Wireless network is widely used in many fields of social life because of its strong flexibility, expansibility and mobility. It can be said that people's daily life at this stage is inseparable from the wireless network system. Below I searched and sorted out the wireless network technology and characteristics for everyone. Welcome to reading. I hope it helps you!
Wireless network technology and characteristics 1 I. Classification of wireless networks
1. wireless personal area network
Wireless personal area network (WPAN). It is to connect personal electronic equipment in personal workplace by wireless technology, and the whole network range is about 10 meter.
2. Wireless local area network
Wireless local area network is a network established in a certain local area by using wireless communication technology, which is the product of the combination of computer network and wireless communication technology. It uses wireless multiple access channel as transmission medium to provide the functions of traditional wired local area network, so that users can truly realize broadband network access at any time, anywhere and at will.
3. Wireless people
Wireless metropolitan area network refers to the establishment of wireless connections between multiple places in a certain city without spending a lot of money to lay optical cables and cables, and without renting lines from outside. In addition, WMAN can be used as a backup network when the leased line of wired network broadband cannot be used well. The purpose of WMAN is to transmit data through radio waves and infrared light waves. Although we are currently using different technologies, such as MMDS and LMDS, IEEE 802. 16 technicians who are responsible for formulating broadband wireless access standards are still developing specifications to standardize these technologies.
4. Wireless WAN
Wireless WAN refers to the wireless network technology established by users through remote public networks or private user networks. It can cover a wide geographical area mainly by using several antenna base stations or satellite systems maintained by wireless service providers. The current wireless network technology is called the second generation system (we usually call it 2G). The second generation system (2G) includes Global System for Mobile Communications (GSM), Cellular Digital Packet Data (CDPD) and Code Division Multiple Access (CDMA). At present, efforts are being made to transition from the second generation (2G) network to the third generation (3G) technology.
Second, the characteristics of wireless network analysis
1. More flexible
Wireless network can take care of places that wired network can't take care of more conveniently, and it is very convenient to set up. For places where the network wiring structure needs to be changed frequently and users need to move computers in a wider range, using WLAN can overcome the inconvenience caused by cable restrictions, and can also be used in places where time is tight, communication needs to be established quickly, it is inconvenient to use wired networks, and it is costly or time-consuming.
The speed is only100M, but it is more convenient to use.
Gigabit wired network has entered the mainstream of backbone network applications, but in practical home or small office applications, 100 Gigabit wired network is still the absolute mainstream. Therefore, from the practical application point of view, the current wireless network can provide the speed close to the wired network. Although this speed guarantee requires higher distance, the contradiction between convenience and performance needs to be broken for the whole network technology at present.
3. Security can guarantee common application.
Today's wireless products can provide multiple security protections. It supports 64/ 128/ 152-bit WEP data encryption, and also supports encryption and security mechanisms such as WPA, IEEE 802. 1X, TKIP and AES. Support SSID broadcast control, support access control based on MAC address, and powerful firewall function, which can effectively prevent intrusion and provide strong security protection for wireless communication.
Although the price is higher than cable, it is acceptable.
For ordinary home users and small office users, the main comparison object of wireless is 100 Mbps wired home network. Similarly, taking four computers to build a small home wireless network as an example, the investment can be divided into two categories. To build a peer-to-peer network, you don't need to invest in a wireless access point, you just need to buy a wireless network card. Take the existing notebook computer with two wireless network cards as an example, other computers need to buy two network cards. Although some 1 1M products can be won by 60-80 yuan, 54M products still need more than 100 yuan.
If a wireless network centered on infrastructure is established, then a wireless AP is necessary. Because the simple SOHO wireless AP has been eliminated in the market, it is necessary to integrate wireless AP and broadband router.
Third, the mainstream technology and characteristics of wireless network analysis
1. Wireless broadband
Wi-Fi, commonly known as wireless broadband, is another name of IEEE 802.11b. It is a short-distance wireless transmission technology, which can support Internet access within several hundred meters. With the development of network technology, IEEE 802. 1 1a and IEEE 802.1g appear, and the standard IEEE 802. 1 1 has been collectively referred to as wireless broadband (that is, Wi-Fi). In practical application, to use wireless broadband (Wi-Fi), users must first have a Wi-Fi-compatible client device.
Wireless network technology and function 2 1. foreword
With the rapid development of Internet, communication network has developed from traditional wired network to wireless network. As a kind of wireless network, WLAN (Wireless Local Area Network) meets people's dream of realizing mobile office and creates a colorful free sky for us.
The concept of 2.2. WLAN
Wireless local area network is a network established in a certain local area by using wireless communication technology, which is the product of the combination of computer network and wireless communication technology. It uses wireless multiple access channel as transmission medium, and provides the functions of traditional wired LocalAreaNetwork (LAN), so that users can truly access broadband network at any time, anywhere and at will.
