Computer Network Types

The main reason for separating MAN as a special category is the already-determined standard for MAN, and the standard is now being implemented. Standart is called DQDB (Distributed Queue Dual Bus) or according to the standard IEEE 802.6. DQDB consists of two unidirectional wires where all the computers are connected, as shown in Figure 1.2. Each bus has a head-end device to start transmitting activity. Computer traffic going to the right of the top of the sender using the bus. Traffic to the left using the bus under.

We will follow traditional usage and call these machines as hosts. The term End System is sometimes also used in the literature. The hosts are connected by a communication subnet, or simply called a subnet. The task is to bring the message of the subnet host to another host, such as phone systems that carry the conversation from the speaker to the listener. By separating the pure communication aspects of a network (subnet) from the application aspects (the host), the complete network design becomes much simpler.

In most WAN, subnet consists of two components, namely the transmission cables and switching elements. Transmission cable (also called a circuit, channel, or trunk) move bits from one machine to another.

Switching element is a special computer that is used to connect two or more transmission lines. When the data cable to the receiver, switching element must choose wired sender to forward messages. Unfortunately there is no standard terminology in the computer name like this. His name is variously called packet switching node, intermidiate system, data switching exchange and so on.


In general, a computer network can dibedekan consisting of five types:

1. the LAN (Local Area Network)

Local Area Network (LAN) is a network of personal property within a building or campus-sized to several kilometers.
LAN is often used to connect personal computers and workstations in company offices or factories for use as a resource (eg, printers, scanners) and exchange information. LAN can be distinguished from other tissue types based on three characteristics: size, transmission technology and topology.

LAN has a limited size, which means that the transmission time in the worst condition are limited and can be known in advance. By knowing keterbatasnnya, causing the possibility to use a certain type of design. It also facilitates network management.

LANs often use a single cable transmission teknologih. Traditional LANs operate at speeds ranging from 10 to 100 Mbps (mega bits / sec) with low delay (tens of micro-second) and has a small error factor. Modern LANs can operate at higher speeds, up to hundreds of megabits / sec.

2. MAN (Metropolitan Area Network)

Metropolitan Area Network (MAN) is basically a LAN version of the larger size and usually use the same technology to the LAN. MAN can include corporate offices are adjacent and can be used for private purposes (private) or public. MAN usually mamapu support voice and data, and can even relate to the cable television network. MAN only have one or two and do not have cable buiah switching element, which serves to regulate cable package with multiple outputs. The existence of switching elements to make the design become simpler.


3. WAN (Wide Area Network)

Wide Area Network (WAN) covers a wide geographical area, sertingkali covering a country or continent. WAN consists of a collection of machines intended to carry out the application programs.


4. Wireless Network

Mobile computers such as notebook computers and personal digital assistants (PDA), a branch of the computer industry is the fastest growing. Many kinds of computer owners who actually have desktop machines installed on a LAN or WAN but because the cable connection is not possible in a car or an airplane, there are many who are interested to have a computer to the network without wires.

Wireless networks have many benefits, which have been commonly known is the portable office. People who were on the way often like to use his portable electronic devices to send or receive calls, faxes, e-mails, reading fail remotely log into the remote machine, and so on, and also want to do these things anywhere, land, sea, air.

5. Internet

Actually there are many in this world networks, often using hardware and software that is different. People who are connected to the network are hoping to be able to communicate with other people who are connected to other networks. Desires such as these require a network connection between the often kampatibel and different. Normally to do this requires a machine called a gateway to engage and carry out the necessary translation, both hardware and software. Collection of interconnected networks is called the internet.