Communication network based on point-to-point communication

Manufacturing: Computer networks are used in many aspects of manufacturing including manufacturing process itself
. Two of them that use network to provide essential services are computer-aided design (CAD) and computer-assisted manufacturing (CAM), both of which allow multiple users to work on a project simultaneously
. Directory services: Directory services allow list of files to be stored in central location to speed worldwide search operations
. Information services: A Network information service includes bulletin boards and data banks
. A World Wide Web site offering technical specification for a new product is an information service
. Electronic data interchange (EDIT): DIE allows business information, including documents such as purchase orders and invoices, to be transferred without using paper
. Electronic mail: probably it's the most widely used computer network application
. Teleconferencing: Teleconferencing allows conference to occur without the participants being in the same place
. Applications include simple text conferencing (where participants communicate through their normal keyboards and monitor) and video conferencing where participants can even see as well as talk to other fellow participants
. Different types of equipment's are used for video conferencing depending on what quality of the motion you want to capture (whether you want just to see the face of other fellow participants or do you want to see the exact facial expression)
. Voice over IP: Computer networks are also used to provide voice communication
. This kind of voice communication is pretty cheap as compared to the normal telephonic conversation
. Video on demand: Future services provided by the cable television networks may include video on request where a person can request for a particular movie or any clip at anytime he wish to see
. Summary: The main area of applications can be broadly classified into following categories:  

Communication network based on point-to-point communication

includes telescoping, which uses order-entry computers or telephones connected to order processing network, and online-reservation services for hotels, airlines and so on. 

Communication network based on point-to-point communication

In a short period of time computer networks have become an indispensable part of business, industry, entertainment as well as a common-man's life
. These applications have changed tremendously from time and the motivation for building these networks are all essentially economic and technological
. Initially, computer network was developed for defense purpose, to have a secure communication network that can even withstand a nuclear attack
. After a decade or so, companies, in various fields, started using computer networks for keeping track of inventories, monitor productivity, communication between their different branch offices located at different locations
. For example, Railways started using computer networks by connecting their nationwide reservation counters to provide the facility of reservation and inquiry from any where across the country
. And now after almost two decades, computer networks have entered a new dimension; they are now an integral part of the society and people
. In 1990,s computer network started delivering services to private individuals at home
. These services and motivation for using them are quite different
. Some of the services are access to remote information, person-person communication, and interactive entertainment
. So, some of the applications of computer networks that we can see around us today are as follows: Marketing and sales: Computer networks are used extensively in both marketing and sales organizations
. Marketing professionals use them to collect, exchange, and analyze data related to customer needs and product development cycles
. Sales application 

Communication network based on point-to-point communication

Internet is a collection of networks or network of networks
. Various networks such as LAN and WAN connected through suitable hardware and software to work in a seamless manner
. Schematic diagram of the Internet is shown in Fig
.  It allows various applications such as e-mail, file transfer, remote log-in, World Wide Web, Multimedia, etc run across the internet
. The basic difference between WAN and Internet is that WAN is owned by a single organization while internet is not so
. But with the time the line between WAN and Internet is shrinking, and these terms are sometimes used interchangeably. 

Communication network based on point-to-point communication

MAN is designed to extend over the entire city
. It may be a single network as a cable TV network or it may be means of connecting a number of LAN's into a larger network so that resources may be shared as shown in Fig
 For example, a company can use a MAN to connect the LAN's in all its offices in a city 
. MAN is wholly owned and operated by a private company or may be a service provided by a public company
. Figure  Metropolitan Area Networks (MAN) The main reason for distinguishing Mans as a special category is that a standard has been adopted for them. It is DB (Distributed Queue Dual Bus) or IEEE 

Communication network based on point-to-point communication

LAN typically used transmission technology consisting of single cable to which all machines are connected
. Traditional LAN's run at speeds of 10 to 100 Mbps (but now much higher speeds can be achieved)
. The most common LAN typologies are bus, ring and star
. A typical LAN is shown in Fig

Communication network based on point-to-point communication

Figure  Communication network based on point-to-point communication As a general rule (although there are many exceptions), smaller, geographically localized networks tend to use broadcasting, whereas larger networks normally use are point-to point communication
. Classification based on Scale Alternative criteria for classifying networks are their scale
. They are divided into Local Area (LAN), Metropolitan Area Network (MAN) and Wide Area Networks (WAN)
. Local Area Network (LAN) LAN is usually privately owned and links the devices in a single office, building or campus of up to few kilometers in size
. These are used to share resources (may be hardware or software resources) and to exchange information
. LAN's are distinguished from other kinds of networks by three categories: their size, transmission technology and topology
. LAN's are restricted in size, which means that their worst-case transmission time is bounded and known in advance
. Hence this is more reliable as compared to MAN and WAN
. Knowing this bound makes it possible to use certain kinds of design that would not otherwise be possible
. It also simplifies network management.