Security of Wireless Access Points

The Internet has become the fastest growing industry in China and even in the world, relying on its unique advantages. According to the latest statistics from DCCI, the number of Internet users in China reached 182 million in 2007. It is expected that the number of Internet users in China will reach 2.44 billion in 2008. The decline in computer prices, further accelerating the development of the Internet, a family with more than one computer has been very common, more than one computer at the same time **** enjoy Internet access is the first choice of many families and organizations. However, the traditional wired network, due to its cumbersome wiring, is also the trouble of many families.

In recent years, with the rapid development of wireless technology, wireless local area network (Wireless Local Area Net_work, WLAN) technology has been very mature, Internet access speed is also getting faster and faster. 2009 mainstream products not only can reach the rate of ordinary wired Ethernet, and the security has been the basic guarantee. As a wireless Internet key equipment wireless AP its performance and location of the placement of good and bad, directly affecting the wireless network transmission signal strength.

The so-called wireless AP is a wireless access point (wireless LAN transceiver): wireless hub for wireless networks, is the core of the wireless network. It is the access point for computer users into the wired Ethernet backbone. To effectively improve the overall performance of the wireless network, using a good wireless AP has become an important and indispensable part. How to better use the wireless AP, enjoy to *** enjoy the real fun of the Internet, you need to grasp the following aspects: First, the installation location, should be higher

