Series-1/Part 2/Computer Networking/Q&A
Part 2/Computer Networking- Question and answer #GsTechnoguide
Top Networking Question with Answer
Q
:-16) What is a Network?
Answer: Network is
defined as a set of devices connected to each other using a physical
transmission medium.
For Example, A computer network is a group of computers connected with
each other to communicate and share information and resources like hardware,
data, and software. In a network, nodes are used to connect two or more
networks.
Q
:-17) What is a Node?
Answer: A node is a
point where a connection is established.Two or more computers are connected
directly by an optical fiber or any other cable. It is a network component that
is used to send, receive and forward the electronic information.
A device connected to a network is also termed as Node
Q
:-18) What is Network Topology?
Answer: Network topology
is a physical layout of the computer network and it defines how the computers,
devices, cables, etc are connected to each other.
Q
:-19) What is the OSI reference model?
Answer: Open System Interconnection,
the name itself suggests that it is a reference model that defines how
applications can communicate with each other over a networking system.
It also helps to
understand the relationship between networks and defines the process of
communication in a network.
Q :-20) Explain TCP/IP
Model
Answer: The most widely
used and available protocol is TCP/IP i.e. Transmission Control Protocol and
Internet Protocol. TCP/IP specifies how data should be packaged, transmitted
and routed in their end to end data communication.
Here below is a brief explanation of each layer:
- Application Layer: This is the top layer in the
TCP/IP model. It includes processes that use the Transport Layer Protocol
to transmit the data to their destination. There are different Application
Layer Protocols such as HTTP, FTP, SMTP, SNMP protocols, etc.
- Transport Layer: It receives the data from the
Application Layer which is above the Transport Layer. It acts as a
backbone between the host’s system connected with each other and it mainly
concerns about the transmission of data. TCP and UDP are mainly used as
Transport Layer protocols.
- Network or Internet Layer: This layer sends the packets
across the network. Packets mainly contain source & destination IP
addresses and actual data to be transmitted.
- Network Interface Layer: It is the lowest layer of the
TCP/IP model. It transfers the packets between different hosts. It
includes encapsulation of IP packets into frames, mapping IP addresses to
physical hardware devices, etc.
Q :-21) What are the layers in OSI Reference Models? Describe each layer briefly.
Answer: Here below are the seven layers of OSI Reference Models:
1)
Physical Layer (Layer 1st): It converts data bits
into electrical impulses or radio signals. Example: Ethernet.
2)
Data Link Layer (Layer 2nd): At the Data Link layer, data packets are encoded and
decoded into bits and it provides a node to node data transfer. This layer also
detects the errors that occurred at Layer 1.
3)
Network Layer (Layer
3rd): This layer transfers variable length data sequence from one node
to another node in the same network. This variable-length data sequence is also
known as “Datagrams”.
4)
Transport Layer (Layer 4th): It transfers data between nodes and also provides
acknowledgment of successful data transmission. It keeps track of transmission
and sends the segments again if the transmission fails.
5)
Session Layer (Layer 5): This layer manages and controls the connections between
computers. It establishes, coordinates, exchange and terminates the connections
between local and remote applications.
6)
Presentation Layer (Layer 6): It is also called as “Syntax Layer”. Layer 6 transforms
the data into the form in which the application layer accepts.
7)
Application Layer (Layer
7): This is the last layer of the OSI Reference Model and is the one
that is close to the end-user. Both end-user and application layer interacts
with the software application. This layer provides services for email, file
transfer, etc.
Q :-22) What is the difference between Hub, Switch, and Router?
|
Hub |
Switch |
Router |
|
Hub is very cheap among three, least
intelligent and least complicated of the three. |
Switches work similarly like Hubs
but in a more efficient manner. |
The router is smartest and most
complicated out of these three. It comes in all shapes and sizes. Routers are
similar like little computers dedicated for routing network traffic |
|
In a Network, Hub is a common
connection point for devices connected to the network. Hub contains multiple
ports and is used to connect segments of LAN |
Switch is a device in a network
which forwards packets in a network |
Routers are located at gateway and
forwards data packets |
Q
:-23) What are Routers?
Ans: The router is a
network device that connects two or more network segments. It is used to
transfer information from the source to the destination.
Routers send the
information in terms of data packets and when these data packets are forwarded
from one router to another router then the router reads the network address in
the packets and identifies the destination network.
Q
:-24) What is HTTP and what port does it use?
Ans: HTTP is
HyperText Transfer Protocol and it is responsible for web content. Many web
pages are using HTTP to transmit the web content and allow the display and
navigation of HyperText. It is the primary protocol and port used here is
TCP port 80.
Q
:-25) What is HTTPs and what port does it use?
Ans: HTTPs is a
Secure HTTP. HTTPs is used for secure communication over a computer network.
HTTPs provides authentication of websites that prevents unwanted attacks.
