I want to use 3G or 4G for failover, What additional hardware and setup (recommended) is needed when using the CCR1009-8g-1s-1s+pc for the router. Is there a WiKi section for setting the CCR up in this configuration, I haven’t found anything yet?
The ros is the same in all devices. Specific settings are related to your needs and to physical differences between the routerboard models.
You can use a supported USB stick and configure it as an extra network device.
It remains your own task to define what you consider “failed” and how to switch to the 3G/4G device.
E.G. it is possible to set a default route to the device at a higher distance than usual, and then make
sure when the normal connection is down the usual default route is dropped.
(it depends on your internet connection method if this happens automatically, and it also depends on
your specification of “failed” if that works. e.g. when your link to the ISP is still up but the ISP has a
problem on their border router so most of the internet is unreachable, do you consider that “failed”?)
It is easy to setup some quick-and-dirty hack, but it is more difficult than you might expect to check
for all possible problems and react in the correct way. For example, you may decide to ping some
system out on the wide internet and when the ping fails, consider your connection or provider “down”
and switch to your alternate. But what if in reality the system you are pinging is down, or the operator
is fed up with all those people pinging his system and has changed the firewall to drop pings?
You will have to cater for that.