1. Network (FE)
by Tanat Tonguthaisri
itpe@nstda.or.th

2. 1. When the subnet mask “255.255.255.0” is
used in a “class A” network, how many host
addresses can be assigned to network devices?
a) 254
b) 256
c) 2 16
d) 2 24

3. 2. Which of the following protocols is used in mail
servers on a TCP/IP network?
a) DHCP
b) SMTP
c) SNMP
d) TELNET

4. 3. Which of the following protocols is supported
by the transport layer of the OSI basic reference
model?
a) HTTP
b) IP
c) PPP
d) TCP

5. 4. Which of the following is the network topology
that is used to connect one central node or hub
with point-to-point links to several other nodes?
a) Bus
b) Mesh
c) Ring
d) Star

6. 5. In home and office networks of Fast or Gigabit
Ethernet, which of the following cables can be
used as a lower cost option for connecting a
client PC to the network?
a) Coax
b) Fiber-optic
c) STP
d) UTP

7. 6. Which of the following is a device that
interconnects LANs at the physical layer of the
OSI basic reference model?
a) Bridge
b) Gateway
c) Repeater
d) Router

8. 7. Which of the following is the most appropriate
information used by routers in order to determine
the routing paths of packets?
a) Destination IP address
b) Destination MAC address
c) Source IP address
d) Source MAC address

9. 8. Which of the following appropriately explains
the function of the transport layer in the OSI
basic reference model?
a) It is responsible for establishing, managing, and terminating
communication connections between the applications running in
different nodes, and provides means for dialogue control
between end systems.
b) It is responsible for maintaining reliable end-to-end
communications and data transfer between systems across the
network, and provides a variety of functions including flow
control, virtual circuit, and error checking and recovery.
c) It provides a set of interfaces for applications to obtain access
to networked services as well as access to a variety of network
services that support applications directly.
d) It provides a variety of coding and conversion functions which
ensure that information sent from the application layer of one
system is readable by that of another system.

10. 9. Which of the following is the appropriate statement
concerning the number of host addresses available to
one sub-network in IPv4?
a) The number of host addresses available in a sub-
network is always fixed, depending on the class of IP
address; 28 for class A, 216 for class B, and 224 for class C.
b) The number of host addresses available in a sub-
network is always fixed, depending on the class of IP
address; 224 for class A, 216 for class B, and 28 for class
C.
c) The number of host addresses available in a sub-
network is determined by the number of “0” bits in the
subnet mask.
d) The number of host addresses available in a sub-
network is determined by the number of “1” bits in the
subnet mask.

11. 10. Which of the following is the local broadcast
address to be used by a computer with IP
address 202.130.17.63 and subnet mask
255.255.255.0 if classless addressing is used?
a) 202.130.0.0
b) 202.130.0.1
c) 202.130.17.1
d) 202.130.17.255

12. 11. When a 9-Kbyte data file is transmitted using the asynchronous
(or start-stop) communication protocol at a speed of 2,400 bps, what
is the “overhead” (time spent on sending start, stop, and parity bits
except data bits) in seconds? Here, a start bit is first sent, followed
by eight data bits, no parity bit, and one stop bit, for each byte of the
data file.
a) 7.5
b) 11.25
c)30
d)37.5

13. 9 K-byte
Start bit + stop bit = 2 bit per byte.
9K x 2 = 18 K-bits for this file.
18 Kbits / 2400 bps = 7.5 seconds.

14. 12. When MAC (Media Access Control) frames
defined by IEEE 802.3 are transmitted over
Ethernet, which of the following methods is used
for error detection?
a) Checksum
b) CRC
c)Hamming code check
d)Parity check

15. 13. Which of the following methods is used for
avoiding unnecessary collisions in the IEEE
802.11 family of wireless LAN standards?
a) CDMA
b) CSMA/CA
c)CSMA/CD
d)TDMA

16. 14. VLAN (Virtual LAN) is used to logically
segment a LAN into different broadcast domains.
In which of the following network devices should
the function of VLAN be supported?
a) Bridge
b) Hub
c)Repeater
d)Switch

17. 15. Which of the following protocols can be used
to temporarily assign an IP address leased from
the pool to the host that asks for an address or to
repeatedly assign the same IP address to the
host according to the MAC address of the host?
a) ARP
b) DHCP
c)SIP
d)SNMP

