ABSTRACT
Service providers are in the process of transforming from legacy packet and circuit-switched networks to converged Internet Protocol (IP) networks and consolidating all network services and business units on a single IP infrastructure. The future users of communication systems will require the use of data rates around 100 Mbps in their homes while all the services and applications require high bandwidth. The next generations of heterogeneous wireless networks are expected to interact with each other and be capable of interworking with IP-based infrastructures. The requirements for Next Generation Networks (NGNs) lead to an architectural evolution that requires a converged infrastructure where users across multiple domains can be served through a single unied domain. Convergence is at the core of IP-based NGNs [1]. The aim of IP convergence is to build a single network infrastructure that is cost effective, scalable, reliable, and secure. The aim of standardization has been to enable a mix and match of services bundled to offer innovative services to the end users. Service enabler in this context is the approach to eliminate the vertical silo structure and to transform into a horizontal layered architecture. In a vertical silo approach, all the service components and architectures are designed for a specic service. Examples are security features, charging function, management, and policy enforcement modules. In this approach, the vertical elements are interrelated and tightly coupled and services can only be offered over a specic access network. In a vertical silo-based approach, the following issues exist. Maintenance and upgrade of individual components is difcult and it will take a long time for the system to be replaced, if needed. Other systems cannot take advantage of and reuse the data repository, functional elements, and policy designs that are deployed by other systems. Optimized designs and enhanced service performance cannot be integrated to other systems. This makes the systems isolated, hence difcult to integrate and this increases the capital and operational expenditures of new system deployment. Although the consolidation of IP core networks is advantageous, the business units and providers must have the exibility to securely manage their own IP networks.
