School me on hub and spoke federations

[Cantor, Scott]

> It is indeed different.  We are now re-coding the app to support this while
> remaining backwards compatible with all the existing customers.  It would be
> VERY cool if there was a single standard attribute for this kind of thing /sigh

Could you explain why it's not about billing to the contracted instance of a service? I don't think I've seen a case yet that wasn't really about that at the root. Organizations sometimes contract for multiple instances of a service, which is where tying contracts to any kind of organizational ID ends up breaking.

(For example, university departments here often buy the same service individually, but they all use our single IdP, so it's one entityID.)

-- Scott