Computer Networks and Security
NEC Computer Engineering · 1,806 practice MCQs
The 'Computer Networks and Security' chapter is essential for understanding the foundational concepts of networking and cybersecurity in the engineering field. This chapter covers critical topics like OSPF, TCP/IP protocols, and network security measures, all of which are vital for the NEC licensing exam.
With 1806 practice MCQs, this chapter equips you with the knowledge needed to tackle complex networking scenarios. To prepare effectively, focus on the key concepts and practice regularly using our extensive question bank to ensure you're ready for the exam.
Sample questions with answers
1.Which type of OSPF LSA represents external routes brought in from other autonomous systems?
- A.Type 2 (Network LSA)
- B.Type 5 (External LSA)
- C.Type 3 (Summary LSA)
- D.Type 1 (Router LSA)
Why: Type 5 (External LSA) is correct because it specifically represents external routes that are imported from other autonomous systems into OSPF, distinguishing it from the other types which represent internal information.
2.Which system call is used to get data from a connected socket?
- A.connect()
- B.send()
- C.recv()
- D.accept()
Why: recv() is the correct answer because it is the system call used to receive data from a connected socket, whereas the other options serve different purposes in socket programming.
3.Which encoding method increases the bandwidth twofold compared to NRZ?
- A.Manchester
- B.AMI
- C.NRZ-I
- D.RZ
Why: Manchester encoding is correct because it encodes each bit as two signal changes, effectively doubling the bandwidth compared to Non-Return-to-Zero (NRZ) encoding, which uses one signal change per bit.
4.What is the formula for effective window?
- A.cwnd + advertised window
- B.min(cwnd, advertised window)
- C.cwnd × advertised window
- D.cwnd - ssthresh
Why: min(cwnd, advertised window) is correct because it determines the effective window size by taking the smaller value between the congestion window (cwnd) and the advertised window, ensuring efficient flow control.
5.Which of the following port numbers is NOT considered well-known?
- A.65000
- B.1433
- C.80
- D.22
Why: 65000 is correct because it is not a well-known port number; well-known ports range from 0 to 1023, while 65000 is outside of this range.
6.What is the largest possible size of an IPv4 packet (with a 16-bit length field)?
- A.32,768 bytes
- B.1,500 bytes
- C.65,535 bytes
- D.8,192 bytes
Why: 65,535 bytes is correct because the maximum size of an IPv4 packet is determined by the 16-bit length field, which can represent values from 0 to 65,535.
7.Which protocol facilitates group communication in IPv6?
- A.IGMPv3
- B.OSPF
- C.MLD (Multicast Listener Discovery)
- D.ARP
Why: MLD (Multicast Listener Discovery) is correct as it is the protocol used in IPv6 for managing multicast group memberships, unlike the other options which serve different functions.
8.What TCP extension allows for window sizes greater than 64 KB?
- A.Window scaling option
- B.SACK option
- C.Urgent pointer
- D.Timestamp option
Why: Window scaling option is correct because it allows TCP to negotiate larger window sizes than the default maximum of 64 KB, enabling better performance in high-bandwidth networks.
9.Which TCP algorithm grows the fastest at the beginning?
- A.Fast Recovery
- B.Vegas
- C.Slow Start
- D.Congestion Avoidance
Why: Slow Start is correct because it increases the congestion window exponentially at the start of a TCP connection, allowing for rapid growth of the transmission rate.
10.Which part of the CIA triad is most at risk from a DoS attack?
- A.Integrity
- B.Authentication
- C.Confidentiality
- D.Availability
Why: Availability is correct because a Denial of Service (DoS) attack primarily targets the availability of resources, making them inaccessible to legitimate users.
11.Which transport service is best for handling DNS requests?
- A.Reliable broadcast service
- B.Connectionless unreliable service
- C.Ordered multicast service
- D.Connection-oriented reliable service
Why: Connectionless unreliable service is correct because DNS requests typically use UDP, which is a connectionless and unreliable protocol, suitable for quick queries without the need for guaranteed delivery.
12.Where can IPv6 fragmentation happen?
- A.Only at routers
- B.Only at the source
- C.Not at all
- D.At both source and routers
Why: Only at the source is correct because in IPv6, fragmentation is handled only by the source node before the packet is sent, unlike IPv4 where routers can also fragment packets.
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Frequently asked questions
- What are OSPF LSAs and why are they important?
- OSPF LSAs (Link State Advertisements) are crucial for routing information in OSPF. They help routers understand the network topology.
- How can I enhance my understanding of socket programming?
- Familiarize yourself with system calls, particularly those used for data transmission, to strengthen your socket programming skills.
- What is the significance of window size in TCP?
- The window size in TCP determines the amount of data that can be sent before waiting for an acknowledgment, impacting network performance.
- Why is IPv4 packet size important?
- Understanding the maximum size of an IPv4 packet is critical for network design and troubleshooting, as it affects data transmission efficiency.
- What role does group communication play in IPv6?
- Group communication in IPv6, facilitated by protocols like MLD (Multicast Listener Discovery), is essential for efficient data distribution to multiple recipients.