1) For each of the following four networks, discuss the consequences if a connection fails. a. Five
devices arranged in a mesh topology b. Five devices arranged in a star topology (not counting
the hub) c. Five devices arranged in a bus topology d. Five devices arranged in a ring topology
2) a) Draw a hybrid topology with a star backbone and three ring networks. b) Draw a hybrid
topology with a ring backbone and two bus networks.
3) a) How are OSI and ISO related to each other? Define data communication and underline
atleast three benefits in our society. b) Distinguish between serial and parallel transmissions.
4) Compare and contrast the OSI and TCP/IP models. Why is TCP/IP the preferred model?
5) Describe the 7 layers of the OSI model in tabular form. What are some of the advantages to
layering?
6) A device is sending out data at the rate of 2000 bps. a. How long does it take to send out 10
bits? b. How long does it take to send out a single character (8 bits)? c. How long does it take
to send a file of 300,000 characters?
7) What is the theoretical capacity of a channel in each of the following cases: a. Bandwidth: 20
KHz SNRdB =20 b. Bandwidth: 100 KHz SNRdB =30 c. Bandwidth: 2 MHz SNRdB =20?
8) What are the propagation time and the transmission time for a 5-Mbyte message (an image) if
the bandwidth of the network is 1 Mbps? Assume that the distance between the sender and the
receiver is 16,000 km and that light travels at 2.4 × 108 m/s.
9) The loss in a cable is usually defined in decibels per kilometer (dB/km). If the signal at the
beginning of a cable with −0.3 dB/km has a power of 4 mW, what is the power of the signal at
8 km?
10) We need to send 365 kbps over a noiseless channel with a bandwidth of 40 kHz. How many
signal levels do we need?
11) From the below streams determine the binary modulated signal of i) ASK ii) MPSK iii) FSK.
a) 10101101 b) 1011101101
12) Assume that a voice channel occupies a bandwidth of 4 kHz. We need to combine four voice
channels into a link with a bandwidth of 12 kHz, from 20 to 32 kHz. Show the configuration,
using the frequency domain. Assume there are no guard bands.