Understanding and Working Principle LAN

LAN (Local Area Network) can be defined as a network or network of computer systems, which are located in one building is limited, a complex building or a campus and not using common media of communication facilities like telephone, but the owner and manager of communications media is the owner of the LAN itself. From the above definition we can know that a LAN is limited by physical location. The use of the LAN itself result in all computers connected in a network can exchange data or other related words. Cooperation is growing from just the data exchange through the use of equipment together. LANs are generally using a hub, the hub will follow the principle of work itself. In this case is that the hub does not have pengetahuantentang destination address so that a broadcast data delivery, and also because the hub has only one collision domain so that if one port is busy then the other ports will have to wait.

Basic components of a LAN

Some of the basic components that normally form a LAN is as follows:

Workstation

Workstation is a node or host in the form of a computer system. Computer systems can be either a PC or can also be a large computer systems such as minicomputers, and even a mainframe. Workstations can work alone (stand-alone) can also use the network to exchange data with other workstations or users.

Server

Hardware (hardware) that function to serve the network and workstations connected on the network; its general resources (resources) such as printers, disks, and so that would be used jointly by the user at the workstation are and work on the server. Based on the types of services known as disc servers, file servers, print servers, and a server can also have multiple service functions at once.

Link

Workstations and servers can not function if the equipment is not physically connected. Relationship in a LAN is known as a transmission medium which is generally in the form of wires. As for some examples of the link is:

1. Twisted Pair Cable

• The cable is divided into two, namely Shielded Twisted Pair and Unshielded TwistedPair (UTP)
• More known as a telephone cable
• Relatively inexpensive
• Short Distance
•   Easily affected by the disorder
• Speed ​​of data that can be supported is limited, 10-16 Mbps

 2. Coaxial Cable

•  Commonly used on television
•  The distance is relatively more distant
•  higher data transmission speeds in the appeal Twisted Pair, 30 Mbps
•  Prices are relatively inexpensive
•  The size is larger than Twisted Pair

3. Fiber Optic Cable

• The long distance
• High data speed, 100 Mbps
• The relatively small size
• Difficult influenced disorders
• Prices are still relatively expensive
• Installation is relatively difficult

Network Interface Card (NIC)

A workstation is not connected directly with a network cable or transceiver cable, but through an electronic circuit that is designed specifically to handle the network protocol known as the Network Interface Card (NIC).

Network Software

Without the software the network then the network will not work as desired. This software also allows one computer system to communicate with other computer systems.

LAN Support Tools

a. Repeater

• In OSI, works on Physical layer
• Continue and strengthen the signal
• Widely used in bus topology
• Its use is easy and relatively cheap price
• Not having knowledge of the destination address so that the delivery data broadcast
• Only have one collision domain so that if one port is busy then the other ports will have to wait.

 b. Hub

• Work on the Physical layer
• Forward the signal
• Not having knowledge of the destination address
• Its use is relatively easy and affordable
• Only have one collision domain

c. Bridge

• Working in the Data Link layer
• Have used the addresses to forward data to its destination
• Automatically create table translator for acceptance masing2 port

 d. Switch

• Working in the Data Link layer
• Each port in the swith has its own collision domain
• Having a central translation table that has a list of interpreters to all ports
• Allows full duflex transmission (both directions)

 e. Router

• Router function to filter or filter the data traffic
• Determine and select an alternative path to be traversed by the data
• Connecting the network between LAN, WAN and even with LAN topology

Understanding Network topology is the arrangement of data flow path in the network that physically connects one node to another node. Here are some of the existing network topology and used to date, namely:

1. Star Topology

Some of the node / nodes connected to the central node / host, which form a physical network such as a star, all communications are handled directly and managed by the host in the form of mainframe computers.

2. Hierarchical Topology

Shaped like a branching tree consisting of the host computer (host) connected to the node / other node in stages. Higher levels of functioning as a regulator working level below.

3. Bus Topology

Some of the node / nodes connected by data paths (buses). Each node can perform the tasks and operations yangberbeda but all have the same hierarchy.

4. Loop Topology

Is the relationship between the node / nodes are serialized in the form of a closed loop. In this form there is no central node / host, all have the same hierarchy.

5. Ring Topology

This form is a combination of loop and bus topology, if one node / node is broken, then it will not affect other nodes due to communication separate from the data path.

6. Topology Web

Is a form of topology, each node / node in the network can be interconnected with other nodes via multiple links. A web form networks with n nodes, will use the link as many as n (n-1) / 2.

NB :

By using all the advantages and disadvantages each configuration, enabling the development of a new configuration that incorporates several new technologies in order topologies with ideal conditions for a network system can be met.