How to build a wireless network

This article will talk about how users are more concerned about how to achieve the establishment of wireless office network, here we must mention the following: equipment selection, control costs, post maintenance.

1. Equipment selection

The equipment includes the brand, the price, the performance, the localization many factors, here we like everybody Brief introduction. At present, the main wireless router brand has a network, Belkin, D-link, Tp-link, Buffalo, H3C and other brands, high-end and Cisco. Prices from hundreds of yuan to thousands of yuan, we recommend that the Enterprise users choose the brand for enterprise users to launch products. For product performance, Based on 802.11g wireless router products are currently a good choice, because the product is not mature based on 802.11n, from the previous test to see the compatibility of each product is also different, the other client's network card can not guarantee the unification, and the wireless router based on 802.11n and network card prices are very expensive. The choice of equipment does not necessarily look at the brand, as long as the application of their own business needs of the good.

2. Cost control

For an enterprise how to control the cost of investment, and get a good return on investment is more important to each boss. The choice of equipment should be in advance according to their actual environment to choose the product category and quantity. such as: a more decentralized office area, more obstacles to the office environment, we should choose a strong signal penetration of the router. (Computer science)

3. Post-Maintenance

In the selection of good products, users also need to consider the product after-sales service and other factors, such as the failure of the above services, firmware timely upgrade, and even to consider the entire network after the attack recoverability and recovery time.

Recommendation of Wireless LAN scheme for three kinds of network environment

After a brief introduction of the technology and metrics of wireless products, we will introduce three kinds of wireless applications in the real environment. Depending on the application, wireless products usually have several working statuses:

1.AP Wireless access point (signal overlay mode) and AP client (wireless client mode)

2.WDS Wireless Distributed System (bridging mode) and Ap+wds blending mode (both bridging and overlay)

3.802.1X authentication and client Seamless roaming



AP wireless access Point and AP Client

This scenario is for users who are limited by space and are suitable for small network types: home, about 30 of the business. This enables multi-user high-speed Internet access in a limited range.



WDS wireless Distributed system and Ap+wds blending mode

This program is for the room structure is more complex, multi-layer or multiple room users, suitable for medium network type: Campus network, enterprise network, the use of this structure to ensure the transmission speed, stability and coverage to achieve the best balance.

802.1X authentication and client Seamless roaming

The scope of this scheme is more widely recommended for large enterprises, airports, bars, guesthouses and other public places to use. This can achieve high-density, high-speed wireless access, mobile Internet (roaming), 802.1x certification and billing.

Summarize:

We recommend that users before the use of equipment manufacturers to do a good job design and budget, but also may wish to refer to several successful cases, then believe that your company's wireless network program construction help.
In recent years, more and more products to join the wireless this huge family, notebooks, mobile phones, cameras, projectors and other equipment become a daily essential office and communication equipment. We often see at the café door some of the Soho people who are using laptops and wireless Internet access, and business users who use PDAs to download mail. It is also because of the strong mobility characteristics, so that many people rely more on wireless internet. In addition, the use of wireless networks is becoming one of the ways in which some small and medium enterprises use the information exchange. However, setting up an office wireless device is not as simple as we would like to buy some equipment to assemble, which includes many factors before the office LAN is built, including the coverage of Office radio signals, the security of building wireless networks, the compatibility of wireless devices, and so on. Today we are going to talk about how the office realizes the Wireless network environment.

Range of wireless signal coverage

Just now we talked about the advantages of using wireless network, we also want to talk about some of its shortcomings, first of all, the wireless network coverage is one of the factors we should consider. Speaking of the signal coverage, first we need to see its transport protocol, common wireless network Protocols are: IEEE 802.11,ieee 802.11a, IEEE 802.11b, IEEE 802.11g, and the draft standard 802.11N. Although IEEE 802.11\802.11a has been eliminated by the new standards, it is undeniable that the Institute of Electrical and Electronics Engineers introduced the first wireless LAN standard in 1997, a milestone in the development of IEEE 802.11 wireless network technology.

Standard operating frequency transmission speed remark

802.11A 5ghz54mbps Non-mainstream technology fast compatibility difference price high

802.11B 2.4ghz11mbps technology speed slow compatibility good price low

802.11g 2.4ghz/5ghz54mbps Mainstream technology fast compatibility good price low

802.11N (draft) 2.4ghz/5.8ghz300mbps future technical speed fast compatibility difference price high

Misunderstanding, the stronger the signal, the better.

