Whether you admit it or not, as long as you are online, you may not be able to leave WiFi. Yes, unconsciously, WiFi has almost captured the entire world.
In terms of space, WiFi is like an invisible net, which is scattered in people's intensive places. At home, on the road (vehicle), in office buildings, restaurants, playgrounds, cafes, libraries, etc., WiFi is the most widely covered signal; in terms of equipment, ABI Research found that as of the end of 2014 A total of 9.98 billion WiFi devices have been sold worldwide, and a total of approximately 4.5 billion WiFi products are currently in use. At the same time, Wi-Fi equipment is expected to continue to grow at an annual growth rate of 10% in the next five years.
But it is such a technology that people rely on and develop rapidly. It is hard to achieve absolute advantage in the smart home of the current fire. In many smart home wireless technologies, WiFi is still not the protagonist. In fact, among the more than 2.3 billion WiFi devices sold in 2014, mobile phones, tablets and e-readers accounted for nearly 70% of total shipments. Smart homes, industrial Internet of Things, and automobiles all belong to "other parts." ".
Why? Why is the presence of WiFi in the smart home field that many people use is low?
The technology that can't be hit and hit is "hard". WiFi is not a big problem as a connection to the Internet, but at least three points are not enough for smart homes.
——1, it is a faint security. Here, I don’t directly say how the security encryption technology of WiFi is vulnerable, and it’s no longer an example of which smart home device in foreign countries is “destroyedâ€. I just want everyone to think about it, without knowing the family WiFi traffic. If you are used by strangers for no reason, you can understand that WiFi is not a difficult thing to crack. And if the smart home is attacked, it may not be as simple as a little traffic.
——2, fuzzy health. Wireless technology will have some radiation, but compared to other technologies, WiFi is often the most threatening to health, even if we use it often and most of the time without discomfort. So is it harmless? The World Health Organization has pointed out that there is currently no evidence that mobile phone radiation will have a negative impact. In general, for 20 minutes, the body absorbs more radiation than a one-year wireless router.
However, some insiders pointed out that if WiFi is used incorrectly, it will cause harm to the human body. The amount of radiation received by the human body is related to frequency and distance. The higher the frequency, the greater the damage, the greater the distance, the less harmful. Therefore, if a large-power WiFi device is used, the device is close to the device, and the autoimmune power is low, it is possible to have physical discomfort such as dizziness and insomnia due to WiFi.
- 3, "Unbearable lightness of life." In general, smart homes are systems that involve multiple devices, while WiFi networks carry very limited devices. According to relevant reports, "WiFi networking capabilities are relatively low. Currently, the actual size of WiFi networks generally does not exceed 16 devices. In actual home environments, the number of switches, lighting, and home appliances is far more than 16." . This obviously does not fit in with the development of smart homes.
The promotion of public cognition. WiFi has a natural networking advantage and does not require intermediate equipment, but for the public, this does not seem to have much of a special feature.
—— As far as this year is concerned, it should be regarded as a great opportunity for WiFi. Many Chinese companies have also made a lot of efforts. In mid-January, Xiaomi launched a universal intelligent module for home appliances at the flagship new product launch, at a price of 22 yuan. On March 11-14, at AWE2015 (2015 China Home Appliances Expo), the WiFi module became a smart home experience zone. One highlight; in March, 360 launched the "360 Zhilian module", the price of 1 yuan, the first batch of 10,000. Note that these modules are all WiFi modules.
- It stands to reason that this very strong "module wind" should be able to help WiFi to win the smart home, but "and eggs." Although the voice of the manufacturers is very loud, the market is very busy, but the smart home perception has been greatly improved. Only a weak word can make this wind stop: can it be smart home through WiFi networking? How simple is the question, but how painful it is for WiFi!
Cruel external competition. In addition to WiFi, there are many other wireless technologies that are eyeing the smart home market. This is the third reason why WiFi is difficult to dominate. Among many smart home wireless technologies, Bluetooth, ZigBee and Thread are undoubtedly the biggest threats.
——Bluetooth is similar to WiFi, and has made a lot of changes for smart home. In December 2014, the Bluetooth SIG officially announced the release of the Bluetooth Core Specification version 4.2. The faster data transfer speed, more powerful privacy protection and support for the IPv6/6LoWPAN network made the new version "history." The most outstanding Bluetooth technology." Errett Kroeter, senior director of the Bluetooth Technology Alliance brand and developer market, said at a media conference at the time that the introduction of Bluetooth version 4.2 was to allow Bluetooth Smart to continue to connect everything in life – from personal sensors to smart The best solution for the family.
——ZigBee is a model that is “more powerful than you, and harder than youâ€. In smart home applications, ZigBee has advantages over WiFi: 2.4G direct-sequence spread spectrum and frequency modulation technology, which is more resistant to interference than general FSK, ASK and frequency hopping digital radio stations; provides three levels of security mode, including no security settings Using access control lists to prevent illegal access to data and symmetric passwords using the Advanced Encryption Standard (AES 128), security is more secure; in low-power standby mode, 2 No. 5 dry batteries can support 6 nodes working 6-24 Month, even longer.
