Establishment of home wireless local area network

Families usually dial-up the Internet, and only one person can use network resources, while other family members can't. In order to make every member use the network resources, they bought a wireless router and set up a home wireless local area network, so that the family can watch TV, play games and chat online at the same time, which solved the problem of family members competing for the network. To provide efficient, high-quality, standardized, transparent and all-round services for the whole family, every family member can surf the Internet happily, and the cable cost is also saved. There is no need to use a switch, and other computers can also use wireless networks. This is also the reason why I want to set up a wireless LAN, which also reflects the role and value of the wireless LAN.

key word

56K modem, wireless access station, wireless AP, wireless router

1. Overview of WLAN

Wireless local area network (WLAN) technology gradually matured and put into commercial use in the 1990s. It can be used as an extension of traditional wired networks, and can also replace traditional wired networks in some circumstances. Wireless LAN has the following remarkable characteristics: simplicity: WLAN bridge transmission system is installed quickly and simply, which can greatly reduce the tedious work of laying pipes and wiring; Flexibility: Wireless technology enables WLAN devices to be installed and adjusted flexibly, so that wireless networks can reach areas that are difficult to be covered by wired networks; Low comprehensive cost: On the one hand, WLAN network reduces the wiring cost; on the other hand, WLAN technology can better protect the existing investment in the dynamic environment that needs frequent movement and change. At the same time, because WLAN technology itself is an IP transmission technology oriented to the field of data communication, it can be directly connected to the intranet of enterprises and schools through a 100-megabit adaptive network port, which saves the related equipment such as protocol converter from the architecture; Strong expansibility: WLAN bridge system supports various topologies and smooth expansion, and can easily smoothly expand from a small-capacity transmission system to a medium-capacity transmission system.

Wireless local area network, also known as WLAN, is generally used in broadband homes, buildings and parks, with typical distances ranging from tens of meters to hundreds of meters. At present, the technology adopted is mainly 802. 1 1a/b/g series. WLAN uses wireless technology to transmit data, voice and video information in the air. As an alternative or extension of traditional wired network, WLAN liberates individuals from their desks, enabling them to obtain information anytime and anywhere, thus improving the office efficiency of employees.

2. Characteristics of WLAN

A unique feature. Wireless local area network (WLAN) is a kind of non-cable medium local area network that uses electromagnetic waves to send and receive data. The data transmission rate of WLAN has now reached 108Mbps, and the transmission distance can reach more than 20km. It is the supplement and extension of wired network, which realizes the portability and mobility of computers in the network.

Convenient installation. Usually, the wiring construction project of wired network has a long construction period, which has a great impact on the surrounding environment, while wireless LAN avoids or reduces the workload of network wiring. Usually, as long as one or more access point devices are installed, a local area network covering the whole building or area can be established. Because there is no need for wiring, the tedious work of wiring through walls or ceilings is omitted, so the installation is easy and the network construction time can be greatly shortened.

Flexible use. The location of equipment in wired network is limited by the location of network information points, while wireless local area network can access the network anywhere within the signal coverage. Because there is no cable restriction, users can move and work in different places, and network users can access information in real time no matter where they are.

Save costs. Lack of flexibility in network planning will inevitably lead to low utilization rate of a large number of information points. Once the development of the network exceeds the design requirements, it will cost more to carry out network transformation, and wireless LAN technology can avoid or reduce this phenomenon. This advantage lies in that when the user network needs to rent a large number of telecommunication lines for communication, self-built WLAN will save a lot of rental fees for users. In a dynamic environment that requires frequent movement and changes, the investment of WLAN is more rewarding.

Easy to expand. It can be flexibly configured according to needs, and it can be extended from a small LAN with only a few users to a large network with thousands of users.

Security can be achieved. The internal network may not allow any security threats from the internal network and external network. WEP is set to manual configuration in AP and wireless network card, and the administrator should inform all users of passwords at the same time to realize key sharing. If you want to change the WEP password, you need to repeat the above process.

