If you want to succeed in your next CCNA interview, here is a carefully curated list of CCNA interview questions and answers that will come in handy in your preparation. In this blog, we have listed the most frequently asked CCNA interview questions that will help both the freshers and experienced candidates boost their interview preparation.

Before we begin with the interview questions, let’s take a look at what is CCNA?

What is CCNA?

CCNA (Cisco Certified Network Associate) is a prominent IT certification offered by the networking giant, Cisco. Through this certification, networking professionals can validate their knowledge of understanding, configuring, operating, configuring, and troubleshooting medium-level switched and routed networks. CCNA certifications are available in eight areas, namely Cloud, Collaboration, Data Center, Industrial, Routing and Switching, Security, Service Provider, and Wireless.

Learn more about Cisco Certifications.

Top CCNA Interview Questions and Answers

Q1. What is a ‘router’?

Ans. A router is a device that forwards data packets along with a network.

Q2. What is a ‘protocol’ in networking?

Ans. A protocol in networking is a set of invisible computer rules that enable two devices to connect and transmit data to one another.

Q3. Differentiate between a switch and a hub

Ans. Switches are used at the data link layer, while hubs are used at the physical layer.

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Q4. How many layers are there in an OSI reference model? Name them.

Ans. There are 7 layers in an OSI (Open Systems Interconnection) reference model. They are:

  1. Physical layer
  2. Data link layer
  3. Network layer
  4. Transport layer
  5. Session layer
  6. Presentation layer
  7. Application layer

Q5. Explain the difference between a ‘broadcast domain’ and a ‘collision domain’?

Ans. A broadcast domain is a logical division of a computer network, in which all nodes can reach others by broadcast at the data link layer.

A collision domain is a section of a network where data packets can collide with one another when being sent on a shared medium or through repeaters.

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Q6. What is the size of an IP address?

Ans.  32 it for IPv4 and 128 bit for IPv6.

Q7. What is a DLCI?

Ans.  DLCI (Data Link Connection Identifiers) are used to uniquely identify each virtual circuit that exists on the network.

Q8. Name different types of networks

Ans.  There are two different types of networks – 1) peer-to-peer and 2) server-based.

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Q9. What is the difference between a ‘half-duplex’ and a ‘full-duplex’ system?

Ans.  In a half-duplex system, communication takes place in only one direction, while in a full-duplex system, communication takes place in both directions.

Q10. What is PoE (Power over Ethernet)?

Ans.  Power over Ethernet (PoE) refers to the technology which allows electric power along with data on Ethernet cabling.

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Q11. Explain the use of ‘ping’ command?

Ans.  Ping (Packet Internet Groper) is a computer network tool that is used to test whether a particular host is reachable across an IP network.

Q12. Explain ‘round-trip time’?

Ans.  Round-trip time, or round-trip delay, is the time required for a packet to travel from a specific source to a specific destination and back again.

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Q13. What is the difference between public and private IP?

Ans.  Public IP is used across the internet, while private IP is used within the local LAN.

Q14. What is the difference between ‘cross cable’ and ‘straight cable’?

Ans.  Cross cables are used to connect the same group devices while straight cables are used to connect different group devices.

Q15. At which layer of OSI does frame relay technology work?

Ans.  At the data link layer.

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Q16. What is the size of a Cisco ping packet?

Ans.  The size of a Ping packet in Cisco by default is 100 bytes.

Q17. How many VTP modes are in a switch? Name them.

Ans.  There are three types of VTP modes. They are – server, client, and transparent.

Q18. Explain the difference between static and dynamic IP addressing?

Ans.  Dynamic IP addresses can change every time a device connects to the internet. Static IP addresses are reserved and do not change with time.

Q19. What is ‘subnet’? Why is it used?

Ans.  Subnets are used in IP networks to optimize the performance of a network because it reduces traffic by breaking a large network into smaller networks.

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Q20. What does MTU stand for? What is the default size?

Ans.  MTU stands for the maximum transmission unit. The default MTU size is 1500 bytes.

Q21. When does network congestion occur?

Ans. Network congestion happens when applications send more data than the network devices like routers and switches can accommodate. This is a common occurrence when many users try using the same bandwidth.

Q22. What is the LLC sublayer and what is its function?

Ans. LLC is an abbreviation for Logical Link Control and it offers optional services to application developers. These options include providing flow control to the network layer by using stop/start codes. It also corrects an error in the network.

Q23. What is BootP?

Ans. BootP or Boot Program is a protocol for booting diskless workstations in a network. These diskless workstations use BootP to determine their own as well as a server’s IP address.

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Q24. What is 100BaseFX?

Ans. 100BaseFX is a version of Fast Ethernet that uses fiber optic cable as the main transmission medium for wiring campus backbones. 100 stands for data speed in Mbps.

Q25. What is HDLC?

Ans. It is the abbreviation for High-Level Data-Link Control protocol. It is a popular ISO-standard, bit-oriented, Data Link layer protocol.

Q26. Explain VLAN.

Ans. It is the abbreviation for Virtual Local Area Network. It provides data link connectivity for a subnet.

Q27. What are the benefits of using VLANs?

Ans. There are three primary benefits of using VLANs, which include –

  • Security, reduced number of trunk links
  • Reduced costs
  • Allows creating collision domains other than physical locations

Q28. What is latency?

Ans. It is the expression of time taken for a data packet to move from one designated point to another.

Q29. Can you tell me which is the second layer of an OSI layer model?

Ans. Data link layer is the second layer of an OSI model.

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Q30. What is BOOTP?

Ans. It is the short form of Bootstrap Protocol. BOOTP is a computer networking protocol, used in IP networks for automatically assigning an IP address to network devices from a configuration server.

Q31. Tell me the easiest way to remotely configure a router?

Ans. To configure a router remotely, the most popular and easy way is using Cisco AutoInstall Procedure. However, it should ensure that the router is connected to the WAN or LAN.

Q32. What is Route Poisoning?

Ans. Route Poisoning is the process of making a route unreachable by inserting a table entry of 16 to it. This is done to prevent the problems of inconsistent updates on a route.

Q33. Name different types of passwords that can be used to secure a CISCO router?

Ans. 5 types of passwords can be used to secure a CISCO router, and these are –

  • Console
  • Aux
  • VTY
  • Enable password
  • Enable secret

Q34. Why should we use network segmentation to manage a large network?

Ans. Segmenting a network helps to ease network traffic and ensures that users receive high bandwidth at all times.  This translates to better performance, especially for a growing network.

The above questions will give you an idea of how to prepare for a CCNA interview. The number of CCNA certified professionals is growing in the IT industry and you need to have all the terminologies, techniques, and best practices on your fingertips in order to be successful in a job interview.



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