What Is a Wireless Access Point?

A wireless access point is an access point for a wireless network, commonly known as a "hot spot." There are mainly routing and switching integrated equipment and pure access point equipment. The integrated equipment performs access and routing work. Pure access equipment is only responsible for wireless client access. Pure access equipment is usually used as a wireless network extension and interacts with other APs. Or the main AP is connected to expand the wireless coverage, and the integrated device is generally the core of the wireless network.

A general wireless AP has two functions:

1. As the central point of the wireless local area network, other computers equipped with wireless network cards can access the wireless local area network through it;

2. Provide long-distance wireless connection to wired local area network, or long-distance wired connection to small wireless local area network, so as to achieve the purpose of extending the network range.

Wireless APs can also be used to connect small wireless LANs for expansion purposes. When there are enough wireless network users, a wireless AP should be connected to the wired network to connect the wireless network to the wired network backbone. The AP acts as a bridge between the wireless workstation and the wired backbone, enabling seamless integration of wireless and wired. APs allow wireless workstations to access network resources while increasing available resources for wired networks. ^[1]

Difference between wireless AP and wireless router

Different functions

Wireless AP: The full name of AP is Access Point, and its function is to convert the wired network into a wireless network. Image points say that wireless APs communicate between wireless and wired networks

A typical enterprise application, including attaching several wireless access points to a wired network, and then providing wireless access to the office

802.11b / g-based wireless APs are the most commonly used devices to build small wireless LANs. They act as bridges between wireless workstations and wired LANs in the MAC of the medium access control sublayer. The maximum connection distance is 300 feet. With a wireless AP, just like a HUB on a wired network, a wireless workstation can quickly and easily connect to an existing wired network. Most wireless APs support multi-user (30-70 people) access, data encryption, multi-rate sending and other functions. Some outstanding products also provide comprehensive wireless network management functions in small areas such as homes and offices. One wireless AP can realize wireless access for all machines. APs in the market are basically divided into two categories: simple APs and extended APs. In addition to the basic AP functions, the extended AP may also include several Ethernet switching ports, routing, NAT, DHCP, and print server functions.

With the intelligence of mobile terminals and

Relying on its unique advantages, the Internet has become the fastest growing industry in China and even the world. According to the latest statistics from DCCI, the number of Internet users in China in 2007 reached 182 million. It is estimated that the number of Internet users in China will reach 244 million in 2008. The decline in computer prices has further accelerated the development of the Internet. It is very common for a family to have multiple computers, and multiple computers sharing the Internet at the same time are the first choice for many families and units. However, due to the tedious wiring of the traditional wired network, it is also a trouble for many families.

In recent years, with the rapid development of wireless technology, wireless local area network (WLAN) technology has become very mature, and Internet speeds have become faster and faster. The mainstream products in 2009 not only can reach the speed of ordinary wired Ethernet, but also the security has been basically guaranteed. As a key device for wireless Internet access, the performance of the wireless AP and its location directly affect the strength of the wireless network transmission signal.

The so-called wireless AP is the wireless access point (wireless local area network transceiver): the wireless hub used in the wireless network is the core of the wireless network. It is the access point for computer users to enter the wired Ethernet backbone. To effectively improve the overall performance of wireless networks, the use of wireless APs has become an indispensable and important link. How to make better use of wireless APs and enjoy the real fun of shared Internet access, you need to grasp the following aspects:
First, the installation position should be higher

