AuthorityID best practices

[Fen Labalme <fen@idcommons.org>]

I'm a bit confused by the second of two URN's in a standard XRID:

  1) XRIDescriptor/AuthorityID identifies the describing authority

  2) XRIDescriptor/Authority/AuthorityID identifies the authority described by 
this Authority

So in our market vocabulary, the resolver that produced this XRID always 
produces XRIDs with the same #1 AuthorityID

The #2 AuthorityID must match the one attached to the resolver pointed to by 
the current Authority, such that when it is then called for its resolution 
step, it will return this value as its "#1" AuthorityID.

Question: where is this #2 URN stored in the Registry?  If whenever it 
assembles an XRID with an XRIDescriptor/Authority element (for the resolution 
of further delegated subsegments) it must also know that resolver's associated 
URN, it seems like there is a bootstrapping problem here (not to mention the 
fact that I don't believe current registries have a field for this).

Of course, as I stated above: I'm a bit confused by this, so maybe I don't 
understand how these values are used.  Can someone please enlighten me?

Thanks,
=Fen