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Chapter 11
Broadband Network Services: Frame Relay, SMDS, ATM, B-ISDN, and AINs

To be great is to be misunderstood.

—Ralph Waldo Emerson, Self Reliance, 1841

Broadband networks offer great potential. As emerging technologies, they also are greatly misunderstood, for which fact we authors, consultants, and lecturers are eternally grateful. (Hopefully, we foster understanding, rather than confusion.)

The concept of broadband networking has its roots in the early 1970s when the CCITT first defined Broadband ISDN. Anticipating the development of highly bandwidth-intensive applications, and the demand for them, B-ISDN was defined on a very preliminary basis—the result of these continuing efforts remain many years distant. In the meantime, however, a number of developments have taken place. First, the demand for computer internetworking grew at levels which astounded even the most astute computer and data network pundits. Second, imaging systems developed and increasingly required networking. Third, the potential for videoconferencing applications became apparent. Fourth, the development and commercialization of the Internet and World Wide Web truly has been mind-boggling. Finally, entertainment networking now has captured the attention of telephone companies and others as they seek to compete to develop networks that will carry TV content, as well as voice, data, video, image, facsimile, and all other forms of data over a single network.

Chapter 10 addressed broadband infrastructure technologies. This chapter will address the service offerings which frame the applications. The focus here is on three network service offerings: Frame Relay, Synchronous Multimegabit Data Service (SMDS), and Asynchronous Transfer Mode (ATM). Together, they fall under the umbrella term Fast Packet Services (Figure 11.1). Fast refers to the fact that they rely on a broadband transmission infrastructure (> 45 Mbps) in the form of SONET/SD, and on very fast and capable switching systems, as well. Packet is a generic term referring to the manner in which data is segmented—into packets, frames, blocks, cells, etc.—that are handled separately, yet generally linked in some way, through the network. Services is the operative word here. No matter how elegant the underlying technologies, their ultimate value is in enabling the creation and delivery of services of value. At the bottom of Figure 11.1 are noted the access standards defined by the ITU-T.


Figure 11.1  Fast packet networking. Courtesy of Frame Relay Forum

This chapter will conclude with a brief exploration of Advanced Intelligent Networks (AINs) and B-ISDN. AINs reflect the marriage of computer, database, and network technologies, offering tremendous potential in the creation and delivery of services. B-ISDN is the ultimate network service delivery concept.

“Do not despise the bottom rungs in the ascent to greatness,” wrote Pulilius Syrus (Moral Sayings) in the 1st Century, B.C. So it is with fast packet networking, which has its roots in X.25 (slow) packet networking, which has its roots in the AlohaNET packet radio network. (It seems as though good ideas have long and even multiple lives.) Without belaboring that point, we will explore the comparisons between X.25 and Frame Relay.

Frame Relay

Frame Relay has experienced unprecedented growth since its commercial introduction by Wiltel (since acquired by LDDS Worldcom) in 1992. AT&T, the largest U.S. domestic provider with about 35% of the market, enjoyed a 600% increase in Frame Relay service in 1995, following a 500% increase in 1994. The 1995 worldwide market for Frame Relay equipment and services is forecast at a total of $2.19 billion, up from the 1994 market of $1.71 billion, an increase of 28%. The carrier service revenues for Frame Relay were estimated by Infonetics Research to be approximately $700 million in 1995 and forecast to be $2.3 billion in 1997. The worldwide frame relay customer count grew from approximately 5,000 in January 1995 to about 15,000 by January 1996 [11-1].


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