CCNA Questions and Answers for Exam

CCNA Questions and Answers for Exam

Question 1: What is the primary function of a router?

Answer: The primary function of a router is to connect multiple networks together, directing network traffic between them based on routing tables and protocols.

Question 2: What is a subnet mask?

Answer: A subnet mask is a 32-bit number used in IP address configuration that tells devices which portion of an IP address represents the network and which portion represents the host.

Question 3: What is the purpose of a VLAN?

Answer: A VLAN (Virtual Local Area Network) is used to logically divide a network into smaller broadcast domains. It helps improve network security, performance, and manageability.

Question 4: What is the difference between TCP and UDP?

Answer: TCP (Transmission Control Protocol) is a connection-oriented protocol that provides reliable and ordered delivery of data. UDP (User Datagram Protocol) is connectionless and provides fast transmission but without guaranteed delivery.

Question 5: Explain the three-way handshake used in establishing a TCP connection.

Answer: The three-way handshake involves three steps: SYN, SYN-ACK, and ACK. The client initiates the handshake by sending a SYN packet to the server, which responds with a SYN-ACK packet. Finally, the client sends an ACK packet to complete the handshake.

Question 6: What is the purpose of ARP (Address Resolution Protocol)?

Answer: ARP is used to resolve an IP address to a corresponding MAC address on a local network. It maintains a table (ARP table) of IP-MAC address mappings.

Question 7: What are the main differences between IPv4 and IPv6?

Answer: IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses. IPv4 has a maximum of roughly 4.3 billion unique addresses, whereas IPv6 provides an almost unlimited number of unique addresses. IPv6 also includes built-in support for security and auto-configuration.

Question 8: What is the purpose of ICMP (Internet Control Message Protocol)?

Answer: ICMP is used for error reporting and diagnostic functions in IP networks. It is typically used by network devices to send error messages indicating issues with packet delivery.

Question 9: What is the difference between a hub and a switch?

Answer: A hub is a simple networking device that broadcasts incoming data packets to all connected devices, while a switch selectively forwards data packets to the intended recipient based on MAC addresses.

Question 10: Explain the role of NAT (Network Address Translation) in a network.

Answer: NAT is used to translate private IP addresses to public ones and vice versa. It enables multiple devices in a private network to share a single public IP address, providing internet access to all devices simultaneously.

Question 11: Describe the purpose of DHCP (Dynamic Host Configuration Protocol).

Answer: DHCP is used to automatically assign IP addresses and other network configuration parameters to devices on a network. It simplifies network administration and eliminates the need for manual IP configuration.

Question 12: What is STP (Spanning Tree Protocol) and why is it necessary?

Answer: STP prevents loops in Ethernet networks by dynamically blocking redundant links. It ensures a loop-free topology, allowing redundant paths for improved network availability.

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