I am reading about PI 7.1 and going through eSOA architecture. What I understand is, The eSOA says that we have some out of the box services avalable from SD, for example creating a sales order. This can be exposed as a web service from R3. When this available as a web service, and if the calling application is capable of calling web services, where is the need for PI? Why do we need to use PI for SOAP to SOAP communication?
How inside out and outside in approaches are different in eSOA architecture as far as PI and R3 are considered? Can some one clear my doubts?