Case Study: Cadenza

Introduction

Architected the backend and database for a new voice network management application (Cadenza), designing a complex schema that enforced business rules to prevent data collisions and creating a single source of truth for all SIP/TDM circuits.

The Business Challenge: Modernization for Survival

The company's core challenge was significant and unnecessary expenditure tied to its legacy telecommunications infrastructure. A large voice network of traditional, high-cost TDM private wires represented a potential saving of over £250,000 annually. The critical task was to migrate these circuits to modern, cost-effective SIP connections to realize these savings and improve cash flow. While an initial migration effort had already saved £100,000, the process was clearly not fast or efficient enough to save the business.

The Old Way: Spreadsheets and Manual Risk

The migration process was hampered by a fragmented and manual workflow. Circuit data was tracked across various spreadsheets, with a separate Access database likely monitoring costs. Crucially, the prevention of service-disrupting data collisions and number replication relied on painstaking manual cross-referencing. This approach was not only a significant time sink but also introduced a high risk of errors that could impact clients and delay cost-saving efforts.

The Solution: A Single Source of Truth

Cadenza solved the core problem by creating a robust, centralized "single source of truth." The solution's foundation was a meticulously designed database schema that leveraged a combination of SQL unique and check constraints to programmatically prevent data collisions and enforce business logic at the database level. In the application layer, C# pure functions were used to process data consistently and predictably. This architecture made it impossible to create the duplicate or conflicting entries that had plagued the manual spreadsheet system.

Beyond just tracking circuits, Cadenza was designed to be a comprehensive model of the entire voice network ecosystem. This was achieved by mapping the relationships between three core entities:

• Assets: These represented the physical and virtual hardware that powered the voice network. This included specific gateway devices like an iG330 or Cisco 2951, each with a defined capacity of TDM trunks and channels, as well as software services like the "Speakerbus iCS" VoIP PABX.
• Data Centers: These were the physical locations housing the voice network Assets, allowing for a clear geographical and infrastructural overview.
• Dial Plans: This defined the logical routing structure, assigning specific number prefixes to customer endpoint locations (on-net) or to third-party providers like BT or Cloud9 that served as connection points (off-net).

By linking every connection to a specific Asset, which in turn was located in a Data Center and governed by a Dial Plan, Cadenza created a holistic and easily searchable view of the entire operation.

A Guided Workflow for Circuit Provisioning

Cadenza transforms the complex task of provisioning a new circuit into a simple, wizard-like process, ensuring data integrity at every step.

• Step 1: Initiation. The process begins on the Private Wires dashboard, where a user clicks "Add Private Wire." The system immediately generates a unique Private Wire Reference and a SIP URI, establishing a foundational record.
• Step 2: Defining Endpoints (Forks). With the base record saved, the user defines the connection's endpoints by adding "On-Net" or "Off-Net" forks, selecting the customer, the specific gateway Asset, and the TDM channel, all while the system validates the choices in real-time.
• Step 3: Validation and Activation. After defining the circuit's endpoints, the user adds the final commercial details, such as the Billing Customer and Activation Date. Once activated, the circuit becomes a live, tracked part of the voice network.

Full Lifecycle Management

Cadenza's role extends far beyond initial setup; it provides a secure framework for managing the entire lifecycle of a circuit while maintaining data integrity.

• Configuration Locking: Once a private wire is activated, its core configuration is locked down. Attempting to alter a key field on a live circuit presents the user with an explicit warning to prevent accidental changes.
• Decommissioning and Resource Management: To decommission a circuit, a user simply enters a Disconnection Date. Once this date passes, Cadenza's backend logic automatically releases the associated TDM channels and trunks, making those valuable assets available for reuse.
• Comprehensive Audit and Version History: The History Page provides a complete and granular audit trail. An administrator can see a chronological list of every change made to a circuit, with each entry acting as a clickable snapshot of the circuit's state at that specific point in time.

Business Impact and Conclusion

The most significant impact of Cadenza was the dramatic acceleration of the company's core cost-saving initiative. By replacing a slow, error-prone manual process with a guided, automated system, Cadenza streamlined the transformation of legacy TDM circuits to modern SIP connections. This not only sped up the realization of savings but also facilitated the removal of expensive, outdated hardware in favor of a more flexible and cost-effective in-house "software as a service" platform. Cadenza was, therefore, a pivotal tool in the company's strategic effort to modernize its infrastructure and reduce operational overhead.