3. The theoretical basis of WLAN

At present, there are two main transmission media used in WLAN, namely infrared and radio waves. According to different modulation methods, wireless local area networks using radio waves as transmission media can be divided into spread spectrum methods and narrowband modulation methods.

Infrared (IR) local area network. Compared with radio wave mode, infrared communication mode can provide extremely high data rate, high security and relatively cheap and simple equipment. However, due to the poor transmission and diffraction ability of infrared rays to obstacles, the transmission distance and coverage are greatly limited. Usually, the coverage of IR LAN is limited to one room.

Spread spectrum LAN Spread spectrum technology is mainly divided into frequency hopping technology (FHSS) and direct sequence spread spectrum (DSSS). The so-called direct sequence spread spectrum is to spread the signal with high-speed spread spectrum sequence at the transmitter and despread it with the same spreading code sequence at the receiver, thus restoring the spread spectrum signal to the original signal. Frequency hopping technology is different from direct sequence spread spectrum technology. The carrier frequency of frequency hopping is controlled by pseudo-random code, and its frequency changes constantly according to random law. The frequency of the receiver also changes randomly, which is consistent with the changing law of the transmitter. The level of frequency hopping directly reflects the performance of frequency hopping system. The higher the frequency hopping, the better the anti-jamming performance, and the military frequency hopping system can reach tens of thousands of hops per second.

Narrowband microwave local area network. This kind of LAN uses microwave radio frequency band to transmit data, and the bandwidth is just enough to accommodate signals. However, this network product usually needs to apply for a radio spectrum license, and other ways can use the ISM band without a license.

Disadvantages of wireless LAN

Performance: WLAN relies on radio waves for transmission. These radio waves are transmitted by wireless transmitters, and obstacles such as buildings, vehicles and trees may hinder the transmission of electromagnetic waves, thus affecting the performance of the network.

Rate: The transmission rate of wireless channel is much lower than that of wired channel. At present, the maximum transmission rate of WLAN is 54Mbit/s, which is only suitable for personal terminals and small-scale network applications.

Security: In essence, radio waves do not need to establish a physical connection channel, and wireless signals are divergent. Theoretically, it is easy to monitor any signal within the broadcast range of radio waves, resulting in communication information leakage.

4. Wireless network protocol

The standard protocol for routing LAN in MAC layer is CSMA/CD, that is, carrier sense Multipoint Access/Collision Detection. However, it is not easy for adapters of wireless products to detect whether there is a channel conflict.

IEEE802. 1 1 completely defines a new protocol, namely carrier sense multiple access/collision avoidance (CSMA/CA). On the one hand, carrier sense checks whether the medium is idle; On the other hand, by waiting for random time, the probability of signal collision is minimized, and when the media is intercepted and idle, it is sent first.

5. Hardware equipment

Wireless bridge (access point): It can support 65 users to run at the same time. The distance can reach 100 meter (328 feet) and the speed can reach 1 1 Mbps. This speed is more than five times faster than the previous generation wireless LAN products, which is equivalent to the speed of standard wired Ethernet LAN. Products include: WP-200 1 wireless bridge, WP-200 1B wireless bridge (built-in bridge).

Wireless network card: No matter where your laptop or desktop computer is, you can immediately and securely connect to any Wi-Fi-verified device or network. You can get the same performance as wired network anytime and anywhere. There are a variety of wireless network cards to choose from, including PCI interface of desktop computer: WMP 1 1 PCI wireless network card. There are PCMCIA interfaces suitable for notebooks: WN-101PCMCIA wireless network card, WPC1/PCMCIA wireless network card, A2424-2A PCMCIA wireless network card, and USB interfaces suitable for notebooks and desktops: WN-/Kloc-0.

Wireless router: wired router integrates the functions of wireless bridge (i.e. wired router +AP). Not only can you enjoy broadband access, but you can also easily have the function of wireless local area network. The products are: WA-2204 wireless router, BEFW 1 1S4 wireless router, FR3002AL wireless router.

