Top 30 CCNA Routing and Switching Interview Questions and Answers

Are you preparing for an interview related to networking skills? If yes, then you can read this amazing article, which consists of the Top 30 CCNA Routing and Switching Interview Questions and Answers.

These questions are specially designed to provide you with an overview of the questions that could be asked during the interview. What are we waiting for? Let’s get straight to the topic!

What is CCNA?

Cisco offers an entry-level information technology (IT) certification called the CCNA (Cisco Certified Network Associate), which focuses on networking principles. It verifies familiarity with fundamental security and automation as well as network installation, configuration, and troubleshooting.

Obtaining this certification usually indicates a basic level of knowledge required for a variety of networking positions at a lower level. Let’s take a look at the “Top 30 CCNA Routing and Switching Interview Questions and Answers!”

Top 30 CCNA Routing and Switching Interview Questions and Answers

The following are some of the top 30 CCNA routing and switching interview questions and answers:

1. What is the difference between a hub, a switch, and a router?

A router connects various networks (such as your home LAN to the internet) and chooses the optimal method for data transmission, a hub links devices in a local area network (LAN) but broadcasts all data, and a switch intelligently transmits data only to the intended receiver inside a LAN.

2. Explain the purpose of a VLAN. How does it work?

A logical grouping of network devices known as a VLAN (Virtual Local Area Network) enables a single physical network switch to be divided into several separate broadcast domains, enhancing performance, security, and organization by managing data flow.

3. What is the difference between a Layer 2 switch and a Layer 3 switch?

A Layer 3 switch can do all Layer 2 tasks plus IP address-based routing (between separate networks/VLANs), whereas a Layer 2 switch forwards data based on MAC addresses (inside a single network/VLAN).

4. Can you describe the function of the Spanning Tree Protocol (STP)?

A network technique called the Spanning Tree technique (STP) dynamically chooses and blocks redundant pathways while maintaining network connectivity, preventing Layer 2 switching loops in an Ethernet network topology.

5. What is the purpose of the ARP (Address Resolution Protocol) in networking?

Direct communication between devices is made possible via the Address Resolution Protocol (ARP), which dynamically converts a Layer 3 IP address to its matching Layer 2 physical MAC address inside a local network segment.

6. What are the different types of IP addresses, and what do they signify?

IP addresses can be further divided into two categories: Static (manually assigned and permanent) and Dynamic (automatically assigned by DHCP and temporary). Public addresses are globally unique and routable on the internet, while private addresses are used within internal networks and are not routable on the internet.

7. How do you configure a static route on a Cisco router?

Use the global configuration command ip route [destination-network] to set up a static route on a Cisco router. [subnet-mask] [exit-interface | next-hop-ip] [administrative-distance-optional] Then save the setup after that.

8. What is RIP (Routing Information Protocol) and how does it work?

The routing information protocol, or RIP, is a distance-vector routing protocol that advertises routing tables to nearby routers every 30 seconds to dynamically find the shortest path.

It employs the hop count, or the number of routers needed to reach the target, as its measure.

9. What is OSPF (Open Shortest Path First), and how does it differ from RIP?

The industry-standard link-state routing protocol OSPF (Open Shortest Path First) converges significantly faster than the more antiquated distance-vector protocol RIP, which only uses the more straightforward hop count as its metric. OSPF uses Dijkstra's algorithm to determine the shortest path based on cost (bandwidth).

10. What is the purpose of the router's routing table, and how is it built?

Using a combination of directly connected networks, manually configured static routes, and dynamic routes learned through routing protocols (such as OSPF or EIGRP), the router's routing table is a database that holds the best path information to various network destinations, enabling the router to efficiently determine the next hop for forwarding data packets.

11. Explain the concept of CIDR (Classless Inter-Domain Routing).

By employing a variable-length subnet mask (VLSM), indicated by a prefix length (e.g., /24), CIDR (Classless Inter-Domain Routing) replaces the previous class-based system (A, B, C) for IP addressing and enables more effective and flexible IP address distribution as well as improved route aggregation.

