How to properly distribute Internet providers?

Question

Computer networks

An interesting task came up.

- Provider "Istok M", giving - 40 Mbit / s
- Provider "Datagroup", giving - 20 Mbit / s
Need help in distributing their services so that when disconnected, the entire office is not turned off.

What options have already been considered:
- two routers work, and if the Internet falls from one of the providers, the second one picks up the first ( How to do this, they never figured out )
- tasks are divided for each of the routers: one is configured exclusively for the Internet, the second is configured for 1C , mail and telephony. But then you need to decide which of the providers is used for which task.
And a question about the transfer speed , if we distribute Internet streams for different tasks, will 10Mbps be enough for the first task / second task, or leave a stream of 20Mbps from the group date?
I would like to hear a suggestion from experts, or someone faced a similar task.

Answer 1

The most correct, but now improbable:
- to bring both on one router, to receive AS, to configure BGP and to forget. Why is it impossible? And they stopped giving AS a long time ago, I would like to do it myself ...
Less correct, but more possible
- to get both to one router and when the ping disappears, for example 8.8.8.8 on one interface, switch to another that went through it
Even less correct
: divide services by routers and when it disappears, there is a mosk for the provider whose link is gone :D

Answer 2

For the very beginning, it does not hurt to voice what kind of router (s) are used. For most NOT home, as a rule, in descriptions, examples, options for balancing channels, monitoring and dynamic route switching, etc. are given.
As CityCat already noted about AS, we skip it. And so: we scatter the channels to taste (for example, by services, priorities, loads) and monitor the availability of the "eternal" resource through different interfaces. In case of a fall, we dynamically change routes or their metrics to the second channel

Answer 3

We take a router that can do this well.
For example, medium models from Mikrotik. They are not expensive - 5000-10000 rubles.
There are millions of step-by-step instructions on the Internet on how to do this with Mikrotik.