Service providers are in the midst of a gradual evolution from circuit-switched to IP-based packet-switched infrastructures. IP is attractive for two main reasons: cost savings and revenue. Carriers expect operational and infrastructure savings from deploying new IP-based services because they believe that implementing applications on IP networks will be much less expensive than running them on circuit-switched networks. In addition, every carrier is looking for new ways to enhance its service suites, which are rapidly becoming commodities.
The evolution to IP-based infrastructures means more shared networks. Because IP emphasizes logical over physical connections, IP makes it easier for multiple carriers to coexist on a single network. This encourages cooperative sharing of interconnected networks, structured as anything from sales of wholesale circuits to real-time capacity exchanges. It also means increased competition because there are reduced barriers to entry; new companies can enter the market without the huge fixed costs associated with traditional network models.
Most of the evolution so far has taken place in the transport and access parts of the network and in the development of IP infrastructure elements, such as gateways, softswitches, and the IP Multimedia Subsystem (which is discussed in Chapter 10, "Next-Generation Networks"). The market for next-generation IP application services is beginning to take shape, and IP-based application servers have been developed to deliver actual revenue-generating services for carriers.
The problem is that IP has been positioned as a magical potion that will cure everything, and the industry has suffered from too much hype and wishful thinking. Equipment and service providers have been guilty of promoting such thinking, claiming that their products can enable multiple new services without clearly identifying just what those new services will be. While there are indeed very good reasons to transition to IP, it is important to be realistic and pragmatic about them. The migration to IP is not without risk. In terms of the IP application services market, two key questions need to be answered: Will the quality of the real-time services over IP be good enough in the next few years to drive carriers and customers to switch? To what extent will enterprises take advantage of their existing IP infrastructure and data communications expertise to implement their own services, thus avoiding additional service provider charges?
Traditional Internet applications, such as e-mail, Telnet, FTP, and the World Wide Web, are referred to as elastic applications because they are tolerant of network delays and packet losses. Unlike those applications, advanced real-time applications are highly sensitive to timely data delivery. Quality of service (QoS) is the most important obstacle for the Internet and IP networks to overcome, especially in light of the growing use of voice and video. As QoS emerges within the Internet, the ability to differentiate services will result in differentiated pricing. QoS capabilities will allow revenue-generating service levels to be implemented and service-level agreements (SLAs) to be negotiated.
The ability to control and manage a network effectively will allow the creation of value-added services and packages. Providing value-added IP services implies increased attention to tools and equipment that help service providers succeed. These include software that gives service providers greater network control and visibility; intrusion prevention systems that support always-on stateful inspection (i.e., a form of stateful inspection that provides cumulative data against which subsequent communication attempts can be evaluated and acted on in real-time) and deep packet analysis capabilities; software that can deliver flexible bandwidth; tools that offer granular analysis of bandwidth consumption by customers; and tools that enable creative solutions that reduce costs, such as the robots from CityNet Telecommunications (www.citynettelecom.com) that string fiber through sewers at a fraction of the cost of digging up city streets to lay the fiber.
Value-added IP services allow carriers greater differentiation from their competitors. Evolving next-generation IP services include IP virtual private networks (VPNs), IP telephony (IPT) and Voice over IP (VoIP), IP centrex and IP call centers, application hosting, mobility management/follow-me services, unified messaging, instant messaging (IM), presence management, Video over IP, IP television (IPTV), and different types of conferencing, including audioconferencing, videoconferencing, and Web/data conferencing. As carriers consolidate and wireless broadband networks are deployed, a major challenge will be developing viable business models to market, bill, provision, and provide excellent customer care for all these services.
Many incumbent carriers are choosing to initially implement IP-based services on an overlay network. Carriers that take this approach do not have to replace circuit-switched network elements, which usually have minimal ongoing operational expenses. In an overlay network scenario, the packet-switched network is isolated from the circuit-switched network, and the two are connected via a gateway.
Part I: Communications Fundamentals
Telecommunications Technology Fundamentals
Traditional Transmission Media
Establishing Communications Channels
Part II: Data Networking and the Internet
Data Communications Basics
Local Area Networking
Wide Area Networking
The Internet and IP Infrastructures
Part III: The New Generation of Networks
Broadband Access Alternatives
Part IV: Wireless Communications
Wireless Communications Basics
WMANs, WLANs, and WPANs
Emerging Wireless Applications