With the development of network technology, notebook computers
With the popularization, people have higher and higher requirements for mobile office.
Traditional wired LAN is limited by wiring because
This kind of efficient, fast and flexible wireless LAN came into being.
Born. Now many universities and large enterprises are aware of it.
Wireless LAN.
1 Advantages of WLAN
Wireless local area network WLAN
Network is a combination of computer network and wireless communication technology.
The product of combination. It uses wireless multiple access channel as transmission.
Media, using electromagnetic waves to complete data interaction and realize tradition.
Functions of wired local area network. Wireless LAN has the following characteristics
Features:
1. 1 is easy to install.
Wireless LAN eliminates a lot of wiring work,
You only need to install one or more wireless access points (access
Point, AP) can cover the whole building's LAN,
But also convenient for management and maintenance.
1.2 high mobility
In WLAN, each node can move at will,
Not limited by geographical location. Currently, AP can cover
10 ~100m. Within the coverage of wireless signals, all
Can access the network, WLAN can be used for different operations.
Business, roaming between networks in different countries.
1.3 scalability
Wireless LAN has many configurations, and each access point
Can support access of more than 100 users, as long as there is no existing one.
Add AP on the basis of wired LAN, how many can you use?
The small network of the family has expanded into a large network of thousands of users.
hostage
Analysis of wireless LAN technology
The foundation of WLAN is still the traditional wired office.
LAN is an extension and replacement of wired LAN. be at home
On the basis of wired LAN, through wireless hub, wireless
Access node (AP), wireless bridge, wireless network card, etc.
The device supports wireless communication. Wired network one
Similarly, wireless local area networks also need transmission media. only
It is the transmission medium adopted by WLAN, not twisted pair.
Or optical fiber, but infrared (IR) or radio waves.
(RF), the latter is mostly used.
3 main protocol standards of wireless local area network
Wireless access technology is different from wired access.
One is that the standards are not uniform, and different standards are different.
Apply. At present, there are 802. 1 1 standards and new ones.
Your bluetooth standard and HomeRF (Home
Court network) standard.
3. 1 802. 1 1 Brief Introduction to the Protocol
In 1997, IEEE formulated-
-IEEE 802. 1 1 protocol standard. Total data transmission speed
The rate is designed to be 2Mbit, and the communication between two devices can
In a device-to-device manner, or at a base station.
Or under the coordination of the access point.
3. 1. 1
Is the standard of wireless local area network. Its carrier
The frequency is 2.4GHz, which can provide 1, 2, 5.5 and.
The multiple transmission speed is11mbit/s.ieee802.11b.
Is the most famous and common wireless LAN standard.
The broadest standard. It is sometimes incorrectly marked as.
Wireless network. In fact, Wi-Fi is a wireless local area network alliance.
(WLANA), this can only guarantee
Commodities using the trademark can cooperate with each other and compete with standards.
It doesn't really matter whether it is accurate or not.
3. 1.2 IEEE 802. 1 1a
It is the revised standard of the original standard 802. 1 1.
Approved in 1999. The 802. 1 1a standard is adopted.
The same core protocol as the original standard, the working frequency is
5GHz, and the maximum original data transmission rate is 54 mbit/s.
3. 1.3 IEEE 802. 1 1g
Its carrier frequency is 2.4GHz, the original transmission speed.
The degree is 54Mbit/s, and the network speed is about 24.7Mbit/
S .802. 1 1g devices are backward compatible with 802.11b.
Now many wireless router manufacturers have responded to the market.
If necessary, it will be opened separately on the IEEE 802. 1 1g standard.
Issue a new standard to increase the theoretical transmission speed to
108mbit/s or125mbit/s
3.2 bluetooth
Bluetooth (IEEE 802. 15) is a new standard,
"Bluetooth" is an extremely advanced high-capacity close range.
The technical standard of wireless digital communication, its goal is to realize
The maximum data transmission speed is 1Mbit/s (effective transmission speed
The rate is 72 1kbit/s) and the maximum transmission distance is 10cm~ ~
10m, which can be reached by increasing the transmission power. blue
Tooth is more mobile than 802. 1 1, for example, 802. 1 1.
