Wireless Network Technologi

posting this time I will discuss the notion of a computer network without cables, as well as the kind of wireless network configurations.

the following description of the wireless network : 

Introduction.

The current network technology has evolved rapidly. Various technologies have been developed to assist in human communicative. If during the 80s computer network technology relies solely on technology-based cable network, currently the technology started to leave because some many of its limitations, such as the magnitude of the costs that must be issued by the organization if the use of these technologies (wired network), in addition to this technology are also not flexible because it really depends on the wire. Now if we consider the start many companies are starting to implement technology wirelessly (wireless) or commonly called as Wireless Fidelity (WiFi). This can have a look at the many companies offering Hotspot Area (the area that there is a WiFi-based internet network) that can be accessed by everyone either for free or by way of registration to the service provider.

See the trend of increasing company offering HotSpot Area in public areas like shopping areas (mall), library, restaurant, kaffe, and in fact almost all educational institutions like colleges already provide Hotspots are to their students as part of the ancillary facilities, teaching and learning program. So need it we know

about this technology (WiFi), how it works, selected species, as well as how the security of this network which is the issue that is very necessary to look for when we want to switch to using this technology.

2 types of configuration of Wireless LAN (WLAN)

In general there are two types of configuration for network based on WLAN, namely:

based : Ad - hoac

On these networks, communication between one computer device to each other is done spontaneously/directly without going through a specific configuration for a signal from the Access Point can be received well by computer devices within the network.

Based : Infratrukstur

 

On the network, one or more Access points (APs) relates the WLAN network via cable-based networking. So in this type of networks, to serve the computers in the network, then the Access Point requires a connection to a cable-based networking.

Because of the many types of WLAN networks that exist in the market, then the IEEE 802.11 standard specifying the interface (interface) between the WLAN client (wireless client) with the Network Access Point (network APs). To distinguish the difference between a WLAN network one with another, then the network 802.11 WLAN using the Service Set Identifier (SSID). With this tag then it can distinguish between the WLAN network with each other for the network

WLAN with each other must have had a different SSID number marker. Access Point (AP) uses to determine the SSID of traffic data which is in the package peruntukkan for Access Point.

Standard 802.11 also specifies the frequency with which it can be used by WLAN network. For example, to industrial, scientific, and medical (ISM) operate on the frequency of radio 2, 4 GHz. 802.11 also specifies three types of physical layer for transmission on Open Systems Interconnection model (OSI), i.e.: direct-sequence spread spectrum (DSSS) and frequency-hopping spread spectrum (FHSS), and infrared.

In addition to the above frequency division, standard 802.11 frame types also divide into three categories, namely: control, data, and management. Standard 802.11 enabled device (device) which follows the 802 standards to communicate with each other at a speed of 1 Mbps and 2 Mbps in the range of approximately 100 meters. Another type of 802.11 standards will be developed to provide the data transfer speed is faster with a better level of functionality that exists today.

Currently there are several types of variants of the 802.11 standard: 802 .11A, 802 .11b, 802.11 g. The standard 802 .11A Standard 802 .11A is used for extended wireless network that uses a frequency of 5 GHz Unlicensed National Information Infrastrusture (UNII). Network speed is faster than standard 802.11 and 802 .11b standards on transfer speeds up to 54 Mbps. Speed can

be much faster if using appropriate technology.

To use the standard 802 .11A, computer devices (devices) require only 6 Mbps speed support communication, 12 Mbps, and 24 Mbps. 802 .11A Standards also operates a channel/Channel 4 (four) times more than that can be done by standard 802.11 and 802 .11b. Although the standard 802 .11A has in common with the standard 802 .11b on layers of Media Access Control (MAC), it is still not compatible with 802.11 or 802 .11b standard because the standard 802 .11A uses the 5 GHz frequency radio while on the standard 802 .11b uses the 2.4 GHz frequency.

The excess of the standard 802 .11A is because it operates at 5 GHz radio frequency so it doesn't need to compete with wireless communications devices (cordless) such as cordless phones (cordless phone) which generally use a frequency of 2.4 GHz.

The main difference between the standard which others with standard 802.11 802 .11A and 802 .11b is that on the standard 802 .11A use additional modulation types are called Orthogonal Frequency Division Multiplexing (OFDM) at the physical layer in the OSI model.

Although the standard 802 .11A is not compatible with the 802 .11b standard, some vendor/manufacturer companies attempt to get around this Access Point by making a sort of bridge (bridge) which can link between the standard 802 .11A and 802 .11b access point on the device they are artificial. The Access point is made in such a way that it can be in use on 2 (two) standard type in the standard 802 .11A and 802 .11b standards without any interplay with each other.

The standard 802 .11A is a very expensive option when in implementations. This is because it requires more Access point to achieve the speed the highest communication. The cause is due to the fact that the frequency of 5 GHz wave has a weakness in the range. The standard 802 .11b Standard 802 .11b is the most widely used standard in class 802. Standard This is a development of 802.11 standards for the physical layer with high speed. 802 .11b is used to define a wireless network for direct-sequence spread spectrum

(DSSS) which uses wave frequency, scientific, indusrial medicine (ISM) 2.4 GHz and communicate at speeds up to 11 Mbps. it faster than the speed of 1 or 2 Mbps Mbos offered by standard 802 .11A. 802 .11b is also compatible with all devices that operate on DSSS 802.11 standards.

802 .11b only concentrate only on the physical layer and Media Access Control (MAC). This standard is only using one type of frame that has a maximum width of 2.346 bytes. However, it can be further divided into 1,277 byte jik on connect on a cross (cross) with the access point so that it can also communicate with the network based on ethernet (based on wiring).

802 .11b only emphasizing on operation of DSSS devices only. This standard provides a method for those devices to search for (discover), associations, and authenticate each other. Standari also provides a method to handle collisions (collision) and fragmentation and enable encryption via WEP Protocol methods (wired

equivalent protocol).

Standard 802.11 g

Standard 802.11 g is essentially similar to the 802 .11A standard that provides high-speed communication lines up to 54 Mbps. However, the frequency was used in this standard is the same as frequencies used standard 802 .11b i.e. frequency 2.4 GHz and can also be compatible with the standard 802 .11b. It is not owned by the standard 802 .11A.

Like 802. a, devices in standard 802.11 g use OFDM modulation for high speed data transfer rate. Unlike the standard 802 .11A perangkatperangkat, devices in standard 802.11 g can automatically switch to the quadrature phase shift keying (QPSK MODULATION) for communicating with perangkatperangkat on a wireless network using the 802 .11b standard.

Compared to 802 .11A, 802.11 g has advantages in terms of compatibility with the standard 802 .11b networks. However, a problem that may arise when a standard 802.11 g devices that try to switch to 802 .11b networks or even vice versa is a matter of interference in the use of frequency disuruh 2,4 GHz. Because as described in the beginning that the frequency of 2.4 GHz frequency is the most widely used by wireless-based devices other.

This is the posting of mine about computer networks wirelessly.

Thanks you for your visit, may be useful..

Regard : rikies