Subject: [e2md] Ponderings on different roots for different sorts of metadata

From: Dean Willis <[email-masked]>
Date: Mon, 3 May 2010 22:46:10 -0500

In "The DNS" as preached by the disciples thereof, there is a single  
root, and all namespaces are encompassed within that root.

This is subtly different from how several people have told me they  
want to use E2MD. Essentially, as I understand it, current practice is  
to use different roots for different topics. If one wants the calling  
name for  a phone number, one looks that phone number up in e.164.arpa  
on a given server, and if one wants the default route to that number,  
one might well look in that number in the same e164.arpa tree on an  
entirely different server, which is attached to an entirely different  
hierarchy of numbers all the way up to an entirely different e164.arpa  
root. A client must be configured to know which server to ask for any  
given sort of data, and asking the wrong one could result in a  
significant malfunction.

I can see how this makes the DNS people nervous. I know, it's not all  
that different from how we use ENUM in practice, but so far that  
hasn't required any special tweaking of the ENUM spec to allow it. If  
we have to come out and make an explicit allowance for alt-root  
operations, I think we're going to get a special sort of attention  
traditionally reserved for victims of the Inquisition. Thumbscrews,  
anybody?

Should we consider approaches for making this stuff all work without  
alt-root solutions? We've had a couple of proposals put on the table:

If I recall correctly, these proposals include:

1)  Having a single root that dereferences using a URI to some other  
service that handles the "alternate source" issue.

2) using different roots besides e164.arpa for private networks.

3) Using some sort of "delegation" model (perhaps a prefix) to find  
the right server for a specific sort of question.

Noted that whatever we come up with here doesn't have to be the way  
people actually use the protocol, but it does need to be a complete  
enough answer that it is plausible and could actually be used, safely,  
on the Internet, if somebody wanted to.

--
Dean