The characteristics of 3.3. WLAN
WLAN began to exist as an extension of wired LAN, and various organizations, enterprises and institutions have widely adopted WLAN technology to build their office networks. However, with the further development of application, WLAN is gradually developing from the traditional LAN technology into a "public wireless LAN" and becoming a means of broadband access to the Internet. Wireless LAN has the characteristics of easy installation, easy expansion, easy management, easy maintenance, high mobility, strong confidentiality and anti-interference.
4.WLAN standard
Because WLAN is based on computer network and wireless communication technology, in the computer network structure, the logical link control (LLC) layer and the application layer above it may have the same or different requirements for different physical layers. Therefore, WLAN standards are mainly aimed at physical layer and media access control layer (MAC), involving technical specifications and standards such as wireless frequency bands and air interface communication protocols.
4. 1 IEEE 802. 1 1X
( 1)IEEE802. 1 1
1990 the IEEE 802 standardization Committee established the IEEE802. 1 1WLAN standard working group. IEEE802. 1 1 (alias: Wi-Fi(WirelessFidelity)) is a standard recognized by a large number of LAN and computer experts in June 1997, which defines the physical layer and media access control (MAC) specifications. The physical layer defines the signal characteristics and modulation mode of data transmission, and defines two radio frequency transmission modes and one infrared transmission mode. Radio frequency transmission standards are frequency hopping spread spectrum and direct sequence spread spectrum, and the working frequency band is 2.4000~2.4835GHz.
IEEE802. 1 1 is a wireless LAN standard originally formulated by IEEE, which is mainly used to solve the wireless access between users and user terminals in office LAN and campus network. The service is mainly limited to data access, and the highest rate can only reach 2Mbps. Because the speed and transmission distance can't meet people's needs, IEEE802. 1 1 standard has been replaced by IEEE 802.5438+01b.
(2)IEEE802. 1 1b
1September 1999, IEEE802. 1 1b was officially approved. The standard stipulates that the working frequency band of WLAN is 2.4-2.4835GHz, the data transmission rate reaches 1 1Mbps, and the transmission distance is controlled at 50- 150 feet. This standard is a supplement to IEEE 802. 1 1. It adopts compensation code keying modulation mode, point-to-point mode and basic mode. In terms of data transmission rate, it can automatically switch between 1 1 Mbps, 5.5 Mbps, 2 Mbps and 1 Mbps according to the actual situation, which changes the WLAN design situation.
IEEE802. 1 1b has become the mainstream WLAN standard and has been adopted by most manufacturers. Products are widely used in offices, families, hotels, stations, airports and other occasions. However, due to the emergence of many new WLAN standards, IEEE 802. 1 10a and IEEE 802+06438.1868668661
(3)IEEE802. 1 1a
1999 formulated the IEEE802. 1 1a standard, which stipulated that the WLAN working frequency band was 5. 15-8.825GHz, the data transmission rate reached 54Mbps/72Mbps(Turbo), and the transmission distance was controlled at10-. This standard is also a supplement to IEEE 802. 1 1, and extends the physical layer of the standard. Using the unique spread spectrum technology of orthogonal frequency division multiplexing (OFDM) and QFSK modulation, it can provide 25Mbps wireless ATM interface and 10Mbps Ethernet wireless frame structure interface, and support various services such as voice, data and images. A sector can access multiple users, each user.
The IEEE802. 1 1a standard is the follow-up standard of IEEE802. 1 1b, originally designed to replace the 802.1/b standard. However, it does not need a license to work in the 2.4GHz band, which belongs to the special frequency band for industry, education and medical treatment and is open. Some companies have not expressed their support for the 802. 1 1a standard, and some companies are more optimistic about the latest mixed standard-802.11g.
(4)IEEE802. 1 1g
At present, IEEE has issued the latest version of IEEE802. 1 1g authentication standard, which proposes that the transmission rate of IEEE802. 1 1a is better than that of IEEE 802.1b, and two modulation methods are adopted. Include OFDM adopted in 802. 1 1a and CCK adopted in IEEE802. 1 1b to be compatible with 802.1a and 802.1/kloc.
Although 802. 1 1a is more suitable for enterprises, it is very possible for WLAN operators to choose 802.10b equipment in order to take into account the existing investment.
(5)IEEE802. 1 1i
The IEEE802. 1 1i standard combines the user port authentication and device authentication in IEEE802. 1x, modifies and integrates the WLANMAC layer, defines the strict encryption format and authentication mechanism, and improves the security of WLAN. The newly revised IEEE802. 1 1i standard mainly includes two contents: Wi-Fi protected access (WPA) technology and robust security network (RSN). Wi-Fi Alliance plans to adopt 802. 1 1i standard as the second edition of WPA, which will be implemented in early 2004.
