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A Basic Structure of Wireless Local Area Network

A Basic Structure of Wireless Local Area Network

LAN stands for Local Area Network. It is very common in small organizations, as well as colleges and universities. It is used to connect the computers for easy sharing of information. The process becomes even more worthwhile if it is wireless. This article explains the working procedure of the Local Area Network.
Shah Newaz Alam
Most laptops that are manufactured today come along with the wireless network feature. Thus, it is a very simple task to connect all the laptops in a local area network. You have to simply follow the steps that are given in the wireless network connection wizard, to form a network of your own, and allow other laptop users to join your network. Similarly, you can connect many desktop computers to form a wireless LAN, but in this case, you will need a wireless setup or a wireless router.

It is a set of rules that decides the performance or execution of a certain task. In communication, it decides the way information will be transferred and received. It also decides the speed and bandwidth that can be allowed for the flow of information. For a wired LAN structure, the Ethernet LAN standard was used. However, this structure was not sufficient for this wireless network, as there wasn't any fixed medium for the transfer of information. Additional information was needed for transmitting the packets or frames of data. For wireless LAN, IEEE 802.11g standards are used, whereas IEEE 802.11b standards were used previously. The former ones can work at a speed that is up to 56 Mbps, whereas 802.11b could work at speeds of 10 - 12 Mbps. This standard also allows the working at a frequency of 2.4 GHz.

Frame Structure
802.11 standard defines the two basic layers for the transmission and reception of data: the physical layer and the MAC (Media Access Control) layer. The data in wireless LAN is sent in the form of frames, just as in the case of any other network. The frame structure in wireless networks can be described as follows:

Frame Control Field: It is a 2-bytes long field. A lot of information is confined in it, and it has 11 sub-fields. Information that includes the protocol version, power management, and whether the information being transmitted is data or command, is mentioned in this field.

Address Field: In this aspect, the destination address is defined. Unlike other network protocols, the 802.11 structure allows four address fields. One of them holds the MAC address of the final recipient, and another holds the MAC address of the source recipient. The remaining two are used to hold the MAC address of the immediate recipient, and the transmitting station.

Frame Body: This is the field that contains the data that is to be transmitted.

Frame Check Sequence (FCS): This is the last frame field. It is 4 bytes long, and it allows the receiver to perform error control operations.

The data is thus sent by one device to another in the format described above. All this information in a frame helps it in successfully identifying the destination machine. This machine does the required checks before acknowledging the frame. It also performs the procedures like whether the received information is data or a command. This type of information, as mentioned above in the frame structure, is contained in the Frame Control Field.

Other Features
The 802.11 structure allows the different client machines that are connected in a LAN, to communicate at multiple data rates. The data rate is selected depending upon the highest possible speed, at which there will be minimum number of errors.

There are various features of wireless LAN that make it easy to implement setup. For laptops, it does not require any external accessory. If you want to connect a wireless network to a wired LAN, you just need to simply bridge the connection, and your network gets enlarged.