Interview Questions : CCNA | Network Security | Part 1

This is questions and answers series of CCNA interview question. This is number 1 video of this series if you want to watch other videos, visit my other blogs on the website. Those who don’t know about CCNA, for that CCNA is network certification, short for Cisco Certified Network Associate Routing & Switching (CCNA) certification. On passing this certification, it validates the ability 0f candidates to install, configure, operate, and troubleshoot medium-size routed and switched networks.

Q1. What is the purpose of the Data Link?

Ans: Data Link is the second layer out of seven layers of OSI model. OSI model stands for Open Systems Interconnection model and it is used as a standard to communicate digital data from source to destination.

For incoming data, Data Link layer detect and correct errors in data stream coming from the physical layer.

For outgoing data, this layer receives data from network layer and convert it into frames. Later, provide addressing information by adding the header to each frame. It also provides flow control mechanism and error control mechanism.

Q2. When does network congestion occur?

Ans: Network Congestion is a term when there is so much data in network layer due to which it slows down network response time.

Congestion is the main reason of deteriorating quality in terms of data packet loss and more latency.

Q3. Differentiate full-duplex from half-duplex.

Ans: In simple words, there is two-way communication at the same time in full duplex communication while in half duplex communication, two-way communication is there but not simultaneously.

Q4. What is Network latency?

Ans: Latency is a term used to denote the time duration for getting an output after providing input. Ideally, network latency should be zero.

Q5. Explain the benefits of VLANs.

Ans: A virtual LAN (VLAN) is a combination of one or more LANs which configured so that all the work system are on the same network virtually.


  • If configured correctly, it improves the performance of a network.
  • Improves overall security of the network.

Q6. How does RIP differ from IGRP?

Ans: RIP and IGRP are different routing protocols. RIP stands for Routing Information Protocol while IGRP stands for Interior Gateway Routing Protocol. RIP and IGRP both are distance vector protocols.

RIP takes best route decision to the network based on the number of hops in order to determine the best route to a network while IGRP takes best route decision to the network based on bandwidth, reliability, MTU and hop count.

Q7. What are the different memories used in a CISCO router?

Ans: Here is the list of memories used in CISCO router:

  • ROM (Read Only Memory)
  • RAM (Random Access Memory)
  • Flash RAM
  • NVRAM (Non-Volatile Random Access Memory)

Q8. What is 100BaseFX?

Ans: 100BASE-X also referred as “Fast Ethernet”. It provides a data transmission speed of 100 Mbps using baseband.

Q9. What are the advantages of a layered model in the networking industry?

Ans: Here are the advantages of a layered model in the networking industry:

  • Promote industry standardization by providing the role of the different layer.
  • Network Administrator able to troubleshoot network problems easily in a layer without affecting the other layers.

Q10. What is HDLC?

Ans: HDLC stands for High-level Data Link Control. It refers the group of rules and protocols for transmitting data from different network nodes.

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Disclaimer: This tutorial is for educational purpose only. Individual is solely responsible for any illegal act.


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