IT 420

Fall 2017

Homework 1

Note: Where applicable, units of the solution must be correct for full credit.

Answer the following questions concerning chapter 1:

1.1 As a message moves from the network interface layer up to the application layer in

the receiver, headers are ______ .

a. added b. removed c. rearranged d. modified

1.2 Which pair of layers are peer layers?

a. Application layer in the sender and transport layer in the sender

b.Application layer in the receiver and transport layer in the receiver

Application layer in the sender and application layer in the receiver

d.Application layer in the sender and transport layer in the receiver

1.3 Which of the following data units is directly encapsulated in an internet layer packet?

a.A TCP segment b. A network interface layer frame

c. A physical layer connection d. An application layer message

1.4 Choose which layer each of the following phrases describes:

a. Application b. Transport c. Internet d. Network Interface e. Physical

______ Interacts with the user

______ Uses physical (MAC) addresses

______ Uses IP addresses

_______ Encodes data using physical phenomena, such as changing voltage

______ Uses ports for process to process communication

______ May use cabling or wireless connections

______ Host to host communication

_______Sends information across a single network

Assume a five layer TCP/IP model. The initial data at the application layer is A bytes. A B byte header is added at the transport layer, a C byte header is added at the internet layer and a D byte header is added at the network interface layer. The network interface layer also adds a E byte trailer. Express the answers to the questions below in terms of A, B, C, D, and E.

How many total bytes are sent to the hardware?

What percentage of the bytes sent to the hardware is the original application layer data?

What percentage of the bytes sent to the hardware is overhead?

3.In the five-layer networking model, data sent to the physical layer consists of the application data, network interface layer header, network interface layer trailer, internet layer header, and transport layer header. In the diagram of data sent to the physical layer below, label each part using one of the terms above. (Order matters.)

4.Perform the following calculations. Make sure the units of the solution are correct.

a.10 Kbps * 3

b.10 Mbps * 3 sec

c.Convert 2400 bits to bytes

5.Answer the following questions concerning analog signals:

5.1 As the period of a sine wave decreases, the frequency __________________ .

a. decreases b. increases c. remains the same d. doubles

5.2 The frequency of a sine wave is defined as:

a.the number of cycles per second

b.the maximum amplitude of the wave

c.the time for one cycle

d.the difference between the high frequency and the low frequency

6.Consider the following sine wave: s(t) = 4sin(23t + )

a.What is the amplitude?

b.What is the frequency?

c.What is the phase?

7.Draw the following sine wave in the time domain, showing amplitude and phase:

s(t) = 3sin (22t + )

8.A sine wave has a period of 5 msec. What is the frequency?

9.What is the period of a 2 KHz sine wave?

10.Consider the following composite signal.

f(t) = 5sin(22t) + 6sin(23t) + 7sin(24t)

a.Graph this in the frequency domain, showing amplitude and frequency

b.Assuming the frequency is in Hertz, what is the bandwidth for this signal?

11.A composite signal has a bandwidth of 150 KHz. The component sine wave with the highest frequency is at 250 KHz. What is the frequency of the component sine wave with the lowest frequency?

12.What is a possible unit for each measurement?

a.Frequency ___________________

b.Period ___________________

c.Phase

d.Analog Bandwidth