Basic knowledge of wireless networks (1)

Wireless Networks all know that mobile communication, wireless Internet access, and wireless LAN are all part of wireless networks, but many friends cannot distinguish them. The following section summarizes the basic knowledge of wireless networks.

Basic knowledge of wireless networks 1: What is WLAN? What is the most popular wireless networking technology?

WLAN is short for Wireless LAN, that is, Wireless LAN. Wireless LAN uses wireless technology to achieve fast Ethernet access. Looking at the current market, IEEE 802.11b technology has surpassed Bluetooth, HomeRF and other technologies in terms of performance and price, and has gradually become the most widely used standard for Wireless Access to Ethernet. Due to the continuous maturity of IEEE 802.11b technology, wireless LAN applications are emerging globally.

Basic knowledge of wireless networks 2: What are the advantages of wireless networks compared with wired networks?

Compared with wired networks, the main advantage of WLAN is that it does not require wiring and is not restricted by wiring conditions. Therefore, it is very suitable for mobile office users and has broad market prospects. At present, it has expanded from traditional special industries such as health care, inventory control and management services to more industries, and even started to enter the fields of families and enterprises.

Basic knowledge of wireless networks 3: Does wireless networks have adverse effects on human health?

The emission power stipulated by IEEE 802.11 cannot exceed 100 MW, and the actual emission power is about 60 ~ 70 mW. What kind of concept is this? The transmit power of the mobile phone is about 200 to 1 W, and the handheld walkie talkie is up to 5 W. In addition, wireless networks are not directly accessible to the human body like mobile phones, so they should be safe.

Key Aspect 4: What are common wireless network protocols and their features?

The most common examples are IEEE 802.11, IEEE 802.11a, IEEE 802.11b, and IEEE 802.11g. IEEE 802.11 is a wireless LAN Standard originally developed by IEEE (Association of Electrical and Electronics Engineers.

IEEE 802.11b, also known as Wi-Fi, uses an open 2-4 GHz direct sequence spread spectrum with a maximum data transmission rate of 11 Mbps, you can also adjust the transmission rate to 5.5 Mbps, 2 Mbps, and 1 Mbps Based on the signal strength. No linear transmission is required. The maximum outdoor transmission range is 300 meters, and the maximum indoor transmission range is 100 meters if obstacles exist. This is the most widely used transmission protocol.

Basic knowledge of wireless networks 5: How wide can WLAN cover?

Generally, the scope of WLAN coverage depends on whether the environment is open or not. If an external antenna is not added, it is about 250 m in the field of view. If it is a semi-open space with an interval, it is about 35 ~ About 50 meters. Of course, if an external antenna is added, the distance can be further reached, which is related to the increase value of the antenna, So it depends on the user's needs.

Basic knowledge of wireless networks 6: What are the basic configurations required for creating a WLAN?

Generally, a wireless network is equipped with a wireless network card and an AP, so that network resources can be shared in a wireless mode in combination with the existing wired architecture. If only a few computers are connected to the peer network, do not use AP. You only need a wireless network card for each computer.

AP is short for Access Point, which is generally translated as "Wireless Access Node" or "bridge ". It serves as a bridge between a wireless workstation and a wired local area network in the MAC of the media access control layer. With an AP, it is like a Hub in a wired network. A wireless workstation can be quickly and easily connected to the network.