Because of the wireless AP in the wireless network plays the role of a hub, it is actually the wireless network signal transmission "base station", so it is installed in a location Must be selected in order not to affect the entire wireless network signal transmission stability. Considering that wireless communication signals are propagated in a straight line direction, if there are obstacles in the transmission process, the strength of wireless communication signals will be weakened, especially when encountering metal obstacles, the attenuation of wireless signals is even greater. In order to avoid wireless signal interference from external obstacles, you can install the wireless AP, as far as possible, it will be the most high position of the installation, or in the top of the obstacle and then add a communication relay point, of course, you can also use the tower to increase the height of the wireless AP's outdoor antenna, in this way, you can effectively eliminate the wireless workstations and wireless AP to ask the moving or fixed obstacles, thus ensuring that the wireless AP signal coverage is large enough. AP signal coverage is large enough, then the overall communication performance of the wireless network will be greatly enhanced.　　Second, the coverage, a small amount of overlap With Ethernet, we can effectively connect multiple wireless APs, so as to build a wireless roaming network, so that users can freely roam throughout the network. However, when a visitor moves from one subnetwork to another, there will be a phenomenon that the distance between the visitor and the original wireless AP is getting farther and farther, so that the wireless Internet signal will get weaker and weaker, and the Internet speed is getting slower and slower until the signal connection with the original network is interrupted; if there is a small amount of overlap between the signal coverage area of another subnetwork's wireless AP and that of the original network, then it will be possible to access the wireless roaming network with a small amount of overlap, so that users can roam wirelessly throughout the network. If there is a small amount of overlap between the wireless AP signal coverage area of another subnet and the wireless AP signal coverage area of the original network, then the visitor will automatically enter the new subnet coverage area at the moment of disconnection from the original network, which ensures that the visitor is always online when roaming between different networks and will not find the connection disconnection phenomenon. Therefore, in the formation of wireless roaming network, in order to ensure that the wireless network has sufficient bandwidth, it is necessary to generate each wireless AP's respective wireless signal coverage area for a small amount of cross-coverage, to ensure that each wireless sub-network can be realized seamlessly.　　Third, control bandwidth, ensure speed In theory, the bandwidth of the wireless AP can reach 1 1Mbps / s or 54Mbps / s such a size, but the size of the bandwidth is the size of the other wireless workstations to **** enjoy, in other words, if the wireless AP at the same time with a larger number of wireless workstations to connect, then each wireless workstations can be shared to get the network bandwidth will gradually become smaller. In other words, if a wireless AP is connected to more wireless workstations at the same time, the bandwidth that each wireless workstation can share will gradually become smaller. Therefore, in order to ensure that the communication speed of the entire wireless network is not affected, we must control the number of wireless workstations to ensure that each workstation can get enough bandwidth. So a wireless AP, in the end, how many wireless workstations can be connected at the same time, in order not to reduce the communication speed of the entire network? Generally speaking, support for IEEEE802.1lb standard wireless AP can be connected to about 20 workstations at the same time, if the number of workstations connected to the number of more than this number, the communication speed of the wireless network will be significantly reduced; of course, if a wireless AP connected to the number of workstations at the same time is less, it will lead to the high cost of the network.　　Fourth, the communication signal, refuse to go through the wall If its signal through the wall or other interference, it will greatly reduce the communication distance; in order to avoid unnecessary weakening of the communication signal suffered, you must control the placement of the wireless AP, so that the signal as far as possible do not go through the wall, not to mention through the pouring of reinforced concrete walls. Through practical testing found that, within a distance of 10 meters, the wireless AP's transmission signal across two brick walls, its signal strength is still able to maintain the highest transmission strength in the standard, but once the wireless signal across the pouring of reinforced concrete walls, its signal strength dropped by half. It is easy to see that the wireless communication signal will be greatly attenuated when it passes through metal walls. Therefore, in more than two floors of the building in the formation of wireless LAN, it is best to install a wireless AP in each floor, which can ensure that all wireless workstations within the floor can be in the coverage of the wireless AP. In addition, if there are more rooms within a floor, you should make sure that there are no more than two walls between the wireless AP and the wireless workstations, or you will need to install more wireless APs to make sure that each wireless workstation can get enough signal strength. Of course, in order to ensure that all wireless workstations within a building can be connected to a network at the same time, you also need to twisted-pair cable will be installed on each floor or in other locations where the wireless AP is connected together.　　Fifth, placed in the center of the position, in the center As the wireless AP signal coverage in a circular area, in order to ensure that every wireless workstation connected to it can effectively receive the communication signal, it is best to place the wireless AP in the center of the connected workstations. For example, you can place the wireless AP in the central position of the computer room or room, and then each workstation around the wireless AP is placed around the room, so as to ensure that every workstation in the room can be high-speed access to the wireless network. In addition, we should note that the wireless network will usually automatically adjust the Internet speed according to the distance of the communication distance, in general, the closer the distance of the workstation from the wireless AP, the stronger the anti-interference ability of its communication signals, then the faster the Internet speed, on the contrary, if the distance between the workstation and the wireless AP is farther away, then the communication signals are susceptible to external interference, then the Internet speed will be slower. Therefore, in order to ensure that the Internet speed is always in a high-speed state, you must control the distance between the wireless AP and the workstation, try not to let them too far away. If the distance is really far away, you can install an omnidirectional antenna for the wireless AP, while the workstations far away need to install a directional antenna, and at the same time adjust the direction of the antenna to ensure that they have a suitable small angle with the horizontal line.　　Six, correctly set up, successful roaming As mentioned earlier, to realize wireless roaming, you need to be more than one wireless AP signal coverage Fan with each other overlap a small portion, but to roam successfully, you also need to set up the appropriate wireless AP. First of all, you need to log into the wireless AP's parameter setting interface, in which to find the SSID setting option, and then all the wireless AP's SSID name is set to the same, so as to ensure that the roaming users roam in the same network; and then you also need to modify the IP address of each wireless AP, so that all the wireless APs belong to the same network segment of the IP address; the following, you also need to modify the signal coverage of the wireless APs each other's channel. channels of the wireless APs. Considering the signal overlap area between two neighboring wireless APs, in order to ensure that the signal channels used in this part of the region can not cover each other, specifically the wireless APs covering each other's signals must use a different channel, otherwise it is easy to cause interference between the signals between the wireless APs, which leads to a decline in the overall performance of the wireless network. A wireless AP can use a total of 11 channels, of which only 1, 6, 11 these three channels are not covered at all, so you can set the neighboring wireless AP to use these channels, to ensure the success of wireless roaming.