System in the office and campus, Bluetooth can put a
Devices are connected to LAN (local area network) and WAN (wide area network).
LAN), and even support global roaming. In addition, Bluetooth has become
Low cost, small size, and can be used for more equipment. "Bluetooth"
The biggest advantage is that when updating the network backbone, such as
If it is carried out in the "Bluetooth" architecture, the whole network will be used.
The cost is definitely lower than laying cables.
4 Security of WLAN
Wireless local area networks use public electromagnetic waves as carriers.
Body, vulnerable to illegal user intrusion and data eavesdropping.
WLAN must consider three security factors:
Information security, authentication and access control. In order to protect
In order to prevent the security of WLAN, we should use appropriate technology.
It mainly includes: physical address (MAC) filtering and service set labeling.
Identifier (SSID) Matching, Wired Equivalent Privacy (WEP), Yes or No
Wired equivalent privacy (WEP), virtual private network (VPN),
Wi-Fi protected access (WPA). Aim for your own network
The characteristics and requirements, choose the corresponding technology.
5 Small wireless office network networking scheme
5. 1 Wi-Fi and Bluetooth selection
According to the present situation of wireless technology, it mainly
It uses Bluetooth and 802. 1 1b/a/g wireless technology.
Set up wireless office network. The comparison is as follows:
(1) The data transmission rate of Bluetooth technology is 1Mbit/
S, the communication distance is about10m; And 802.11b/a/g.
The data transmission rate reaches 1 1Mbit/s, which is effective.
The distance is as long as 100m, which has the characteristics of "mobile office".
Point, can meet the needs of users to run a large number of bandwidth-consuming networks.
Network operation, so 802. 1 1b/a/g is more suitable for office use.
Wireless networks (especially laptops) should be built in public offices.
(2) In terms of cost, 802. 1 1b/a/g is relatively cheap.
Price, at present, many notebooks are generally fast-moving platforms, this
Integrated 802. 1 1b/a/g wireless network card, users only need to
Purchase wireless LAN access equipment (wireless AP)
A wireless network can be established. Bluetooth should be based on the network profile.
Provide point-to-point and point-to-multipoint wireless connections. exist
Grounding of all equipment within any effective communication range.
All bits are equal. Of course, from another perspective,
Bluetooth is more suitable for families to set up wireless LAN.
5.2 Wi-Fi wireless network networking scheme
Before setting up a Wi-Fi wireless network, you need to prepare a wireless network without one.
Wired network card and wireless AP, if the computer itself does not.
Line network card, then you can buy PCMICA with the same protocol.
802. 1 1b wireless network card with USB interface. The other one is just
It is the choice of wireless AP, and it is recommended that such users choose less.
USB wireless access point for office use. According to financial strength
Choose something with stronger functions and performance, which is related to the office.
Stability and security of computer surfing the internet.
For example, in an actual formation, there are five computers.
1 put it in a separate room, and the other four are in the process.
Public large room, using ADSL dial-up electricity.
Words are also on the machine 1. Therefore, a wireless AP is installed.
Go to the machine 1, and other machines are connected through the wireless gateway.
The AP connected to 1 machine forms a wireless network.
5.3 Installation of Wireless Network
After the equipment is ready, it needs to be installed.
Configuration.
The first is the installation of wireless network card, whether to use notes.
This kind of built-in wireless network card, or install wireless network through extension.
Card, you need to install the driver of wireless network card first.
Next, install the wireless network, which requires a meter.
The operating system of the computer is at least SP2 Windows XP.
Its wireless support has also been greatly improved. can
Go directly to Wireless Network Installation in Control Panel.
Wizard "to configure. In addition, according to the settings you choose.
Set IP grounding for each computer's wireless network card.
Address, security settings.
6 conclusion
Wireless local area network organically combines network and mobile applications.
In a word, it overcomes the shortcomings of wired LAN, and works with
With the improvement of various technologies and standards, WLAN will
More and more mature, providing people with high speed and flexibility.
Multimedia network based on.