This document provides a list of 20 common interview questions for CCNA certification along with brief answers summarizing key networking concepts. Some of the questions cover routing, data link layers, network congestion, switches, routing protocols like RIP and IGRP, the OSI model layers, bandwidth, latency, Cisco router memory, and the differences between user and privileged modes. The document also provides additional online resources for CCNA exam preparation.

1. Top 20 CCNA Interview Questions and
Answers
CCNA Interview Questions for beginners and professionals with a list of top 20 interview questions.
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Question:1
What is Routing?
Answer:
Routing is the process of finding a path on which data can pass from source to destination. Routing
is done by a device called routers, which are network layer devices.
Question:2
What is routing on a network?
Answer:
This might seem like a basic question, but the interviewer might ask it just to see if you know the
basics. Routing is done by routers. Routers have a routing table that send network traffic from one
location to another location or segment on the network. Routers reduce network traffic compared to
regular hubs. When a user sends network traffic across the network, a hub broadcasts to all
segments of the network. With a router, the device analyzes the TCP/IP packet, sees the destination
location, and then uses its lookup table to route the packet to the right network segment and
destination. Switches also route traffic in a similar fashion.
Question:3
What is 100BaseFX?
Answer:
This is Ethernet that makes use of fiber optic cable as the main transmission medium. The 100
stands for 100Mbps, which is the data speed.
Question:4
Is it better to add a network segment to a growing network or continue to use the same
subnet mask?
Answer:
Growing networks start to suffer from network congestion. When you segment the network, routers
are better able to route traffic to specific parts of the network without broadcasting signals across
only one segment. When you reduce broadcasting, you lower congestion, which speeds up your
network. With a growing large network, it’s better to start segmenting the network and create subnet
masks for different segments.
Question:5
What is the purpose of the Data Link?
Answer:

2. The job of the Data Link layer is to check messages are sent to the right device. Another function of
this layer is framing.
Question:6
What is network congestion?
Answer:
With all of the streaming applications and peer to peer software, network congestion is common on a
large network. Network congestion occurs when too many people are trying to use limited
bandwidth. Most companies have a limited amount of bandwidth they can use before they pay extra,
which is why companies limit bandwidth by blocking streaming and peer to peer applications using
firewalls.
Question:7
Differentiate User Mode from Privileged Mode
Answer:
User Mode is used for regular task when using a CISCO router, such as to view system information,
connecting to remote devices, and checking the status of the router. On the other hand, privileged
mode includes all options that are available for User Mode, plus more. You can use this mode in
order to make configurations on the router, including making tests and debugging.
Question:8
What are data packets?
Answer:
Data packets are the encapsulation units that transmit information across a network. A data packet
contains the sender’s information, the recipient’s information, and the data contained. It also
contains the numeric identification number that defines the order and packet number. When you
send data across the network, that information is segmented into data packets. The recipient then
puts these packets together to be able to read the information. Basically, data packets contain the
information and routing configurations for your transferred message.
Question:9
What is the key advantage of using switches?
Answer:
When a switch receives a signal, it creates a frame out of the bits that was extracted from that
signal. With this process, it gains access and reads the destination address, after which it forwards
that frame to the appropriate port. This is a very efficient means of data transmission, instead of
broadcasting it on all ports.
Question:10
What is the difference between RIP and IGRP?
Answer:
When you send traffic on a network, the router (default gateway in Windows computer terminology)
determines how to route the traffic. RIP determines where to send the traffic by determining the
shortest amount of “hops.” A hop is the next router in the traffic’s path. Each router is considered a

3. hop. With IGRP, several more factors are considered. IGRP takes into consideration the bandwidth
availability, MTU, reliability and the amount of hops.
Question:11
What is the function of the Application Layer in networking?
Answer:
The Application Layer supports the communication components of an application and provides
network services to application processes that span beyond the OSI reference model specifications.
It also synchonizes applications on the server and client.
Question:12
Define bandwidth in terms of network architecture
Answer:
While the term bandwidth is thrown around for most basic networking speeds and capacity,
bandwidth is technically the data capacity of a network. It measures the volume of data for a
transmission connection. Bandwidth is measured in kilobits per second or “Kbps.”
Question:13
When does network congestion occur?
Answer:
Network congestion occurs when too many users are trying to use the same bandwidth. This is
especially true in big networks that do not resort to network segmentation.
Question:14
What is the Application Layer in network connectivity?
Answer:
The Application Layer is what your developers and software use to send traffic across the network.
The Application Layer is especially important for synchronizing software between the server and the
client machine.
Question:15
What is BootP?
Answer:
BootP is a protocol that is used to boot diskless workstations that are connected to the network. It is
short for Boot Program. Diskless workstations also use BootP in order to determine its own IP
address as well as the IP address of the server PC.
Question:16
What is subnetting on your network?
Answer:
Subnetting is a way to segment your network into smaller “groups.” Subnetting is accomplished by
manipulating the subnet mask, which is distributed to desktop computers and routers. Subnetting
allows you to create smaller networks within your network, which then reduces congestion on larger
networks.

4. Question:17
What is a Window in networking terms?
Answer:
A Window refers to the number of segments that is allowed to be sent from source to destination
before an acknowledgement is sent back.
Question:18
What is the difference between user mode and privileged mode on a Cisco router?
Answer:
These two modes are somewhat self-explanatory. The user mode allows the user to view router
status and basic system information. With privileged mode access status, the router can be
configured and all status messages and errors can be viewed. User mode and privileged mode
separates standard users on the network and network administrators who need to not only view
router status but also make changes to the router’s configurations.
Question:19
What are the different memories used in a CISCO router?
Answer:
 NVRAM stores the startup configuration file
 DRAM stores the configuration file that is being executed
 Flash Memory – stores the Cisco IOS.
Question:20
What is network latency?
Answer:
Network latency refers to the performance of one device when it communicates with another.
Network latency is affected by bandwidth speeds, network card performance, cabling and
congestion. High latency can also mean users won’t be able to properly communication with
applications, which will “time out” if latency is too high.
For More CCNA Interview Questions and Answers Visit - https://www.hub4tech.com/interview/ccna
Use Full Link for CCNA Certification
CCNA Tutorial- http://www.hub4tech.com/ccna-tutorial
CCNA Online Training- http://www.hub4tech.com/training/ccna-online-training.php?id=1
CCNA & CCNP Online Training-http://www.hub4tech.com/training/ccna-ccnp-online-training.php?id=15
CCNA Routing & Switching (200-120) Practice Test - http://www.hub4tech.com/ccna-routing-switching-
200-120-practice-test-exam
CCNA Practical Video Tutorial- http://www.hub4tech.com/ccna-practical/basic-router-configuration