ET 271 Data Communications Chapter 7
Local Area Networks: The Basics
Name: Roy Meyer
1. What is the definition of a local area network?
A communications network that interconnects a variety of data-communicating devices within a small area
2. List the advantages and disadvantages of local area networks.
Advantage: High transfer rate, low error rate
Disadvantage: small area
3. What are the basic topologies of local area networks? List two advantages that each topology has over the others.
Bus: can use baseband signaling, broadband signaling
Star wired bus: one computer controls the others, simple operation
Star wired ring: supports baseband signals, information flows in one direction
Wireless: no wires, can work at speeds up to millions of bits per second, the workstations can be located anywhere
4. What is meant by a passive device?
Simple connection point between two runs of cable that does not regenerate the signal on the cable
5. What is meant by a bidirectional signal?
Kind of transmission in which a signal transmitted from a workstation propagates in both directions on the cable away from the source
6. What are the primary differences between baseband technology and broadband technology?
Baseband carries one channel of digital data
Broadband supports multiple channels of digital data
7. What purpose does a hub serve?
A hub connects two or more workstations
8. What is the difference between a physical design and a logical design?
Physical design- pattern formed by the locations of the elements of a network
Logical design- process of mapping how data moves around a given network from workstation to workstation
9. What are the basic operating principles behind CSMA/CD? BE SPECIFIC.
3 different protocols: 1-persistent (constantly listens), non-persistent (listen, waits, listens) p-persistent (listens, transmits probability)
10. What is the basic purpose of the token in a token ring?
Carry and drop off the data
11. What does the term 100BaseT stand for?
100 Mbps over a twisted pair wire
12. What is the difference between Fast Ethernet and regular Ethernet?
Fast Ethernet: The group of 100-Mbps Ethernet standards designated by the IEEE 802.3u protocol
Regular Ethernet: 10Mbps standard
13. List three advantages of FDDI over token ring?
Longer distance, faster speed, more workstations
14. Describe an example of a broadband bus system, besides cable television.
Cable internet, a computer network, telephone
15. Physically, a hub looks the same as a MAU. Logically they are different. Explain how they are different.
The ring is constantly maintained on a MAU,
16. Which of the Ethernet standards (10 Mbps, 100 Mbps, 1000 Mbps, and 10 Gbps) allow for twisted pair media? What are the corresponding IEEE standard names?
All of them
For twisted pair: 10BaseT (802.3), 100BaseT (802.3u), 1000BaseT (802.3z), 10GBaseT (802.3ae)
17. Your company wants to create a wireless network for the entire office building. The building is 10 stories high, and the company wants to incorporate IEEE 802.11a by placing one access point on the 10th floor. Will this layout work? Explain.
No, signal range is too short