18. 16. Which of the following can be used to
interconnect multiple LANs on the network layer
(layer 3) of the OSI basic reference model and to
relay packets of data?
a) Bridge
b) Gateway
c)Repeater
d)Router

19. 17. When the subnet mask 255.255.255.240 is
used for a server, which of the following is a valid
IP address of the server?
a) 193.144.134.31
b) 194.123.178.16
c)195.206.108.25
d)196.168.206.47

20. 240 = 128 + 64 + 32 + 16
= 27 + 2 6 + 25 + 24
= 111100002
31 = 000111112
16 = 000100002
25 = 000110012
47 = 001011112

21. 18. Which of the following is the signaling
protocol that is widely used to initiate, manage,
and terminate multimedia communication
sessions, such as voice and video calls over the
Internet?
a) RTP
b) SIP
c)SMTP
d)SNMP

22. 19. Which of the following is a security feature
that can allow network administrators to specify
exactly which stations should have access to the
wireless network?
a) IP address filtering
b) MAC address
filtering
c)Packet filtering
d)URL filtering

23. 20. Which of the following information in IP
header is used for routing the IP packets
across networks?
a) Destination address and source
address fields
b) Destination address field
c) Destination address, source address,
and protocol fields
d) Source address field

24. 21. Which of the following network
topologies is commonly used, especially in
Fast or Gigabit Ethernet, for connecting
network devices via a centralized unit such
as a hub or a switch?
a) Bus
b) Mesh
c) Ring
d) Star

25. 22. What is the minimum number of
communication cables that are needed to connect
six network devices in a full mesh topology? Here,
at least one communication cable is required to
connect two network devices.
a) 5
b) 6
c) 12
d) 15

26. n * (n-1) / 2 = 6 * 5 / 2
= 15

27. 23. Which of the following is the IP network
addressing and routing scheme whereby data is
routed to the “nearest” or “best” destination as
viewed by the routing topology?
a) Anycast
b) Multicast
c) Singlecast
d) Unicast

28. 24. Which of the following protocols can be used to access e-
mail messages that are stored on a remote, and possibly
shared, mail server, and thereby are manipulated from a
desktop computer at home, a workstation at the office, and a
notebook computer while traveling, without the need to
transfer messages back and forth between these computers?
a) FTP
b) IMAP
c) POP3
d) SMTP

29. 25. Which of the following is an appropriate
explanation concerning the function of a
proxy server?
a) It is a centralized point of access to the Internet, and also provides an
effective and efficient way to improve network performance by memory and
disk caching of commonly visited web sites.
b) It is used for translating, or resolving, domain names into IP addresses.
Every time a domain name is entered, it resolves that name to the
appropriate IP address and allows communication across the Internet.
c) It provides a simple and secure way to upload and download information,
either text or graphics, between the server and clients over the Internet.
d) It provides a way to manage and automate the assignment of IP addresses
from a central point, and sends a new IP address and other network
configuration information automatically when a client is plugged into the
Internet.

30. 26. In the OSI basic reference model, which of the following
is the appropriate layer that provides end-to-end
communication services for applications, and also provides
convenient services such as connection-oriented or
connectionless data stream support, reliability, flow control,
and congestion control?
a) Data link layer
b) Network layer
c) Session layer
d) Transport layer

31. 27. Which of the following is an appropriate
combination of the protocols that are used for
transmitting and receiving e-mail as shown in the
diagram below? (3) Transfer e-mail
Mail server Mail server
(1) Send e-mail (2) Receive e-mail
Mail client
(1) (2) (3)
a) POP3 POP3 SMTP
b) POP3 SMTP POP3
c) SMTP POP3 SMTP
d) SMTP SMTP SMTP

32. 28. Which of the following describes the role
of DNS in the TCP/IP network?
a) Allocating an unused IP address from the IP
addresses registered in the server, in response to a
request from a PC for IP address assignment
b) Enabling access to the Internet by converting an in-
company private IP address into a global IP address
c) Linking a name, such as a domain name or a host
name, with an IP address
d) Making it possible to call a program in a server by
specifying its name without regard to the IP address
of the server

