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.
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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.