Chapter 10: End-of-Chapter Questions

The modern performs the coding and decoding in a datacom network. It is required except when a telephone is used as a terminal.

I. The firm owns all of the circuitry for a LAN, and the devices communicating with each other are typically close together such as in the same room or building. Circuitry for a MAN is owned by the firm, but the distance covered may be as large as thirty miles. MANs are generally much closer, such as the network for a campus. WANs may cover any distance and utilize communications circuitry owned by common carriers.

2. The Internet is a collection of networks that are joined together to permit access and use anywhere in the world. An intranet uses Internet protocols to facilitate communication within the firm. An extranet is an intranet that is expanded to include selected users outside the firm.

3. POS terminals are used to keep a retailer’s database current and provide feedback to sales clerks to enable them to complete the transaction. POS terminals also have an external focus, linking with such environmental elements as customers. Data collection terminals keep a manufacturer’s database current and have an internal focus.

4. Likely transmission speeds for a LAN are 10 to 100 Mbps. For a MAN they are 100 Mbps, and for a WAN they are between 9600 bps and 1 Mbps.

5. Data transmission using the public telephone system is slower than computer-to-computer connection because of the telephone protocols. Telephone circuitry is often of relatively poor quality, unsuitable for high-speed data transmission.

6. The token in a Token-Ring network is used to designate one computer in the network as the one that currently controls communications.

7. Ethernet computers are used in a LAN, and typically are physically close together.

8. Distributed processing is a form of decentralized processing, enabling the processing of data by widely dispersed computer resources. Client/server, on the other hand, is a combination of centralized and decentralized processing. The server processes data in a centralized manner, and the clients do so in a decentralized manner.

9. Network plannmg consists of capacity planning, staff planning, and performance monitoring.

10. IBM has aimed its SNA at users of large computers and has aimed its Token Ring protocol at users of small computers. By segmenting the market in this way, IBM retains a competitive edge in the large computer market.

11. A data transmission crash is when two or more computers try to use a network at the same time. In an Ethernet network, when a crash occurs, the sending computer does not receive confirmation that the message was received safely. The sending computer simply resends until the confirmation is received.

12. A hub is more secure than a switch because access is restricted to only those computers that are physically connected to it. A switch and a router are devices that connect many LANs and do not rely on physical connection for security.

13. A bridge simply connects two LANs. A router is more sophisticated and can connect many LANs.

14. A circuit is a path through a network that is always open. Packets enable pieces of the total data to be communicated to follow different routes to the destination computer. The packet routes are determined by packet switching protocols.

15. A virtual private network provides a secure, fast, and inexpensive communications line by means of a collection of Internet lines and tunneling software that establish intermediary telephone equipment locations.

Topics for Discussion

I. Since you are in charge of operations for a small organization with less than 15 employees, you probably would not spend too much time in staff planning. But since Internet sales produce more than $4 million in revenues, you would engage in capacity planning to ensure that the data volumes can be handled, and in performance monitoring, to ensure that your e-commerce customers receive the level of service that they need.

2. An increase in the number of preferred vendors imposes demands that private lines cannot easily meet. Secure data communications can be established using an extranet or a virtual private network.

3. The determination of whether to use a LAN, MAN, or WAN is based on the distance to be covered by the network. Since all employees are located in the same building, a LAN would be used. Its speed, and those of a MAN, could handle the large volume transmissions.

4. Data communications capabilities have transformed all CBIS subsystems (MS, MIS, DSS, knowledge-based systems, and virtual office) from solutions with a narrow, central focus to those with no geographical limitations. Data communications technology has enabled the CBIS to support business organizations as they expand their operations to a global scope. The importance of data communications in the CBIS can only be expected to increase.