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COM309 Network Theory & Design

Module 1 Assignment

For this module you are required to complete the following assignments:

Chapter 1

•Exercises: #3 and 5

3. Two companies consider pooling resources to perform a joint venture. The CEO of the first company meets with his legal team, and the legal team consults a number of middle managers in the proposed product area. Meanwhile, the CEO of the first company sends an email to the CEO of the second company to offer a couple suggestions concerning the joint venture. Does this scenario follow the OSI model? Explain.

5. You are working from home using a microcomputer, a DSL modem, and a telephone connection to the Internet. Your company is connected to the Internet and has both local area networks and a mainframe computer. List all the different network connections involved in this operation.

•Thinking Outside the Box #4

#4 Describe a real-life situation that uses at least three of the network layouts described in this chapter.

Chapter 2

•Exercises: #1, 2, 4, and 9

1. What is the frequency in Hertz of a signal that repeats 80,000 times within one minute? What is its period?

2. What is the bandwidth of a signal composed of frequencies from 50 Hz to 500 Hz?

4. What is the baud rate of a digital signal that employs differential Manchester and has a data transfer rate of 2000 bps?

9. A signal starts at point X. As it travels to point Y, it loses 8 dB. At point Y, the signal is boosted by 10 bB. As the signal travels to point Z, it loses 7 dB. What is the dB strength of the signal at point Z?

•Thinking Outside the Box #1 and 2

#1 You are working for a company that has a network application for accessing a database corporate profiles. From your computer workstation, a request for a profile travels over the corporate local area network to a modem. The modem, using DSL, connects to the Internet and finally into the database service. the data base service is essentially a modem and a mainframe computer. Create a table ( or draw a figure) that shows every time data or signals are converted to different form in the process. For each entry in the table, show where the conversion is taking place, the form of the incoming information, and the form of the outgoing information.

#2 Telephone systems are designed to transfer voice signals (4000 Hz). When a voice signal is digitized using pulse code modulation what is the sampling rate, and how many quantization levels are used? How much data does that generate in one second? Are these the same sampling rate and quantization levels used on a CD? Can you verify your answer?

COM309 Network Theory & Design

Module 2 Assignment

For this module you are required to complete the following assignment:

• Chapter 3 Exercises: pp. 100-101: #1, 2, 5, 12, and 13

1. Table 3-1 shows Category 1 wire transmitting a signal for 5 to 6 kilometers (3 to 4 miles) but Category 5e for only 100 meters (328 feet). Is Category 1 the best wire for long-distance transmissions? Explain.

2. List three different examples of crosstalk that don’t involve wires and electric signals. (Hint: Look around you.)

5. The local cable TV company is considering removing all the coaxial cable and replacing it with fiber optic cable. List the advantages and disadvantages of this plan.

12. Given that a satellite signal travels at the speed of light, exactly how long does it take for a signal to go from the Earth to a satellite in geosynchronous orbit, and back to Earth? Show your calculations.

13. How long does it take a signal to reach a satellite in low-Earth orbit? Show the calculations

•Thinking Outside the Box #4

You need to connect two buildings across a public road, and it is not feasible to use a direct cable connection. Under what circumstances would you use a microwave link? A radio link?an infrared laser link? What about th other wireless alternatives?

• Chapter 4. Chapter 4 Exercises: #1, 3, 6 and 12

1. What are the advantages, if any, of the older EIA 232F interface over the newer USB interface?

3. If I have a device that has a Universal Serial Bus 3.0 interface, but my computer only has a Universal Serial Bus 2 connector, is my device going to work? Explain why or why not.

6. List two examples not mentioned in the book for each of the following connections: half-duplex and full-duplex.

12. What types of devices are best served with an isochronous connection?

•Thinking Outside the Box #2

You are using a computer system that has 20 terminals connected to a mainframe computer using roll-call polling. Each terminal is polled once a second by the mainframe and sends a 200-byte record every 10 seconds. The boss says you should remove terminals, install computer workstations, and replace the polling with asynchronous connections Which is more efficient: keeping the terminals and polling, or using workstations and asynchronous connections?

