Ah, ok! Thanks Tony!

So, just to see if I get this correctly, when transposing all this to my D-Link router at home (to have another example): this one is set at :
Router IP address: 192.168.0.1
DHCP IP Address Range 192.168.0.100 to 192.168.0.199

In this case, the subnet is the DHCP address range (100 to 199), and not the entire 254 addresses available through the 192.168.0.x IP number?

Only: in this case, the router's IP is not part of the subnet then... does that matter in any way? Or not at all?
Thanks!