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CCNA Interview Question

A list of top frequently asked CCNA interview questions and answers are given below.


1) What is the difference between switch and hub?

Switch Hub
Switches are used at data link layer. Hubs are used at physical layer.
Switches create separate collision domain and a single broadcast domain. Hubs create single collision domain and a single broadcast domain.
Address learning No addressing.
Forward/filter decision using mac address. No filtering.

2) What are the advantages of using Switches?

Switches are used to receive a signal and create a frame out of the bits from that signal. The signals enable you to get access and read the destination address and after reading that it forward that frame to appropriate frame. So, switches are very important part of transmission.


3) What is Routing?

Routing is a process of finding a path to transfer data from source to destination.


4) What are Routers?

The process of routing is done by the devices known as Routers. Routers are the network layer devices.


5) What are the different types of networks?

These are the two major types of networks:

  • Peer-to-Peer Network
  • Server-based Network

6) What is the purpose of Data Link Layer?

The main purpose of data link layer is to check that whether messages are sent to the right devices. Another function of data link layer is framing.


7) What is VLAN?

VLAN stands for Virtual Local Area Network.


8) What is subnet? Why is it used?

Subnets are used in IP network to break up larger network into smaller network. It is used to optimize the performance of network because it reduces traffic by breaking the larger network into smaller networks. It is also used to identify and isolate network's problem and simplify them.


9) What is the difference between communication and transmission?

Communication is a process of sending and receiving data by an externally connected data cable whereas transmission is a process of sending data from source to destination.


10) What is Topology in CCNA?

Topology is an arrangement of various elements (links, nodes etc.) of computer network in a specific order. These are the different types of topology used in CCNA:

  • Bus
  • Star
  • Ring
  • Mesh
  • Tree
  • Hybrid etc.

11) What is the passive topology in CCNA?

When the topology enables the computers on the network only to simply listen and receive the signals, it is known as passive topology because they don't amplify the signals any way.


12) What is RAID in CCNA?

RAID is a method which is used to standardize and categorize fault-tolerant disk systems. RAID levels provide various facilities like performance, cost, reliability etc. These three are the mostly used RAID levels:

  • Level 0: (Striping)
  • Level 1: (Mirroring)
  • Level 5: (Striping and Parity)

13) What is the point-to-point protocol in CCNA?

Point-to-point protocol is an industry standard suite of protocols which uses point-to-point link to transport multiprotocol datagram.


14) What are the possible ways of data transmission in CCNA?

These are the three possible ways of data transmission:

  • Simplex
  • Half-duplex
  • Full-duplex

15) What are the protocol data units (PDU) in CCNA?

Protocol data units (PDU) are the minimum possible units used at different layers of the OSI model to transport data.

Layers PDU
Transport Segments
Network Packets/Datagrams
Data-link Frames
Physical Bits

16) What is the difference between RIP and IGRP?

RIP depends on number of hops to determine the best route to the network while, IGRP considers many factors before decides the best route to take i.e. bandwidth, reliability, MTU and hops count.


17) What are the different memories used in a CISCO router?

Three types of memories are used in a CISCO router:

  • NVRAM: It is used to store the startup configuration file.
  • DRAM: It stores the configuration file that is being executed.
  • Flash Memory: It is used to store the system IOS.

18) What is the difference between full-duplex and half-duplex?

Although both are the communication devices and both are used to transmit and receive data but full-duplex facilitate you to transmit and receive data at the same time while half-duplex cannot receive while it is transmitting data.


19) What is BootP?

BootP is a short form of Boot Program. It is a protocol that is used to boot diskless workstation connected to the network. BootP is also used by diskless workstations to determine its own IP address and also the IP addresses of server PC.


20) What is a Frame Relay?

Frame Relay is used to provide connection oriented communication by creating and maintaining virtual circuits. It is a WAN protocol that is operated at the Data Link and physical layer to maintain high performance rating.


21) What is Latency?

Latency is the amount of time delay. It is measured as the time difference between at the point of time when a network receives the data and the time it is sent by another network.


22) What is MAC address?

MAC address stands for Media Access Control address. This is an address of a device which is identified as the Media Access Control Layer in the network architecture. The MAC address is unique and usually stored in ROM.


23) What is the difference between ARP and RARP?

ARP stands for Address Resolution Protocol. ARP is a protocol that is used to map an IP address to a physical machine address.

RAPR stands for Reverse Address Resolution Protocol. RARP is a protocol that is used to map a MAC address to IP address.