IEEE802. 1 1i standard is very important in WLAN network construction, and data security is the first priority for WLAN equipment manufacturers and WLAN network operators.
(6)IEEE802. 1 1e/f/h
The IEEE802. 1 1e standard improves the WLANMAC layer protocol, supports multimedia transmission, and supports the QOS mechanism of all WLAN wireless broadcast interfaces.
IEEE802. 1 1f defines the communication between access nodes and supports the access point interoperability protocol (IAPP) of IEEE 802.1/.
IEEE802. 1 1h is used for spectrum management technology of 802.1/a.
4.2HIPERLAN
The Broadband Wireless Access Network (BRAN) team of the European Telecommunications Standardization Association (ETSI) set out to work out the pan-European standards for accessing Hiper(HighPerformanceRadio), and successively launched HiperLAN 1 and HiperLAN2. When HIPERLAN 1 was introduced, the data rate was low and no one paid attention to it. HIPERLAN2 standard was completed in 2000, and the highest data rate of HIPERLAN2 standard can reach 54 Mbit/s. HIPERLAN2 standard defines the detection function and handover signaling of WLAN in detail to support various wireless networks such as dynamic frequency selection, wireless cell switching, link adaptation, multi-beam antenna and power control. The standard also gives some definitions on the performance, security and quality of service (QOS) of WLAN.
HiperLAN 1 correspondence1eee802.1/b, HiperLAN2 and1eee082.1/a have the same physical layer, and the same components can be used, Hiper LAN. HIPERLAN2 standard is also a relatively perfect WLAN protocol at present.
4.3HomeRF
HomeRF working group was established in 1997, and is led by American Home Radio Frequency Committee. Its main task is to establish an interoperable voice and data communication network for home users. HomeRF version was launched in August 2006, integrating voice and data transmission technologies. The working frequency band is 10GHz, and the data transmission rate reaches 10Mbps. As far as WLAN security is concerned,
HomeRF is a synthesis and improvement of existing wireless communication standards: TCP/IP transmission protocol in IEEE802. 1 1 specification is adopted for data communication; When voice communication is carried out, the digital enhanced cordless communication standard is adopted.
In addition to IEEE802. 1 1 committee, European Telecommunications Standardization Association and American Household Radio Frequency Committee, WLANA(WirelessLAN Association) has also done a lot of work in the technical support and implementation of WLAN. WLANA is a non-profit organization established by WLAN manufacturers, and its members include 3Com, Aironet, Cisco, Intersil, Lucent, Nokia, Symbol and ZTE. Its main job is to verify the compatibility of similar products from different manufacturers and to train users of WLAN products. 4.4 China wireless LAN specification
The Ministry of Information Industry of People's Republic of China (PRC) is formulating supporting standards for WLAN industry, including general technical requirements for public WLAN and testing specifications for public WLAN equipment. The technical systems involved in this standard include IEEE802. 1 1X series (IEEE 802.1,802.1/a, IEEE 802. 1b, The Communication Metrology Center of the Ministry of Information Industry undertook the formulation of relevant standards, and conducted a large number of tests in conjunction with equipment manufacturers and domestic operators. At the same time, the Communication Metrology Center of the Ministry of Information Industry and ZTE Corporation jointly built a WLAN test platform to comprehensively evaluate the performance index, compatibility, security and reliability of WLAN system equipment.
In addition, the "China Broadband Wireless IP Standard Working Group (www.chinabwips.org)" approved by the Science and Technology Company of the Ministry of Information Industry carries out the standardization of mobile wireless IP access, IP mobility, mobile IP security and mobile IP services. In May 2003, Two WLAN national standards drafted by China Broadband Wireless IP Standard Working Group were promulgated in the first batch: specific requirements for telecommunications and information exchange between information technology systems of local area networks and metropolitan areas Part 1 1: specifications for media access (MAC) and physical (PHY) layers of wireless local area networks, information technology-telecommunications and information exchange between systems-specific requirements for local area networks and metropolitan areas Part 1/ Kloc-0/ Part: Media Access (MAC) and Physical (PHY) two national standards are based on ISO/IEC 8802.1and ISO/IEC 8802.1B. The release of these two national standards will standardize the application of WLAN products in China.
5.WLAN network structure
Generally speaking, WLAN has two types of networks: peer-to-peer networks and infrastructure networks.
Peer-to-peer network: It consists of a group of computers with wireless interface cards. These computers are directly connected with each other through the same workgroup name, ESSID and password, and carry out point-to-point and point-to-multipoint communication within the coverage of WLAN.
Infrastructure network: In the infrastructure network, wireless terminals with wireless interface cards take wireless access point AP as the center, and connect wireless local area networks with wired networks through wireless bridge AB, wireless access gateway AG, wireless access controller AC and wireless access server AS to form various complex wireless local area networks and realize wireless mobile office access.
