Home > Articles > Networking

Demands on Today's Data Communications Technologies

📄 Contents

  1. The Evolution of Data Transmission Technologies
  2. Contemporary Bandwidth Requirements
While the personal computer market made sweeping advances, data transmission stayed stagnant. Now with the introduction of Asynchronous Transfer Mode (ATM) and Gigabit Ethernet, see how data transmission technologies have evolved and compare contemporary bandwidths.
This chapter is from the book

This chapter is from the book

1.1 -The Evolution of Data Transmission Technologies

For decades the development of data transmission technologies has not kept pace with the explosive increase in the capabilities of individual computer systems. Processor performance and data storage capacity in PCs, for example, increased a hundredfold in the 1980s, while data speeds in wide area networks increased only tenfold over the same period. Data speeds in local area networks even remained unchanged for long intervals, mainly due to the lengthy standardization processes involved in introducing new technologies. In the mid-1990s, however, this situation began to change, as high-speed technologies such as Asynchronous Transfer Mode (ATM) and Gigabit Ethernet were finally standardized and a wide range of affordable products for use with these technologies became available.

1.1.1 Local Area Networks

The majority of the local area networks (LANs) in use today are still based on transmission principles developed in the early to mid-1980s: 10/100 Mbit/s Ethernet (IEEE 802.3), and 4 or 16 Mbit/s Token Ring (IEEE 802.5). Since a substantial increase in network bandwidth was not feasible for many years, the number of network nodes per segment had to be reduced in order to accommodate the increasing use of multimedia and network-oriented applications made possible by faster processors. In the 1980s, for example, 802.3 Ethernet networks with more than 300 stations were not unusual, whereas today the average number of stations per segment is between 10 and 20 and falling.

A new LAN standard, called Fiber Distributed Digital Interface (FDDI), was introduced at the end of the 1980s. Based on fiber optic media, FDDI technology provided a data speed of 100 Mbit/s. FDDI was the first technology that made it possible to build high-performance backbone structures, but it gained acceptance only slowly because it required expensive hardware components, such as lasers on network cards and optical fiber cabling. Furthermore, it was soon apparent that even its bandwidth of 100 Mbit/s, shared by all nodes, would not be sufficient for emerging multimedia applications; in other words, FDDI was a medium-term solution at best. Nonetheless, for lack of alternative network technologies, many backbones were converted to FDDI in the years following its introduction. This all changed once again when LAN switching, 100 Mbit/s Ethernet, and 155 Mbit/s ATM technologies became marketable, providing more flexible and economical backbone solutions than those based on FDDI. Since then, the use of FDDI has been declining, and it is rarely considered as an option when new networks are designed. At the beginning of the first decade of the third millennium, further improvements in speed with technologies such as Gigabit Ethernet and 10 Gigabit Ethernet are starting to become widely deployed.

Although ATM is often mentioned in the same context as other high-speed technologies such as Fast Ethernet, Gigabit Ethernet, and LAN switching, there is a significant difference between ATM and all other communication technologies used in local area networks. Unlike the connectionless transmission mechanisms used by other LAN topologies, ATM uses connection-oriented data communication. Before transmission starts, a signaling process sets up a channel with the required bandwidth, delay, and other characteristics. User data is sent over this channel until a command on the signaling channel ends the connection. Insufficient bandwidth is not the only limitation that makes traditional network topologies unable to handle today's multimedia applications, since the effective bandwidth can be increased by limiting the network to one station per segment, as seen in segment-switching topologies. In addition to bandwidth, the transmission of multimedia applications over networks also requires real-time behavior that simply cannot be provided by the connectionless LAN data transmission technologies of the 1980s. ATM permits unrestricted use of multimedia applications in LANs. A connection between two ATM stations is not affected by the number of other stations in the network, since each station is supplied with transmission paths of fixed bandwidth and guaranteed communication characteristics, which are set for each connection in a "traffic contract."

Similar quality of service (QoS) mechanisms have been implemented in the IP protocol family over the past years. They enable the transmission of real-time IP services such as audio and video over broadband connectionless infrastructures such as Gigabit Ethernet. This has lead to the situation that today in local area networks ATM is primarily implemented for demanding, high performance backbones with specific needs, whereas the majority of LANs are migrating toward Gigabit Ethernet as a backbone infrastructure.

1.1.2 Wide Area Networks

While the transmission capabilities of LANs have been evolving in few step functions over the past decades, the available data speeds in wide area networks (WANs) have increased steadily over the years. X.25 connections, for example, widely used in the 1970s with data speeds of 2.4 kbit/s and 4.8 kbit/s, were replaced by Frame Relay links with speeds of 1.5 Mbit/s and 45 Mbit/s in North America, and 2 Mbit/s and 34 Mbit/s elsewhere (Figure 1.1). The Integrated Services Digital Network (ISDN), introduced in the mid-1980s, permitted more efficient use of communication lines by bundling analog and digital services. Especially in Europe, ISDN became an important medium for telephony and data transmission, until in 2000 xDSL technologies started to provide even higher data rates over the same telephony infrastructure. While ISDN provides transmission capacities of between 56 kbit/s (Basic Rate ISDN, or BRI) to 2 Mbit/s (Primary Rate ISDN, or PRI), the various xDSL services deliver data speeds from 128 bit/s to 8Mbit/s.

Figure 1.1Figure 1.1 The evolution of data transmission technologies, 1980–2000.

When the ISDN specifications were developed in the early 1980s, it was assumed that bandwidths of 128 kbit/s (BRI) and 2 Mbit/s (PRI) would be sufficient for years to come. Soon after the protracted standardization process for ISDN was concluded, however, it was already apparent that the payload bandwidth of n x 64 kbit/s on which ISDN is based would not meet the rapidly increasing demands placed on data communications technology. The next step had to be the development of what were termed "broadband transmission systems," with bandwidths far beyond 2 Mbit/s. In the second half of the 1980s, standardization work was begun on a broadband ISDN (B-ISDN) specification, intended to be the future universal wide area network technology. The Asynchronous Transfer Mode, or ATM, was selected by the ITU in 1988 as the transport mechanism for B-ISDN. Since then, major telecommunications providers around the world have been setting up and operating B-ISDN (mostly referred to as ATM) communication networks.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020