Exercise 1
Exercise 1
Exercise 1
8. Name the four basic network topologies, and cite an advantage of each type.
- Mesh topology: fast communication, robust, privacy
- Star topology: less expensive, robust
- Ring topology: easy configuration, fault isolation
- Bus topology: easy installation, cheap
9. For n devices in a network, what is the number of cable links required for a mesh, ring, bus,
and star topology?
- Mesh topology: n(n-1)/2
- Star topology: n
- Ring topology: n-1
- Bus topology: one backbone and n drop lines
10. What are some of the factors that determine whether a communication system is a LAN or
WAN?
LAN (Local Area Network)
worldwide
Owned
15. A color image uses 16 bits to represent a pixel. What is the maximum number of different
colors that can be represented?
- 216 = 65 536
16. Assumes six devices are arranged in a mesh topology. How many cables are needed? How
many ports are needed for each device?
17.
Cables
Cables =
=
(1)
2
6 (61)
2
6 (5)
2
=
= 15
Ports
Each devices need to connected to each other.
Ports = 6 devices x 5 devices
= 30 devices
18. For each of the following four networks, discuss the consequences if a connection fails.
a. Five devices arranged in a mesh topology
The others device will still work
b. Five devices arranged in a star topology (not counting the hub)
The hub still can be access by other device except the failed one.
c. Five devices arranged in a bus topology
Bus is in a straight line (like series circuit), if one device fails, the other devices will eventually fail too
d. Five devices arranged in a ring topology
Ring will make the device to connect back onto itself. If one device fail, the other devices will
eventually fail too
19. You have two computers connected by an Ethernet hub at home. Is this a LAN, a MAN, or a
WAN? Explain your reason.
It is a LAN because LAN usually connects in small area such as house and we use Ethernet hub to
connect LAN
20. In the ring topology in Figure1.8, what happens if one of the stations is unplugged?
In a ring topology, unplugging one station, interrupts the ring. However, most ring networks use
a mechanism that bypasses the station; the ring can continue its operation.
21. In the bus topology in Figure1.7, what happens if one of the stations is unplugged?
In a bus topology, no station is in the path of the signal. Unplugging a station has no effect on
the operation of the rest of the network.
22. Draw a hybrid topology with a star back bone and three ring networks.
23. Draw a hybrid topology with a ring back bone and two bus networks.
24. Performance Is inversely related to delay. When you use the Internet, which of the following
applications are more sensitive to delay?
a. Sending an e-mail
b. Copying a file
c. Surfing the Internet
24. When a party makes a local telephone call to another party, is this a point-to-point or multi point
connection? Explain your answer.
Point to point because it is between two party. Multi point need more than two parties to communicate
25. Compare the telephone network and the Internet. What are the similarities? What are the
differences?
SIMILARITIES
Both can be used for communication
Both can be wire / wireless
DIFFERENCES
Telephone is limited to voice communication only
while Internet can be in written form or video
Can share data using Internet