Modern telecom operators are gradually transitioning from monolithic systems to modular architecture. This accelerates innovation and prepares infrastructure for autonomous networks. However, integrating new cloud services with legacy BSS/OSS systems remains a major business challenge.
Transition to Open Digital Architecture and 3GPP standards
To overcome the limitations of proprietary systems, the industry is adopting TM Forum's Open Digital Architecture (ODA) framework. It replaces monolithic BSS/OSS with a component-based, API-first architecture. Using Open APIs allows decoupling business logic from technical network details.
In parallel, the network Core is evolving. In accordance with 3GPP standards, modern networks are built on Service-Based Architecture (SBA) principles. Migrating to cloud technologies to support 5G Standalone enables the deployment of network functions as independent services.
Legacy integration and security
Since an overnight rip-and-replace of legacy infrastructure is impossible, operators require a reliable integration layer. An example of addressing this challenge is using the UnityBase platform (jointly developed by Intecracy Group and InBase). The platform enables the creation of flexible data buses that connect legacy system logic with modern API contracts.
Modernization also brings security risks. According to the ENISA Threat Landscape 2025, the exploitation of legacy signaling protocols (SS7, Diameter) remains a threat to mobile networks. Furthermore, a CFCA study estimates global telecom fraud losses in 2025 at $41.82 billion. To protect signaling channels, operators are recommended to implement Zero Trust models and strict microservice authentication.
Telecom architecture maturity levels
To assess infrastructure status and plan migration, operators use four levels of technological maturity:
- Level 1: Monolithic. Tightly coupled BSS/OSS and physical infrastructure.
- Level 2: Hybrid. Partial virtualization and API implementation for new services.
- Level 3: Service-oriented. ODA component architecture, Open APIs, and containerization.
- Level 4: Cloud-Native. Cloud 3GPP SBA core, auto-scaling, and end-to-end orchestration.
Implications for business
Failure to modernize legacy BSS/OSS systems limits an operator's ability to launch new 5G services quickly, while maintaining outdated signaling protocols exposes networks to severe security vulnerabilities and financial risks, with global telecom fraud projected to reach $41.82 billion in 2025. Conversely, transitioning to modular, cloud-native architectures enables rapid innovation and prepares operators for autonomous networks.
How to respond
- Assess your current infrastructure using the four telecom architecture maturity levels to plan a gradual migration.
- Adopt TM Forum's Open Digital Architecture (ODA) and Open APIs to decouple business logic from network details.
- Implement a reliable integration layer, such as the UnityBase platform, to connect legacy systems with modern API contracts without a risky rip-and-replace.
- Secure signaling channels against threats by implementing Zero Trust models and strict microservice authentication.
Prepared by a Software Ukraine member. Original publication.