How to connect branches to the domain correctly?

Question

Active Directory

Good afternoon, I work in a company that has branches in other cities.
AD is being implemented everywhere. At the moment, the task is to lay the foundation (groups, policies, etc.), which would then simply connect all users and everything worked. Something has already been done, namely, divisions and groups have been created, and at the moment all 3 branches and users in them are simply scattered across certain divisions. I would like to clarify whether this concept is correct? Because there is a video https://www.youtube.com/watch?v=45FzcvixuZs&t=1276s in which the speaker talks about sites, I look and realize that everything is done wrong where I work. Than the wrong structure of the domain can threaten? All branches are connected via gre tunnels and have a high-speed connection

Answer 1

You do not confuse AD and sites. Rather, sites are, of course, part of AD, but are used when you have different subnets with branches and each has its own DC that must be replicated with the main DC. So, in principle, on a DC you can organize OUs by branches, place a DC in each branch and replicate everything among themselves. Well, unless you decide to allocate branches to subdomains ....