Chapter 8: Summary Back to Contents
 
1.
 Describe the features of a contemporary corporate network infrastructure and key networking technologies.

A contemporary corporate network infrastructure relies on both public and private infrastructures to support the movement of information across diverse technological platforms. It includes the traditional telephone system, mobile cellular communication, wireless local area networks, videoconferencing systems, a corporate Web site, intranets, extranets, and an array of local and wide area networks, including the Internet. This collection of networks evolved from two fundamentally different types of networks: telephone networks and computer networks.

           A simple network consists of two or more connected computers. Basic network components include computers, network interfaces, a connection medium, network operating system software, and either a hub or a switch.

           Contemporary networks have been shaped by the rise of client/server computing, the use of packet switching, and the adoption of TCP/IP as a universal communications standard for linking disparate networks and computers. Client/server networks have distributed much of the organization’s computing power to the desktop and factory floor. Packet switching makes more efficient use of network communications capacity by breaking messages into small packets that are sent independently along different paths in a network and then reassembled at their destination. Protocols provide a common set of rules that enable communication among diverse components in a telecommunications network. TCP/IP is a suite of protocols that has become the dominant model of achieving connectivity among different networks and computers. It is the connectivity model used in the Internet.
2. Evaluate alternative transmission media, types of networks, and network services.

The principal physical transmission media are twisted copper telephone wire; coaxial copper cable; fiber-optic cable; and wireless transmission using microwave, satellite, low-frequency radio waves, or infrared waves. The choice of transmission medium depends on the distance and volume of communication required by the organization and its financial resources. Twisted wire enables companies to use existing wiring for telephone systems for digital communication, although it is relatively slow. Fiber-optic and coaxial cable are used for high-volume transmission but are expensive to install. Microwave and satellite are used for wireless communication over long distances. The transmission capacity of a medium, known as the bandwidth, is determined by the range of frequencies it can accommodate.

           There are different types of networks and network services available to organizations. Network selection and design should be based on the organization’s information requirements and the distance required for transmission. Local area networks (LANs) connect PCs and other digital devices together within a 500-meter radius and are used today for many corporate computing tasks. Network components may be connected together using a star, bus, or ring topology. Wide area networks (WANs) span broad geographical distances, ranging as far as entire continents or across the globe, and are private networks that are independently managed. Metropolitan area networks (MANs) span a single urban area, whereas campus area networks (CANs) span a campus of buildings or a military base.

           A number of network services are available to organizations requiring high-bandwidth transmission. Frame relay is a shared network service with transmission speeds ranging from 56 Kbps to more than 40 Mbps; it relies on digital circuits that require less error checking than packet switching. Asynchronous Transfer Mode (ATM) provides transmission speeds of 1.5 Mbps to more than 9 Gbps, parceling data into fixed 53-byte cells. ATM can pass data between computers from different vendors and is popular for transmitting data, video, and audio over the same network. Integrated Services Digital Network (ISDN) is an international standard for dial-up network access that uses existing local telephone lines to integrate voice, data, image, and video services. Basic rate ISDN can transmit data at a rate of 128 Kbps.

           Digital Subscriber Line (DSL) technologies, cable modems, and T lines are often used for high-capacity Internet connections. Like ISDN, DSL technologies also operate over existing copper telephone lines to carry voice, data, and video, but they have higher transmission capacities than ISDN. Asymmetric Digital Subscriber Line (ADSL) supports a transmission rate of 1.5 to 9 Mbps when receiving data and up to 640 Kbps when sending data. Symmetric Digital Subscriber Line (SDSL) supports the same transmission rate for sending and receiving data of up to 3 Mbps.

           Cable modems, which operate over cable TV lines, can provide high-speed access to the Web or corporate intranets at speeds of up to 4 Mbps. T lines are high-speed data lines leased from communications providers. A T-1 line supports a data transmission rate of 1.544 Mbps.

3. Assess the role of the Internet and the World Wide Web in a firm’s information technology infrastructure.

The Internet is a worldwide network of networks that uses the client/server model of computing and the TCP/IP network reference model. Every computer on the Internet is assigned a unique numeric IP address. The Domain Name System (DNS) converts IP addresses to domain names so that users only need to specify a domain name to access a computer on the Internet instead of typing in the numeric IP address. No one owns the Internet and it has no formal management organization. However, worldwide Internet policies are established by organizations and government bodies such as the Internet Architecture Board and the World Wide Web Consortium. The Internet must also conform to the laws of the sovereign nation-states in which it operates, as well as the technical infrastructures that exist within the nation-state.

           The Internet’s global reach and connectivity, scalability, distributed design, universal standards, richness, and interactivity have made it the primary infrastructure for electronic business and electronic commerce. Major Internet services include e-mail, Usenet, LISTSERV, chatting, instant messaging, Telnet, FTP, and the World Wide Web.

           The World Wide Web provides a universal set of standards for storing, retrieving, and displaying information in a client/server environment, enabling users to link to information resources housed on many different computer systems around the world. Web pages are based on Hypertext Markup Language (HTML) and can display text, graphics, video, and audio. Web site directories, search engines, and push technology can help users locate the information they need on the Web. Web technology and Internet networking standards provide the connectivity and interfaces for internal private intranets and private extranets that can be accessed by many different kinds of computers inside and outside the organization.

4. Identify and describe the most important tools for communication and e-business.

The principal applications for communication are e-mail, chatting, instant messaging, Usenet newsgroups, and LISTSERV services. These tools reduce time and cost when firms must manage organizational activities and communicate with many employees. Groupware, teamware, and electronic conferencing software provide tools to support communication and collaboration when people work together in groups or work teams, often in different locations. Firms are also starting to realize economies by using Internet telephony, which enables Internet technology to be used for telephone voice transmission. Internet technology can also reduce communication costs by enabling companies to create virtual private networks (VPNs) as low-cost alternatives to private WANs.
5. Identify and describe the challenges posed by networking and the Internet and management solutions.

Challenges posed by networking and the Internet include loss of management control over information systems; the need for organizational change; and the difficulty of ensuring infrastructure scalability and reliability. Solutions include developing a strategic networking plan and carefully managing the business and organizational changes associated with intensive networking and the Internet.