Antenna: An antenna is generally called an antenna. Because of the different frequencies, this kind of antenna is different from the antenna used in general TV and mobile phones. WLAN uses a higher frequency band of 2.4GHz, and its antenna function is to transmit source signals to far places by using the characteristics of the antenna itself. As for how far it can be transmitted, generally, besides considering the output power intensity of the source, there is also an important factor that is the gain value of the antenna itself. The higher the dB value, the farther it can be transmitted. Generally speaking, for every 6dB increase, the distance of data transmission can be doubled. Generally speaking, there are two kinds of antennas: directional unidirectional and omnidirectional. The former is more suitable for long-distance use, while the latter is more suitable for regional application.

Wireless hub: it is not only the bridge and link between wireless workstations, but also the access point for wireless workstations to enter wired Ethernet. It is responsible for managing the information flow in its coverage area (wireless unit). A set of wireless hubs covering overlapping areas can support the continuous roaming function of wireless workstations in a large range, while maintaining network connection all the time, which is very similar to the way of cellular mobile communication. In addition, placing multiple wireless hubs in the same place can achieve higher overall throughput.

STA(Station): A network node equipped with wireless network equipment. Personal computers with wireless network adapters are called wireless clients. Wireless clients can communicate with each other directly or through AP.

Wireless LAN cards: generally there are PCMCIA, USB, PCI, etc., mainly PCMCIA wireless network cards of portable computers and USB wireless terminals of desktop computers installed on PCs.

AP (Access Point Wireless Access Point): AP is equivalent to a base station, and its main function is to connect the wireless network to Ethernet. Secondly, it is equivalent to an Ethernet hub, so that a PC equipped with a wireless network card can enjoy the resources of wired LAN or even WAN through AP***. An AP can connect multiple wireless users in the range of tens to hundreds of meters.

Wireless bridge: it is mainly used for long-distance transmission (such as the connection between two buildings) and consists of AP and high-gain directional antenna. Wireless LAN access point antenna can choose unidirectional and omnidirectional.

6. Topological structure

Bridge connection type: When different LANs are interconnected, if it is inconvenient to use wired mode due to physical reasons, wireless bridges can be used to realize point-to-point connection between them. Wireless bridges not only provide physical and data link layer connections between them, but also provide higher-level routing and protocol conversion for users of the two networks.

Base station access type: When the wireless local area network is established by using the access mode of mobile cellular communication network, the communication between stations is interconnected by means of base station access and data exchange. Each mobile station can not only establish its own network through the switching center, but also establish its own working network with remote sites through the WAN.

Hub access type: wireless hubs can be used to form a star-shaped wireless LAN, which has similar advantages to wired hub networking. On the basis of this structure, WLAN can work in a way similar to switched Ethernet, which requires Hub to have simple switching function within the network.

No central structure: Any two sites in the network need to communicate directly. WLAN with this structure generally uses public broadcast channel, and the MAC layer adopts CSMA multiple access protocol.

Second, establish a home wireless local area network.

(A) the choice of networking mode

1. wireless access point

There are some differences between home wireless LAN and wired LAN. The simplest and most convenient way is to choose a peer-to-peer network, that is, take wireless AP or wireless router as the center (traditional wired LAN uses hubs or switches), and other computers communicate through wireless network cards, wireless AP or wireless routers.

With the addition of wireless AP, the networking mode is enriched, and various requirements of home wireless networking are met in terms of function and performance. With the development of technology, AP is no longer a simple bridge between wired and wireless. Various products with additional functions emerge in an endless stream, which provides strong support for various home broadband access methods at present. Let's start with the types of internet access and look at the networking scheme of home wireless LAN.

2. ordinary telephone line dial-up internet access

If the family uses the dial-up Internet access mode of 56K Modem, the establishment of wireless local area network can only be completed by two or more computers equipped with wireless network cards (as shown in Figure 3, because there is no wireless AP product with ordinary Modem dial-up function at present). One of the computers acts as a dial-up gateway. Other computers achieve the purpose of "wireless" by receiving wireless signals. In this way, if there are only two computers, the wireless AP can be omitted, and the wireless network cards of the two computers can be directly connected to the LAN. Of course, to enjoy the network, you need to install gateway software such as WinGate on networked computers.

