Download Practice questions for exam

1. Which of the following below is/are capability of ICMP protocol?
a. report package count
b. report network congestion
c. both b and d
d. report availability of remote host
2. Which of the following below is a loop back IP address?
a. 127.0.1.0
b. 127.0.0.0
c. 127.1.0.0
d. 127.0.0.1
3. In 10base2, 10base5, what does 2 and 5 stand for?
a. maximum speed
b. maximum number of segments
c. minimum number of segments
d. length of segments
4. TELNET used _________ protocol for data connection
a. TCP
b. UDP
c. both TCP and UDP
d. DHCP
e. IP
5. ____________ is added to data packet for error detection.
a. parity bit
b. checksum bit
c. both a and b
d. error bit
6. What is the port number for HTTP?
7. What is the port number for HTTPS?
8. Which of the following are Application Layer protocols?
a. FTP, HTTP
b. DHCP
c. IS-IS
d. POP3
9. Dynamic addressing allows many devices to share limited address space on a
network
a. true
b. false
10. MAC addresses are also known as:
a. hardware addresses
b. physical addresses
c. logical addresses
d. both a and b
11. What is the difference between a switch and a hub?
a. switches operate at physical layer while hubs operate at data link layer
b. switches operate at data link layer while hubs operate at physical layer
c. switches limit collision domains while hubs do not
d. switches limit broadcast domains while hubs do not
12. What is the correct term for network data at the data link layer?
a) Segment
b) Packet
c) Frame
d) Ethernet
13. Which network layer protocol is used to derive MAC addresses from IP
addresses?
a) IP
b) ICMP
c) IGMP
d) ARP
14. What term is used to define headers and trailers surrounding data in OSI?
a) Frames
b) Packets
c) Segments
d) Protocol data units
15. What type of cable is required in order to connect a PC to a switch?
a) Straight through
b) Crossover
c) Rollover
d) Console
16. What is the length of an Ethernet MAC address?
17. Which of the following components does TCP use in the header in order to
identify whether or not a packet was successfully delivered?
a) ACK
b) SYN
c) FIN
d) SEQ
18. Which layer in the OSI reference model is responsible for things like encryption,
decryption, and formatting?
19. Which layer in the TCP/IP model uses port numbers in order identify upper layer
services?
20. The process of forwarding ports to unknown unicast addresses out all ports is
known as __________.
a) Forwarding
b) Learning
c) Flooding
d) Flashing
21. What portion of the frame header does a switch look to in order to identify the
destination node?
a) Source MAC
b) Destination IP
c) Source IP
d) Destination MAC
22. You are trying to identify a standard to use as the core of your Ethernet LAN. You
need an inexpensive and flexible yet high speed standard. Which should you
choose?
a) 100BaseT
b) 802.3
c) 1000BaseT
d) 10BaseT
23. Which type of traffic does a network switch always forward directly to the
destination?
a) Known Unicast
b) Unknown Unicast
c) Broadcast
d) Multicast
24. Which network design describes switches that have multiple redundant
connections to most other switches?
a) Full mesh
b) Star
c) Partial mesh
d) Hybrid
24. What protocol is used for VLAN trunking on modern switches?
a) PPP
b) 802.1Q
c) VTP
d) None of the above
25. Draw a network diagram with 2 core routers, 2 access routers, 3 switches and a
total of 5 hosts. On your diagram, clearly specify the broadcast domains and
collision domains. How many of each type do you have for your chosen network
design? Assume only one default VLAN for all hosts.
26. Given the scenario in Question 25, now assume 2 of your hosts belong to
VLAN1, and the other 3 to VLAN2. Specify again the number of broadcast and
collision domains.
27. What is required in order to configure routing between multiple VLANs?
a) Layer 2 switch
b) Layer 3 switch
c) Router
d) Hub
28. Give four reasons for implementing VLANS in a large network.
29. You have a system with IP address 10.250.100.15/16. Given this IP address which
of the following are not allowed as host addresses on the network? (Choose Two)
a) 10.250.0.0
b) 10.250.255.254
c) 10.250.255.255
d) 10.250.100.0
30. What is the network broadcast address for the network on which a device with IP
address 172.31.34.150/19 resides?
a) 172.31.255.255
b) 172.31.31.255
c) 172.31.64.255
d) 172.31.63.255
31. What is the network ID for a system with IP address 172.20.54.101/18?
a) 172.20.0.0
b) 172.20.32.0
c) 172.20.64.0
d) 172.20.16.0
32. You start with a class B address and need to implement 8 subnets. What will you
use as a subnet mask?
a) 255.255.0.0
b) 255.255.255.0
c) 255.255.224.0
d) 255.255.128.0
33. You start with a class A address and need to set up 200 subnets. What mask
should you use?
a) 255.255.0.0
b) 255.224.0.0
c) 255.255.254.0
d) 255.240.0.0
34. Which of the following is used with private LAN addresses in order to gain
access to the Internet using a public address?
a) ACL
b) DNS
c) NAT
d) SSL
35. You have the following IP address for a client: 192.168.17.254/26. What is the
network ID?
a) 192.168.0.0
b) 192.168.17.0
c) 192.168.17.192
d) 192.168.17.128
36. Given the following IP address: 10.104.15.6 what is the network ID if subnet
mask is 255.255.252.0?
