I am currently setting up a remote office that will be connected to our HQ via a P2P connection. We leverage a Windows AD Domain, and I wanted to know what would motivate someone to migrate from a single site multiple subnet topology to multiple sites/subnets. What factors should be considered?
If you have a DC at the branch site, you want to use Sites and Subnets to associate the branch DC with the site that contains the branch subnet(s) - so that all users at that site will preferentially authenticate the local DC, not your central DCs.
If you only have DCs at your central site, there's little or no gain to using sites and subnets.