Peer-to-Peer Network
All computers are equal. There is no hierarchy and no central authority. The first network type.
Client Server
Novell created Netware and pushed the concept of client servers. Computers could interact with the central server.
Domains
MS created domains, which was similar. In the year 2000, MS came out with new domain. Symbolized by a triangle, the domain has a domain controller server (DC) which contains a database called the Active Directory database. The domain controller controls the entire domain. The purpose is for centralization. Everything is managed in one place.