Example 1
A phone with a Yota sim card with a tariff for a smartphone (let's call it "donor") works on the Yota network. All packages go to the operator with the only possible value TTL = 64
Example 2
Inexperienced owner donor phone launched tetering and trying to use the internet in addition to PC and even on the same phone. What happens: the packets from a donor leave, still with TTL = 64. Packets from the PC to the donor reach with TTL = 128 (value by default PC), a donor loses a point and go to the provider with TTL = 127. Packet from the second phone to reach the donor with TTL = 64, loses at TTL donor unit and leaves the operator with TTL = 63. As a result, Yota sees packages with three different TTL values, that is not possible, if the phone is a donor does not distribute the Internet in AP mode, and block distribution, offering to pay for it.
Example 3
Phone donor rutovanny (or jailbroken), that is, it is possible to change the default TTL. Change the TTL so that packets from other devices (possibly nerutovannyh) the loss of a unit of TTL have the same meaning as the TTL on a donor "by default". On the example we have assigned to the donor TTL = 63 (as it is done - see below). We see that with the device in which the passage through the donor unit and lose value obtained TTL TTL default is 64 (iOS and Android Soup) is the same as that of the donor - 63.
That is, any other iOS and Android devices can safely use the distribution from the donor and no additional gestures should be done with them. The problem will occur for devices that have a default TTL not 64. For example, a PC. Exit the situation in three ways:
1. Change the TTL device to 64. In this scheme, the PC can simultaneously work with other iOS and Android devices
2. Do not change the TTL in the device (PC in our case) (for example, if for some reason this cannot be done), and change the TTL by default in the donor. If the PC has a default value of TTL = 128, then we change the default value in the donor to 127. Thus, all packets again go to Yota with one TTL. But in this case, another iOS or Android device will not be able to connect to the distribution (simultaneously with the PC) if their default TTL is not 128.
3. The third method is described in the example below. This is the most convenient way, but not suitable for all devices.
Example 4
The point of the example is that TTL is fixed on the donor for any outgoing packets. In this case, it does not matter at all what devices will be connected to the donor - the TTL in their header will be the same.