Defined in MEF 55, LSO Interface Reference Points (IRP) are the logical points of interaction between specific functional management components (LSO Architectural Entities). They can be thought of as convenient conceptual boundary points where APIs are 'located'. The reference points are shown below in the LSO Reference Architecture diagram.
The seven LSO Interface Reference Points fall into two categories:
Intra-Domain (or Intra-Company, or 'North-South')
Inter-Domain (or Inter-Company, or 'East-West')
Figure: LSO Reference Architecture