1. Why is the network layer necessary in computer networks?
a) To establish connections between devices
b) To provide physical addressing
c) To facilitate communication between different networks
d) To ensure data encryption
Answer: c) To facilitate communication between different networks
Explanation: The network layer is responsible for routing and forwarding data packets between different networks, enabling communication across interconnected networks.
2. Which service is NOT provided by the network layer?
a) Error detection
b) Packet forwarding
c) Addressing
d) Encryption
Answer: a) Error detection
Explanation: Error detection is typically performed at the data link layer, whereas the network layer focuses on routing and forwarding packets between networks.
3. Which of the following is a design issue related to the network layer?
a) Data encryption
b) Error correction
c) Routing
d) Physical addressing
Answer: c) Routing
Explanation: Routing, determining the best path for data packets to travel between networks, is a fundamental design issue addressed by the network layer.
4. Which routing algorithm finds the least-cost path to a destination node?
a) Bellman-Ford algorithm
b) Hierarchical Routing
c) Dijkstra’s algorithm
d) Broadcast Routing
Answer: c) Dijkstra’s algorithm
Explanation: Dijkstra’s algorithm calculates the shortest path from a source node to all other nodes in a network, making it suitable for finding the least-cost path.
5. What is the main advantage of Hierarchical Routing?
a) Reduced routing overhead
b) Enhanced security
c) Faster data transmission
d) Greater scalability
Answer: a) Reduced routing overhead
Explanation: Hierarchical Routing reduces routing overhead by organizing networks into hierarchical structures, allowing for more efficient routing table management.
6. Which routing algorithm is based on the principle of “distance vectors”?
a) Bellman-Ford algorithm
b) Dijkstra’s algorithm
c) Hierarchical Routing
d) Broadcast Routing
Answer: a) Bellman-Ford algorithm
Explanation: The Bellman-Ford algorithm uses distance vectors (the distances from one node to all other nodes) to calculate the shortest path to each destination.
7. Which routing algorithm can be used for finding the shortest path in a network with negative edge weights?
a) Dijkstra’s algorithm
b) Bellman-Ford algorithm
c) Hierarchical Routing
d) Broadcast Routing
Answer: b) Bellman-Ford algorithm
Explanation: Unlike Dijkstra’s algorithm, the Bellman-Ford algorithm can handle networks with negative edge weights, making it suitable for such scenarios.
8. Which routing technique forwards data packets to all nodes in a network?
a) Dijkstra’s algorithm
b) Bellman-Ford algorithm
c) Broadcast Routing
d) Multicast Routing
Answer: c) Broadcast Routing
Explanation: Broadcast Routing forwards data packets to all nodes within a network, ensuring that every node receives the transmitted data.
9. Which addressing scheme is used by the Internet Protocol (IP)?
a) MAC addressing
b) IPv6 addressing
c) Hierarchical addressing
d) Subnet addressing
Answer: b) IPv6 addressing
Explanation: The Internet Protocol (IP) uses IPv6 addressing, which provides a much larger address space compared to IPv4, accommodating the growing number of devices connected to the internet.
10. In which format are IP addresses typically represented?
a) Binary
b) Hexadecimal
c) Decimal
d) Octal
Answer: c) Decimal
Explanation: IP addresses are commonly represented in decimal format, where each octet is separated by a period (e.g., 192.168.1.1).
11. What is the purpose of fragmentation and reassembly in IP?
a) To compress data packets
b) To encrypt data packets
c) To break large packets into smaller ones for transmission
d) To authenticate data packets
Answer: c) To break large packets into smaller ones for transmission
Explanation: Fragmentation and reassembly allow large IP packets to be divided into smaller fragments for transmission across networks with different maximum transmission unit (MTU) sizes, and then reassembled at the destination.
12. Which protocol is used for reporting errors and diagnostic information in IP networks?
a) TCP
b) UDP
c) ICMP
d) ARP
Answer: c) ICMP
Explanation: The Internet Control Message Protocol (ICMP) is used for reporting errors and diagnostic information in IP networks, such as unreachable hosts or network congestion.
13. What is a key difference between IPv4 and IPv6?
a) IPv6 uses 32-bit addresses, whereas IPv4 uses 128-bit addresses
b) IPv6 has a larger address space than IPv4
c) IPv4 supports multicasting, whereas IPv6 does not
d) IPv6 does not require subnetting
Answer: b) IPv6 has a larger address space than IPv4
Explanation: IPv6 addresses are 128 bits long, providing a much larger address space compared to IPv4’s 32-bit addresses, which were becoming exhausted due to the growth of the internet.
14. Which header field is NOT present in the IPv4 header?
a) Source Address
b) Destination Address
c) Flow Label
d) Time to Live (TTL)
Answer: c) Flow Label
Explanation: The Flow Label field is present in the IPv6 header but not in the IPv4 header. It is used to identify packets belonging to the same flow or traffic stream.
15. Which mechanism allows IPv4 hosts to communicate with IPv6 hosts?
a) NAT
b) DHCP
c) DNS
d) Tunneling
Answer: d) Tunneling
Explanation: Tunneling encapsulates IPv6 packets within IPv4 packets, allowing IPv6 hosts to communicate over IPv4 networks until IPv6 support is widely deployed.