Because the wireless AP plays the role of a hub in a wireless network, it is actually a "base station" for transmitting wireless network signals, so its installation location must be selected so as not to affect the stability of the entire wireless network signal transmission. Considering that the wireless communication signal propagates in a straight direction, if there is an obstacle during the transmission process, the strength of the wireless communication signal will be weakened, especially when the metal obstacle is encountered, the attenuation of the wireless signal It is huge. In order to prevent the wireless signal from being interfered by external obstacles, you can install the wireless AP as high as possible, or add a communication relay point on the top of the obstacle, of course, you can also use the tower To increase the outdoor antenna height of the wireless AP. In this way, mobile or fixed obstacles between the wireless station and the wireless AP can be effectively eliminated, so as to ensure that the signal coverage of the wireless AP is sufficiently large, then the overall communication performance of the wireless network will be Will be greatly improved.
Second, coverage, a small amount of overlap With the help of Ethernet, we can effectively connect multiple wireless APs to build a wireless roaming network so that users can roam wirelessly throughout the network. However, when a visitor moves from one sub-network to another, the distance between the visitor and the original wireless AP will be more and more distant, so that the wireless Internet signal will become weaker and the Internet speed is also lower. Slower and slower until the signal connection to the original network is interrupted; if there is a small overlap between the wireless AP signal coverage area of the other subnet and the wireless AP signal coverage area of the original network, the visitor is about to contact When the original network is disconnected, it will automatically enter the new subnet coverage area. This will ensure that visitors are always online when roaming between different networks without discovering the disconnection. Therefore, when setting up a wireless roaming network, in order to ensure that the wireless network has sufficient bandwidth, it is necessary to perform a small amount of cross coverage on the respective wireless signal coverage area generated by each wireless AP to ensure seamless connection between each wireless subnet. .
3. Control the bandwidth to ensure the speed. In the theoretical state, the bandwidth of the wireless AP can reach the size of 11Mbps / s or 54Mbps / s, but the bandwidth is shared by other wireless workstations. In other words, if the wireless AP When more wireless workstations are connected at the same time, the network bandwidth that each wireless workstation can share will gradually decrease. Therefore, in order to ensure that the communication speed of the entire wireless network is not affected, it is necessary to control the number of wireless workstations in order to ensure that each workstation can obtain sufficient Internet bandwidth. So how many wireless workstations can a wireless AP connect to at the same time, so as not to reduce the communication speed of the entire network? Generally speaking, a wireless AP supporting the IEEEE 802.1lb standard can connect to about 20 workstations at the same time. If the number exceeds this number, the communication speed of the wireless network will be significantly reduced. Of course, if the number of workstations connected to one wireless AP at the same time is small, the networking cost will be too high.
4. Communication signal, refuse to pass through the wall If its signal crosses the wall or is subject to other interference, its communication distance will be greatly shortened; in order to avoid unnecessary weakening of the communication signal, you must control the swing of the wireless AP. Position it so that its signal does not cross the wall as much as possible, let alone the poured reinforced concrete wall. Through actual tests, it was found that within 10 meters, after the transmission signal of the wireless AP crosses two brick walls, its signal strength can still maintain the highest standard transmission intensity, but once the wireless signal passes through the poured reinforced concrete When it was on a wall, its signal strength dropped by half. It is not difficult to see that when a wireless communication signal passes through a metal wall, its signal strength will be greatly attenuated. Therefore, when setting up a wireless local area network in a building with more than two floors, it is best to install a wireless AP on each floor, so that all wireless workstations within this floor can be covered by the wireless AP. Inside. In addition, if there is a large number of room intervals in the first floor, you should ensure that there is no more than two walls between the wireless AP and the wireless workstation. Otherwise, you need to install more wireless APs. Make sure that each wireless workstation has sufficient signal strength. Of course, in order to ensure that all wireless workstations in a building can be connected to the same network at the same time, you also need to connect wireless APs on each floor or installed in other locations through twisted pair cables.
V. Placement in the center Because the signal coverage of the wireless AP is a circular area, in order to ensure that each wireless workstation connected to it can effectively receive the communication signal, it is best to place the wireless AP in the connected area. The center of the workstation. For example, the wireless AP can be placed in the center of the computer room or room, and then each workstation is placed around the wireless AP, so that each workstation in the computer room can access the wireless network at high speed. In addition, everyone should note that the wireless network usually automatically adjusts the Internet speed according to the distance of the communication distance. In general, the closer the workstation is to the wireless AP, the stronger the anti-interference ability of the communication signal is, and the Internet speed will be. The faster, on the contrary, if the distance between the workstation and the wireless AP is longer, the communication signal is more susceptible to external interference, and the Internet speed will be slower. Therefore, in order to ensure that the Internet speed is always at a high speed, you must control the distance between the wireless AP and the workstation, and try not to leave them too far away. If the distance is really long, you can install an omnidirectional antenna for the wireless AP, and a distant workstation needs to install a directional antenna, and adjust the antenna direction to ensure that they have a suitable small angle with the horizontal line.
6. Correct settings, successful roaming As mentioned earlier, to achieve wireless roaming, you need to overlap the signal coverage of multiple wireless APs with a small part of each other, but to successfully roam, you need to perform appropriate Settings. First you need to log in to the parameter setting interface of the wireless AP, find the SSID setting option, and then set the SSID names of all wireless APs to be the same, so as to ensure that roaming users roam in the same network; then you also need to modify the settings of each wireless AP. IP address, so that the IP addresses of all wireless APs belong to the same network segment; below, you also need to modify the channels of wireless APs whose signals cover each other. Considering that there is a signal overlapping area between two adjacent wireless APs, in order to ensure that the signal channels used in this area cannot cover each other, specifically, wireless APs with signals covering each other must use different channels, otherwise it is easy to cause each Signals between wireless APs interfere with each other, which causes the overall performance of the wireless network to decrease. A wireless AP can use a total of 11 channels, of which only 1, 6, and 11 are not covered at all, so you can set adjacent wireless APs to use these channels to ensure wireless roaming success .