Comprehensive dialysis wireless Internet access

Wireless Internet access is becoming increasingly popular. Various wireless access methods and various wireless networks provide more and more convenient Internet access methods for the majority of Internet users. The following is a full analysis of wireless Internet access. Hope to help you.

As wireless network cards gradually increase, brands are also popping up, and the prices of network cards are becoming more common and popular. China Mobile Communications, China Unicom, and China Telecom are the leaders of wireless manufacturers. Their layout and tariff policies have influenced the development of the entire industry market. Although the performance prices of wireless network cards vary by brand, the SIM card and uimcard used together with the network card have different prices in different regions, but the performance does not differ.

Wireless Internet access is divided into two types. One is to enable the data function through the mobile phone and enable wireless Internet access through the mobile phone or wireless network card, the speed is determined by the use of different technologies, terminal support speed and signal strength. Another wireless Internet access method is a wireless network device. It is a wireless Internet access method based on a traditional LAN and built on Wireless AP and wireless network card. Generally, as long as the internet terminal is not connected to a wired line, it is called wireless Internet access.

The range covered by a wireless LAN is the maximum distance that devices transmit signals, such as wireless network interfaces and Wireless AP wireless access points. According to the 802.11 standard), the maximum distance that a wireless device can cover is usually 300 meters. However, the coverage scope depends on whether the environment is open or not, when the device is not equipped with an external antenna, it is about 300 m in the field of view. If the device is in a semi-open space or has an isolated area, the transmission is about 35 ~ About 50 meters. If you use an external antenna for Link), the transmission distance can reach 30 ~ 50 kilometers or even further, depending on the gain of the antenna. Therefore, you need to apply the application as needed.

The functions and tumor markers of wireless network cards are the same as those of common computer network cards. They are used to connect to lan. It is only a device for sending and receiving signals. It can be connected to the Internet only when the egress of the Internet is found. All wireless network adapters can only be confined to the configured Wireless LAN.

A wireless network card is a network card that uses wireless signals to connect to a network card without a wired connection. Different interfaces are used for wireless NICs, including PCMCIA wireless NICs, PCI wireless NICs, MiniPCI wireless NICs, USB wireless NICs, and CF/SD wireless NICs.

The function and function of the wireless network adapter are equivalent to a wired modem, which is also known as "cat ". It can use the SIM card of a mobile phone to connect to the Internet Anywhere with wireless phone signals.

The function and function of the wireless network adapter is like a wireless MODEM ). Common interfaces include PCMCIA, USB, CF/SD, etc. For 3G network adapters, speed is a key factor to win. The speed will directly influence users' selection, let's take a look at the speed of each of the three NICs.

Mobile TD-SCDMA network card, the highest theoretical speed of 384 Kbps, And the 2.5G era EDGE wireless network card speed the same, as the computer 3G wireless Internet charges, this speed users will certainly not accept. Fortunately, mobile also saw this deficiency, introduced the HSDPA technology in the second phase of the construction of TD-SCDMA, the highest theoretical speed to 2.2 Mbps, it can be said that there is a qualitative improvement.

The maximum theoretical speed of China Unicom's WCDMA network adapter is 14.4 Mbps, and the speed of the three network adapters is the fastest. The high speed of the WCDMA network adapter is also benefited from the introduction of HSDPA technology. From foreign experience, the speed of the WCDMA network adapter is generally up to 3.6 Mbps, which has already exceeded the downstream speed of China's 2 m ADSL.

Telecommunications CDMA-EVDO network card, the maximum theoretical speed is 3.1 Mbps. The current version of the EVDO Nic is Rev A. to catch up with the speed of China Unicom at 14.4Mbps, China Telecom has begun to deploy A faster version B (Rev B) in some large and medium-sized cities ), by then, the maximum theoretical speed will reach 9.3 Mbps, further narrowing the gap with China Unicom.

From the theoretical data, China Unicom WCDMA network card speed advantage is obvious, followed by the Telecommunications CDMA-EVDO network card, the slowest is mobile TD-HSDPA network card. So what is the actual effect?

According to the test, the actual average downlink speed of the TD network card for website optimization is 60-70 kb/S, and the actual average uplink speed is 30-40 kb/S. The actual average downlink speed of the China Unicom WCDMA network card is 170-180KB/S, the actual average uplink speed is 130-150KB/S. For the telecom EVDO network adapter, the actual average downlink speed is 150-170KB/S, and the actual average uplink speed is 120-130KB/S. As expected, China Unicom's WCDMA network card is still the fastest, but its leading EVDO network card is not as wide as the theoretical speed gap. The mobile TD network card is still disappointing, only half of the first two.

What are the risks of wireless Internet access?

As you know, wireless network nodes can normally reach a range of about 300 meters. Therefore, any computer with a wireless network card installed within 300 meters can access wireless network nodes, and may enter the wireless network. Obviously, this convenient access method is easy to bring security threats to wireless networks. For example, a hacker computer within 300 meters also has the opportunity to access your wireless network to control "every action" in your computer "; although wireless networks are not as strict as wired networks in terms of information confidentiality, you certainly do not want illegal attackers to easily know your whereabouts on the network, such as the websites you visit, any privacy emails sent to external users may be clearly understood by illegal visitors.
 
Even more seriously, illegal visitors not far from studying in Canada will easily steal information about your various online accounts once they enter your wireless network, this will cause greater security losses to you. Therefore, in the face of various security risks in wireless networks, you must take actions in time to take countermeasures, such as through encryption or network verification and identification technologies, make sure that only the user or network device specified in advance can access your wireless network, and other operations that want to forcibly use various wireless network technologies to access your wireless network will be rejected.

Security Status of wireless Internet access

Due to the inherent technical defects of wireless networks, the security of wireless Internet access has not been fully guaranteed until now. However, if wireless Internet users take timely and effective measures, it is still difficult for illegal attackers to intrude into wireless networks.

Generally, in terms of network security, goat's placenta is mainly manifested in data encryption and access control. Data Encryption often ensures that the transmitted information can only be accepted and understood by the desired network users, access control ensures that the network information can only be obtained by authorized users. For a common network, its information is transmitted to a specified destination through a cable. As long as the physical link is not damaged, the information of the common network will not be leaked; however, because the wireless network information is transmitted through microwave radiation, all wireless workstations may receive Network Information in the area covered by wireless network nodes, wireless Network Nodes cannot ensure that information can only be transmitted to specific devices. Therefore, the data confidentiality of wireless Internet access is worse than that of wired networks.

Currently, technical protocols such as IEEE 802.11a, IEEE 802.11b, and IEEE 802.11g are used in wireless networks. Pregnant women can set wireless Internet access security through reasonable network parameters, it can ensure that the wireless network authenticates the identity of each online user. Of course, the security setting function of the wireless network only prevents General intrusion. If a user with a higher level of attacks encounters, the security setting function of wireless networks is powerless.