COM309 Network Theory & Design

Module 3 Assignment

For this module you are required to complete the following assignments:

• Chapter 5:exercises #1 – 6

1. Compared to the other multiplexing techniques, state two advantages and two disadvantages of each of the following:

a. Frequency division multiplexing

b. Synchronous time division multiplexing

c. Statistical time division multiplexing

d. Dense wavelength division multiplexing

2. A benefit of frequency division multiplexing is that all the receivers do not have to be at the same location. Explain what this benefit means and give an example.

3. Twenty-four voice signals are to be multiplexed and transmitted over twisted pair. What is the total bandwidth required if frequency division multiplexing is used?

4. Twenty-four voice signals are to be multiplexed and transmitted over twisted pair. What is the bandwidth required (in bps) if synchronous time division multiplexing is used, if we use the standard analog-to-digital sampling rate, and if each sample is converted into an 8-bit value?

5. If only four computers are transmitting digital data over a T-1 line, what is the maximum possible data rate for each computer?

6. What is the synchronization bit in a T-1 frame used for? Why is it necessary?

Thinking Outside the Box #4

Compare and contrast the older multiplexing techniques such as frequency division and time division multiplexing with the newer techniques such as discrete multitone and orthogonal frequency division multiplexing. What appears to be the trend in these newer protocols?

• Chapter 6: exercises #1 – 7

1. Which is the most difficult type of noise to remove from an analog signal? Why?

2. Which is the most difficult type of noise to remove from a digital signal? Why?

3. Explain the relationship between twisted pair wires and crosstalk.

4. Which type of cable is most susceptible to echo?

5. Given the character 0110101, what bit will be added to support even parity?

6. Given the character 1010010, what bit will be added to support odd parity?

7. Generate the parity bits and longitudinal parity bits for even parity for the characters 0101010, 0011010, 0011110, 1111110, and 0000110.

Thinking Outside the Box #3

Given today’s networking technology, 3-bit and 7-bit sliding window sizes seen very restrictive. What would be a more reasonable size today? Explain your reasoning.

COM309 Network Theory & Design

Module 4 Assignment

For this module you are required to complete the following assignments:

• Chapter 7: Exercises: #1, 2, 3, 5 and 9

1. What properties set a local area network apart from other forms of networks?

2. Describe an example of broadband bus system.

3. Is a hub a passive device or an active device? Explain.

5. If a network were described as 1000BaseT, list everything you would know about that network.

9. How is a hub similar to a switch? How are they different

Thinking Outside the Box #1

A retail department store is approximately square, 35 meters (100 feet) on each side. Each wall has two entrances equally spaced apart. Located at each entrance is a point-of-sale cash register. Suggest a local area network solution that interconnects all eight cash registers. Draw a diagram showing the room, the location of each cash register, the wiring, the switches, and the server. What type of wiring would you suggest?

• Chapter 8: exercises # 1, 5, 7, 11 and 13

1. Skip this exercise.

5. 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 tenth floor. Will this layout work? Explain.

7. In a client server system, a client transmit a request to a server, the server performs a processing operation, and the server returns a result. List all the possible problems that can occur with transmission in this scenario.

11. Windows Server 2000/2003/2008 uses Active Directory for its directory service, and NetWare/OES uses NDS. How are the two directory services alike? How are they different?

13. In what ways are UNIX and Linux similar? In what ways are they different?

Thinking Outside the Box #3

You are creating a network at home that consists of multiple computers, a high quality printer, and a router with access to a high-speed internet connections. Surely you do not need Windows server 2008 or OES/NetWare, but is there a particular desktop operating system that can be installed on each computer that will optimize the operations of your home network?

COM309 Network Theory & Design

Module 5 Assignment

COM309 Network Theory & Design

Module 6 Assignment

For this module you are required to complete the following assignments:

• Chapter 10: exercises # 1 – 5

1. Does the U.S. government support the Internet? Explain.

2. Given an IP packet of size 540 bytes and a maximum packet size of 200 bytes, what are the IP Fragment Offsets and More flags for the appropriate packet fragments?

3. The Hop Limit field in IP version 6 is 8 bits long (the same size as the equivalent Time to Live field in IPv4). Since this hop count is decremented each time an IP datagram enters a router, what are the implications of such a small field size?

4. Suppose there is a small commercial retail building with essentially one room. On one side of the room is a real estate agency and on the other side of the room is a guy who sells tea. What is the relationship between this setup and the concept of IP addresses with TCP port numbers?