12. What is NAT (Network Address Translation), and why is it used in networking?

Network address translation, or NAT, is a technique where a router changes the IP address information in packet headers as they pass through a traffic device. It is mainly used to conserve the limited number of IPv4 addresses by enabling multiple devices on a private internal network (using private IP addresses) to share a single public IP address when connecting to the internet.

Related Link: What is NAT?

13. What is the difference between IPv4 and IPv6?

While IPv6 uses 128-bit addresses (e.g., 2001:db8::1) represented in hexadecimal notation, offering an almost infinite number of unique addresses, built-in security, and simplified header processing, IPv4 uses 32-bit addresses (e.g., 192.168.1.1) and is represented in dotted-decimal notation, offering approximately 4.3 billion unique addresses.

Related Link: What is an IPv6 Address?

14. What is the role of a default gateway in a network?

Devices can connect outside of their immediate local network by using the default gateway, which is the router's IP address on a local network segment that serves as the departure point for all traffic going to distant networks (such as the internet or another subnet).

15. How would you troubleshoot a network that is not able to reach external sites?

In the following ways, you can troubleshoot a network that is not able to reach external sites:

a) Local Host/ Client Checks (L1-L4),

b) Router/ Gateway Checks (L3-L4), and

c) DNS & Upstream Checks (L5-L7).

16. Can you explain what an access control list (ACL) is and give an example of how it works?

As a network traffic filter, an Access Control List (ACL) is a sequential list of rules (statements) set up on a router or switch that instructs the device which network traffic to allow or prohibit, depending on parameters like source/destination IP addresses, protocols, or port numbers.

17. How does the DNS (Domain Name System) function in a network?

As the Internet's phone book, the Domain Name System (DNS) converts human-readable domain names, such as google.com, into computer-readable IP addresses, such as 172.217.14.238, which are required for devices to find and connect to servers on a network.

18. Explain the differences between TCP and UDP. When would you use each?

Whereas UDP (User Datagram Protocol) is a connectionless protocol that emphasizes speed and efficiency without guaranteeing delivery or order (perfect for video/voice streaming, DNS lookups, and gaming), TCP (Transmission Control Protocol) is a connection-oriented protocol that ensures ordered, dependable delivery and error checking (perfect for web traffic, email, and file transfers).

19. What are the different types of VPNs, and how do they work?

The two primary types of VPNs are Site-to-Site VPNs, which connect two geographically separate networks, usually using IPsec, to appear as one private network, and Remote-Access VPNs, which connect a single user or device to a private network via the internet, usually using IPsec or SSL/TLS.

20. Can you describe what a routing loop is and how to prevent it?

Setting a low Time-to-Live (TTL) counter in the packet header and utilizing split-horizon or poison reverse in distance-vector protocols are the main ways to avoid a routing loop, which happens when packets are repeatedly forwarded between two or more routers in an endless cycle because no router knows the correct exit path.

21. What is the function of a trunk port in VLAN configuration?

Through the use of the IEEE 802.1Q tagging protocol, a trunk port is a switch port that is set up to transport traffic for several VLANs at once across a single link between two switches or a switch and a router.

22. Explain what PPPoE (Point-to-Point Protocol over Ethernet) is.

Internet service providers (ISPs) frequently use PPPoE (Point-to-Point Protocol over Ethernet), a network protocol that encapsulates PPP frames inside Ethernet frames. Its main purpose is to provide session management and authentication (similar to dial-up) over a regular Ethernet connection in order to create a secure, independent broadband connection.

23. What is the purpose of the "show ip interface brief" command?

Cisco devices may rapidly provide a succinct status summary of all interfaces, including their Layer 1 (protocol status: up/down), Layer 2 (line status: up/down), and set Layer 3 IP addresses, by using the show ip interface brief command.

