History of SAP PI/PO and Difference between SAP PI & SAP PO

For us to understand the difference between SAP XI/PI/PO, first we need to understand the main functionalities of the middleware tool. Middleware should provide below functionalities

• Connectivity: Which protocol to use – SOAP, FTP?
• Routing: Who are the receivers of the message – Multiple receivers? Condition based routing?
• Transformation: What kind of conversion or mapping required? XML to text?
• Runtime:  messages monitoring and security
• Workflow (BPM): How to execute a series of steps? Integration scenario with a Purchase Order approval process

History Overview

XI Architecture Overview

It was installed on a dual-stack Netweaver installation with ABAP and Java stacks.

Adapter Engine: responsible for Connectivity. It provides capabilities of talking to different communication protocols using different adapters.

Integration Engine: responsible for Routing & Transformation. Very heavy message processing was done through Integration Engine as, each message is routed, transformed and executed in this component.

Business Process Engine: responsible for BPM. Engine which executed ccBPM (Cross Component Business Process Management) workflows. ccBPM is based on Business Process Execution Language (BPEL) and required a dual-stack installation as its runtime environment was on Web AS ABAP.

Challenges:
One major drawback of XI inefficient performance due to back and forth communication between components. Also due to the dual-stack architecture and multiple components, message persistence impacted the performance.

PI Architecture Overview

With SAP introducing Advanced Adapter Engine (AAE), PI was able to process messages end to end without Integration Engine (IE) runtime. This reduced the cross communication between components and improved performance massively.

Advanced Adapter Engine (AAE): responsible for Connectivity, Routing & Transformation.
Integration Engine (IE): responsible for Routing & Transformation
Adapter Enginer (AE): responsible for Connectivity.
Business Process Engine (BPE): responsible for BPM.

Advanced Adapter Engine (AAE): AAE has capabilities to handle routing, transformation and connectivity which were segregated to different components in SAP XI. Integration Configuration Object (ICO) was introduced for design time instead of traditional XI objects such as sender agreement, receiver determination and receiver agreement. ICO made it possible to connect, transform and route message in AAE without Integration Engine (IE) runtime. Also, dual stack message persistence was eliminated since ICO scenarios were executed independently by AS Java.

Challenges:
Although PI installation with AAE  enhanced performance in comparison with XI, still improvements were needed to extend connectivity and performance. AAE could only handle limited set of connections and still required IE runtime for development and administrative purposes. Plus, RNIF adapter and the CIDX was not available in AAE. Also, earlier versions of AAE did not include iDoc and http adapters since they belonged to ABAP stack. Moreover, BPE still required ABAP stack for runtime as it was ccBPM. As you notice, although performance was improved compared to XI, SAP couldn’t completely decouple the need of Integration Engine (IE).

B2B Add-on:
B2B add-on was also introduced to PI with versions PI 7.1. B2B comes with a set of B2B protocol adapters, converter modules and B2B infrastructure services for serving the EDI integration needs of most industries.

AEX -Advanced Adapter Engine Extended:

Finally, with SAP PI 7.30 version SAP eliminated the need of Integration Engine (IE) and introduced the Advanced Adapter Extended (AEX). AEX is a single engine which includes Enterprise Service Bus (ESB), Integration Directory (ID) and AAE capabilities. With AEX, PI became a Java AS only installation and SAP completely decoupled ABAP stack. Also with PI 7.3 SAP introduced iDoc_AAE adapter and http_AAE which run on Java. The complete removal of ABAP stack is a major change in the SAP PI architecture.

Challenges:
Although PI with AEX improved performances by completely decoupling ABAP stack and the need of Integration Engine (IE), it did not include Business Process Management (BPM) capabilities.

PO Architecture Overview

To overcome all these challenges with PI, SAP released Process Orchestration which was a Java only installation. Yes! No ABAP stack installation was availabe from PO 7.31. Plus, with new PO version SAP has added fully functional Netweaver Business Process Management (NW BPM) and Business Rule Management (BRM) which were fully executable on Java. Therefore, Process Orchestration (PO) is a combination of Process Integration (PI) with AEX, Business Process Management (BPM) and Business Rule Management (BRM) which only runs on Java.

NW BPM – Netweaver Business Process Management:
Unlike ccPBM, NW BPM runs on Java-based environment called CE (Composite Environment). Also, NW BPM uses Business Process Model Notation (BPMN) language while ccBPM uses Business Process Execution Language (BPEL). Although ccBPM design time was on ABAP stack, you require Eclipse based tool NWDS (Netweawer Development Studio) for NW BPM. Even if you have extensive experience in ccBPM, you need to start learning NW BPM from scratch.

BRM – Business Rule Management:
Business Rule Management (BRM) contains modeling capabilities targeting business analysts. Rules are owned by LoB not by IT.

Basically SAP PO contains all the functionalities of PI, plus BPM and BRM in a single Java stack.