Introduction of Networking

 Network 

Network is a collection of Computer and Electronic Devices connected to one another to allow sharing of data, files and other computing resources.

The smallest form of Network is LAN ( Local Area Network) which is used by small infra organizations for creating Network which then muzzle ups to MAN ( Metropolitan Area Network) which generally covers a geographical region of the size of a metro area which then lifts up to WAN ( Wide area Network).

Internet:

• Internet is worldwide network of computer networks.
  

How does it work:

• Most computers aren't connected directly to internet
• They are connected to smaller networks
• Which are connected through gateways(Routers/Switches) to the internet backbone.

Networking Devices

Network devices are devices used to connect computers or other electronic devices together so that they can share files or resources. These devices move and control network.

Network devices are :

Network Interface Card

Switch

Hub

Router

What is Protocol?

• A Protocol is a established set of rules that determine how data is transmitted between different devices in the same network.
• It Defines the Format of Data that is being Sent and Received.
• Some protocols are Designed for Reliable and High-Performance Network communication by Compressing Data.
• Applications like Web Browsers contains a list of software that supports Advance Protocols, necessary for Application to Function.

Introduction to IP Address

• Internet Protocol is a set of rules governing the format of data sent over the internet or the network.
• An IP Address is a 32-bit sequence contains I's and 0's
• IP is used to identify machines on a network
• IP address consist of four sections
• Each section is 8 bits long
• Each section has range from O to 255

Types of IP Address

• There are 2 types of IP address
• Static IP Address -Y IP Address assigned to host manually
• Dynamic IP Address -Y IP Address assigned by server when host boots

Classification of IP Address

Class	Address Range	Supports
Class A	1.0.0.1 to 126.255.255.254	Supports 16 million hosts on each of 127 networks.
Class B	128.1.0.1 to 191.255.255.254	Supports 65,000 hosts on each of 16,000 networks.
Class C	192.0.1.1 to 223.255.254.254	Supports 254 hosts on each of 2 million networks.
Class D	224.0.O.O to 239.255.255.255	Reserved for multicast groups.
Class E	240.0.0.0 to 254.255.255.254	Reserved for future use, or Research and Development Purposes.

Network Topologies

Topologies:

• The Pattern of interconnection of nodes during a network is named the topology.

Types of Topology:

• Bus Topology
• Star Topology
• Ring Topology
• Tree Topology
• Mesh Topology

Network Topology

Bus Topologies:

• A linear bus consists a main run on single cable with terminator at each end all Nodes (File server, Workstations) are connected to the only linear cable as shown below.

Star Topology:

• A star is meant with each node (File server, Workstations, and peripherals) are connected on to a central network hub or concentrator as shown in below.
• The Hub is going to manage all functions in a network and it also act as repeater

Ring Topology:

In a Ring Topology, a local network will be configured as a closed loop that uses token for regulating traffic on a network.

Tree Topology:

• A Tree topology combines characteristics of a linear bus and star topologies.
• It consists groups of star configured workstations connected to a linear bus backbone cable.
• Tree Topologies provide the expansion of an existing network to configure a network to satisfy their needs.

Mesh Topology:

In this sort of topology, a host is connected to at

least one or multiple hosts. This topology has

hosts in point-to-point reference to every other host or can also have hosts which are in point-to-point reference to few hosts only.

Concept of Ports

• The term Port can check with either physical or virtual connection points

Example of physical connection port:

• Ethernet Port
• USB Port

1. Virtual Port - A port is associated with an IP address of host as well as the type of protocol used for communication. The purpose of ports is uniquely identify different applications or services running on a single computer.
2. Total number of ports in a computer range from 1 to 65535 (port number O is reserved and can't be used)

Important Port numbers and Services

ftp	21/tcp	#FTP. control
Ssh	22/tcp	#SSH Remote Login Protocol
telnet	23/tcp	#Telnet protocol – unencrypted text communications
Smtp	25/tcp	#Simple Mail Transfer Protocol
http	80/tcp	#World Wide Web
kerberos	88/tcp	#Kerberos
pop3	110/tcp	#Post Office Protocol - Version 3
imap	143/tcp	#lnternet Message Access Protocol
Idap	389/tcp	#Lightweight Directory Access Protocol
https	443/tcp	#HTTP over TLS/SSL
ftps	990/tcp	#FTP control, over TLS/SSL
telnets	992/tcp	#Telnet protocol over TLS/SSL
imaps	993/tcp	#1MAP4 protocol over TLS/SS

 OSI Reference Model 

OSI Model:

• Open Systems Interconnect (OSI) Model.
• Who Made : International standard Organization (ISO).
• OSI isn't a protocol, it's a model for understanding and designing a architecture that's flexible and robust.
• The OSI model describes how data flows from one computers, through a network to another computer.

It Consist of 7 Layers:

                                                                                                     

Click Here to Know About OSI Model

                                                                                                      

TCP/IP Model

Networking professionals are differ in their opinions on which model to use. because of the character of the industry it's necessary to become aware of both. Both the OSI & TCP/IP models are going to be mentioned throughout the curriculum. the main target are going to be on the follow: TCP as a OSI Layer 4 protocol IP as a OSI Layer 3 protocol Ethernet as a Layer 2 & Layer 1 technology Remember that there's a difference between a model and an actual protocol that's utilized in networking. The OSI model are going to be wont to describe TCP/IP protocols.