Subtopics in this chapter
- 5.1Introduction to computer networks, physical layer and data link layer
- 5.2Network layer and transport layer
- 5.3Application layer and network security
- 5.4Synchronization, network management, protocols and programming model
- 5.5Control and central processing units
- 5.6Computer arithmetic and memory system and IO
What is usually tested
Networking questions follow the layers: the OSI and TCP/IP models, devices, Ethernet and CSMA/CD, IP addressing and subnetting, routing protocols, IPv6, TCP versus UDP, ports, congestion control, DNS, e-mail and FTP. Security questions cover cryptography, RSA, digital signatures, firewalls and common attacks. The chapter also includes socket programming calls, WAN technologies such as frame relay and ATM, and computer organisation: control units, addressing modes, RISC versus CISC, pipelining, cache memory and multiprocessors.
Sample questions with answers
Choose an answer to check it, or open "Show answer". These 12 are taken from the 210 questions for this chapter in the practice bank.
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Which OSI layer is responsible for routing?
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Answer: B. Network
The network layer handles logical addressing and routing.
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Which protocol maps an IP address to a MAC address?
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Answer: A. ARP
ARP resolves IP addresses to MAC addresses.
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TCP establishes a connection using:
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Answer: B. Three-way handshake
SYN, SYN-ACK, ACK: the three-way handshake.
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The default subnet mask of a Class C network is:
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Answer: C. 255.255.255.0
Class C default mask is /24 = 255.255.255.0.
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The default port number for HTTPS is:
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Answer: C. 443
HTTPS uses port 443 by default.
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The default port number of HTTP is:
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Answer: B. 80
Port 25 is SMTP, 53 is DNS and 110 is POP3.
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In a digital receiver, sampling time (clock) recovery means:
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Answer: A. Deriving the timing of the bit intervals from the received signal
The receiver must sample each bit at the correct instant, so it extracts the clock from the incoming data.
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Frame time recovery (framing) at a receiver means:
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Answer: B. Identifying where each frame begins in the received bit stream
A known framing pattern is searched for so that the bits can be assigned to the right time slots.
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In a microprogrammed control unit, the control signals are generated from:
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Answer: D. Microinstructions stored in a control memory
A hardwired control unit, in contrast, generates the signals with logic circuits.
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Compared with microprogrammed control, hardwired control is:
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Answer: A. Faster but harder to modify
Changing a hardwired design means changing the circuits; a microprogram can simply be rewritten.
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Cache memory is placed between:
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Answer: D. CPU and main memory
Cache sits between the CPU and main memory to reduce access time.
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Booth's algorithm is used for:
Show answer
Answer: D. Multiplying signed binary numbers in two's complement form
It handles positive and negative multipliers uniformly and skips over runs of identical bits.
Practise this chapter
The full mock tests mix 10 questions from this chapter with 10 from each of the other nine, under the real 2-hour limit. Chapter practice mode lets you work through this chapter alone, untimed, with the explanation shown after every question. Go to the mock tests