Sample Questions/Answers 101: OSI Layers, IPv4/IPv6, Computer Network, Network Security

 QUESTIONS:

 

1. Computers are also called as Nodes? True or False

2. Which of the following modes of communication is not supported by IPV4 network?

A.   Unicast

B.   Broadcast

C.   Anycast

D.   Multicast

3. The keyboard/monitor relationship is an example of which transmission mode?

A.   Simplex

B.   Half Duplex

C.   Full Duplex

4. LAN Technologies include Ethernet, Token Ring and FDDI. What is the full form of FDDI?

5. The following technologies fall under which network?

Modems, ISDN (Integrated Services Digital Network), Digital Subscriber Line(DSL), Frame Relay, T1, E1, T3 and E3 and SONET (Synchronous Optical Network).

6. What does WWW and FTP stand for?

7. Difference between baseband and broadband?

8. What is the full form of TDM (used in baseband) and FDM (used in broadband)?

9. Name 6 physical topologies?

10. What are the two most common types of logical topologies?

11. What is the token passing on bus topology called?

12. What are the two types of Network Architecture?

13. What is the PDU in OSI layer I – Physical Layer?

14. How many pins the network connector has and which pins are used?

15. Which layers does Ethernet operate on?

16. What is a guided media?

17. What is a coaxial cable?

18. What are the devices that operate in physical layer?

19. What is a throughput?

20. What are the various unguided media used in physical layer?

21. The physical layer is concerned with physical network topology.

True or False

22. What does CSMA/CD stand for?

23. What are the services of Data link layer?

24. Ethernet, token ring, FDDI and PPP are protocols of which layer of the OSI?

25. Which device operate at OSI Model Layer 2? MAC address works at the data link layer, True or False.

26. What is the PDU of Data link layer?

27. What does OUI, NIC and MAC stand for?

28. What is the size of MAC address?

29. Which service is not provided by Ethernet?

A. A check for the recipient that the raw data being transmitted does not contain errors.

B. An ability to broadcast to all interfaces on the same LAN.

C. Confirmation for the sender that data has reached the recipient.

D. Addressing between physical interfaces.

 30. What is the maximum length for the client data payload in a standard Ethernet frame?

A.   1200 bytes

B.   1500 bytes

C.   There is no defined maximum

D.   46 bytes

31.Hamming code is a set of error-correction codes that can be used to detect and correct the errors that can occur when the data is moved or stored from the sender to the receiver. True or False

32. Checksum is the value to verify the integrity of a file or data transfer. True or False

33. Congestion control in network layer is achieved by QoS. True or False and what does it stand for?

34. What are the four addressing modes?

35. What is a Subnet Mask?

36. What does NAT stand for?

37. Subnetting is the process of dividing a network into equal segments. It is a logical subdivision of IP network. What is the subnet mask of Class C IPv4 address with CIDR value 29?

38. Functions of Network Layer?

39. What does DVR, OSPF, RIP EIGRP, BGP, AS stand for?

40. Please draw routing protocols in a listed flow chart?

41. What is a VLSM? What does it stand for?

42. What does ARP, RARP, and ICMP stand for?

43. ARP associates IP address with the physical address? True or False

44. ARP request is Unicast and ARP response is Broadcast. True or False

45. What is RARP

46. In which layer we see ICMP? ICMP packet is generated and sent to the sender when the last fragment of the datagram is discarded by the router. True or False

47. What is the metrics used for RIP, OSPF and EIGRP?

48. What is the purpose of show ip route?

49. The network layer protocol for internet is __________

a) ethernet
b) internet protocol
c) hypertext transfer protocol
d) file transfer protocol

50. What is the min. and max. size of IPv4 header length(4bit field)?

51. What is the min. and max. size of IP packet(header and data) in bytes included in ‘total length’(16 bits) segment of IP header?

52. The time to live(TTL) field has 8 bits and is used to prevent packets from looping around forever (if you have a routing loop). True or False

53. What is the size of source address and destination address in an IPV4 packet header?

54. Which layer the following fall into:

Domain Name System, Hypertext Transfer Protocol, Simple Mail Transfer Protocol, Post Office Protocol, File transfer protocol, Telnet, DHCP – Dynamic Host Configuration Protocol.

