Rather than the resource description document pointing to a series of scope URIs that must be dereferenced (as was the case in UMA V1.0.x), the resource server in UMA V2.0 can instead make use of the OpenID Connect discovery document and its
scopes_supported metadata item, which, when filled with (the same) scope description document URIs, allows for development-time discovery of the necessary scope information.
In some circumstances, it may be desirable to couple UMA software entity roles tightly. For example, an authorization server application might also need to act as a client application in order to retrieve protected resources so that it can present to resource owners a dashboard-like user interface that accurately guides the setting of policy; it might need to access itself-as-authorization server for that purpose. For another example, the same organization might operate both an authorization server and a resource server that communicate only with each other behind a firewall, and it might seek more efficient communication methods between them.
In other circumstances, it may be desirable to bind UMA flows to transport mechanisms other than HTTP even if entities remain loosely coupled. For example, in Internet of Things scenarios, Constrained Application Protocol (CoAP) may be preferred over HTTP.
In such cases, parts of UMA's flows may require profiling or extension because it is only defined over HTTP. Where appropriate, use the
uma_profiles_supported configuration property to flag usage of a documented profile or extension.