Networks classification

Network Hardware

There are two type of transmission technology:

Broadcast networks have a single communication channel that is shared by all the machines on the network. Short messages, called packets in certain contexts, sent by any machine are received by all the other. An address field with the packet specifies for whom it is intended. Upon receiving a  packet is intended for itself, it processes the packet; if the packet is intended for some other machine, it is just ignore.

    As an analogy, consider someone standing at the end of a corridor with many rooms off it and shouting .

Although the packet may actually be received (heard) by many people, only Watson responds. The other just ignore it. Another example is an airport announcement asking all flight 444 passengers to report to gate 10.

Broadcast systems generally also allow the possibility of addressing a packet to all destinations by using a special code in the address field. When a packet with his code is transmitted, it is received and processed by every machine on the network. This mode of operation is called broadcasting. Some broadcast system also support transmission to a subset of the machines, something known as multicasting. one possible scheme is to reserve on e bit to indicate multicasting. the remaining n-1 address bits hold a group number. Each machine can "subscribe" to any or all the the groups. When a packet is sent to a certain group, it is delivered to all machines subscribing to that group.

On the other hand, point-to-point (peer-to-peer) networks  consist of many connections between individual pairs of machines. To go fro the source to the destination, a packet on this type of network may have to first visit one or more intermediate machines. Often multiple routes, of different lengths are possible, so routing algorithms play an important role in point-to-point networks. As a general rule (although there are many exception), smaller, geographically localized networks tend to use broadcasting, whereas larger networks usually are point-to-point

Ref: computer networks, Third edition Prentice-Hall published in New                         Delhi,1996,by Andrew s. Tanenbaum, pp..7,8

 

Local Area Networks (LAN)

a)                                                                                                                                                                                                                                                                                        Top

Local Are Networks (LANs) : These connect over a relatively small geographical are, typically connecting computers within a single  office or building. In most cases they connect to a common electronic connection- commonly known as a network backbone.  LAN's can connect to other networks either directly or through a WAN or MAN.

            Ref: Distributed systems and Networks, The McGraw-Hill companies, William Buchanan published 2000, pp..189,

 

b)

A computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves.  Most LANs connect workstations and personal computers. Each node (individual computer ) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions.                                                                                   

               Ref: http://www.webopedia.com/TERM/l/local_area_network_LAN.html

for more information : 

                Ref: http://www.techweb.com/encyclopedia/defineterm?term=lan

 

Metropolitan Area Networks (MAN)

a)

Metropolitan Area Networks (MAN's): These connect networks around a town or city. it is smaller than a WAN, but larger4 than a LAN. An example of a Man is the EaStMAN (Edinburgh and Stirling MAN) network that connects universities and colleges in Edinburgh and Stirling, UK.

                Ref: Distributed systems and Networks, The McGraw-Hill companies, William Buchanan published 2000, pp..189,

b)

Short for Metropolitan Area Network, a data network designed for a town or city. In terms of geographic breadth, MANs are larger than local-area networks (LANs), but smaller than wide-area networks (WANs). MANs are usually characterized by very high-speed connections using fiber optical cable or other digital media.

                Ref: http://www.webopedia.com/TERM/M/MAN.html

 

Wide Area Networks (WAN)                                                                                                Top

a)

Wide Area Networks( WANs) : These connect networks over a large geographical area, such as between different buildings, towns or even countries.

            Ref: Distributed systems and Networks, The McGraw-Hill companies, William Buchanan published 2000, pp..189,

b)

A wide area network (WAN) is a geographically dispersed telecommunications network. The term distinguishes a broader telecommunication structure from a local area network (). A wide area network may be privately owned or rented, but the term usually connotes the inclusion of public (shared user) networks.

             Ref: http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci214117,00.html

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