33. 29. When the CRC (Cyclic Redundancy
Check) function is implemented by
calculating a generator polynomial, which of
the following is used as a CRC code
(sometimes simply called CRC)?
a) Dividend
b) Quotient
c) Remainder
d) Summation

34. 30. Which of the following is the broadcast MAC
address that is used by multiple protocols, such as
ARP (Address Resolution Protocol) and RIP
(Routing Information Protocol), in order to transmit
data to all of the hosts on the local subnet?
a) 00-00-00-00-00-00
b) EE-FF-EE-FF-EE-
FF
c) F0-F0-F0-F0-F0-F0

35. 31. In an IPv4 environment, when the subnet
mask “255.255.255.224” is used for a class C
network, how many IP addresses including
reserved or ineffective addresses can be
assigned to subnets and hosts per subnet
respectively?
Number of IP addresses
Subnet Host
a) 8 32
b) 16 16
c) 16 32
d) 32 8

36. 224 = 128 + 64 + 32
= 27 + 2 6 + 25
= 111000002
No. of subnets = 23 = 8
No. of Hosts = 25 = 32

37. 32. Which of the following is the appropriate layer
of the OSI basic reference model that provides
RPC (Remote Procedure Call) support, maintains
the integrity of the connection between nodes, and
controls data exchange?
a) Application layer
b) Network layer
c) Presentation layer
d) Session layer

38. 33. Which of the following is a connectionless
protocol that offers speed and low overhead as its
primary advantage in the transport layer of the OSI
basic reference model?
a) ARP
b) ICMP
c) IP
d) UDP

39. 34. Which of the following is a protocol used by the
ping command in order to verify that the
communication link between source and
destination is working in the TCP/IP network
environment?
a) ARP
b) ICMP
c) SMTP
d) SNMP

40. 35. Which of the following is an appropriate
combination of information that a DHCP server
dynamically provides for a client host to
participate in the TCP/IP network?
a) IP address, MAC address, default gateway
address, and DNS server address
b) IP address, MAC address, DNS server address,
and routing information
c) IP address, subnet mask, default gateway
address, and DNS server address
d) IP address, subnet mask, default gateway
address, and routing information

41. 36. Which of the following is the appropriate
combination that is defined as a socket address in
TCP/IP network environments?
a) IP address and port number
b) IP address and socket number
c) MAC address and port number
d) MAC address and socket number

42. 37. Which of the following is the server that can be
used to intercept all messages entering and
leaving the network and to effectively hide the true
network addresses?
a) DHCP server
b) DNS server
c) E-mail server
d) Proxy server

43. 38. Which of the following is the data transmission technique that has
features or characteristics shown below?
It is designed for cost-efficient data transmission for
intermittent traffic between LANs and between end-points
in a WAN.
Data is transmitted in a variable-size unit.
Error correction (i.e., retransmission of data) is left up to
the end-points.
It is based on the X.25 protocol, but it is faster because of
a simplified X.25 protocol with minimal services.
It provides a mid-range service between ISDN and ATM.
a) Cell relay
b) Frame relay
c) Message Switching
d) Packet Switching

44. 39. In the network shown below, the STP (Spanning Tree Protocol) is
used on both S1 and S2 switches. When the link between two PCs A
and C is established via L1, which of the following is the appropriate
link that is used to transfer data between two PCs B and D?
A B
S1
L1 L2 L3
S2 a) Always L1
b) Always L2
C D
c) Always L3
d) Either L2 or L3

45. 40. In a URL (Uniform Resource Locator) specified to
access a Web page through the Internet, which of the
following is the appropriate sequence of four basic parts:
the name of the Web page, directory and/or subdirectory
which holds the Web page, access protocol, and host
name?
a) host name, protocol, directory, page
b) host name, protocol, page, directory
c) protocol, host name, directory, page
d) protocol, page, directory, host name

46. 41. Which of the following is used for encoding and
interpreting binary files, images, video, and non-
ASCII character sets within an e-mail message on
the Internet?
a) IMAP
b) MIME
c) POP3
d) SMTP

47. /24 
11111111. 11111111.11111111.00000000
/28 
11111111. 11111111.11111111.11110000
/29 
11111111. 11111111.11111111.11111000