I thank everyone that replied, but most if not all the answers do not take into account the limitations of NOT changing the current (192.168.1.1) address of the gateway and/or are anyway using the "added router in the middle" option where the proposed Microtik hex router is replaced by some other brand/make/model.
I understand (a little) the way multi-WAN routing works, but due to the exposed limitations that cannot work.
The whole problem revolves around the fact that the (hypothetical) device (if it is a sort of router) has an own address of 192.168.1.1 and that it should be able to route/switch to one of the three DSL/4G router/modems each one having the same 192.168.1.1 address.
I am now thinking of a ethernet relay like the ones used in home automation, similar to this one (example):
but I read somewhere that it is not a good idea to use the relay contacts on the actual ethernet cable, so I could use one of them to control the power of the three routers/modems, but this would introduce a (bearable, still ...) delay as the routers take some time (tens of seconds, one is particularly slow and takes over a minute) to boot and establish connection.
How fast does it need to switch? An alternate approach would be to have all routers physically connected, but only one of them powered. You could probably do this with a smart power board and some scripting to switch the power points over if pinging an outside server stops working.
Yes, I thought about this approach, but as said at least one of these dsl routers is very, very slow at booting, more than 1 minute, 2 or more if I recall correctly, in the "three level cascading/rotating" setup the pinging script would need to be timed (either in seconds or in number of failed pings) to allow the booting time for the selected router before deciding that even the router that was just connected has no internet and decide to connect to the third one.
I could leave the "other" routers powered on at all times and use three el-cheapo unmanaged switches to connect them and power on/off these switches instead, this would be almost instantaneous.
Comments
I thank everyone that replied, but most if not all the answers do not take into account the limitations of NOT changing the current (192.168.1.1) address of the gateway and/or are anyway using the "added router in the middle" option where the proposed Microtik hex router is replaced by some other brand/make/model.
I understand (a little) the way multi-WAN routing works, but due to the exposed limitations that cannot work.
The whole problem revolves around the fact that the (hypothetical) device (if it is a sort of router) has an own address of 192.168.1.1 and that it should be able to route/switch to one of the three DSL/4G router/modems each one having the same 192.168.1.1 address.
I am now thinking of a ethernet relay like the ones used in home automation, similar to this one (example):
https://relaypros.com/Relay/Relay/ETHERNET_RELAY_CONTROLLERS
but I read somewhere that it is not a good idea to use the relay contacts on the actual ethernet cable, so I could use one of them to control the power of the three routers/modems, but this would introduce a (bearable, still ...) delay as the routers take some time (tens of seconds, one is particularly slow and takes over a minute) to boot and establish connection.
How fast does it need to switch? An alternate approach would be to have all routers physically connected, but only one of them powered. You could probably do this with a smart power board and some scripting to switch the power points over if pinging an outside server stops working.
Yes, I thought about this approach, but as said at least one of these dsl routers is very, very slow at booting, more than 1 minute, 2 or more if I recall correctly, in the "three level cascading/rotating" setup the pinging script would need to be timed (either in seconds or in number of failed pings) to allow the booting time for the selected router before deciding that even the router that was just connected has no internet and decide to connect to the third one. I could leave the "other" routers powered on at all times and use three el-cheapo unmanaged switches to connect them and power on/off these switches instead, this would be almost instantaneous.