37. You need to convert 255.255.240.0 to prefix notation. Which of the following is a
correct conversion?
a) /20
b) /21
c) /23
d) /24
38. Which of the following is not a valid Class B address?
a) 10.0.0.0
b) 173.16.0.0
c) 128.10.0.0
d) 127.0.0.0
39. Which of the following is not a valid Class C address?
a) 191.250.254.0
b) 192.16.12.0
c) 200.100.10.0
d) 193.10.10.0
40. The correct CIDR notation for the subnet mask 255.255.240.0 is /20.
a) True
b) False
41. The correct range of available addresses for a network on which resides a PC
with IP address 192.168.1.33/27 is 192.168.1.17-192.168.1.47.
a) True
b) False
42. A system on your network is configured with the following address:
172.31.34.255/20. Which of the following should be configured as the default
gateway in order to communicate with remote host assuming the router interface is
the first in the subnet?
a) 172.31.0.1
b) 172.31.32.1
c) 172.31.16.1
d) Other. Which?
43. Which of the following subnet masks is not valid?
a) 255.255.255.240
b) 255.255.192.0
c) 255.255.128.0
d) 255.255.140.0
44. You need to identify the reason a client cannot connect with neighboring
systems on different subnets. The IPCONFIG is as follows for the client:
192.168.10.33/28 Default Gateway: 192.168.10.31. Which of the following is most
likely the issue?
a) IP address
b) Subnet Mask
c) Default Gateway
d) DNS server
45. What is the purpose of subtracting 2 IDs when measuring the number of
available host IDs on a subnet?
46. Which of the following is defined as the length of time it takes for routers in the
same internetwork to update each other's routing tables?
a) Latency
b) Time delay
c) Convergence
d) Round trip
47. You are designing a corporate network. List at least four of the most important
network design criteria you should have in mind.
48. Explain what tier-1, tier-2, and tier-3 networks are.
49. Explain the difference between a service, a primitive and a protocol.
50. Explain the difference between half-duplex, full-duplex and simplex.
51. In the OSI Model, what does OSI stand for?
52. What are the four layers of the TCP/IP Model?
53. List four multiple access methods/technologies.
54. Besides bandwidth and latency, what other parameter is needed to give a good
characterization of the quality of service offered by a network used for (i) digitized
voice traffic? (ii) video traffic? (iii) financial transaction traffic?
55. What are some of the physical media that Ethernet can run over?
56. A TCP segment consisting of 1500 bits of data and 160 bits of header is sent to
the IP layer, which appends another 160 bits of header. This is then transmitted
through two networks, each of which uses a 24-bit packet header. The destination
network has a maximum packet size of 800 bits. How many bits, including headers,
are delivered to the network layer protocol at the destination?
57. Why are the wires twisted in twisted-pair copper wire?
58. Define flow control.
59. Describe stop-and-wait flow control.
60. List and briefly define three versions of ARQ
61. What is bit stuffing and how does it work?
62. What is frequency-hopping spread spectrum?
63. What is the relationship between the bandwidth of a signal before and after it
has been encoded using spread spectrum?
64. What are the advantages of packet switching compared to circuit switching?
65. Explain the difference between datagram and virtual circuit operation.
66. What is the essential difference between Dijkstra’s shortest path tree and a
minimum spanning tree?
67. Apply Dijkstra and Prim’s algorithms on the following graphs. Draw the
corresponding trees.
68. Why
is it that
when the
load
exceeds
the
network
capacity,
delay
tends to
infinity?
69. What
is load
balancin
g?
70. What
is the
differenc
e
between
storeand-forward and cut-through switching? Can you think of advantages and
disadvantages of each?
71. Draw a network diagram in which due to improper network design / equipment
choice a broadcast storm is possible. Label/identify the network nodes
appropriately.
72. A Layer-2 switch can forward frames from one subnet to another.
a) true
b) false
73. Assume two hosts, A - 10.1.2.1/24 and B – 10.1.3.1/24 are connected through a
switch. Can they communicate? If not, troubleshoot the problem.
74. List some basic functions performed at the MAC layer.
75. What is CSMA/CD.
76. What is the difference between an interior router protocol and an exterior router
protocol? Give examples for each.
77. Explain the use of multiplexing in the context of a transport protocol.
78. What are hash functions and how are they used in the context of cryptography?
79. What services are provided by IPSec?
80. Perform encryption and decryption using the RSA algorithm for the following:
a. p = 3; q = 11, d = 7; M = 5
b. p = 5; q = 11, e = 3; M = 9
c. p = 7; q = 11, e = 17; M = 8
d. p = 11; q = 13, e = 11; M = 7
e. p = 17; q = 31, e = 7; M = 2
81. In a public-key system using RSA, you intercept the ciphertext C = 10 sent to a
user whose public key is e = 5, n = 35. What is the plaintext M?
82. Explain the main differences between IMAP and POP3. Think in terms of
advantages and disadvantages of each.