It imposes hierarchy and a division of labor among processors. Only one designated processor, the master, controls (in a tightly coupled arrangement) slave processors dedicated to specific functions.
In the transaction server, the client component usually includes GUI and the server components usually consists of SQL transactions against a database. These applications are called OLTP (Online Transaction Processing) OLTP Applications typically,
Receive a fixed set of inputs from remote clients. Perform multiple pre-compiled SQL comments against a local database. Commit the work and Return a fixed set of results.
In 3-tier Client/Server systems, the application logic (or process) lives in the middle tier and it is separated from the data and the user interface. In theory, the 3-tier Client/Server systems are more scalable, robust and flexible.
Example: TP monitor, Web.
In 2-tier Client/Server systems, the application logic is either buried inside the user interface on the client or within the database on the server.
Example: File servers and Database servers with stored procedures.
If the number of incoming clients requests exceeds the number of processes in a server class, the TP Monitor may dynamically start new ones and this is called Load balancing.