Computer Network

 A collection of computing devices connected in order to

communicate and share resources.

 Connections between computing devices can be physical

using wires or cables or wireless using radio waves or
infrared signals.
 Computer Networking
 Computer networking refers to the practice of connecting multiple
computers and other devices together to share resources and
communicate with each other.

 This interconnection can be done through various technologies and

protocols, enabling data and information to be exchanged between
devices, whether they are located in the same room or on opposite
sides of the world.

 The primary goal of computer networking is to facilitate data sharing,

communication, and resource utilization among connected devices.
How Does a Computer Network Work?
 Basics building blocks of a Computer network are Nodes and Links.
 A Network Node can be illustrated as Equipment for Data
Communication like a Modem, Router, etc., or Equipment of a Data
Terminal like connecting two computers or more.


 Link in Computer Networks can be defined as wires or cables or free

space of wireless networks.
 The working of Computer Networks can be simply defined as rules or
protocols which help in sending and receiving data via the links which
allow Computer networks to communicate.
 Each device has an IP Address, that helps in identifying a device.

Basic Terminologies of Computer Networks

 Network: A network is a collection of computers and devices that are
connected together to enable communication and data exchange.
 Nodes: Nodes are devices that are connected to a network. These can
include computers, Servers, Printers, Routers, Switches, and other
devices.
 Protocol: A protocol is a set of rules and standards that govern how
data is transmitted over a network. Examples of protocols include
TCP/IP, HTTP, and FTP.
 Topology: Network topology refers to the physical and logical
arrangement of nodes on a network. The common network topologies
include bus, star, ring, mesh, and tree.

 Service Provider Networks: These types of Networks give

permission to take Network Capacity and Functionality on lease from
the Provider. Service Provider Networks include Wireless
Communications, Data Carriers, etc.

 IP Address: An IP address is a unique numerical identifier that is

assigned to every device on a network. IP addresses are used to
identify devices and enable communication between them.
 DNS: The Domain Name System (DNS) is a protocol that is used to
translate human-readable domain names (such as www.google.com)
into IP addresses that computers can understand.

 Firewall: A firewall is a security device that is used to monitor and

control incoming and outgoing network traffic. Firewalls are used to
protect networks from unauthorized access and other security threats.
 Types of Computer Network Architecture
Computer Network falls under these broad Categories:-

 Client-Server Architecture: Client-Server Architecture is a type

of Computer Network Architecture in which Nodes can be Servers
or Clients. Here, the server node can manage the Client Node
Behavior.

 Peer-to-Peer Architecture: In P2P (Peer-to-Peer) Architecture,

there is not any concept of a Central Server. Each device is free for
working as either client or server.
 Network Devices
An interconnection of multiple devices, also known as hosts, that are
connected using multiple paths for the purpose of sending/receiving
data or media. Computer networks can also include multiple
devices/mediums which help in the communication between two
different devices; these are known as Network devices.
NIC Card ( Network Interface Card)
Hub
Repeater
Switch
Router
Modem
 Advantages of Computer Networking
 Central Storage of Data: Files can be stored on a central node (the
file server) that can be shared and made available to every user in an
organization.
 Connectivity: There is a negligible range of abilities required to
connect to a modern computer network. The effortlessness of joining
makes it workable for even youthful kids to start exploring the data.
 Faster Problem-solving: Since an extensive procedure is
disintegrated into a few littler procedures and each is taken care of by
all the associated gadgets, an explicit issue can be settled in lesser
time.
•Reliability: Reliability implies backing up information. Due to some reason
equipment crashes, and so on, the information gets undermined or inaccessible
on one PC, and another duplicate of similar information is accessible on
another workstation for future use, which prompts smooth working and further
handling without interruption.
•Flexible: This innovation is known to be truly adaptable, as it offers clients
the chance to investigate everything about fundamental things, for example,
programming without influencing their usefulness.
•Security through Authorization: Security and protection of information are
additionally settled through the system. As just the system clients are approved
to get to specific records or applications, no other individual can crack the
protection or security of information.
•Storage capacity: Since you will share data, records, and assets with
other individuals, you need to guarantee all information and substance
are legitimately put away in the framework. With this systems
administration innovation, you can do most of this with no issue, while
having all the space you require for capacity.
 Network Switch
Network switch is networking hardware that connects devices on
a computer network by using packet switching to receive and
forward data to the destination device.
Switches have many ports, and when data arrives at any port,
the destination address is examined first and some checks are
also done and then it is processed to the devices. Different types
of communication are supported here like unicast, multicast, and
broadcast communication.
Features of Network Switches
 It operates in Data Link Layer in OSI Model.
 It performs error checking before forwarding data.
 It transfers the data only to the device that has been addressed.
 It operates in full duplex mode.
 It allocates each LAN segment a limited bandwidth.
 It uses Unicast (one-to-one), multicast (one-to-many), and broadcast
(one-to-all) transmission modes.
 Packet Switching techniques are used to transfer data packets from
source to destination.
 Switches have a more significant number of ports.
 Types of Switches
 Managed Switch

 Unmanaged Switch

•Unmanaged Switches: Unmanaged Switches are the devices that are

used to enable Ethernet devices that help in automatic data passing.
These are generally used for home networks and small businesses. In
case of the requirement of more switches, we just add more switches
by plug and play method.
Managed Switches: Managed Switches are switches having more
complex networks.
 SNMP (Simple Network Management Protocol) can be used for
configuring managed switches.
 These types of switches are mostly used in large networks having
complex architecture.
 They provide better security levels and precision control but they are
more costly than Unmanaged switches.
 How Does a Network Switch Works?

 When the source wants to send the data packet to the destination, the
packet first enters the switch and the switch reads its header and finds
the MAC address of the destination to identify the device then it
sends the packet out through the appropriate ports that lead to the
destination devices.

 Switch establishes a temporary connection between the source and

destination for communication and terminates the connection once the
conversation is done. Also, it offers full bandwidth to network traffic
going to and from a device simultaneously to reduce collision.
Switching Techniques
Switching techniques are used to decide the best route for data
transmission between source and destination. These are classified into
three categories :

 Circuit Switching

 Message Switching

 Packet Switching
 Advantages of Switches
 Prevents traffic overloading in a network by segmenting the network
into smaller subnets.
 Increases the bandwidth of the network.
 Less frame collision as the switch creates the collision domain for
each connection.

 Disadvantages of Switches
 It can not stop traffic destined for a different LAN segment from
traveling to all other LAN segments.
 Switches are more expensive.
 Managed Switches Unmanaged Switches
1 Managed switches provides
Unmanaged switches works like
flexibility to the network
a plug and play switch
administrator
2 Provides extensive set of security Provides basic set of security
features features
3 Managed network switch has
advanced features which allows Unmanaged network switch
users to manage, configure, and comes with fixed configuration
monitor
4 Uses (SNMP) to monitor the
Built-in QoS services
performance
5 More Expensive Less Expensive