First of all, let's take a look at some of the wireless product hardware indicators: transmission power, acceptance sensitivity and antenna gain. At present, the main potential of wireless network is in the range of signal coverage and transmission rate, usually enhance the signal method is to improve the transmission power and enhance the antenna gain.

Transmitting power: The wireless device uses the transmitting power to measure the performance of the transmitting signal, the larger the transmitting power, the farther the distance between the wireless products, the wider the coverage and the stronger the penetrating ability. The unit of measurement for transmitting power is dbm. This is the same as the light bulb we use in life, the larger the wattage, the brighter the bulb, the wider the range of illumination.

Gain: Gain is the ability of the antenna to enhance the emission and reception of the signal, the greater the gain, the stronger the signal emission, the higher the sensitivity. The measurement unit of gain is DBI, the size of the antenna and the internal material have a great relationship with the antenna gain.

Why is the signal stronger the better is a misunderstanding? The reason is because the signal is too strong, so its scope is larger, then the controllable area is reduced, the user's security is reduced. such as: A Dead end of a unit, office area of more than 300 square meters, users can receive signals, but his security is not the best.

The higher the standard, the better.

In wireless products based on the draft 802.11N standard products are currently the most technologically advanced, signal coverage of the products far away. It is precisely because of this that many enterprises in the procurement of equipment often too much pursuit of hardware indicators, but ignore the ease of use and price of products. According to the current part in the market price of 11n products sold, most of the router product prices between 1700-1900 yuan, and based on the 11n wireless card is also between 800-900 yuan, the price is not expensive. What is the concept of such a price? At present the market sales of 802.11G based wireless router price in about 200, 11g wireless network card in 150 yuan, compared to 11n products are 11g product price 7-8 times. Although the 11N product technology leader, but because the price and the technology is immature and so on factor we do not recommend the small and medium-sized enterprise to use, compared with 11g's product is more suitable for the small and medium-sized enterprise use.

Security for building a wireless network

Unauthorized access to a user

We know that wireless signals are transmitted in the air, as long as within the signal coverage, some illegal users can not need any physical connection to access the data of the wireless network, therefore, must be in many ways to prevent illegal terminal access and data leakage problem.

The solution is to use authentication to prevent unauthorized users from accessing, in other words, using various encryption methods to prevent illegal users from invading. Binding MAC address is our most common easiest way, each wireless card has a unique MAC address, through the AP set up with the NIC MAC address binding to achieve encryption, but this security method is also applicable to the information requirements of the home users, for enterprise users, We recommend using WEP and WPA two common encryption methods.

Access access to illegal AP

In addition to the threat of unauthorized access to the security of the wireless local area network, access to the illegal AP can also pose a threat to the entire network. When a wireless AP accesses a wired hub, it encounters an illegal AP attack, and an illegally installed AP can jeopardize the valuable resources of the wireless network.

The solution can take advantage of the legitimacy of the AP and periodic site review to prevent, in this verification process not only the AP needs to confirm the legality of wireless users, wireless terminal equipment must also verify that the AP is a false access point, and then can communicate.

Attacks by viruses and hackers

In addition to the above two points, virus and hacker attacks will also pose a threat to the wireless local area network, many networks have a set of carefully installed security devices as the shell of the network to prevent illegal attacks, but in the shell-protected network is very vulnerable vulnerable to attack. Hackers can quickly access the backbone of the network through simple configuration, exposing the network to the attacker, so the need to strengthen preventive measures. Even a network with a certain border security device can also expose the network to attack.

A common solution is to install firewalls, upgrade clients and antivirus software, and isolate the company's wireless network from its core network.

Service and performance Limitations

We know that the current wireless LAN transmission bandwidth is limited, compared with the wired network is far from enough, in the actual use of the physical layer because of the cost, the actual throughput is only half of the standard, and the actual throughput is shared by all users. If the hackers send a large number of PING,AP bandwidth from Ethernet will be saturated, if the broadcast traffic, multiple AP will be blocked at the same time, the attacker can send signals in the same wireless channel with the wireless network, so that the attacked network will be automatically adapted through the CSMA/CA mechanism, Also affects the transmission of the wireless network, in addition, the transmission of large data files or complex client/server system will generate a lot of network traffic.

In the face of this problem solution is, often network monitoring if the quality of AP and signal status is unstable, it is recommended to test equipment, such as testing, so that can effectively identify the network rate, frame type, to help fault location.