the operator queries its local copy of the ported number database (LNPDB) and routes the call directly. This method requires instant synchronization with the central state MNP registry.
Limitations of Legacy SS7 and Diameter Protocols
Traditional networks rely on SS7 (2G/3G) and Diameter (4G/LTE) signaling protocols. According to the ENISA Threat Landscape 2025 report, the exploitation of these legacy protocols poses ongoing security risks. In addition to vulnerabilities, legacy signaling creates the following infrastructure limitations:
- Latency: additional queries increase call setup times.
- Scalability challenges: expanding capacity requires specialized hardware and licensing.
- Low flexibility: systems are difficult to integrate with cloud services.
Transition to API-First and TM Forum ODA Standards
To bridge the technological gap, the industry is adopting TM Forum's Open Digital Architecture (ODA) standards. This approach replaces monolithic BSS/OSS with microservices. In 5G Standalone networks, core elements interact with MNP databases via HTTP/2 APIs instead of Diameter, enabling in-memory caching and millisecond query processing.
According to the CFCA Global Fraud Loss Survey 2025, telecom fraud losses in 2025 are estimated at $41.82 billion. Transitioning to an API-first architecture allows for strict query authorization, traffic encryption via TLS, and seamless integration with anti-fraud systems.
Implications for business
The transition to API-first MNP routing directly impacts operational efficiency, security, and customer experience. Operators relying on legacy signaling face increased latency, high scaling costs, and vulnerability to telecom fraud. Adopting modern standards allows telecom providers to mitigate security threats, reduce call setup times to milliseconds, and integrate seamlessly with cloud services and anti-fraud systems.
Migration Strategies and Technological Solutions
A complete replacement of the network core is risky, so operators are deploying hybrid API gateways that translate legacy queries into modern API requests. For voice traffic management and flexible routing, solutions such as the DooxSwitch VoIP platform from the Intecracy Group consortium are used, supporting LCR routing and integrating via open APIs.
To automate administration and synchronize local databases with MNP registries, solutions based on the UnityBase low-code platform are applied. It uses a single metadata model to generate REST APIs, while its Enterprise and Defence editions provide row-level security (RLS) and detailed activity auditing, which is crucial for registry protection.
How to implement MNP routing when transitioning to 5G Standalone?
In 5G Standalone, core elements query ported number databases via HTTP/2 APIs within a service-based architecture (SBA), allowing these nodes to be deployed as microservices.
How to avoid delays when synchronizing with the central registry?
An API-first approach with in-memory caching on the operator's side is used. The local database synchronizes with the central registry asynchronously via secure web services, eliminating any impact on the call setup process.
How to prepare
To successfully modernize MNP routing, telecom operators should take the following practical steps:
- Deploy hybrid API gateways to translate legacy queries into modern API requests, avoiding the risks of a complete network core replacement.
- Utilize modern VoIP platforms like DooxSwitch to manage voice traffic and support LCR routing via open APIs.
- Leverage low-code platforms such as UnityBase to automate administration, synchronize local databases with MNP registries, and secure data with row-level security.
- Implement in-memory caching and asynchronous synchronization with central registries via secure web services to eliminate call setup delays.
Prepared by a Software Ukraine member. Original publication.