5. Somewhere in the middle of the United States are two Internet routers with routing tables that are all messed up. The two routers keep sending their packets back and forth to each other, nonstop. Will an error message ever be generated from this action? If so, who will generate the error message and what might it look like?

Thinking Outside the Box #2

Two banks want to establish an electronic link between themselves, over which they can transmit money transfer. Can they use a virtual private network and a tunneling protocol, or is a better technique available? Defend your answer.

• Chapter 11: exercises # 1 – 6

1. The telephone line that connects your house or business to the central office (the local loop) carries your conversation and the conversation of the person to whom you are talking. What do you estimate is the bandwidth of a local loop?

2. If you play a CD for a friend over the telephone, will the friend hear high-quality music? If not, why not?

3. If you place a telephone call and it leaves your LATA and enters another LATA, what kind of telephone call have you placed? What kind of telephone company handles this telephone call?

4. For each of the following scenarios, state whether a telephone line or a trunk should be used:

a. The connection from your home to the local telephone company

b. The connection between a large company’s PBX and the telephone company

c. The connection between two central offices

5. Many within the telephone industry feel we will eventually run out of area codes and telephone numbers. How many different area codes are currently available? What would you suggest to increase the number of telephone numbers?

6. State whether each of the following was a result of the Modified Final Judgment of 1984, the Telecommunications Act of 1996, or neither:

a. The FCC was created to watch over interstate telephone systems

b. AT&T had to sell off its local telephone companies

c. The LATA was created

d. Cable television companies could provide local telephone service

e. Customers could choose between different long-distance telephone providers

f. AT&T split off its technology division, which became Lucent

Thinking Outside the Box #2

You are consulting for a hospital that wants to send three-dimensional, high-resolution, color ultrasound images between the main hospital and an outpatient clinic. A patient will be receiving the ultrasound at the clinic, while a doctor at the main hospital observes the images in real time and talks to the ultrasound technician and patient via a telephone connection. What type of telecommunication service presented in this chapter might support this application? Indentify the telecommunications service, and be sure to list the particular details concerning the service. Explain your reasoning.

COM309 Network Theory & Design

Module 7 Assignment

For this module you are required to complete the following assignments:

? Chapter 12: exercises # 1 – 6, and 11

1. A major university in Illinois used to place the computer output from student jobs on a table in the computer room. This room is the same computer room that housed all the campus’ mainframe computers and supporting devices. Students would enter the room, pick up their jobs, and leave. What kinds of security problems might computer services encounter with a system such as this?

2. You have forgotten your password, so you call the help desk and ask them to retrieve your password. After a few moments, they tell you your forgotten password. What has just happened and what is its significance?

3. Create (on paper) a simple example of a substitution-based cipher.

4. Create (on paper) a simple example of a transposition-based cipher.

5. Using the Vigenére Cipher and the key NETWORK, encode the phrase “this is an interesting class.”

6. Using the transposition-based cipher from this chapter and the same key, COMPUTER, encode the phrase “birthdays should only come once a year.”

11. One feature of a firewall is its ability to stop an outgoing IP packet, remove the real IP address, insert a “fake” IP address, and send the packet on its way. How does this feature work? Do you think it would be effective?

Thinking Outside the Box #4

You have a computer at home with a wireless MIC and wireless router. List all the security measures that should be employed so that your home network is secure.

COM309 Network Theory & Design

Module 8 Assignment

For this module you are required to complete the following assignments:

• Chapter 13: exercises # 1, 7, 11, and 12

1. State during which phase or phases of the systems development life cycle the following actions are performed:

a. Installing the system

b. Training users

c. Writing documentation

d. Performing feasibility studies

e. Testing the system

f. Updating the system

7. If a component has a MTBF = 10 hours and a transaction takes 20 minutes, calculate the reliability of the component.

11. What are the differences between network line continuity testers and network cable testers?

12. You are working for a small company that has a local area network with two hubs. The communications line between the hubs has just been cut, but you don’t know that. How can you determine what has happened?

Thinking Outside the Box #1

You have been asked to create a help desk for the computer support division of your company. What services will your help desk provide? How will you provide those services? What type of employees will you hire to work at the help desk?