55. Ip and port together makes socket. True or False

56. What are the three ranges of port numbers?

57. What are the port numbers for the below TCP Protocols?

FTP(File Transfer Protocol)

SSH(Secure Shell)

Telnet

SMTP(Simple Mail Transfer Protocol)

HTTP(Hypertext Transfer Protocol)

POP3(Post Office Protocol)

HTTPS(HHTP Secure)

58. What are the port numbers for the below UDP Protocols?

SIP(Session Initiation Protocol)

NTP(Network Time Protocol)

DHCP(Dynamic Host Configuration Protocol)

59. What are the port numbers for the below TCP/UDP Protocols?

DNS(Domain Name System)

SNMP(Simple Network Management Protocol)

60. Which layer does end to end delivery?

61. What is the full form of CRC?

62. How is error control performed in transport layer?

63. Multiplexing and demultiplexing is performed in transport layer. True or False

64. Reliable and connection oriented TCP provides error-checking and recovery mechanism? True or False

65. What is the size of IPv6 header?

66. What is the maximum size of IPv4 and IPv6 packet?

67. The three addressing format of IPv6 are unicast, broadcast and multicast? True or False

68. What are the two types of IPv6 Unicast Address?

69. Which IPv6 address is valid?

A.2031:0:130F::9C0:876A:130B

B.2001:0DB8:0000:130F:0000:0000:08GC:140B

C.2001:0DB8:0:130H::87C:140B

D.2031::130F::9C0:876A:130B

70. Which IPv6 address is the equivalent of the IPv4 interface loopback address 127.0.0.1?

::1, ::, 2000::/3, 0::/10

71. How many bits are contained in each field of an IPv6 address?

72. A way of protecting a computer from intrusion through the ports

A.   Firewall B.Antivirus C. Data Encryption

73. It was the first-generation security standard for wireless network.

A.   LEAP B.WEP C. WPA

74.  It is a wireless security protocol created by Cisco to address the weaknesses in WEP and WPA 

75. What does RSA stand for?

76. Symmetric encryption uses one key for both encryption and decryption, and the asymmetric encryption uses public key for encryption and a private key for decryption. True or False

77. Application layer is based on the client server model. True or False

78. In which layer of OSI model does 3 way handshake happens?

79. TCP handshake connection is half duplex. True or False

80. FTP works in which layer?

81.  Secure shell (SSH) network protocol is used for __________
a) secure data communication
b) remote command-line login
c) remote command execution
d) all of the mentioned

82. SSH uses ___________ to authenticate the remote computer.
a) public-key cryptography
b) private-key cryptography
c) any of public-key or private-key
d) both public-key & private-key

83. Which one of the following protocol can be used for login to a shell on a remote host except SSH?
a) telnet
b) rlogin
c) both telnet and rlogin
d) none of the mentioned

84. Which one of the following is a file transfer protocol using SSH?
a) SCP
b) SFTP
c) Rsync
d) All of the mentioned

85. What are the 3 email protocols?

86. POP3 which supports offline access to the messages is generally used to support multiple clients. True or False

87. Is RSA symmetric or asymmetric?

88. What is the full form of URL?

89. In the DNS, the names are defined in ___________ structure.

a.Linear b.Flat c.Organized d.Inverted

90.  DNS can use the services of ________.

a.UDP  b.TCP  c.UDP or TCP  d.None

91.  What does MRTG and PRTG stand for?

92. What is a Wireshark?

93. What is WinSCP?

94. What is DHCP?

95. What is proxy caching?

96.  Application layer offers _______ service.
a) End to end
b) Process to process
c) Both End to end and Process to process
d) None of the mentioned

97. To deliver a message to the correct application program running on a host, the _______ address must be consulted.
a) IP
b) MAC
c) Port
d) None of the mentioned

98.  Electronic mail uses which Application layer protocol?
a) SMTP
b) HTTP
c) FTP
d) SIP

99. What is a full form of IDS?

100. What is a PGP?

101. What is IPsec?

102. What is SSL?

103. What are the three properties of a secure communication?

104. What is a signature key and verification key in digital signature?

 ANSWERS:

 

1. True

2. C. Anycast

3. A. Simplex

4. Fiber Distributed Data Interface

5. Wide Area Network (WAN)

6. World wide web and File Transfer Protocol

7. Baseband: Communication channel in digital form over a single frequency, bidirectional, every device on a baseband shares the same channel

Broadband: Communication through radiofrequency analog waves that use different frequency range, unidirectional.

