Wireless networking is becoming a trendy trend next to traditional wired networking. Reliable quality, stable operation and simple, affordable installation procedures are the hallmarks of wireless connectivity that is ready to meet the diverse needs of information exchange. , business to entertainment needs ... This article will provide you with the information you need to build a wireless computer network.
Wireless Technology
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Wireless networking technology developed by IEEE and officially launched by the Wi-Fi Alliance worldwide. There are three standards: 802.11a standard, maximum transmission speed 54Mbps; 802.11b standard, maximum transmission rate of 11Mbps; 802.11g standard, maximum transmission rate of 54Mbps (see attached technical specifications). The common characteristics of each technology are as follows:
The 802.11b standard has the lowest transmission rate (11Mbps) but is widely used in production, business and service environments due to the low cost of procurement of equipment and the speed of transmission that meets the needs. Exchange of information on the internet such as web browsing, e-mail, chatting, messaging ...
802.11g high-speed (54Mbps) data transfer rates, suitable for high-throughput data exchange, data flow in the system is the graphics, audio, video files. large. The frequency of 802.11g radio transmissions is the same as that of 802.11b (2.4GHz), so 802.11g networks communicate well with computer networks using 802.11b. However, at current prices, the cost of installing a wireless 802.11g wireless system is 30% higher than the cost of an 802.11b wireless system.
802.11a has the same transmission speed as the 802.11g standard, but the highest operating frequency, 5GHz, large bandwidth should accommodate more information channels than the two standards. And because of the higher frequency of operation of civil telecommunication devices such as mother cell phone, Bluetooth etc., 802.11a wireless network is less affected. due to interference. But this is also the reason why the system is not compatible with the two standard wireless systems.
How to buy a wireless device
Equipment for wireless networks consists of two types: wireless network cards and access point / APs. Wireless network cards come in two types: external (USB) and internal (PCI). Choose which type of hardware depends on the hardware configuration (slot, port of communication) of the PC. The interface in the computer interface through the PCI slot on the motherboard so the assembly procedure, the software installation is similar to when we install sound card, network card, hard disk controller card ... Type The external connector connected to the computer through the USB port should be very convenient to disassemble, suitable for a variety of computers from desktop to laptop, avoid the phenomenon of electromagnetic interference by the device installed in computer-generated. Note that if your PC uses a USB 1.0 port (12Mbps data rate), it will only be 802.11b compliant. If used with the other two standards, it will slow data transfer rates.
The procedure for building a wireless peer-to-peer network is simple. Just equip each computer with a wireless network card, adding that the device's control software is the computers in the network that can exchange data with each other. But if you want to access the existing LAN / WAN system or access the internet, you must have access point equipment. The main functions of this device include reception, signaling between the network cards in the coverage area and the intermediate relay that allows the wireless network card to communicate with the LAN / WAN system. modem) and the internet. However, depending on the manufacturer's point of view, requirements for use and convenience of the network administrator, some Access Point devices have some other network functions such as gateway, Roads A number of April 2003, 5/2003, 8/2003 and 11/2003, the article introduces some types of Access Point and the features of the device.
Building wireless networks
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Figure 1: Check the wireless broadcast quality of the wireless connection through the gadget included with the device |
Setting up a cost-effective wireless network, like other traditional networking systems, may take up to an hour or more to form a wireless network. In fact, most of the problems and problems that occur in the wireless network are due to faulty device driver software, so it is important to use the latest device drivers provided by the manufacturer. provided, updated or downloaded from the internet. If the system is running Windows XP, then install the latest service pack released by Microsoft.
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The distance between the wireless network card and the AP also greatly affects the transmission speed, the farther the AP, the lower the transmission speed. For example, for 802.11b wireless networks, the rate of decline is gradual, with half the previous level (11Mbps down to 5.5Mbps down to 2Mbps ...). Most utility software comes with wireless network cards and APs that display network traffic.
If the work space exceeds the coverage of the existing AP, then we must purchase additional repeaters to increase the broadcasting power as well as the coverage radius of the AP.
