Today, Internet access is available from almost anywhere in the world. Therefore, regardless of where the user is spoiled by progress, he always wants to have high-quality and high-speed Internet. Of course, manufacturers are adjusting to the market, which is why Wi-Fi modems (3G and 4G routers) appeared on sale. These devices solve the problem of simultaneous connection of several users to one 3G / 4G channel, with one SIM card. In order to understand how this problem is solved, you need to understand how a Wi-Fi modem works.
A standard Wi-Fi modem is composed of two main devices: a 3G or 4G module (in fact, this is a regular USB modem to which we are accustomed) and a Wi-Fi router. When you connect a Wi-Fi modem to a computer and initially install the drivers, each module then proceeds to perform its specific task, which, nevertheless, are extremely coordinated with each other.
The mobile Internet module, when connected, provides the user with access to the global network using cellular technologies. In different devices, this module can use both the 3G standard and the more modern 4G (the latter differs from the former primarily in a higher data transfer rate, including for users moving at high speeds). This device is directly involved in the transmission of data from the Internet space.
However, simply receiving information is not enough, it needs to be passed on to end users, that is, laptops, phones, tablets and other devices. It is this task that the Wi-Fi module performs, distributing requests from connected devices so that the mobile Internet module can simultaneously process the requests of each connected consumer.
The device contains a routing table that stores the paths to all consumer devices on the local network. An interconnected network of devices is formed, to each of which the module selects the most optimal and shortest path.
Then the device sends test packets to each address at regular intervals to find out the time it takes for the packet to arrive and whether it will arrive in principle (if the device was turned off). The current state of the network map is continuously maintained using the routing table, due to which the distribution of one channel with the mobile Internet to several devices is achieved.
When using a Wi-Fi modem using one mobile connection and just one SIM card, a more or less constant Internet connection of several different devices and users is provided. However, this way of surfing the web is not considered very good. During the operation of such a network, regardless of the provider providing services, speed jumps and rare outages are possible. Modern technologies still do not allow providing better quality communication, comparable, for example, with a landline connection.