Jaringan nirkabel (Inggris: wireless network) adalah bidang disiplin yang berkaitan dengan komunikasi antar sistem komputer tanpa menggunakan kabel. Jaringan nirkabel ini sering dipakai untuk jaringan komputer baik pada jarak yang dekat (beberapa meter, memakai alat/pemancar bluetooth) maupun pada jarak jauh (lewat satelit). Bidang ini erat hubungannya dengan bidang telekomunikasi, teknologi informasi, dan teknik komputer. Jenis jaringan yang populer dalam kategori jaringan nirkabel ini meliputi: Jaringan kawasan lokal nirkabel (wireless LAN/WLAN), dan Wi-Fi. Jaringan nirkabel biasanya menghubungkan satu sistem komputer dengan sistem yang lain dengan menggunakan beberapa macam media transmisi tanpa kabel, seperti: gelombang radio, gelombang mikro, maupun cahaya infra merah.

Pada tahun 1970 Norman Abramson, seorang profesor di University of Hawaii, mengembangkan komputer pertama di dunia jaringan komunikasi, ALOHAnet, menggunakan biaya rendah seperti ham-radio. Dengan bi-directional topologi bintang, sistem komputer yang terhubung tujuh ditempatkan lebih dari empat pulau untuk berkomunikasi dengan komputer pusat di Pulau Oahu tanpa menggunakan saluran telepon.

"Pada tahun 1979, FR Gfeller dan U. Bapst menerbitkan makalah di Proceedings IEEE pelaporan percobaan jaringan area lokal nirkabel menggunakan komunikasi infra merah disebarkan. Tak lama kemudian, pada tahun 1980, P. Ferrert melaporkan percobaan penerapan kode satu radio spread spectrum untuk komunikasi di terminal nirkabel IEEE Konferensi Telekomunikasi Nasional. Pada tahun 1984, perbandingan antara infra merah dan CDMA spread spectrum untuk komunikasi jaringan informasi kantor nirkabel diterbitkan oleh IEEE Kaveh Pahlavan di Jaringan Komputer Simposium yang muncul kemudian dalam IEEE Communication Society Magazine. Pada bulan Mei 1985, upaya Marcus memimpin FCC untuk mengumumkan ISM band eksperimental untuk aplikasi komersial teknologi spread spectrum. Belakangan, M. Kavehrad melaporkan percobaan sistem PBX nirkabel kode menggunakan Division Multiple Access. Upaya-upaya ini mendorong kegiatan industri yang signifikan dalam pengembangan dari generasi baru dari jaringan area lokal nirkabel dan diperbarui beberapa lama diskusi di radio portabel dan mobile industri.

Generasi pertama dari modem data nirkabel dikembangkan pada awal 1980-an oleh operator radio amatir, yang sering disebut sebagai radio paket ini. Mereka menambahkan komunikasi data pita suara modem, dengan kecepatan data di bawah 9.600-bit / s, untuk yang sudah ada sistem radio jarak pendek, biasanya dalam dua meter band amatir. Generasi kedua modem nirkabel dikembangkan FCC segera setelah pengumuman di band eksperimental untuk non-militer penggunaan spektrum penyebaran teknologi. Modem ini memiliki kecepatan data yang diberikan atas perintah ratusan kbit / s. Generasi ketiga modem nirkabel ditujukan untuk kompatibilitas dengan LAN yang ada dengan data tingkat atas perintah Mbit / s. Beberapa perusahaan yang mengembangkan produk-produk generasi ketiga dengan kecepatan data di atas 1 Mbit / s dan beberapa produk sudah diumumkan oleh waktu pertama IEEE Workshop on Wireless LAN.

Adapun jaringan nirkabel dalam bidang sensor atau biasa disebut Jaringan Sensor Nirkabel (Wireless Sensor Network/WSN). Jaringan sensor nirkabel adalah jaringan perangkat nirkabel yang saling berhubungan yang tertanam dalam lingkungan fisik untuk mengukur kondisi lingkungan seperti suhu, suara, tingkat polusi, kelembapan, angin, dan sebagainya.

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The installation of the Local Area Network (LAN)

The chance of this post I try to give something to friends who might be on the enlightenment that I have to say here, many are already familiar with or even go into what I would post this time, something which I will post this time talking about the installation of Local Area Network (LAN). I emphasize on some of the discussion below :

1. Explaining the network hardware and their functions.
2. Explains IP addressing Address.
3. Calculate IP addressing and Subnet Address IP Address.
4. Explain the network topology.
5. Topology design specifications required.

Network hardware can be broadly at the start of the computer itself to the device used to endorse a global network. As an example of network hardware that is inside the computer is NIIC or Network Interface Card. NIC is also referred to as LAN Card, LAN Card name is more popular than NIC.

NIC or LAND Card

Out of the NIC is generally connecting it with the switch that is used together with another computer.

Switch

Router

If the computer networks connected to different networks, It would require a router device. To protect and secure the network are the Firewall, Proxy server. Besides, the partners are still referred to as a bridge network, wireless router, access point, and so forth.

Each network device requires an IP Address, IP Address There are two types of IPv4 and IPv6, which is commonly used IPv4. IP Address IPv4 version consists of 4 groups of 8-bit binary number is converted to a decimal number that is easy to understand.

Biner	Decimal
00000000	0
11111111	255

IP address is divided into five classes, Class A, Class B, Class C, Class D, Class E, but in actual classes used to provide IP address is class A, Class B, Class C.

