Prerequisite Knowledge Survey

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Prerequisite Knowledge Survey

• Q1. A NIC is a printed circuit board that
  provides network communication capabilities to
  and from a computer.
• A1. True. It is also called an adapter card. It
  contains the 48-bit MAC (Media Access Control)
  address which is also known as the physical
  address or hardware address.

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Prerequisite Knowledge Survey

• Q2. The binary number 10110 is 23 in decimal.
• A2. False. It is 22 (16 4 2).

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Prerequisite Knowledge Survey

• Q3. Digital bandwidth is measured in bits per
  second (bps).
• A3. True. It is the rated throughput capacity of
  a given network medium or a protocol. It can also
  be expressed as kilobits per second (kbps),
  megabits per second (Mbps), or gigabits per
  second (Gbps).

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Prerequisite Knowledge Survey

• Q4. A protocol is a set of rules.
• A4. True. These rules detail how devices on a
  network must exchange information. This includes
  the format of messages that will be exchanged and
  the details of error manage-ment.

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Prerequisite Knowledge Survey

• Q5. Data encapsulation occurs at a single OSI
  model layer only.
• A5. False. When data move from the upper layers
  down through the lower layers, headers, trailers,
  and other pertinent information are added by each
  of these layers.

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Prerequisite Knowledge Survey

• Q6. A network layer packet is called a datagram.
• A6. True. When data go down through the different
  layers, they become known as segments(upper
  layers), packets (layer 3), frames (layer 2), and
  bits (layer 1).

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Prerequisite Knowledge Survey

• Q7. Topology is the physical arrangement of
  network nodes and media.
• A7. True. See it as the general shape of the
  network. Bus, star, ring, point-to-point, and
  mesh are some of the common physical topologies.

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Prerequisite Knowledge Survey

• Q8. A LAN switch, or just a switch, is an OSI
  layer 3 (network layer) device.
• A8. False. It is an OSI layer 2 device. A router
  is a layer 3 device.However, switches can, in
  addition, have layer 3 functionality, and,
  conversely, routers can have layer 2
  functionality built in.

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Prerequisite Knowledge Survey

• Q9. Routers connect bridges and repeaters.
• A9. False. Routers connect multiple networks
  together. They can interconnect different LAN
  media and topologies, and also different media
  access methods such as Ethernet and Token Ring.

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Prerequisite Knowledge Survey

• Q10. You need 5 IP addresses to connect 4 hosts
  through a hub to the Internet.
• A10. False. A host is an addressable device, a
  hub is not. Because there are 4 hosts, only 4 IP
  addresses are needed, none for the hub.

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Prerequisite Knowledge Survey

• Q11. The reason that the wires in a UTP cable are
  twisted is to make it less expensive.
• A11. False. The purpose of twisting is to reduce
  interference to and from outside electrical
  sources. It also reduces the interference to and
  from the other wire pairs in the cable.

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Prerequisite Knowledge Survey

• Q12. Using repeaters reduces the number of
  collision domains.
• A12. False. A repeater regenerates and retimes
  signaling pulses received at its input before
  retransmitting them. It contains no intelligence
  to filter traffic and consequently does not
  influence the number of collision domains.

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Prerequisite Knowledge Survey

• Q13. Routers separate collision domains and
  broadcast domains.
• A13. True. A router separates network segments
  and will only process traffic specifically
  addressed to it in accordance with the content of
  routing tables, thereby separating these domains.

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Prerequisite Knowledge Survey

• Q14. In a full-mesh topology every node is
  connected to the central node.
• A14. False. There is no central node, every node
  is connected to every other node. A total of (n/2
  (n - 1)) connections are required for
  this.Example With 20 nodes, a total of (20/2)
  (20 - 1) 10 19 190 connections are needed
  to establish a full-mesh topology.

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Prerequisite Knowledge Survey

• Q15. Recognized IEEE sublayers are concerned with
  OSI layers 1 and 2.
• A15. True. IEEE 802.2 and IEEE 802.3 map to OSI
  layers 2 and 1 respectively.

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Prerequisite Knowledge Survey

• Q16. The first six hexadecimal numbers in a MAC
  address are the OUI.
• A16. True. The MAC address has 48 bits and is
  usually written as 12 hexadecimal characters. The
  first 6 are known as the OUI or Organizationally
  Unique Identifier and the remaining 6 are
  never-used-before numbers, assigned by the
  manufacturer of the device.

