Telecom operators are at a pivotal juncture. Rapidly rising customer expectations, intensifying competition, and the rollout of technologies such as 5G, IoT and edge computing are transforming the industry and creating an urgent need for greater speed and flexibility. Yet, many communications service providers (CSPs) remain constrained by monolithic and rigid Business Support Systems (BSS) and Operations Support Systems (OSS), where even minor updates to services, processes or integrations can result in significant cost and delays.

These challenges have become a defining issue for the industry and in the sections that follow, we’ll explore how composable architectures are helping CSPs overcome them and regain agility. This shift toward modular, API-first and loosely coupled BSS/OSS systems is enabling CSPs to innovate rapidly, launch new services at digital speed, and scale efficiently. 

TM Forum’s Open Digital Architecture (ODA) provides a clear industry blueprint for this shift, defining the modular building blocks and open interfaces needed to replace monolithic BSS/OSS with flexible, composable systems.

Cerillion, with extensive experience in deploying composable BSS/OSS solutions for leading CSPs, provides practical guidance on how operators can modernise their systems without disruptive rip-and-replace projects. 

The Agility Challenge

Legacy BSS/OSS platforms were built for a time when service portfolios were predictable and network environments were stable. Today’s telecom realities are far different: rapid service innovation, intense partner ecosystems, regulatory complexity and dynamic enterprise demands. According to TM Forum, up to 72 % of 5G revenue growth is dependent on BSS/OSS transformation. 

While earlier research (such as TM Forum) suggested that a high proportion of 5G revenue growth depends on OSS/BSS transformation, more recent GSMA Intelligence analysis underlines that the real value of 5G lies in its role in enterprise digital transformation. GSMA projects that mobile technologies – 5G included will drive $11 trillion of economic value by 2030, and reports that around 85% of enterprises regard 5G as critical to their digital transformation strategies. 

As part of this evolution, ODA sets out a standardised architecture that helps CSPs break down legacy complexity by adopting interchangeable components, common data models, and certified Open APIs.

Telecoms industry spending trends underline the urgency: IDC forecasts that the combined telco software solution market will grow from $48.7 billion in 2024 to $60.4 billion in 2029. Such rapid expansion highlights why CSPs recognise that agility isn’t optional but essential for survival.

Composable BSS/OSS and Market Impact

Composable architecture replaces monolithic systems with modular, API-first components that can be developed, deployed and updated independently. This approach allows CSPs to assemble new services, such as an IoT device bundle and partner app, without waiting months for system upgrades.

The principles of composable architecture align directly with ODA, which promotes modular components, well-defined service domains, and open interfaces that can be assembled and evolved independently.

Composable design brings several key advantages. As each module of the system, whether it’s a product catalogue or order management component, evolves independently, businesses can respond more quickly. Open Application Programming Interfaces (APIs) connect partner services, network functions and business tools, ensuring every element works together seamlessly. This efficiency also allows business users to configure new offers without relying on IT, while cloud-native microservices enable continuous scalability and updates, without disrupting legacy systems. 

By building solutions that conform to ODA’s structure, operators ensure greater interoperability across partner ecosystems and avoid the vendor lock-in associated with traditional monolithic platforms.

According to HTF Market Research, the cloud-native telecoms market exceeded USD 10 billion in 2024, reflecting strong adoption of modern, modular architectures. The shift is more than technical; it’s strategic. Composable systems empower business teams, accelerate time-to-market and support legacy coexistence to manage cost and risk. In this context, Cerillion illustrates how legacy platforms can evolve into flexible, interoperable systems that enable rapid innovation without full-scale replacement.

Benefits Beyond Speed

Composable BSS/OSS delivers much more than just faster service rollout, including:

Reducing downtime and operational complexity.

Allowing business teams to experiment with new pricing, bundles and partnerships more easily.

Enabling third-party integration and ecosystem expansion via API-first platforms.

Adapting quickly to new business models or multi-brand operations.

Strategic Implications for CSPs

Aligning transformation roadmaps with ODA provides CSPs with a proven framework that reduces integration risk, accelerates onboarding of new partners, and ensures long-term architectural consistency.

Operators considering the composable route should pursue the following strategic actions:

Define business drivers and outcomes: Determine the agility and results needed, including faster service launches and ecosystem enablement, before selecting technologies.

Adopt an incremental approach: Modernise components gradually instead of pursuing risky full-scale rip-and-replace projects.

Promote business-IT collaboration: Enable business teams to configure services while IT ensures operational integrity.

Prioritise Open APIs, ODA and partner readiness: Ensure seamless integration with third-party services and ecosystem partners.

Measure success with relevant metrics: Track key indicators such as time-to-market, partner onboarding speed and operational efficiency.

Vendors such as Cerillion provide solutions aligned with Open Digital Architecture, API-first design and hybrid deployment that support agile evolution rather than disruption.

Legacy monolithic systems are no longer fit for the dynamic demands of today’s telecom environment. Composable BSS/OSS architecture offers a path to faster launches, empowered business teams and resilient, future-ready ecosystems.

Transformation is complex, but inaction could cost you missed revenue opportunities, slower growth and loss of competitive position. For CSPs, composable BSS/OSS is not optional; it is a strategic imperative. The responsibility of solution providers is to help operators progress, focusing on enhancement rather than constant disruption.