24. What is the difference between a full-duplex and a half-duplex communication mode?

Half-duplex permits data transfer in both directions, but only one at a time (like a walkie-talkie), whereas full-duplex permits data transmission in both directions simultaneously (like a phone conversation).

25. What is HSRP (Hot Standby Router Protocol), and how does it provide network redundancy?

A Cisco proprietary redundancy protocol called HSRP (Hot Standby Router Protocol) enables two or more routers to share a single virtual IP address and MAC address. One of the routers is designated as the Active router, and the other as the Standby router. This way, in the event that the Active router fails, the Standby router takes over the virtual address right away, ensuring seamless network redundancy.

26. How do you configure port security on a Cisco switch?

The commands switchport mode access, switchport port-security, and usually switchport port-security maximum [value] and switchport port-security violation [action] are used to configure port security when you enter interface configuration mode.

27. Explain the concept of Load Balancing in OSPF.

By adding up to four (by default) equal-cost paths to a destination to the routing table, OSPF carries out Equal-Cost Multi-Path (ECMP) Load Balancing, enabling a router to divide outgoing traffic across all of these parallel optimal routes.

28. What is the significance of the 'show running-config' command in Cisco networking devices?

For real-time troubleshooting and verification, the show running-config command shows the current configuration that is being loaded in the device's RAM. It includes all settings that are currently being used, including any modifications made since the last reboot or save.

29. Can you explain the process of ARP spoofing and how to mitigate it?

Using Dynamic ARP Inspection (DAI) on switches to verify ARP packets against a trusted database is the main way to mitigate ARP Spoofing, a Man-in-the-Middle (MITM) attack in which an attacker sends fictitious ARP messages to associate their own MAC address with another device's IP address (usually the default gateway), intercepting and redirecting traffic.

30. What is the role of DNS (Domain Name System)?

The following are the roles of DNS:

a) Name Resolution,

b) Service Location (SRV Records),

c) Mail Exchange (MX Records),

d) Load Distribution/Balancing, and

e) Reverse DNS Lookup (PTR Records).

Benefits of CCNA Skills for Organizations

S.No.	Benefits	How?
1.	Reduced Downtime	Professionals with CCNA certification are adept at rapidly diagnosing and fixing network problems, reducing downtime, and maintaining the availability of vital services.
2.	Optimized Performance	To ensure effective data flow and improved network speed, they can adopt best practices for VLANs and routing protocols (such as OSPF) and implement Quality of Service (QoS).
3.	Enhanced Security Posture	Basic network security is covered in CCNA training, including how to defend the network perimeter by setting Access Control Lists (ACLs) and comprehending VPN concepts.
4.	Effective Use of Cisco Equipment	Employees who are familiar with the proprietary Cisco IOS commands and capabilities help organizations that employ Cisco equipment by ensuring appropriate configuration and optimal hardware usage.
5.	Improved Scalability	Structured networks can be designed and implemented by staff members who possess CCNA knowledge, which makes network scalability easier and more affordable as the company expands.
6.	Better Return on Investment (ROI)	Effectively setting up and maintaining networks increases the return on investment (ROI) of IT infrastructure by lowering the need for expensive vendor maintenance or hardware upgrades.
7.	Support for Modern Networks	The certification equips the company to implement contemporary, software-defined networking techniques by demonstrating an understanding of wireless ideas and network automation.
8.	Internal Technical Expertise	A team with this standard certification fosters a strong internal knowledge base for day-to-day operations and future planning, reducing the need for outside consultants.

Conclusion

Now that you have gone through the Top 30 CCNA Routing and Switching Interview Questions and Answers, you might be feeling a bit confident about clearing the interview with ease.

However, those who want to make a career in the cybersecurity domain with networking skills can go for the Best CISCO CCNA Course in Delhi offered by Craw Security. During the training sessions, students will be able to try their skills on live projects under the guidance of professionals.

After the completion of the Best CISCO CCNA Course in Delhi offered by Craw Security, students will be able to get a dedicated certificate validating their honed knowledge & skills during the sessions. What are you waiting for? Contact, Now!

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