(2) Hardware installation

We set up TP-LINK TL-WR245 1.0 wireless broadband router and TP-LINK TL-WN250 2.2 wireless network card (PCI interface. Shut down the computer, open the main chassis, insert the wireless network card into the idle PCI slot of the motherboard, and restart. After re-entering the Windows XP system, the system prompts "New Hardware Found" and attempts to automatically install the network card driver, and opens the "New Hardware Found Wizard" dialog box for users to manually install. Click the "Automatically Install Software" option, insert the driver disk attached to the network card into the CD-ROM drive, and click the "Next" button to install the driver. Click the "Finish" button. Open the "Device Manager" dialog box, and we can see that the wireless network card has been installed in the "Network Adapter". After the wireless network card is successfully installed, a connection icon will appear in the taskbar of Windows XP system (the wireless network connection icon will also be added to the network connection window). Right-click this icon and select the command View Available Wireless Connections. In the dialog box that appears, the searched available wireless networks will be displayed. Select a network, and then click the Connect button to connect.

Then, choose a suitable location to place the wireless router indoors and turn on the power. In order to ensure wireless internet access in the future, it needs to be placed near the internet entrance. In addition, it is necessary to pay attention to the distance between the wireless router and the computer with the wireless network card installed, because the wireless signal will be affected by the performance of distance, wall penetration, etc. If the distance is too long, it will affect the speed of receiving signals and data transmission, and it is best to ensure that it is within 30 meters.

1. Set the wireless router.

Before configuring the wireless router, you should read the user manual that comes with the product carefully, from which you can know the default management IP address and access password. For example, the default management IP address of our wireless router is 192. 168. 1, and the access password is admin. After connecting to the wireless network, open IE browser and enter192.168.1.65438 in the address bar. Then click the "Basic Settings" link in the left window and set the IP address in the right window. The default value is192.168.1.1; Make sure to select Allow in the wireless setting option group, set the name of the wireless LAN in the SSID option, and select the default number in the channel option. In the WEP option, you can choose whether to enable this key, which is disabled by default.

2. Wireless client settings

After setting up the wireless router, you need to set up a client with a wireless network card.

Step 1: In the client computer, right-click the wireless connection icon in the system taskbar, select the command View Available Wireless Connections, click the Advanced button in the opened dialog box, click the Wireless Network Configuration tab in the opened dialog box, click the Advanced button, and select Access Point (Structure) Network Only or Any Available Network (Preferred Access Point) in the dialog box that appears.

Step 2: In order to ensure that computers in the wireless LAN can enjoy and exchange access smoothly, the workgroup names of all computers in the LAN should be unified.

Step 3: Right-click My Computer and select Properties to open the System Properties dialog box. Click the Computer Name tab, click the Change button, enter the new computer name and workgroup name in the dialog box that appears, and then click the OK button.

Step 4: After restarting the computer, open My Network Places, and click the "View Workgroup Computer" link in the "Network Tasks" task pane to view the names of other computers in the wireless LAN. In the future, you can also set up a * * * shared folder in each computer to realize the * * * sharing of files in the wireless LAN; Set up printers and fax machines to realize printing and fax operations in the wireless LAN.

3. Set password protection

In order to prevent others from using your wireless network, you must set a password so that your wireless network resources can be used reasonably by yourself and your family. User authentication-password control. Using password control on the site of wireless network certainly provides built-in multi-level security services, including the management of network operating systems and servers such as NovellNetWare and Microsoft NT. Passwords should be strictly controlled and changed frequently. Because the users of wireless network include mobile users, and mobile users often move their notebooks around, strict password policy is equivalent to adding a security level, which helps to confirm whether the website is used by legitimate users.

Configuration of LAN

1. Configure the network card

After installing the network card and the corresponding driver correctly, Windows XP will create a LAN connection for the network card it detects.

