What is a Network?

Network

• Network stands for interconnection.
• A network is a collection of points or nodes connected by communication routes.
• A group of computing devices linked together in a variety of ways so that they can communicate and share resources. Normally, actual wires or cables are used to connect computers in a network.
• Other connections, however, make use of wireless radio waves or infrared signals.

Networking Terms

• Node: Any device on a network is referred to as a node or host in general.
• Data Transfer Rate: Data transfer rate is the speed at which data is sent from one location on a network to another. A major problem in computer networks is the rate of data transport.
• File Server: A computer that handles and saves data for several users on a network is known as a file server.
• Web Server: A machine specifically designed to respond to requests for web pages made by browser clients

Client/Server Interaction

The client/server concept is a new computing frontier made possible by computer networks.

         A network is a collection of computer hardware parts connected by communication channels that enables resource and information sharing. Two computers connected to one another is an example of a network.

Types of Network

• Networking is the process of connecting two or more computing devices for the purpose of sharing data in the world of computers. 
• Computer hardware and software are used to build networks.

Area Networks

Area networks is classified as

• Personal area networks

• Local Area networks

• Metropolitan Area networks
• Wide Area networks

• Wireless Networks

• Home Networks
 
• Internet works- The Internet

·     

Personal Area Network

• Small computer networks 
• Used for communication between computers and other nearby devices
• Wireless and wired devices may be included in a PAN. 
• A PAN normally has a range of 10 metres. 
  • Wired PAN – USB and fire wire connections for wired PAN 
  • Wireless PAN – Bluetooth and infrared wireless PAN 
• Personal computers, printers, fax machines, telephones, Personal Digital Assistants (PDA), scanners and other devices are the example of PAN.

Local Area Network

The Institute of Electrical and Electronics Engineers (IEEE) describes a LAN as 

“a data com system allowing a number of independent devices to interact directly with each other over a modestly small geographic region through a physical communications channel at moderate data rates”.

• Local Area Network (LAN) network links computers and other devices in a small geographic area.
• Ethernet technology is most likely to be the foundation of current wired LANs.
• Examples of LAN includes home, school, computer lab, office building or cluster of buildings in close proximity.
• Isolated LAN connecting 12 computers to a hub in a closet is shown below.

Characteristics of LAN

• Any station on the network can commence data exchange with any other station because all stations are peers.
• Complete communication between all stations is fully managed by the owner.
• The network is limited to a small region, a single building, or a collection of buildings.
• The data rate is high, many Mbps (million bits per second).

What is the need of LAN?

• A LAN enables users to share resources, hardware, software, and user-generated content.
• The sharing of resources enables the investment in each resource to be maximized.

List the Goals of LAN

• When used, LANs are supposed to increase worker productivity.
• To enhance the handling of information.
• To enhance employee connection.
• To cut/control expenses.
• To enable the use of standardized hardware and software.
• An efficient LAN accomplishes goals while meeting the following fundamental criteria: Simplicity, dependability, transparency, and manageability

Benefits of LAN

• Shared resources include hardware, software, files, security & access control, backups & improved communications
• Productivity and Customer relationships.

Metropolitan Area Network

• The metropolitan area network (MAN) is intended to cover an entire city.
• It might be a single network, such a cable television network that is accessible in numerous cities.
• A computer network that typically covers an entire city or a sizable university.
• Rangeis100 km (a city).

• A MAN typically links several local area networks together.
• Uses a high-capacity backbone technology, such as fiber-optic lines.
• Establish connectivity between locales like a city or campus

Advantages of MAN

• It gives a large network a solid foundation and more access to WANs.
• Data transfer in both directions is made possible by the dual bus used in MAN.
• Often, a man occupies many streets or a whole city.

Disadvantages of MAN

• It is challenging to make the system secure from hackers.
• More cable is needed for a MAN connection from one location to another.

Campus Area Network

• Also Known as corporate area network or CAN
• Computer network made up of an interconnection of local area networks with in a limited geographical area.
• The networking equipments (Switches, routers) and transmission media (Optical fibres, copper CAT5 cabling etc) are almost entirely owned by the campus owner.
• An enterprise, university, government etc..

Wide Area Network

• A WAN joins two or more LANs, frequently over great distances.
• A WAN frequently connects several groups in various nations.
• WAN covers a vast geographic area.
• Range: greater than 100 km

Advantages of WAN

• Enables long-distance enterprises to connect on a single network because it covers a vast geographic area.
• Shares software and resources with connected workstations.
• Anyone else on the network can receive messages very rapidly.
• Images, music, or data may be included in these messages.
• Everyone on the network can utilize the same data, and expensive items can be shared among all the computers without the need to purchase separate peripherals for each computer.

Disadvantages of WAN

• To prevent outsiders from entering and damaging the network, a strong firewall is required for establishing a network
• Once established, managing a network is a full-time task that calls for the hiring of network managers and technicians.
• Since numerous users may access data from other computers, security becomes a serious concern.
• Security against viruses and hackers adds complexity and cost.

A switched WAN and a point-to-point WAN

         A switched WAN network is used to connect numerous end nodes through a shared WAN network, whereas a point-to-point WAN consists of two end nodes connected by a leased line, such as a dial-up line connecting a home computer to the Internet.

List few examples of Network.

         Internet, Intranet, Extranet, Wi-Fi.

What is Internet?

         It is a “network of networks” that consists of millions of private and public, academic, business, and government networks (local or global), connected by copper cables, wireless connections, and other technologies.

• An internet is created through the interconnection of two or more networks.
• Several facets of our daily life have been transformed by the Internet.
• The Internet is a communication technology that has put a lot of knowledge at our fingertips.

List few applications of Internet

• Download program and files
• E-Mail, Voice and Video Conferencing
• E-Commerce & File Sharing
• Information browsing

What is Intranet?

         It uses Internet standards (HTML, HTTPS, and TCP/IP protocols) and software to create an internal company network that is only accessible to authorized individuals, such as members or employees of the organization.

List few applications of Intranet

• Sharing of company policies, rules, and regulations
• Access to employee databases
• Distribution of circulars and office orders
• Access to product and customer data
• Sharing of information of common interest
• Launching of personal and departmental home pages
• Submission of reports
• Corporate telephone directories

What is Extranet?

         Extranets are Intranets that employ the same internet technology as authorized users from the outside.

• System for sharing information among organizations.
• Let outsiders to collaborate with firm personnel.
• Available to chosen vendors, clients, and business partners

Examples: Dealers and distributors have access to product files including:

1. Product specifications
2. Photographs
3. Images, etc

Classification of interconnected processors by scale.

Define network topology

         Network topology is defined as how the nodes of a network are connected

What is meant by heterogeneous network?

         A heterogeneous network is made up of interconnected nodes and links of various sorts. Such intricately connected structures hold valuable data that can be utilized to improve one another’s nodes and links and spread knowledge from one type to another. A network with four WAN’s and two LAN’s.