Download CAN1102-2009-10-S1-exampaper

BSc (Hons) Business Information Systems
BSc (Hons) Web Technologies
BIS/08/PT - BWT/09/FT
Examinations for 2009 - 2010 / Semester 1
MODULE: NETWORKS/NETWORKING ESSENTIALS
MODULE CODE: CAN1102/CAN1103
DURATION: 2 HOURS
READING TIME: None
Instructions to Candidates
1. Answer both Section A and any 2 questions from Section B
2. Always start a new question on a fresh page for Section B.
3. Total marks: 100
4. Use of silent calculators is allowed in the Examination Room.
This questionnaire contains 29 Questions and consists of 9 pages.
Page 1 of 9
SECTION A
The following 25 multiple-choice questions contain only one correct
answer. You do not need to copy the questions, write your response legibly
i.e. (a), (b), (c) or (d) on your script in five columns with the respective
question number.
1.
(a)
(b)
(c)
(d)
How many layers does the TCP/IP model have?
7
4 or 5
3
Variable
2.
(a)
(b)
(c)
(d)
Which topology requires a multipoint connection?
Mesh
Star
Bus
Ring
3.
(a)
(b)
(c)
(d)
Which of the following usually operate on a Local Area Network (LAN)?
Ethernet
Internet
Arpanet
None of the above
4.
(a)
(b)
(c)
(d)
Which layer in the ISO:OSI model is concerned with logic transmission only?
Physical layer
Network Layer
Data Link Layer
Transport Layer
5.
(a)
(b)
(c)
(d)
What is the direct purpose of layered communication models?
Reduce complexity
Increase transmission rate
Improve reliability
Enhance security
Page 2 of 9
6.
(a)
(b)
(c)
(d)
What does FEC stands for?
Forward Error Correction
Forward Error Connection
Full Event Correction
Full Error Correction
7.
(a)
(b)
(c)
(d)
What does a CSMA transmitter do when it has data to transmit?
Send out an RTS to all other transmitters
Transmit the data immediately
Sense the channel to see if idle
Broadcast “jamming” signal to all other nodes
8.
(a)
(b)
(c)
(d)
Which of the following device does not provide traffic isolation?
Router
Hub
Bridge
Switch
9.
(a)
(b)
(c)
(d)
How many bits are there in an IPv4 address?
16
32
64
4
10.
(a)
(b)
(c)
(d)
Which one is a feature of IPv6, different from IPv4?
Fragmentation
128-bit address
Variable length header
A field of “more fragments” (MF)
11. In ARP, what does node A do first if it wants to get the physical address of node
B if node B's IP address is known?
(a) Check nearest router's routing table
(b) Send a unicast packet to node B to ask for the physical address
(c) Check its ARP table
(d) Broadcast an ARP request over the network
12.
(a)
(b)
(c)
(d)
Which of the following is NOT a characteristic of a Token Ring network?
Token flows either clockwise or anticlockwise but not in both direction
A node must capture the token before data can be transmitted
Token must be released by the node after data transmission
Token ring networks are robust and if one node fails it does not affect the other
nodes
Page 3 of 9
13.
(a)
(b)
(c)
(d)
Which of the following is NOT true about the MAC address?
It uniquely identifies a network adapter
It can be changed when a host is moved to another network.
It is 48-bits in size
It is usually stored in a ROM chip on the network adapter.
14. Which of the following device would you use to interconnect two LANs which are
using two different LAN technologies i.e. one LAN using Ethernet and the other
LAN using Token Ring?
(a) Hub
(b) Bridge
(c) Router
(d) Switch
15.
(a)
(b)
(c)
(d)
Which of the following is NOT true about a 10Base-T standard?
The transmission speed is 10 Mbps
It uses Twisted pair cables.
It uses a baseband signal
It is easy to detect cable breaks and to add or remove nodes.
16.
(a)
(b)
(c)
(d)
What does CDMA stands for?
Code Diversion Model Access
Coding Discrete Model Access
Code Division Model Access
Code Division Multiple Access
17.
(a)
(b)
(c)
(d)
Which of the following does NOT apply to Bluetooth Technology?
Small range of wireless connection
It uses frequency of 5 – 6 GHz and is uni-directional.
It uses a frequency of 2.4 – 2.5 GHz and is omni-directional.
It allows devices such as phone, camera, printers, notebooks to connect.
18.
(a)
(b)
(c)
(d)
Which of the following is not an application layer protocol?
SMTP
SSL
HTTP
FTP
19.
(a)
(b)
(c)
(d)
What is the port number associated with HTTP?
25
21
23
None of the above
Page 4 of 9
20.
(a)
(b)
(c)
(d)
What is the default subnet mask for a Class A network?
