...

This is done by a chained token transfer. For this the Requester calls the Token Requester API on the Authorization Manager (AM) and the AM in turn calls the Token Requester API of the Host. The Host then returns a token (maybe with prior checks) to the AM which in turn is given to the Requester which then can perform the actual call with it.

Here is an overview of the process:
Image Added

Roles

The following roles are defined:

...