First, open the "Network Connection" item in the control panel, and you can see the established LAN connection in the "Network Connection" window.

Secondly, right-click the Local Area Connection icon and select Properties from the shortcut menu to open the Local Area Connection Properties dialog box. At the top of the dialog box, the network adapter used for connection will be listed. Click the Configure button to open the corresponding dialog box where you can set up a network adapter.

Finally, there are four tabs in this dialog box: General, Advanced, Drivers and Resources, through which we can configure the network adapter accordingly.

2. Settings of network components

Network components refer to clients, services and protocols used for communication when computers are connected to the network.

Step 1: Install the protocol: After the network card is installed correctly, Windows XP will install the Internet protocol by default, that is, TCP/IP protocol. If you need to add other protocols, click the Install button to open the Select Network Component Type dialog box, where users can select the component type to install.

Double-click the Protocol option to open the Select Network Protocol dialog box, which lists the currently available protocols, select the protocol to add, and then click OK to install.

Step 2: Set TCP/IP protocol: TCP/IP protocol is the most important communication protocol on the Internet, which provides network services such as remote login, file transfer, e-mail, WWW, etc. Is the default protocol for system installation.

In the Local Connection Properties dialog box, double-click the Internet Protocol (TCP/IP) item in the list to open the Internet Protocol Properties dialog box, where you can set the IP address, subnet mask, default gateway, etc.

IP address: In a local area network, the IP address is generally 192. 168.0.X, and x can be any number between 1 and 255, but the IP address of each computer in the local area network should be unique. You can also select "Automatically obtain IP address" to let the system automatically assign you an IP address in the local area network.

Subnet mask: This item is generally set to 255.255.255.0 in the local area network.

Default gateway: If the local computer needs to access the Internet through other computers, you need to set the default gateway as the IP address of the proxy server. After setting the above options, click OK.

3. Establishment of the Working Group

Computers in a LAN should belong to a workgroup before they can access each other.

Step 1: Right-click the "My Computer" icon and select the "Properties" command in the shortcut menu to open the "System Properties" dialog box.

Step 2: Click the "Network Identity" tab and click the "Properties" button to open the "Identity Change" dialog box. Click the Workgroup option in the Belong to option group and enter the name of the workgroup in the text box below.

Concluding remarks

Through last week's home network design, I have a certain understanding of WLAN, access points and wireless devices, as well as security precautions.

Prior to this, the knowledge of wireless network construction and wireless equipment was one-sided, and only some one-sided knowledge was learned, which could not be well applied to practical operation, so I encountered many difficulties from the beginning. In the whole design stage, the most profound feeling is to master the way of learning and the method of solving problems. The first is the way to solve the problem. Although we are faced with a lot of information, how to select the needed information and useful information from a lot of information is the key to solve the problem. With the continuous update of wireless technology, it has brought great development to the development of WLAN, and also brought unprecedented challenges to the safety belt of WLAN. With the development trend of IPV6, the development of WLAN will also develop with the development of IPV6.

This paper was completed under the careful guidance of the teacher, and the smooth completion of the paper can not be separated from the care and help of other classmates and friends. During the whole thesis writing process, Mr. Fu Zhihui, classmates and friends actively helped me to consult the materials and provide suggestions and opinions conducive to thesis writing. With their help, the paper was constantly improved and finally helped me complete the whole paper.

refer to

1 Ma Xinluo, Li Xiaozhong, Dong Jianning. Construction and application of wireless local area network. National defense industry press.

Wang, Zheng Shaojing. Practice course of LAN construction and maintenance. Beijing: Tsinghua University Publishing House.

3 Wang Shunman. Xi Enpa (USA). Design and implementation of wireless local area network. Science press.

Cisco Network Technology College course. Fundamentals of wireless local area network. shipping broker

5. Yang Jun's "Building a WLAN in Actual Combat". Beijing Electronic Industry Press.

7 "Home WLAN Networking Scheme". Baidu Wenku