A Frequently Asked CCNA Interview Questions
                     A Frequently Asked 
CCNA Interview Questions
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CCNA is an associate-level certification that validates your skills to fix, configure and troubleshoot 
enterprise network issues. The accreditation is hosted by Cisco, a prominent vendor of network 
equipment that holds the market’s largest share. Many big enterprises use Cisco’s equipment in their 
network infrastructure. Therefore, CCNA certification can be instrumental in getting job opportunities in 
the IT sector as a networking professional. As a certified networking expert, you may find opportunities 
for the Network Support Engineer, Technical Support Engineer, Network and System Administrator, 
Hardware and Networking Engineer, etc. If you are looking ahead to preparing for the CCNA Interview, 
then you are at an accurate place.
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Here are the 20 most common CCNA Interview Questions and 
Answers that may help you crack your interview & earn your dream career 
in the networking field:
1) What do you understand by the OSI model in networking?
Answer: OSI model stands for open systems interconnection model. It is a 
reference model that shows how applications communicate in a network. It 
consists of 7 layers.
Layer 1: Physical
Layer 2: Datalink
Layer 3: Network
Layer 4: Transport
Layer 5: Session
Layer 6: Presentation
Layer 7: Application
2)WhatisRIP?
Answer:  RIP stands for Routing Information Protocol and is also known as 
Interior Gateway Protocol (IGP). It is a distance-vector protocol that uses hop 
count as a routing metric to find the most suitable path between the sender 
and the receiver.
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3) What is the difference between a collision domain and a 
broadcast domain?
Answer: Collision domain:  If two devices try to send data 
simultaneously, a collision will occur leading them to wait and re-transmit the 
data. So, when two devices in a network send information the collision domain 
has to take care of all the devices connected in the network whether it is 
destined for them or not. It happens only in the case of a half-duplex mode.
Broadcast domain: It is the logical division of the network domain in which 
information is broadcasted in the network. A broadcast domain contains all 
devices that receive broadcast traffic from each other.
4) What are Half-duplex and Full-duplex transmission modes?
Answer: Half-duplex: In a point-to-point system, two devices are 
connected using a network cable, and these devices can communicate with 
each other in both directions but only in one direction at a time.
Full-duplex: In a point-to-point system, two devices are connected using a 
network cable, and these devices can apprise with each other in both directions 
at the same time.
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5) Explain the public vs. private IP addressing.
Answer: Public IP is the IP address that can be accessed over the Internet like a web 
server or an email server. The public IP address on your computer allows you to secure your 
own server such as VPN, FTP, WEB, etc. With the help of public IP, you can set up any home 
server to publish it on the Internet.
The private IP address of a system is the IP address that is used to communicate within 
the same network. Private IPs are not loaded on the Internet, and no data cannot be sent to 
them from the Internet; it only works within the local network.
6) What is the difference between Unicast, Multicast, Broadcast, and 
Anycast?
Answer: In a unicast transmission, a single data packet is sent from the source to a 
single destination on the network.
In broadcast, a single data packet is sent to all destinations on the network.
Multicast is like broadcast but, in multicast, you have to be a member of the multicast 
group.
In anycast, the data is sent to the nearest node within the network and that node then 
initiates another anycast to its nearest node.
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7) How are straight-through and crossover cables 
different from each other?
Ans: Straight-through: You can use it when you want to connect 
two different types of devices. It is the most commonly used cable 
format for network cables. It helps to connect a router’s WAN port to a 
LAN port.
Crossover Cable: You can use a crossover cable when you want to 
connect two devices of the same type. It is used only for specific 
applications. You can connect two hubs or switches by using the normal 
port in both hubs or switches.
8) Explain what NOS is.
Ans: A NOS (Network Operating System ) is an operating system that 
manages network resources like an operating system that involves 
special functions for connecting computers and devices into a local area 
network. Example: Windows server 2019, Linux server, etc
9) Explain different categories of Ethernet.
 Answer: Ethernet Different categories are:
Ethernet (10 Mbps)
Fast Ethernet (100 Mbps)
Gigabit Ethernet (1000 Mbps)
10 Gigabit Ethernet (up to 10 billion bits per second)
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10) What are Data Encapsulation and De-Encapsulation?
Answer: When data is sent, each layer adds some extra information like protocol 
information, IP addresses, MAC addresses for the data to reach its destination. It is 
called Encapsulation.
When data is received, each layer will shred the information attached in the header 
and trailer from the encapsulated frame it is called De-Encapsulation.
11) What are the different topologies in networking?
Answer:  The types of networking topologies are :
Bus: Each node is connected to a single cable also known as backbone.
Star: Each node is connected to a centralized hub/switch.
Mesh: All nodes are interconnected to each other so if one path fails data can still 
be transferred.
Ring: Each node is connected to its adjacent ones forming the shape of a ring.
12) What are the different types of cables that are used in 
routing?
Answer: Three different types of cables are used in routing:
Straight-through cable (switch-router)
Crossover cable (PC-PC, switch-switch)
Rollover cable (Console port to a computer)
13) What are Static routing and Dynamic routing?
Answer:  Static routing: Static Routing is a user-defined routing technique. In 
this manual selection of a network, routes are managed by the network 
administrator and ideal for small networks. It does not use complex routing 
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Dynamic routing: Dynamic routing is a networking mechanism 
that enables routers to select paths using routing protocols and routes 
are updated according to the changes in the network. It is ideal for 
large networks. It uses complex routing algorithms and it does not 
provide high security like static routing.
14) Differentiate Domain and workgroup.
Ans: Domains have one or more computers that act as servers. It 
has centralized databases. Domain computers can be on different 
LANs.
The workgroup consists of computers that are peers. In a 
workgroup, each computer has its own database and is on the same 
LAN.
15) What is Kerberos protocol?
Ans: Kerberos is a network authentication protocol that is based on 
time-sensitive ticket-granting-system designed to produce strong 
authentication for client or server applications using symmetric key 
cryptography.
16) What is DHCP in networking?
Answer: Dynamic Host Configuration Protocol (DHCP) is a network 
protocol that is used on IP networks where a DHCP server provides and 
assigns IP addresses to client devices. DHCP also assigns the subnet 
mask, default gateway address, and the Domain Name Server (DNS) 
address.
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17) What is the Domain Name System (DNS)?
Answer: DNS is a database that stores domain names and their respective IP 
addresses for a specific top-level domain (TLD)  such as .com and .net. It finds the 
computer systems and assets on the web.
18) What is HSRP?
Answer: HSRP stands for the Hot Standby Router Protocol developed by Cisco to 
provide gateway-level redundancy without any additional configuration. All the 
routers in an HSRP group distribute a single MAC address and IP address that works 
as a default gateway to the local network.
19) Why is the MAC address called the Physical address?
Ans: MAC address is called the physical address because we can not change the 
value of MAC address. MAC address is an exclusive address to identify devices which 
is provided by the hardware manufacturer. It is of 48 bits, 12 characters separated 
by dots or hyphens.
CCNA training with Infosec Train:
InfosecTrain is one of the leading IT security training providers. We offer a 
comprehensive training program for CCNA Certification. If you want to take the 
expert’s help in getting through the CCNA certification exam, check this CCNA 
certification training course offered by InfosecTrain: 
Cisco CCNA 200-301 Certification training
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