Class	Biner	Decimal
A	0000 0001.X.Y.Z to 0111 1111.X.Y.Z	1.X.Y.Z to 127.X.Y.Z
B	1000 0000.X.Y.Z to 1011 1111.X.Y.Z	128.X.Y.Z to 191.X.Y.Z
C	1100 0000.X.Y.Z to 1101 1111.X.Y.Z	192.X.Y.Z to 223.X.Y.Z

Each class has a public IP for the benefit of local interests

Class	IP Local
A	10.    0.0.0 to   10.255.255.255
B	172.  16.0.0 to 172.  31.255.255
C	192.168.0.0 to 192.168.255.255

Class A has a special IP address that has been allocated for testing the network, which is 127.0.0.0
Write the IP address error will cause the appearance of error messages, for example if address 127.0.0.0 IP address to NIC.

Error message when one writes the IP address

Each class has an IP subnet mask to determine the network number and host and user.

Class	Subnet Mask (Default)
A	1111 1111.0000 0000.0000 0000.0000 0000 or 255.0.0.0
B	1111 1111.1111 1111.0000 0000.0000 0000 or 255.255.0.0
C	1111 1111.1111 1111.1111 1111.0000 0000 or 255.255.255.0

As an example of a class C IP address local: 192.168.0.1 with a subnet mask of 255.255.255.0

a number of binary subnet mask = 24, so the IP address 192.168.0.1/24 could be written as a binary number 0 is equal to 8 pieces, then the IP address 192.168.0.1 has a kind friend as much as 2⁸ = 256, that is : 192.168.0.0 to 192.168. 0.255

192.168.0.0 Cannot be used as an IP address for the network, while 192.168.0.255 is the IP address for the broadcast. So the effective number of IP addresses only 256-2 = 254.

Than 1111 111.1111 1111 .1111 1111.0000 0000 can also be 1111 111.1111 1111 .1111 1111.1000 0000 or 1111 111.1111 1111 .1111 1111.1100 0000

Subnet Mask 1111 1111.1111 1111.1111 1111.1100 0000 Have a number of binary 1 = 26 and the number of binary 0 = 26

So for the same IP address 192.168.0.1/26, subnet mask of 255.255.255.192.
Binary 1 at the end of = 2 and a binary 0 = 6
binary 1 indicates the number of network = 2² = 4
Binary 0 indicates the host for each network = 2⁶ = 64
IP Address in the table it can be:

IP Address	function
192.168.0.0	Network 1
192.168.0.1 to 192.168.0.62	User 1
192.168.0.63	Broadcast 1
192.168.0.64	Network 2
192.168.0.65 to 192.168.0.126	User 2
192.168.0.127	Broadcast 2
192.168.0.128	Network 3
192.168.0.129 to 192.168.0.61	User 3
192.168.0.191	Broadcast 3
192.168.0.192	Network 4
192.168.0.193 to 192.168.0.254	User 4
192.168.0.255	Broadcast 4

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Features of the Tablet PC

A Tablet PC (Tablet PC), a handheld device that has almost all the properties of widely used desktop computers. Most of the Tablet PC features a touch screen, which serve as their primary input device and a computer with the group and act designed to operate.

The term was used by Microsoft in early 2001, although the tablet PC term now widely used by companies of any size reference Slate Tablet PC notebook, even if it is not a laptop to Microsoft's operating, but other operating systems. To recognize most of these tablets with a keyboard and software for capturing handwritten text via the touch screen tablet.

Almost all portable tablet computers with the wireless adapter to the Internet and LAN connections. These tablets use software applications, including Web browsers, games, office suites, and various other applications.

Manufacturers of tablets, most of their tablets do with size 12 universal format ", with a screen resolution of 1280 × 800 pixels. As computers tablets were introduced to replace newspapers, like the typewriter has been replaced a typewriter.

Handheld has to run for some time in silence for several hi-tech computer companies slowly compressed to the line and restart the tablet version of the touch tablet machine that is at the same time, without the keyboard. The tablets are taken by companies to the spirit of blogs, executives of technology, gadgets for dogs and bloggers are beginning to turn their dreams, produced by the project size Tablet PC.

Today, the Tablet PC is seen as a savior for newspapers, book publishers and the publishing industry. The tablet offers another way to watch movies and TV shows while playing. The tablet provides a visually rich web-trap and the world of ever-increasing demands for mobile phones to enjoy. Most tablets gadgets designed to inform, entertain and offer services that can find these places and a dictionary. To share other tablets in two-way communication systems and services in real-time basis.

Another reason why the tablet is to become widely popular versatility. Tablet computers are very small and lightweight, making them easy to work in a compressed space on the touch screen function allows the board to enter data easily and without problems. All tablet computers companies have in common is that they are using technology-based touch screen. Another advantage of using a tablet computer size is that they will also be used to draw and create images using a pen or pencil. This feature provides the ability to have a communication more creative and free with the unit.

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Knowing LAN Wiring

The most important aspect of any LAN cabling is its Category rating. The Categories most often seen specified for new installations are Categories 5e, 6, and 6 Augmented. The difference between these ratings can be narrowed down to the amount of data they can carry over a given length. Category 5e is considered to be the minimum required for copper LAN cabling in networks operating at 1000Base-T, better known as Gigabit Ethernet. Categories 6 and 6 Augmented are both certified for networks running at 10 Gigabits, with Cat6 certified for shorter runs and 6 Augmented good for up to 100 meters. Another important consideration when selecting cable for your LAN is whether or not it will be installed in a plenum space, in which case, plenum-rated cable should be used. Plenum-rated cable gives off no toxic smoke when it burns.

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