Sunday, January 16, 2011

Computer networks (LAN / Local Area Network)

computer network is a collection of computers, printers and other equipment are connected in one unit. Information and data moving through wires or wireless computer network allowing users to exchange documents and data, print on the printer the same and together using hardware / software is connected to the network.

Network Benefits:

* Resource Sharing, can use existing resources together. Suppose a user is located 100 km away from the data, do not get the difficulty in using these data, as if the data are close by. This often means that the computer network mangatasi distance problem.

* High Reliability, with the computer network we will get a high reliability by having alternative sources of supply. For example, all files can be saved or copied to two, three, or more computers that are connected kejaringan. So if one machine breaks, then copy on another machine that can be used.

* Saves money. Computer small berukutan have price / performance ratio better than the large computer. Such as mainframe computers have kecapatan approximately ten times the speed of a small computer / personal. However, the price of mainframes a thousand times more expensive than a personal computer. The imbalance of the ratio of price / performance and speed of this is to make the system designers to build systems that consist of personal computers.

The steps are: To create a small computer network (LAN), there are some equipment and materials we need, such as:

* Tang Cramping
* Lan Tester
* UTP (Unshielded Twisted Pair) / Coaxial (seldom used)
* RJ45 Connector / coaxial cable connector
* Switch-hubs
* Min 2 pieces of a PC (Personal Computer) and the LAN card or NIC (network Interface Card)
Then we specify the composition of UTP cable that will be used in accordance with its function. suppose if we want to connect a PC directly from the PC-CROSS then we use when connecting to a switch kia first-hub, PC-HUB, STRAIGHT then we use. if we want to link two LANs, the HUB-HUB CROSS we use, we also can use one staright if there HUB port uplink.
for ease in memorizing the cable arrangement, we can use one of the ways that I use, namely STRAIGHT -> OBHC if CROSS -> HBOC.


O -> white-orange - Orange
B -> white green - blue
H -> blue white - green
C -> white chocolate - brown


H -> green white - green
B -> white-orange - blue
O -> blue white - orange C -> white chocolate - chocolate

if you have another way please apply, do not be like above. then please each end tested using lan tester. if the light is as expected, then you have succeeded in the process of cramping. please lan card installed in your PC.

to set the IP then we think about is how no IP group that is used on your lan. usually to a local network using the IP group 172.17.XX, 192.168.xx or 10.10.XX 202.168.XX to the local network, the minimal set is:

IP address: (example)
Subnet mask: (example)

for the default gateway can be filled if you want your local networks connecting with the outside network (either other local networks or the Internet.) for the DNS server will you fill if you are connected to the Internet. DNS servers are subject to the rules established by the provider, Telkom Speedy, etc..

if you've set the IP number, you can check whether your computer can communicate with other computers, that is by running the ping command in the command, such as ping (This command produces 4 times the responses), to continually provide our response add attribute-t (trace), such as ping-t

Response provided there are 3 kinds 1. reply from .... Your computer has to communicate with your destination computer.

2. request time out .... network connection there is a problem with your destination computer.

3. destination unreachable .... your computer's network connection problems.