CSC621 Business Data Communications and Networking
Chapter 1: Introduction to Data Communication
Submitted By: Sreedhar Thotakuri
Student ID – Sthota9299
Sullivan Univeristy
Professor: Dr. Nathan P. Johnson

Answers to End-of-Chapter Questions

7. How do LANs differ from MANs, WANs, and BNs?

Answer:

A Local Area Network (LANs) are a group of computers located in the same general
Area usually in a small defined area like one floor or work area and uses shared LANs support high-speed data transmission compared with standard telephone circuits, commonly operating 100 million bits per second (100 Mbps). (Fitzgerald, Dennis, & Durcikova, 2012)

A Metropolitan area network (MANs) covers a city or county area usually span between 3 and 30 miles, MAN is provided by common carriers like telephone companies. MANs data transmission usually ranges from 64 Kbps t0 100 Mbps. (Fitzgerald, 2012).

Wide area network (WAN) covers city, state or national boundaries and it covers hundreds or thousands of miles and it provides data transmission ranging from 64kbps to 10Gbps(Fitzgerald, 2012).
Back bone network (BN) a larger, central network which connects several LANS, MANs, WANs and other BNs and it covers from hundreds of feet to several miles and the data transmission ranges from 100 to 1,000 Mbps. (Fitzgerald, 2012).

14. Explain how a message is transmitted from one computer to another using layers.

Answer.
Network user uses application layer which is software and each computer in the network has software that operates at each of the layers and performs the functions requires by those layers. The network layer receives the message generated by the application layer and if necessary the message is break down into small messages. The network layer addresses the messages and determines their route through the network, records message information before passing it to the data link layer. The data link layer then formats the message to indicate where it starts and ends, it also decides when to transmit it over the physical media and also detects and corrects if there are any errors that occur in transmission. The physical layer will be the physical connection between the sender and receiver which includes the hardware devices like computers, terminals and modems and physical media like cables and satellites. (Fitzgerald, 2012).

18. What is the purpose of a data communication standard?

Answer:

The data communication standard makes easier to develop the software and hardware that link different networks since the software and hardware can be developed one layer at a time, the hardware or software developed by the data communication standard at one network can be easily updated as long as the interface between that layer and the ones around it remains unchanged. (Fitzgerald, 2012).

21. In the 1980s when we wrote the first edition of this book, there were many, many more protocols in common use at the data link, network, and transport layers than there are today. Why do you think the number of commonly used protocols at these layers has declined? Do you think this trend will continue? What are the implications for those who design and operate networks?

Answer:

Currently the TCP/IP is a protocol of choice for all the networks. The Network software is designed to interface with networks using TCP/IP protocol. TCP/IP is an interoperable protocol which is portable to any manufacturer’s hardware. All the manufacturers are developing their products to use TCP/IP as their protocol of choice. For example Novell Netware version 5 using the TCP/IP support for the client file and print services which is a great benefit for the operating networks because they will not have to deal with the compatibilities of various proprietary networks. (Fitzgerald, 2012).

Mini-Cases

V. Asia Importers

What are the potential benefits and challenges that Asia Importers should consider in making the decision about whether or not to move to one integrated service?

Answer:
The potential benefit of integrating the service will enable MS. Wong to consolidate her bills and receiving technical service from single company and with the single source of contact Asia importers can stream line the services and technological services. The potential disadvantage with one integrated service will be the single source will manage more of Asia imports technical infrastructure leaving the firm vulnerable due to single sourcing. If the sole source is unreliable or inefficient this will affect Asia importer’s business.

Reference:
Fitzgerald, J., Dennis, A., & Ducikova, A. (2012). Business data communications & networking. (11th ed.). Hoboken: John Wiley and Sons.