In the expansion of the alliance's strength, it is more determined than WiFi, and the internal technology is perfect. The team of external members is expanded: In December 2014, the ZigBee Alliance announced that it will unify its market-leading wireless standard into ZigBee 3.0, and strive to achieve internal technical unification; this year 3 In the month, it officially announced that China's Internet of Things leader, IoT Sensing, joined the board of directors of the alliance and became the 12th board member of the alliance and the only board member in Asia. Recently, Samsung's brand SmartThings was included in the 13th board of directors in the world.
- Thread as a rising star, can also make WiFi nervous. Although Thread appeared late, it was a famous name. In July 2014, it was proposed by Google's home thermostat manufacturer Nest, and then it was called a response. Samsung, ARM, Core, Freescale, Qualcomm and other world famous enterprises joined. Currently, the Thread Group has grown. In terms of the number of members, there were only 7 at present, and now there are more than 160. In terms of membership quality, founding members Freescale and Core are members of the ZigBee Alliance Board of Directors. Qualcomm, which is newly added to the Thread Group Board of Directors, is an important founding member of the AllSeen Alliance. member.
Of course, even if there is such a problem, even if it is difficult to dominate the smart home field, WiFi is still an important communication technology in the smart home field, so it is not a chance to continue to improve and improve.
At the WiFi Alliance Symposium held in Beijing in January this year, Ms. Kelly Davis-Felner, Vice President of WiFi Alliance Marketing, released 15 predictions for the new year on behalf of the WiFi Alliance, arguing that the performance of WiFi technology will be further improved. Ensuring interoperability and security while increasing energy efficiency, coverage and performance, and leading the smart home, industrial IoT and car networking.
"Connecting everything, connecting everyone, anytime, anywhere" is the vision of the WiFi Alliance. However, today, there is a long way to go.
Industrial Ethernet switches are specifically designed to meet the needs of flexible industrial applications and provide a cost-effective industrial Ethernet communication solution. And its networking mode is more focused on loop design. The ring has the difference between single ring and multiple ring. At the same time, there are private ring protocols designed by various manufacturers based on STP and RSTP, such as RingOn, RingOpen open loop, FRP ring, turbo ring, etc.
The network management switch can be managed through the following ways: management through RS-232 serial port (or parallel port), management through web browser and management through network management software.
1. Management via serial port
The network management switch comes with a serial cable for switch management. First plug one end of the serial cable into the serial port on the back of the switch, and plug the other end into the serial port of an ordinary computer. Then power on the switch and the computer. The "Hyper Terminal" program is provided in both Windows 98 and Windows 2000. Open the "Hyper Terminal", after setting the connection parameters, you can interact with the switch through the serial cable. This method does not occupy the bandwidth of the switch, so it is called "Out of band" (Out of band).
In this management mode, the switch provides a menu-driven console interface or command line interface. You can use the "Tab" key or arrow keys to move through the menus and submenus, press the Enter key to execute the corresponding commands, or use the dedicated switch management command set to manage the switch. Switches of different brands have different command sets, and even switches of the same brand have different commands. It is more convenient to use menu commands.
2. Manage via web
The managed switch can be managed via Web (web browser), but an IP address must be assigned to the switch. This IP address has no other purpose except for the management switch. In the default state, the switch does not have an IP address. You must specify an IP address through the serial port or other methods to enable this management method.
When using a web browser to manage the switch, the switch is equivalent to a Web server, but the web page is not stored in the hard disk, but in the NVRAM of the switch. The Web program in the NVRAM can be upgraded through the program. When the administrator enters the IP address of the switch in the browser, the switch will transfer the web page to the computer like a server, and it will feel like you are visiting a website. This method occupies the bandwidth of the switch, so it is called "in band management" (In band).
If you want to manage the switch, just click the corresponding function item on the webpage and change the switch parameters in the text box or drop-down list. Web management can be carried out on the local area network in this way, so remote management can be realized.
3. Managed by network management software
Network management switches all follow the SNMP protocol (Simple Network Management Protocol), which is a set of network equipment management specifications that comply with international standards. All devices that follow the SNMP protocol can be managed through network management software. You only need to install a set of SNMP network management software on a network management workstation, and you can easily manage the switches, routers, servers, etc. on the network through the LAN.
The management of the network management switch can be managed in the above three ways. Which method is used? When the switch is initially set up, it is often through out-of-band management; after setting the IP address, you can use in-band management. In-band management Because the management data is transmitted through a publicly used LAN, remote management can be achieved, but the security is not strong. Out-of-band management is through serial communication, and data is only transmitted between the switch and the management machine, so the security is very strong; however, due to the limitation of the length of the serial cable, remote management cannot be realized. So which method you use depends on your requirements for security and manageability.
Industrial Managed Switch,Industrial 8 Port Switch,Gigabit L2 Ethernet Switch,Gigabit Poe Industrial Switch
Shenzhen Scodeno Technology Co.,Ltd , https://www.scodenonet.com