scope:

The present document contains the functional requirements for the second phase of the ETSI Open Service Access API, as defined in ES 202 915 [4]. The present document has been compiled in conjunction with Parlay and represents the fourth phase of the Parlay API. The ETSI and Parlay API has been specified and designed using the requirements identified in the present document. The requirements are intended to provide the necessary functionality for benchmark applications.

The new requirements build upon the ETSI OSA Phase 1 API in ES 201 915 [3] and the Parlay 3 specification and should be fully backward compatible. This means that any network operator implementing ETSI OSA Phase 2 or Parlay 4 should be able to interwork with a client application provider implementing ETSI OSA Phase 1 or Parlay 3. In other words ETSI OSA Phase 2 and Parlay 4 will retain ETSI OSA Phase 1 and Parlay 3 as a complete subset.