sensitive applications such as voice or video. IP technologies have since been enhanced to support these and other real-time communications. Many companies apply IP as a "do all" protocol, using it to provide voice, data and video services. Generally these services, though based on IP, never touch the public Internet due to reliability and security concerns. IP traffic is instead carried on private networks, similar to the Internet from a technology perspective, but able to provide superior service. Several backbone providers have built national IP networks. From a service point of view, they are almost indistinguishable from other backbone providers, many of which use a mix of technologies from traditional circuit switches to ATM to IP, except that they have adopted IP-only strategies. Regardless, they provide long haul, high capacity transport services over their optimized IP networks. These IP backbone carriers have helped spawn a new generation of IP service providers which can, for example, offer customers a single, high capacity IP connection, such as DSL service, to provide traditional products. They might offer multi-line voice, for instance, but will use IP-based serving equipment rather than more expensive and complex circuit or ATM gear. IIC BUSINESS MODELS Providing an "exact" definition of an IIC is difficult because change defines an IIC. The key to what makes an IIC is that it provides some The Ultimate Guide to Building and Delivering OSS/BSS physical component of the Internet or Internet-related networks or services. An array of business models thus falls under this definition. These models, taken in turn, provide strong, practical examples of what constitutes an IIC in its many forms. Today's network landscape is shifting from a formerly voice-centric world to one where data traffic dominates. As a result, many new IICs emerge and older IICs reinvent themselves to meet new, shifting demands. Similarly, application services, brought to market by a new generation of application-based IICs, are com