Hi Lynn
Currently, to the best of my knowledge there is not a closed list of relationship types, for any of the <entity>relationship classes in the Open API resource model.
This is true in general for many of the data items that seemingly have a closed list, perhaps due to the difficulty in reaching consensus on the valid value list.
Lifecycle status is one of the places where we have fully closed and typed lists of valid values.
Hope it helps
------------------------------
Jonathan Goldberg
Amdocs Management Limited
Any opinions and statements made by me on this forum are purely personal, and do not necessarily reflect the position of the TM Forum or my employer.
------------------------------