In bi-directional
communication, the HTTPs protocol encrypts the communication so that the
tampering of the data gets avoided. With the help of an SSL certificate, it
verifies if the requested server connection is a valid connection or not. HTTPs
use TCP with port 443.
Q
:-26) What are TCP and UDP?
Answer: Some common
factors in TCP and UDP are:-
- TCP and UDP are the most widely
used protocols that are built on the top of the IP protocol.
- Both protocols TCP and UDP are
used to send bits of data over the Internet, which is also known as
‘packets’.
- When packets are transferred
using either TCP or UDP, it is sent to an IP address. These packets are
traversed through routers to the destination.
The
difference between TCP and UDP are shown in the below :
|
TCP |
UDP |
|
TCP stands for Transmission
Control Protocol |
UDP is stands for User Datagram
Protocol or Universal Datagram Protocol |
|
Once the connection is setup, data
can be sent bi-directional i.e. TCP is a connection oriented protocol |
UDP is connectionless, simple
protocol. Using UDP, messages are sent as packets |
|
The speed of TCP is slower than
UDP |
UDP is faster compared to TCP |
|
TCP is used for the application
where time is not critical part of data transmission |
UDP is suitable for the
applications which require fast transmission of data and time is crucial in
this case. |
|
TCP transmission occurs in a
sequential manner |
UDP transmission also occurs in a
sequential manner but it does not maintain the same sequence when it reaches
the destination |
|
It is heavy weight connection |
It is lightweight transport layer |
|
TCP tracks the data sent to ensure
no data loss during data transmission |
UDP does not ensure whether
receiver receives packets are not. If packets are misses then they are just
lost |
Q
:-27) What is a Firewall?
Answer: Firewall is a
network security system that is used to protect computer networks from
unauthorized access. It prevents malicious access from outside to the computer
network. A firewall can also be built to grant limited access to outside users.
The firewall consists of a hardware device, software program or a combined configuration of both. All the messages that route through the firewall are examined by specific security criteria and the messages which meet the criteria are successfully traversed through the network or else those messages are blocked.
Firewalls can be
installed just like any other computer software and later can be customized as
per the need and have some control over the access and security features. “
Windows Firewall” is
an inbuilt Microsoft Windows application that comes along with the operating
system. This “Windows Firewall” also helps to prevent viruses, worms, etc.
Q
:-28) What is DNS?
Answer: Domain Name Server
(DNS), in a non-professional language and we can call it an Internet’s phone
book. All the public IP addresses and their hostnames are stored in the DNS and
later it translates into a corresponding IP address.
For a human being, it
is easy to remember and recognize the domain name, however, the computer is a
machine that does not understand the human language and they only understand
the language of IP addresses for data transfer.
There is a “Central
Registry” where all the domain names are stored and it gets updated on a
periodic basis. All Internet service providers and different host companies
usually interact with this central registry to get the updated DNS details.
For Example, When you type a website www.abcd.com then your Internet
service provider looks for the DNS associated with this domain name and
translates this website command into a machine language – IP address –
150.192.168.2 (note that, this is the imaginary IP address and not the actual
IP for the given website) so that you will get redirected to the appropriate
destination.
Q
:-29) What is the difference between a workgroup and a Domain?
Answer: In a computer network,
different computers are organized in different methods and these methods are –
Domains and Workgroups. Usually, computers which run on the home network belong
to a Workgroup.
However, computers
that are running on an office network or any workplace network belong to the
Domain.
|
Workgroup |
Domain |
|
All computers are peers and no
computer has control over another computer |
Network admin uses one or more
computer as a server and provide all accesses, security permission to all
other computers in a network |
|
In a Workgroup, each computer
maintains their own database |
The domain is a form of a computer
network in which computers, printers, and user accounts are registered in a
central database. |
|
Each computer has their own
authentication rule for every user account |
It has centralized authentication
servers which set the rule of authentication |
|
Each computer has set of user
account. If user has account on that computer then only user able to access
the computer |
If user has an account in a domain
then user can login to any computer in a domain |
|
Workgroup does not bind to any
security permission or does not require any password |
Domain user has to provide
security credentials whenever they are accessing the domain network |
|
Computer settings need to change manually
for each computer in a Workgroup |
In a domain, changes made in one
computer automatically made same changes to all other computers in a network |
|
All computers must be on same
local area network |
In a domain, computers can be on a
different local network |
|
In a Workgroup, there can be only
20 computers connected |
In a domain, thousands of
computers can be connected |
Q
:-30) What is a Proxy Server and how do they protect the computer network?
Answer: For data transmission,
IP addresses are required and even DNS uses IP addresses to route to the
correct website. It means without the knowledge of correct and actual IP
addresses it is not possible to identify the physical location of the network.
Proxy servers prevent external users who are unauthorized to access such IP addresses of the internal network. It makes the computer network virtually invisible to external users.
Proxy Server also
maintains the list of blacklisted websites so that the internal user is
automatically prevented from getting easily infected by viruses, worms, etc.
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