CONVERGENCE BETWEEN PUBLIC SWITCHING AND THE INTERNET

In recent years the Internet has developed into a global data network that is highly accepted as a multimedia information platform which has the potential to develop into an alternative carrier network in the f uture. Telecom operators increasingly act as Internet service provider s to maximize network utilization, to attract or retain customers, and to generate additional revenue. To leverage their installed base in t he PSTN/ISDN the optimal strategy for telco ISPs is the integration of their point of presence into the central office: packetizing and groo ming of in traffic in the local office relieves load on the PSTN/ISDN trunk network, resolves existing bottlenecks due to Internet traffic u pstream of the CO, and creates new opportunities for revenue-generatin g features for both telephony and Internet subscribers. This article i ntends to show that current telecommunication network elements can be upgraded with innovate rutting-edge technology to build a solid basis for a seamless multimedia network of tomorrow, thereby enabling teleco m operators' and service providers' tremendous investment in existing network infrastructure to be fully utilized. An integrated Internet se rvices platform is presented which turns the CO switch into an optimiz ed link between the PSTN/ISDN and the Internet. Technically. it is pro posed that the central office be expanded with an integrated Internet PoP (IPOP) configured from the following IP components: an internal hi gh-speed data backbone (ATM or Ethernet); modem pools to terminate dia l-in calls from analog modems using the PPP protocol; protocol handler s for UDP, TCP, IF, and lower-layer data protocols (X.25, frame relay, SMDS, etc.); access to data networks; IP router, RADIUS server, and n ame server database; a contents server (optionally), enabling telco IS Ps to become content providers. This effectively turns the CO into an Internet access point that integrates smoothly into the existing telco OA&M/TMN. Investment in additional hardware is minimized, and the exi sting subscriber line and network infrastructure is completely reused. The IP functions integrated in the IPOP can interwork closely with PS TN/ISDN call processing. This is a prerequisite for the creation of ne w revenue-generating features such as supplementary PSTN/ISDN services for Internet calls, voice over IF, IF-activated dialing, and value-ad ded Internet services (on-screen call-waiting indication, near-real-ti me bill viewing, etc.). As the demand for high-bandwidth subscriber ac cess increases, existing line concentrators can be upgraded with wideb and line cards. High-bandwidth IP traffic may be groomed in the concen trator and multiplexed directly on the high-speed (ATM. Ethernet) back bone network. The great benefit of an integrated approach is that the evolution from lower to higher bandwidth is smooth and as the market r equires, thus guaranteeing the balance between necessary investment an d revenue. This integrated approach is illustrated in this article by means of a concrete example using a state-of-the-art CO switch.