What is SAP XI

What is SAP XI?
Exchange Infrastructure can be used as a Middleware Engine to communicate in a distributed environment. The heart of XI is Integration Engine that is used for integrating different technologies using Standard Messaging techniques e.g XML. Different mapping tools are avilable for mapping the distributed system which can be mapped without having any expertice of Technical Details. As a real world example, XI can be helpful in integrating different banks with SAP R/3. XI Engine also support previous releases of SAP R/3 like 4.6C and have many more adapters to communicate with legacy systems.
SAP XI is an integration technology and platform for
1.SAP and Non-SAP systems,
2.A2A and B2B scenarios,
3.Synchronous and Asynchronous communication,
4.Cross component Business Process management and it include built-in engine for designing and executing integration process (Business process).
5.The goal of SAP XI is to provide single point of integration of all systems inside and outside the corporate boundary across technologies and organizational boundaries.
6.The important feature of XI is openness, flexible and transparency to the integration process. It is based on ESA and SOA.
7.The overall key concept of SAP XI is to drive integrated business process across heterogeneous and highly dynamic landscapes in a more manageable cost effective way.
8.The basic idea is to provide runtime infrastructure which allows heterogeneous systems to be tied together with fewer connections and at the same time, in order to connect those applications and let messages flow from one application to other, have a centralized storage of integration knowledge