Clarify relationship between Transmitter and AS

openid-caep-interoperability-profile-1_0.md

@@ -216,22 +216,27 @@ All events MUST be signed using the `RS256` algorithm using a minimum of 2048-bi
 
 ## OAuth Service
 
-### Authorization Server
-* MAY distribute discovery metadata (such as the authorization endpoint) via the metadata document as specified in [RFC8414]{{RFC8414}}
-* MUST support at least one of the following to obtain a short-lived access token. For example, a short lived access token could be defined as one in which the value of the `exp` claim is not longer than 60 mins after `nbf` claim. Please refer to Access token lifetimes in the security considerations of {{FAPI}} for additional considerations. 
+### The SSF Transmitter as an Authorization Server 
+
+A Transmitter can act as an OAuth {{RFC6749}} Authorization Server. As such, it issues access tokens to Receivers.
+
+* Transmitters MAY distribute discovery metadata (such as the authorization endpoint) via the Authorization Server Metadata as specified in [RFC8414]{{RFC8414}}
+* Transmitters MUST support at least one of the following to issue a short-lived access token.
   - client credential grant flow {{RFC6749}} section 4.4
   - authorization code flow {{RFC6749}} section 4.1
 
+A short lived access token could be defined as one in which the value of the `exp` claim is not longer than 60 mins after `nbf` claim. Please refer to access token lifetimes in the security considerations of {{FAPI}} for additional considerations.
+
 ### OAuth Scopes
 Depending on the features supported by the OAuth service and the SSF APIs, the client SHALL discover the OAuth scopes as follows:
 
 1. If the Resource Server, hosting SSF configuration APIs, supports OAuth Protected Resource Metadata {{OPRM}} then the client MUST obtain the required scopes by using it.
 
-2. If the Resource Server does not support {{OPRM}}, then the following scopes MUST be supported -
-   - An OAuth {{RFC6749}} authorization server that is used to issue tokens to SSF Receivers, MUST reserve the scopes for the SSF endpoints with the prefix of `ssf`
+2. If the Resource Server does not support {{OPRM}}, then the following scopes MUST be supported:
+   - An OAuth {{RFC6749}} Authorization Server that is used to issue tokens to SSF Receivers, MUST reserve the scopes for the SSF endpoints with the prefix of `ssf`
    - All the SSF stream configuration management API operations MUST accept `ssf.manage` scope
    - All the SSF stream configuration Read API operations MUST accept `ssf.read` scope
-   - Authorization server MAY postfix scope names with more granular operations eg. `ssf.manage.create`, `ssf.manage.update` etc.
+   - Authorization Server MAY postfix scope names with more granular operations eg. `ssf.manage.create`, `ssf.manage.update` etc.
    - Transmitter managed poll endpoint MAY support the postfix scopes in the same nomenclature as `ssf.manage.poll`
 
 ### The SSF Transmitter as a Resource Server