16. What is the size of the IPv4 address space?
a) 32 bits
b) 64 bits
c) 128 bits
d) 256 bits
Answer: a) 32 bits
Explanation: IPv4 addresses are 32 bits long, allowing for approximately 4.3 billion unique addresses.
17. Which routing algorithm is considered more efficient for small-scale networks?
a) Bellman-Ford algorithm
b) Dijkstra’s algorithm
c) Hierarchical Routing
d) Broadcast Routing
Answer: b) Dijkstra’s algorithm
Explanation: Dijkstra’s algorithm is more efficient for small-scale networks because it computes the shortest path from one node to all other nodes, optimizing routing for smaller network topologies.
18. What is the primary drawback of the Bellman-Ford algorithm?
a) High memory usage
b) Inability to handle negative edge weights
c) Slow convergence in large networks
d) Limited scalability
Answer: c) Slow convergence in large networks
Explanation: The Bellman-Ford algorithm’s convergence time increases significantly in large networks, making it less suitable for such scenarios compared to Dijkstra’s algorithm.
19. Which routing technique forwards data packets to a specific group of nodes?
a) Broadcast Routing
b) Unicast Routing
c) Multicast Routing
d) Anycast Routing
Answer: c) Multicast Routing
Explanation: Multicast
Routing forwards data packets to a specific group of nodes interested in receiving the transmitted data, conserving network bandwidth compared to broadcasting to all nodes.
20. What is the primary advantage of using IPv6 over IPv4?
a) Enhanced security features
b) Larger address space
c) Faster data transmission
d) Better compatibility with legacy systems
Answer: b) Larger address space
Explanation: IPv6 provides a significantly larger address space compared to IPv4, ensuring that there are enough unique addresses to accommodate the growing number of devices connected to the internet.
21. Which algorithm guarantees finding the shortest path between any two nodes in a network?
a) Dijkstra’s algorithm
b) Bellman-Ford algorithm
c) Hierarchical Routing
d) Broadcast Routing
Answer: a) Dijkstra’s algorithm
Explanation: Dijkstra’s algorithm guarantees finding the shortest path between any two nodes in a network, making it suitable for network routing.
22. Which protocol is responsible for fragmenting IP packets when necessary?
a) TCP
b) UDP
c) ICMP
d) IP
Answer: d) IP
Explanation: The Internet Protocol (IP) is responsible for fragmenting IP packets when their size exceeds the maximum transmission unit (MTU) of the network over which they are being transmitted.
23. Which IPv6 address type is used for communication within the same subnet?
a) Link-Local
b) Global Unicast
c) Unique Local
d) Multicast
Answer: a) Link-Local
Explanation: Link-Local addresses are used for communication within the same subnet and are automatically configured on IPv6-enabled devices.
24. Which routing algorithm is susceptible to the “count-to-infinity” problem?
a) Bellman-Ford algorithm
b) Dijkstra’s algorithm
c) Hierarchical Routing
d) Broadcast Routing
Answer: a) Bellman-Ford algorithm
Explanation: The “count-to-infinity” problem can occur in distance-vector routing algorithms like the Bellman-Ford algorithm, where incorrect routing information can cause routing loops and slow convergence.
25. Which field in the IPv4 header is used to prevent packets from looping indefinitely?
a) Time to Live (TTL)
b) Header Checksum
c) Protocol
d) Options
Answer: a) Time to Live (TTL)
Explanation: The Time to Live (TTL) field in the IPv4 header specifies the maximum number of hops (routers) that a packet can traverse before being discarded, preventing packets from looping indefinitely in the network.
26. What is the primary purpose of the Next Header field in the IPv6 header?
a) To specify the source address
b) To indicate the payload type
c) To define routing information
d) To mark the end of the packet
Answer: b) To indicate the payload type
Explanation: The Next Header field in the IPv6 header specifies the type of the next header following the IPv6 header, indicating the type of data contained in the packet’s payload.
27. Which routing algorithm is more suitable for networks with dynamic topology changes?
a) Dijkstra’s algorithm
b) Bellman-Ford algorithm
c) Hierarchical Routing
d) Broadcast Routing
Answer: a) Dijkstra’s algorithm
Explanation: Dijkstra’s algorithm is more suitable for networks with dynamic topology changes because it recalculates routes based on updated information, adapting to changes in network conditions.
28. Which addressing scheme allows network administrators to divide an IP network into smaller subnetworks?
a) MAC addressing
b) IPv4 addressing
c) Hierarchical addressing
d) CIDR addressing
Answer: d) CIDR addressing
Explanation: Classless Inter-Domain Routing (CIDR) addressing allows network administrators to divide an IP network into smaller subnetworks, providing flexibility in network design and address allocation.
29. Which routing algorithm guarantees convergence in finite time for any network topology?
a) Dijkstra’s algorithm
b) Bellman-Ford algorithm
c) Hierarchical Routing
d) Broadcast Routing
Answer: a) Dijkstra’s algorithm
Explanation: Dijkstra’s algorithm guarantees convergence in finite time for any network topology, ensuring that the shortest path to each node is calculated accurately.
30. Which protocol is used for dynamically assigning IP addresses to hosts on a network?
a) TCP
b) UDP
c) DHCP
d) DNS
Answer: c) DHCP
Explanation: The Dynamic Host Configuration Protocol (DHCP) is used for dynamically assigning IP addresses to hosts on a network, automating the process of IP address configuration and management.