... how is 10.1.1.x and 10.1.2.x subnetting? The subnet is 255.255.255.0, 255.255.0.0, or 255.0.0.0... The subnet is what tells the network, how many bytes of the network ip, belongs to which computer, or device on the network...
David - If you are wanting to share between two different subnets, it really doesn't matter, if it is within the same local area (which typically would mean on the same router), you can share with ease... Personally, if you are going to share files, it is best to use ftp, or a web-based system... Though using microsoft, it will not be secure to the least bit... But you can open it up for ftp, vpn, or local area network sharing... Most of the time, the LAN sharing will only broadcast through it's local router, it will not go beyond that unless you set it up to do so (by default it will think that beyond it's router is the internet)... But then you have to go into more then just subnetting for that...
Say for instance you have 10 computers, and 4 routers... You want all the computers running on the same network ip... You want one computer to be close to the modem, while the rest will be running off the other routers in other areas... You then set your primary router to the LAN ip you want, and set it's subnet to 255.255.255.255, you then hook the other three routers to the primary router, setting the routers to the LAN ip and subnets; 255.255.255.0, 255.255.0.0, 255.0.0.0; respectively of course... Using this method, most file sharing software such as Microsoft file share, will broadcast through all the routers because they are all using the same LAN ip, the router will then take care of the subnetting... (or so as to I remember it should)... Also, this means that more then one computer can have the exact same ip address, so long as they have different subnets; or so as I remember it... (it has been a long time since I have done subnetting...)(just so you know, I could be wrong about the same ips, they may still have to have different ips..)