Most Asked Interview Question on CCNA Routing & Switching

Preparing for an interview focused on CCNA Routing & Switching can be challenging. Here’s a list of commonly asked interview questions, along with brief explanations or answers, to help you prepare effectively:

1. Basic Networking Concepts:

Q1: What is a network?

• Answer: A network is a collection of interconnected devices that communicate with each other to share resources and information.

Q2: What are the different types of networks?

• Answer: Types include LAN (Local Area Network), WAN (Wide Area Network), MAN (Metropolitan Area Network), PAN (Personal Area Network), and WLAN (Wireless Local Area Network).

2. OSI Model:

Q3: Can you explain the OSI model?

• Answer: The OSI (Open Systems Interconnection) model has seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

Q4: What are the functions of the Network layer?

• Answer: The Network layer is responsible for routing, forwarding, addressing, and packet switching.

3. IP Addressing and Subnetting:

Q5: What is an IP address?

• Answer: An IP address is a unique identifier assigned to each device connected to a network, used for communication.

Q6: What is subnetting and why is it used?

• Answer: Subnetting is the process of dividing a network into smaller sub-networks to improve performance and manageability.

Q7: How do you calculate the subnet mask for a given network?

• Answer: Identify the number of required subnets and hosts per subnet, then determine the subnet mask that accommodates these requirements.

4. Routing Concepts:

Q8: What is the difference between static and dynamic routing?

• Answer: Static routing involves manually configuring routes, while dynamic routing uses protocols to automatically update and manage routing tables.

Q9: Can you name some dynamic routing protocols?

• Answer: Examples include RIP (Routing Information Protocol), OSPF (Open Shortest Path First), EIGRP (Enhanced Interior Gateway Routing Protocol), and BGP (Border Gateway Protocol).

Q10: What is the purpose of the default gateway?

• Answer: The default gateway is the router that forwards traffic from a local network to other networks or the internet.

5. Switching Concepts

Q11: What is a VLAN and why is it used?

• Answer: A VLAN (Virtual Local Area Network) is a logical subgroup within a network that segments devices into different broadcast domains to improve security and efficiency.

Q12: What is the difference between a switch and a router?

• Answer: A switch operates at the Data Link layer to forward frames based on MAC addresses, while a router operates at the Network layer to route packets based on IP addresses.

Q13: How does STP (Spanning Tree Protocol) work?

• Answer: STP prevents loops in a network by creating a spanning tree that selectively blocks certain paths to ensure there is only one active path between any two network devices.

6. Network Security:

Q14: What are ACLs (Access Control Lists)?

• Answer: ACLs are a set of rules applied to router interfaces to control incoming and outgoing traffic based on IP addresses and protocols.

Q15: What is the purpose of NAT (Network Address Translation)?

• Answer: NAT translates private IP addresses to public IP addresses, allowing multiple devices on a local network to share a single public IP for internet access.

7. Practical Scenarios and Troubleshooting:

Q16: How would you troubleshoot a network connectivity issue?

• Answer: Steps include checking physical connections, verifying IP configurations, testing connectivity with tools like ping and traceroute, and reviewing device logs and configurations.

Q17: What steps would you take to configure a new router?

• Answer: Basic steps include assigning an IP address to interfaces, configuring routing protocols, setting up passwords for security, and verifying the configuration.

8. Advanced Concepts:

Q18: Can you explain the differences between TCP and UDP?

• Answer: TCP (Transmission Control Protocol) is connection-oriented and ensures reliable data transmission, while UDP (User Datagram Protocol) is connectionless and faster but less reliable.

Q19: What is HSRP (Hot Standby Router Protocol)?

• Answer: HSRP is a Cisco redundancy protocol that ensures network availability by providing failover capability for routers.

Q20: What is the purpose of DHCP (Dynamic Host Configuration Protocol)?

• Answer: DHCP automatically assigns IP addresses and other network configuration parameters to devices on a network, simplifying management.

To excel in a CCNA Routing & Switching interview, focus on understanding core networking concepts, practical configuration, and troubleshooting skills. Reviewing these common questions and ensuring you have hands-on experience with network devices and simulators will prepare you effectively for the interview.

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