PeopleSoft Architecture

Hi,

This post will describe the PeopleSoft's internet architecture and the various ways one can connect to the PeopleSoft application.

PeopleSoft provides multiple ways to connect to the underlying application. These are :

• 2-Tier : Typical client-server based model
• 3-Tier : Client-server model
• 4-Tier : Web-based model

2-Tier

This is a typical client-server model mostly used by the developers.

The two tiers are the local machine where PSIDE.exe + the connectivity software is installed and the database server. The connectivity software is the database client. This method needs a ConnectID to be provided in the configuration manager.

This model is mostly used by the developers who connect to the database directly from Application Designer.

The obvious drawback of this method is that it puts a load of pressure on the DB server whenever there is a large development team.

Other drawbacks are :

• every developer machine needs to have the database client installed
• since all the machines will need a ConnectID - essentially a database user id - it allows all the users to have direct access to the underlying database

3-Tier

To address the drawbacks of the 2-Tier model, PeopleSoft offers the 3-tier mode.

In this method, the client application connects to the App Server that is already connected to the DB server. Thus, this method does not require the ConnectID and associated password.

Here, the three tiers are the local machine where the PSIDE.exe is installed, the App Server and the DB server.

Under this model, most of the communication is between the App Server and the DB server thereby releasing the load on the latter. Hence, this model is suitable for larger development teams.

Other advantages of this model are :

• database client need not be installed on each of the client machines
• reduced network traffic between the client and the App server

4-Tier

PeopleSoft's 4-Tier mode is its Pure Internet Architecture that is popularly called the PIA. This is entirely a web-based solution. It was introduced with PeopleTools 8. There are no PeopleSoft executables on the client.

The four tiers here are the web browser, Web Server, App Server and the DB server.

Under this model, the client - web browser - connects to the Web server that is connected to the App server that ultimately is connected to the DB server.

 So, how does it really work?

 The following diagrams explains it.

1. The web client contacts the web server via http or xml
2. The web server, using JOLT, connects to the App server
3. The App server, using SQL, connects to the DB server, retrieves the information and sends the result back to the client via the web server

Note : The final image is taken from here.

The diagram also shows that this method allows integration with third-party / legacy applications as well as enterprise directory. Additionally, it provides the user with the flexibility of connecting to the PeopleSoft application through wired / wireless / mobile devices.

The above architecture is application independent, i.e., all PeopleSoft applications like HCM, FSCM, etc. follow the same architecture.

A more detailed explanation of the PIA can be found here.