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Prerequisite Knowledge Survey

• Q17. The number 2989 in decimal notation is BAD
  in hexadecimal notation.
• A17. True. It is derived as follows2989 16
  186, remainder 13 D186 16 11 B,
  remainder 10 ACheckB 11 16 16
  2816A 10 16 160D 13, thus 2816 160
  13 2989.

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Prerequisite Knowledge Survey

• Q18. Errors can be detected with the use of CRCs.
• A18. True. CRCs (Cyclic Redundancy Checks)
  consist of the result of a mathema-tical
  algorithm that is applied by both the sender and
  the receiver of the data. If they agree, the data
  are considered to be received without error.

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Prerequisite Knowledge Survey

• Q19. Broadcasting is sending a single frame to
  many nodes at the same time.
• A19. True. The broadcast MAC address contains all
  hex Fs, and the IP broadcast address has all hex
  Fs in the HostID. All nodes with these addresses
  receive the same copy of the frame.

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Prerequisite Knowledge Survey

• Q20. CSMA/CD is a non-deterministic protocol.
• A20. True. CSMA/CD which stands for Carrier Sense
  Multiple Access/Collision Detection, is a
  probabilistic protocol, also called a
  non-deterministic protocol, and is used by
  Ethernet.Token ring uses a deterministic
  protocol.

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Prerequisite Knowledge Survey

• Q21. FDDI is characterized by a logical ring and
  a physical dual-ring topology.
• A21. True. With FDDI (Fiber Distributed Data
  Interface), data, driven logically (meaning by
  software), are travelling sequentially from node
  to node as in a ring. However, the actual
  designed, physical layout consists of a double
  ring.

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Prerequisite Knowledge Survey

• Q22. Token passing attaches token frames to data
  frames to access the network.
• A22. False. What happens is, that a node has to
  capture a free token first. This allows it to
  start transmitting data after changing the state
  of the token from free to busy. This ensures that
  no other node also can start to transmit, because
  every node needs a free token to do that.

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Prerequisite Knowledge Survey

• Q23. NICs interface with networks and with hosts
  through serial connections.
• A23. False. Although the interface with the
  network is a serial connection (bit-by-bit), the
  interface with the host uses a parallel interface
  (byte-by-byte).

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Prerequisite Knowledge Survey

• Q24. Transparent bridges filter traffic based on
  IP addresses.
• A24. False. Routers do that. Regular trans-parent
  bridges perform filtering based on MAC addresses,
  unless they also have layer 3 capabilities.

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Prerequisite Knowledge Survey

• Q25. Routers are less complicated devices than
  transparent bridges.
• A25. False. Because routers make routing
  decisions based on many more parameters than
  bridges do, they are also more versati-le, and
  consequently more complicated, (and expensive)
  than bridges.

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Prerequisite Knowledge Survey

• Q26. The maximum value of an octet is decimal
  256.
• A26. False. It is 255. An octet has 8 bits, with
  values from 00000000 to 11111111 or, in decimal
  notation, 0 to 255. The highest value is
  therefore 255. But, because the value of 0 is
  included, there are a total of 256 unique bit
  combinations

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Prerequisite Knowledge Survey

• Q27. The network portion of the IP address
  129.219.34.9 is 129.219.
• A27. True. It is a Class B address. Thus the
  first 2 octets form the NetID or prefix
  (129.219). The remaining 2 octets are the HostID
  or suffix (34.9).

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Prerequisite Knowledge Survey

• Q28. The maximum number of hosts in a Class C
  network is 256.
• A28. False. It is 254, because all 0s and all 1s
  are not allowed to be used in the NetID.This
  leaves 256 - 2 254 hosts that can be
  accommodated in a Class C network.All 0s are
  reserved for the network address (also called the
  wire address), and all 1s are reserved for the
  broadcast address.

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Prerequisite Knowledge Survey

• Q29. The minimum number of bits that can be
  borrowed to form a subset is 4.
• A29. False. The minimum number is 2. This allows
  for addresses 01 and 10.With two bits, 22 4
  combinations are possible, but dont forget, we
  just discussed that 00 and 11 are reserved for
  wire and broadcast address respectively.

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Prerequisite Knowledge Survey

• Q30. 131.82.21.35 AND 255.255.0.0 131.82.0.0.
• A30. True. In binary10000011.01010010.00010101.0
  010001111111111.11111111.00000000.00000000------
  --------------------------------------------
  AND10000011.01010010.00000000.00000000or in
  decimal 131 . 82 . 0
  . 0