255.255.255.0
255.255.255.255
255.255.0.0
None of the above
21. You are asked to create 10 Class C subnets with at least 10 hosts per subnet.
Which subnet mask must you use?
(a) 255.255.255.192
(b) 255.255.255.224
(c) 255.255.255.240
(d) 255.255.255.248
22.
(a)
(b)
(c)
(d)
HDLC is an acronym for ____.
high-duplex line communication
high-level data link control
half-duplex digital link combination
host double-level circuit
23. In IEEE 802.11, a ____ is made of stationary or mobile wireless clients and an
optional central base station, known as the access point (AP).
(a) ESS
(b) BSS
(c) CSS
(d) None of the above
24.
(a)
(b)
(c)
(d)
The ____ layer of Ethernet consists of the LLC sublayer and the MAC sublayer.
data link
physical
network
none of the above
25.
(a)
(b)
(c)
(d)
Fast Ethernet has a data rate of ____ Mbps,
10
100
1000
10,000
[25 x 2 marks]
Page 5 of 9
SECTION B
ATTEMPT ANY TWO QUESTIONS
Question 26 (25 marks)
(a) Name 3 popular electronic mail access protocols?
[3 marks]
(b)
i.
What is DNS?
ii.
Briefly, describe what it does and how it works?
iii.
Why does DNS use a distributed approach as opposed to a single server?
[2+3+2 marks]
(c) HTTP supports both non-persistent and persistent connections.
i.
Describe each type of connection and state which HTTP protocol version
supports each type?
ii.
How and where is the type of connection specified in the HTTP protocol?
[6+2 marks]
(d) Assume that a new application layer protocol is developed for video conferencing
application. Which transport layer protocol do you think will be used and why?
[3 marks]
(e) FTP is said to have an “out-of-band” connection. Explain what it means?
[4 marks]
Page 6 of 9
Question 27 (25 marks)
(a) Describe briefly the difference between flow control and congestion control in
relation to a connection-oriented protocol such as TCP.
[6 marks]
(b) What is the initial rate of data transfer in the slow start phase of TCP congestion
control, if the MSS is 1060 bytes and an average RTT of 200 milliseconds?
[2 marks]
(c) Each host on the Internet is currently assigned an IP address 32 bits long (IPv4).
IPv4 addresses are usually written as a series of four decimal numbers. IPv4
addresses traditionally belong to one of five classes of address, depending on
the type of network.
i. Describe the structure of Class C address and a type of network it is
suited for.
ii. Give two advantages of creating subnets within a larger network.
iii. On an isolated network two hosts have been configured to work on the
same subnet with IP addresses 10.10.201.254 and 10.15.201.254. Can
this configuration work? What would the subnet mask need to be?
iv. Give five differences between IPv6 and IPv4?
[3+2+4+5 marks]
(d) Describe very briefly the purpose of the following protocols:
i. DHCP
ii. ICMP
iii. RARP
[3 marks]
Page 7 of 9
Question 28 (25 marks)
(a)
The IEEE 802 series of standards describe both the Physical and Data Link
layers of their respective technologies. Two important standards are 802.3 and
802.5, respectively known as CSMA/CD (Ethernet) and Token Ring.
i. Explain how CSMA/CD operates and describe how Ethernet deals with
collisions.
ii. Give the structure of a typical Token Ring frame and explain how
communication is effected in a Token Ring Network.
[4+4 marks]
(b)
A datagram of 3000 bytes has to travel over a network with a MTU size of 1000
bytes. Explain how fragmentation can be used to solve this problem.
You should give the value of the 3 key fields used in fragmentation for each
fragment created.
[8 marks]
(c)
Nowadays many companies are shifting towards the IEEE 802.11x standard for
extending their network.
i. Outline two popular flavours of this wireless standard. Elaborate on the
operating frequency, range and speed of each flavour.
ii.
What are the two modes of operation of this standard and explain the
difference between the two.
iii. Mention one security issue with this wireless technology and explain how
this issue can be addressed.
[3+4+2 marks]
Page 8 of 9
Question 29 (25 marks)
(a) Mention the five main security services.
[5 marks]
(b) What is a passive attack? Give an example of passive attack?
[4 marks]
(c) What four types of active attacks and mention their respective attacks to which
security services?
[4 marks]
(d) Distinguish between authentication and non-repudiation.
[4 marks]
(e) Which type of algorithms can be used to provide the following security services:
i. Message integrity
ii. Message integrity and authentication
[4 marks]
(f) Describe how public key cryptography can be used to provide message
confidentiality when Alice wants to communicate with Bob.
[4 marks]
***END OF PAPER***
Page 9 of 9