8. TDM-Time-division multiplexing and FDM-Frequency-division multiplexing

9. Bus Topology, Ring Topology, Star Topology, Extended Star Topology, Hierarchical Topology, Mesh Topology

10. Broadcast and Token Passing (Token Ring and FDDI uses Token Passing)

11. Arcnet

12. Peer-to-Peer Model and Client-Server Model

13. Bits

14. An Ethernet cable RJ45 connector has 8 pins. Pins 1 & 2 (green) and pins 3 & 6 (orange) [GO to remember]are used for data communications while pins 4 & 5 (blue) and pins 7 & 8 (brown) [BB-bye bye to remember]are not used.

15. Ethernet, Token Ring, and Frame Relay are all examples of Data Link layer or Layer 2 protocols.

16. Guided Media is the physical connection(cables) between two devices. Magnetic Media, twisted pair of cables, coaxial cables, fibre-optic cables come under this category.

17. A coaxial cable consists of a copper wire, covered with an insulated material.

18. Devices that operate at the physical layer include repeaters, hubs, cables and connectors.

19. Throughput is the actual rate that information is transferred.

20. Ground propagation, Sky Propagation, Line of sight propagation. An unguided transmission transmits the electromagnetic waves without using any physical medium. Therefore it is also known as wireless transmission.

21. True

22. Carrier sense multiple access with collision detection.

23. Data Link Control (Framing/encapsulation and link access, reliable delivery, flow control, error detection, error correction) and Media access control(MAC, LAN switching, Physical addressing, QaS, VLAN(Virtual Local Area Network))

24. They are data link layer protocols.

25. Switch. True

26. Frames

27. Organizational Unique identifier, Network interface controller/Card and Media Access Control

28. 48-bits (six groups of two hexadecimal digits)

29.  C. Confirmation for the sender that data has reached the recipient.

30.  B – 1500 Bytes

31. True

32. True

33. True. Quality of Service(QoS)

34. Unicast Addressing Mode, Multicast Addressing Mode, Broadcast Addressing Mode and Anycast Addressing Mode.

35. It is a 32-bit address either represented in binary or decimal value, which determines the network portion and the host portion of an IP address.

36. Network Address Translation

37. 248

38. A. Routing Packets from the source host to destination host. The routes can be based upon static routing tables (rarely changed) or through dynamic routing.

B. Provides Mechanism for Congestion control(through QoS)

C. Provides logical address to the host.

D. Tackles issues like transmission delays, transmission time, avoidance of jitters.

E. Accepts data from transport layer above, divides, encapsulates into packets and sends it to the data link layer and vice versa during receiving of the data.

39. DVR – Distance Vector Routing

OSPF-Open Shortest Path First

RIP-Routing Information Protocol

EIGRP-Extended Interior Gateway Routing Protocol

BGP-Border Gateway Protocol

AS-Autonomous system

40. Routing Protocols----Static, Default, Dynamic

Dynamic--------IGP(Interior Gateway Protocol) and EGP(Exterior Gateway       Protocol)

IGP : DVR(Distance Vector routing protocol)àRIP(routing information protocol), IGRP(interior gateway routing protocol)

       : Link State Routing ProtocolàOSPF(open shortest path first), ISIS(intermediate system to intermediate system)

       : Hybrid Routing Protocol à EIGRP(extended interior gateway protocol)

EGP: Path Vector Routing ProtocolàBGP(Border gateway protocol—if we have to do routing between external autonomous networks) àIBGP(interior border gateway protocol) an EBGP(Exterior border gateway protocol)

41. Variable-Length Subnet Masking(VLSM) amounts to ‘subnetting subnets’.

42. ARP-Address Resolution Protocol

RARP-Reverse Address Resolution Protocol

ICMP-Internet Control Message Protocol

43. True (Mapping of physical address through logical address is done through ARP- here IP and MAC of host is known – but MAC of receiver is not known(logical known) – so mapping is done by sending packets to the logical address of the host – receiving of which packet is replied which includes the physical address of the host.)

44. False (ARP request is broadcast and ARP response is unicast). (ARP is a dynamic mapping).

45. Mapping of logical address through physical address is done through RARP.

46. Network Layer. False ? ICMP packet is generated and sent to the sender when the first fragment of the datagram packet is discarded by the router.

47. RIP- Metrics used is hop.

OSPF – Metrics used are bandwidth and delay.

EIGRP – Metrics used are bandwidth, delay, load and reliability.

48. The show ip route command is used to show the router's routing table.

49. Answer: b
Explanation: There are several protocols used in Network layer. Some of them are IP, ICMP, CLNP, ARP, IPX, HRSP etc. Hypertext transfer protocol is for application layer and ethernet protocol is for data link layer.

50. Min 20 bytes, Max – 60 Bytes

51. Min 20 Bytes, Max – 65,535 Bytes

52. True

53. 32 bits source IP address, 32 bits destination IP address.

