There are two important aspects to be considered related to the introduction of IP in wireless and cellular networks:
IP services have been introduced in cellular networks (e.g., GPRS) as described in other chapters of this book. Provisioning of IP connectivity and IP services is currently supported mostly through mechanisms designed specifically for cellular networks (e.g., for mobility management), and in some cases IP is used as transport (e.g., GPRS). The introduction of IP mechanisms to support provisioning of IP services and the migration toward more complex IP services (e.g., multimedia services through SIP) in future IP wireless networks represents a significant disruption in the concepts and technology used in cellular networks. An important issue to be considered in this framework is the transition between current networks to future IP wireless networks. Network operators and service providers have made large investments in terms of network infrastructure, licenses, and service agreements for current cellular networks. Therefore, it is to be expected that the introduction in cellular networks of any IP-based disruptive technology is justifiable only by a high rate of growth in the demand for data and IP multimedia services. A low growth rate for data services will push operators toward the introduction of new services to attract more users while at the same time minimizing the modifications to the network infrastructure. On the other end, a high growth rate for data and multimedia services will lead operators to choose more aggressive solutions to allow more advanced and appealing IP-based services and solutions to optimize provisioning of IP-based services. Network operators will therefore need to develop strategies to cope both with low and high growth rates for data services, allowing both for slow evolution of their networks and aggressive modifications to the network based on disruptive solutions. Smooth evolution and disruptive evolution are transition issues to be considered. In this scenario, the issue of transition between current networks and future networks is twofold:
In conclusion, particular attention needs to be placed on the technical solutions adopted in IP wireless networks for support of new services and for the evolution to new network architectures in order to guarantee that any evolutionary or disruptive step will allow for backward compatibility. |