Communication Between SAP XI Landscapes 

Business partners who use SAP Exchange Infrastructure (XI) can exchange messages between their system landscapes.

·        If both business partners use SAP XI 3.0, then you can connect the two Integration Servers to exchange data. See also: Integrating SAP XI 3.0 Business Partners.

·        An SAP XI 3.0 Integration Server can also send and receive SAP XI 2.0 messages. Therefore, it is also possible to integrate business partners who use SAP XI 2.0. See also: Integrating SAP XI 2.0 Business Partners.

·        Small business partners who do not use SAP XI can use the Partner Connectivity Kit (PCK) to exchange messages with the system landscape of a business partner who uses SAP XI 3.0. See also: Integrating Smaller Business Partners with the PCK.

Business partners do not necessarily have to be two different companies; they could also be two independent IT areas within a single company.