How does campuses has same network login domain?

[Muz]

I can access the same login network student ID from different campus in different area, which is like 30 km far. Are they connected through a server like CISCO or something?

I heard it uses something call Active Directory? Azure AD?

The network domain is called, STUDENT.HELP.LOCAL.

I can't access the domain from my home network though.

Also, I was wondering, if two PCs can connect to a same domain? If the two PCs are in different house.