lled out in the Modified Final Judg- ment were implemented on January 1, 1984. The 22 Bell telephone companies were merged into seven Regional Bell Operating Companies (RBOCs). The RBOCs were allowed to sell local and toll calling within the 197 defined local or in-state Local Access And Transport (LATA) areas. They also retained the Yellow Pages. AT&T retained manufacturing and inter-LATA (primarily interstate) and international toll calling. Part III Wide Area Networks and the Internet Chapter 4 Carrier Networks Chapter 5 Broadband and Wide Area Network Services Chapter 6 The Internet This page intentionally left blank Carrier Networks In this chapter: The Public Network Long-Haul Networks: The Core Technologies Used in Carrier Networks Convergence in Core and Metropolitan Networks Transporting Movies and TV in the Core Middle-Mile Networks Last-Mile Access Networks Access Networks in Cable Operators' Networks Telecommunications Services in National Emergencies Signaling Summary Appendix Carrier Networks Carriers are striving to streamline functions to save money on labor and equipment costs, and to increase productivity while upgrading networks to carry additional traf- fic. Upgrading networks, while costly, simplifies the tasks of carrying mixed types of traffic including analog telephone, Internet, high-definition television (HDTV), and movies. Through these improvements, carriers can manage all of this varied traffic by using the same multipurpose equipment and management software. Simplifying network structures saves money on staffing. This is because fewer technicians and engineers are required to manage, maintain, and install software and equipment. Certain installation functions that formerly required multiple trips to a site by a technician can now be performed remotely, cutting down on technical staff visits. Moreover, customers can now make changes to enterprise services via web interfaces that in the past needed to be made by technicians. In addition, there are fewer types of maintenance software wi