Service providers face increasingly complex challenges in turning an 'empty network' into one that is efficiently delivering VoIP services, without a slow and complex process of manual service provisioning - these challenges are particularly acute when serving enterprise customers. In response, service providers are investing in more integrated and automated VoIP delivery processes that provide a coherent model of subscribers and services. These integrated systems also help to meet the customer demand for more sophisticated self-service portals that provide a complete view of services and users, including automated service activation.