IP Services

This chapter discusses the evolution from circuit-switched to Internet Protocol (IP)based packet-switched infrastructures to support the variety of IP services in use today, including IP telephony (IPT), IP television (IPTV), and virtual private networks (VPNs). IPT involves the transmission of voice, fax, and related services over IP-based packet-switched networks. IPTV systems deliver digital television service to a subscriber, using IP over a broadband connection. VPNs are a critical requirement for businesses because they distribute mission-critical and sensitive traffic to remote locations; they offer networking security and performance comparable with that available at the office.