Then proceed to configure the software for the network, namely:
Thawa Thawa Th HI HI HI HI HI HI HI HI HI HI HI HI HI HI HI HI, If the wireless network under construction has internet access, contact your internet connection provider (ISP) for an IP address and instructions on how to set up your wireless network adapter.
Use DHCP service As with normal computer networks, the DHCP service should be used so that the system automatically provides IP addresses to all network devices participating in the network. This will save a lot of effort for the network administrator.
SSID Similar to the concept of domain names in the internet, the SSID (Service Set Identifier) is the string representation of a wireless network. All network devices (wireless access points, wireless network cards, etc.) of a wireless network must be declared with a common SSID in order to work together. Often the network administrator will tell the whole system a network name, but the SSID itself is a loophole that allows hackers to judge what type of network device is used in the system to try to access it inappropriately. French.
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Figure 2: Find the network presence in the coverage area with Windows XP's Wireless Zero tool |
The infomation channel The bandwidth of the 802.11b and 802.11g standard allows for the construction of 14 different channels for transmission of information, but nowadays one uses one of the numbered channels 1 to 11, and avoids the confusion of channels 1, 6 and 11 to improve signal quality.
Next, install and configure the wireless network card driver software. There are two modes of setting: Infrastructure mode if using access point, router, SSID and information channel; Ad hoc mode for peer-to-peer mode. After adding the control software, if the computer is running Windows XP, the wireless network administrator function called Wireless Zero Configuration (WZC) will be activated, through this function (the icon is in the tray We will know the list of wireless networks that are present around the computer (with wireless network card). Double-click on a wireless network in the list to perform a connection procedure for that network.
As a general rule, the list of wireless networks present around your computer is classified into two categories: Available networks that list all available wireless networks; Preferred networks is a list of all wireless networks that Windows XP WZC, prioritized from high to low, will automatically perform the network connection procedure. These two lists are located in the properties window of the wireless network adapter configuration utility. The procedure for booting this window is as follows: Right-click the icon labeled My Network Places, select the Properties menu, and then click the Wireless Networks menu.
System Security: Prevent unnecessary curiosity
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Figure 3: Wireless network card configuration screen |
In order for the system to operate safely and securely in the internal system, you should follow the following guidelines:
Use password : Do not use system passwords that are just spaces or are automatically generated by device software.
No SSID identifier provided : By default, the AP automatically provides SSID network identification information for all devices within its coverage radius upon request. This gives the computer user full access to the network, but the disadvantage is that the hacker uses illegal access, so for local area networks need to disable the function. This makes the network more secure.
Only allow devices with certain MAC addresses to be joined to the system All networked devices have a unique 12-character string that identifies each device, called the Media Access Control (MAC) address. For a more secure operating system, only networked devices with a certain MAC registry number are allowed to access the system. The list of MAC addresses of wireless network devices used in the network is declared through the Access Point management software. In Windows XP or 2000, the procedure for determining the MAC address of a network device is as follows: Click Start-> Run, type cmd and press OK. In the DOS window of the cmd utility, enter the ipconfig / all command line (note between ipconfig and / all with delimited spaces). After the ':' sign of the Physical Address message is the MAC address of the network device. With Windows 98 / Me just enter the winipconfig command in the Run window, the MAC address will be on the message labeled 'Adapter Address'.
Apply WPA or WEP security standards to the system WEP (Wireless Encryption Protocol) and WPA (Wi-Fi Protected Access) are wireless network security technologies. However, today's hackers have found a way to disable WEP security, so it's important to use the WPA standard to protect your system. If your system is currently using the WEP standard, contact your manufacturer for instructions on how to migrate to WPA.
Disable Windows file sharing : Start the Windows Explorer software. Right-click each icon representing the drives in your computer and select the menu labeled Sharing and Security (Windows XP) or Sharing (Windows versions 9x, NT). Uncheck the box labeled 'Sharing this folder on the network'.
