Communication Transfer Protocol, Config Request ??

I'm configuring NCM's Global Device Defaults and came across with the possibility of choosing 3 different protocols for the following actions.

Can someone tell me what does Config Request really mean?

Since it is the only action that supports SNMP, I'm guessing that by seting a RO community it gets the configuration from the device, and leaves it ready to transfer using FTP or other.

Is that correct?

I'm new to the forum, and it would be really helpful if someone could tell me where can I find some documentation about NCM, like an advanced user guide or official SolarWinds documentation.

Thanks in advanced