6. Wireless LAN application
As a wireless extension of wired network, WLAN can be widely used in living quarters, amusement parks, hotels, airport stations and other amusement areas to realize tourism and leisure Internet access. It can be used in government office buildings, campuses, enterprises and institutions to realize mobile office and facilitate meetings and classes. It can be used in medical treatment, financial securities and other aspects, and realize online diagnosis of patients by doctors on the road and outdoor online trading of financial securities.
For environments with difficult wiring, such as old buildings, desert areas, and constantly changing environments, such as various exhibition buildings; For temporary broadband access, mobile workstations, etc., establishing WLAN is an ideal choice.
6. 1 Application in sales industry
For large supermarkets, the circulation of goods is very large, and the daily receiving work includes order processing, invoice, warehousing and so on. You need to enter data into databases in different locations. The warehousing and storage management of the warehouse involves a large number of goods moving, and the data is constantly changing. At present, many practices are to manually record and then input the data into the database, which is time-consuming and error-prone. Using WLAN can easily solve the above two problems. In every corner of the supermarket, in the receiving area, in the delivery area, on the shelves, in the warehouse, you can use WLAN to process all kinds of documents on the spot.
6.2 Application of Logistics Industry
With China's entry into WTO, ports and storage areas put forward higher requirements for the digitalization of logistics business. A logistics company generally has a network processing center, and some offices are located in relatively remote places. Used for transport vehicles, loading and unloading units, cargo statistics and other working conditions. , need to input and transmit data to the central computer room in time. The deployment of WLAN is an essential infrastructure for the modernization of logistics industry.
6.3 Electric Power Industry Application
How to measure, control and control remote substations is an old problem in power system. WLAN can monitor and record the operation of substations, provide real-time monitoring data for the central monitoring room, and transmit the control commands of the central monitoring room to all substations. This is a potential application of WLAN in power system, but wired network can not be completely detected and controlled.
6.4 Service Industry Application
Due to the miniaturization of mobile terminals and PCs, passengers must deal with mail in time when entering the hotel lobby, so InternetWLAN access in the hotel lobby is essential. Rooms also need wireless Internet service, especially in high-star hotels. Guests may surf the Internet in bed, and they want wireless Internet everywhere. Due to its mobility and convenience, WLAN is favored by some large and medium-sized hotels.
At airports and stations, this is the waiting time for passengers to wait for the plane. It is not a happy thing to turn on the laptop to surf the Internet at this time. At present, WLAN has been deployed in most airports and stations in North America and Europe, and it is being gradually implemented and built in China.
6.5 Application in Education Industry
Wireless LAN allows teachers and students to interact in teaching. Students can use mobile terminals to ask questions and submit homework to teachers in teachers, dormitories and libraries; Teachers can give tutoring classes to students from time to time. Students can use WLAN to access the campus network in any corner of the campus. Wireless local area network can be used as an auxiliary means of multimedia teaching.
6.6 Securities Industry Application
With WLAN, the stock market is as popular and active as the vegetable market. It turns out that many people who speculate in stocks use the stock market to watch the market, but now they don't need it. Wireless LAN allows you to see the market in real time and trade at any time. You don't have to go to a big house in the stock market, and you don't have to pay any fees for a big house.
6.7 Application of Exhibition Hall
In the exhibition halls of some large-scale exhibitions, WLAN is generally installed, and service providers, exhibitors and customers can access the Internet at any time when they enter the hall. The mobility, reconfiguration and flexibility of WLAN provide unlimited profit space for temporary rental service industries such as conference halls and exhibition centers.
6.8 Small and Medium Office/Home Office Applications
WLAN allows people to work online, send and receive emails in small and medium-sized offices or anywhere in their homes, and can connect to the Internet anytime and anywhere. Internet access fee is the same as cable network. With WLAN, our free space has increased.
6.9 Office application between enterprise office buildings
For some medium and large enterprises, there is a main office building and other affiliated office buildings, which need communication between buildings and departments. If you build a limited network, you need to pay an expensive monthly fee and maintenance fee, while WLAN can still realize the function of a limited network without comprehensive wiring.
7.WLAN security
In WLAN applications, VLAN(VirtualLocalAreaNetworks) isolation, MAC address filtering, service area authentication ID(ESSID), password access control and WEP (Wired Equivalent Privacy) can meet the security requirements of home users and users with low security requirements in public scenes. However, for users with high security requirements in public scenes, there are still security risks. It is necessary to introduce some security mechanisms in wired networks into WLAN, implement complex encryption and decryption algorithms in wireless AP, and authenticate users legally for the second time by using PPPoE or DHCP+WEB authentication through wireless access controller AC, so as to monitor users' business flow in real time. This WLAN security strategy needs to be practiced, further discussed and improved.
;