54. Application Layer

55. True

56. Well-known ports. The well-known ports are those from 0 - 1,023.

Registered ports. The registered ports are those from 1,024 - 49,151.

Dynamic and/or private ports(Ephemeral Ports) The dynamic and/or private ports are those from 49,152 - 65,535.

(The default ephemeral port numbers are in the range 1024 – 65535.)

57. FTP(File Transfer Protocol)à20 & 21

SSH(Secure Shell)à22

Telnetà23

SMTP(Simple Mail Transfer Protocol)à25

HTTP(Hypertext Transfer Protocol)à80

POP3(Post Office Protocol)à110

HTTPS(HHTP Secure)à443

58. SIP(Session Initiation Protocol)à5060

NTP(Network Time Protocol)à123

DHCP(Dynamic Host Configuration Protocol)à67 & 68

59. DNS(Domain Name System)à53

SNMP(Simple Network Management Protocol)à161

60. Transport layer. (End to end delivery is also called port to port delivery).

61. Cyclic Redundancy check

62. Through Checksum

63.  True

64. True

65. AN IPv6 header is fixed as 40 bytes long.

66. 65,535 bytes. (The payload length field of IPv6 (and IPv4) has a size of 16 bits, With 16 bits, an IPv6 payload of up to 65,535 bytes can be indicated.)

67. False. The three addressing format of IPv6 are unicast, anycast and multicast.

(The three addressing format of IPv4 are unicast, broadcast and multicast).

68. Global Unicast Address(GUA), Link-local Address(LLA)

69. A -2031:0:130F::9c0:876A:130B

70. ::1

71. 16 bits

72. A. Firewall

73. B.WEP

74. A.LEAP

75. Rivest,Shamir, Adleman

76. True

77. True

78. Transport Layer (Through TCP (Transmission Control Protocol)which is a Transport Layer host-to-host protocol for connection-oriented communication between two computers on an IP network).

79. False. (The connection is full duplex, and both sides synchronize (SYN) and acknowledge (ACK) each other. The exchange of these four flags is performed in three steps: SYN, SYN-ACK, ACK,)

80. Application layer.

81. D – All of the above

82. Answer: A
(Explanation: Public encryption key is slower but more flexible. Every cryptographic security system requires a private key for private access and a public key for location.)

83. C (Explanation: SSH is more secured then telnet and rlogin.)

84. Answer: d
(Explanation: SCP (Secure copy protocol), SFTP (SSH File Transfer Protocol) and Rsync all are file transfer protocols which are used by SSH.)

85. SMTP(Simple Mail Transfer Protocol), POP3(Post Office Protocol 3), IMAP(Internet Message Access Protocol)

86. False. (IMAP is designed to handle multiple clients, POP is used to support single client.)

87.  It is an asymmetric algorithm that uses a publicly known key for encryption, but requires a different key, known only to the intended recipient, for decryption.

88. Uniform Resource Locator

89. d.Inverted

90. c. UDP or TCP

91. Multi Router Traffic Grapher (MRTG) 

Paessler Router Traffic Grapher(PRTG)

92. Wireshark is a network packet analyzer.

93. WinSCP (Windows Secure Copy) is an open source SecureFTP client for Windows. (note - WinSCP is for file transfer to and from your server while PuTTY is used to interact with the server directly)

94. DHCP means dynamic host configuration protocol; it hands out IP addresses for devices in your network.

95. Proxy caching is a feature of proxy servers that stores content on the proxy server itself, allowing web services to share those resources to more users. A caching proxy server accelerates service requests by retrieving the content saved from a previous request made by the same client or even other clients

96. A. End to End

97. C – Port (IP address lets you know where the network is located. Whereas MAC address is a unique address for every device. Port address identifies a process or service you want to carry on.)

98. A (Explanation: Email uses various protocols like SMTP, IMAP and POP. The most prominent one used in application layer is SMTP.)

99. An Intrusion Detection System (IDS) is a network security technology originally built for detecting vulnerability exploits against a target application or computer.

100. Pretty Good Privacy (PGP) is an encryption system used for both sending encrypted emails and encrypting sensitive files.

101. Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts the packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs).

102. Stands for "Secure Sockets Layer." SSL is a secure protocol developed for sending information securely over the Internet

103. Secrecy, Authentication, Message Integrity (SAM-Acronym to remember).

104. The private key used for signing is referred to as the signature key and the public key as the verification key.

 

THANK YOU.