We are in an era of new networks that we loosely term next-generation networks. Data traffic in these networks is equal to or surpassing voice as the most mission-critical aspect of the network. Remember that when all the traffic is ones and zeros, everything is data, and voice is just another data application. Integration of voice, data, and video without protocol conflicts greatly simplifies the migration of legacy communication systems and network applications to next-generation transport technologies. The undeniable appeal of interactive multimedia applications, content, and programming also signals the need for a convergent infrastructure that offers minimum latencies to ensure the responsiveness that customers need.
Traffic is growing at an alarming rate. More human users, more machine users, and more broadband access are all contributing to the additional traffic. Established carriers and new startups are deploying huge amounts of fiber-optic cable and wireless broadband, introducing new possibilities, and optical technology is revolutionizing the network overall. This new era of abundant capacity stimulates development and growth of bandwidth-hungry applications and demands service qualities that can allow control of parameters such as delay, jitter, loss ratio, and throughput. Bandwidth-intensive applications are much more cost-effective when the network provides just-in-time bandwidth management options. Next-generation networks will provide competitive rates due to lower construction outlays and operating costs.
Converging Public Infrastructures
Public infrastructures are converging on a single set of objectives. The PSTN looks to support high-speed multimedia applications, and therefore it also looks to provide high levels of QoS and the ability to guarantee a granular diversification of QoS. The PSTN has traditionally relied on a connection-oriented networking mode as a means of guaranteeing QoS, initially via circuit switching and now incorporating ATM as well.
The public Internet is also intended to support high-speed multimedia applications, and it must deal with providing QoS guarantees. But we are investigating slightly different options for how to implement this in the Internet than in the PSTN (see Chapter 8, "The Internet and IP Infrastructures"). Included in the IETF standards are Integrated Services (IntServ), Differentiated Services (DiffServ), and the new panacea, Multiprotocol Label Switching (MPLS), all of which are described later in this chapter.
Broadband Service Requirements
For next-generation networks to succeed, they must offer a unique set of features, including the following:
A number of developments have been key to allowing us to deliver on this set of requirements. One important area is photonics and optical networking. Chapter 11, "Optical Networking," describes the revolution that started with the ability to manufacture glass wires; went further to introduce erbium-doped fiber amplifiers (EDFAs); grew to encompass Wavelength Division Multiplexing (WDM), Dense Wavelength Division Multiplexing (DWDM), and Coarse Wavelength Division Multiplexing (CWDM); and is proceeding to introduce new generations of high-performance fiber, reconfigurable optical add/drop multiplexers (ROADMs), optical cross-connects, optical switches and routers, and the optical probes and network management devices that are very important for testing networks. We're looking forward to a future of end-to-end optical environments.
A number of broadband access technologies, both wireline and wireless, have been developed to facilitate next-generation networking. Chapter 12 covers these options, which include the twisted-pair DSL family; hybrid fiber coax (HFC) alternatives that make use of cable modems; fiber-to-the-node and fiber-to-the-home/fiber-to-the-premises; broadband wireless, including direct broadcast satellite, Wi-Fi, and WiMax; Free-Space Optics; and innovative new uses of powerlines to support high-speed communications. As discussed later in this chapter, multiservice core, edge, and access platformsincluding the IP Multimedia Subsystem (IMS), multiservice provisioning platforms (MSPPs), and the MPLS architectureare being developed.
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