Re: [Inip-discuss] Domain Names

[Edward Lewis <[e-mail]>]

My in-box is a mess[0], I just found this looking for another message.  So
my response to this is terribly delayed.

[0] - I'm using an up-to-date commercial email reader that apparently
cannot correctly sort by date. ;)

On 1/7/16, 16:57, "Lyman Chapin" <[e-mail]> wrote:

>In graph-theoretic terms, the domain name space constitutes a labelled
>directed rooted tree in which the syntax of the label associated with
>each vertex other than the unlabelled root is defined by RFCs 1035, 1123,
>and 2181. The term "nth level domain name label" refers to a member of
>the set of all vertices for which the path to the root contains n edges.
>For n=1 the term most often used is "top level domain name label" or
>simply "top level domain" (TLD). A fully qualified domain name is a
>sequence of labels that represents a path from the root to a leaf vertex
>of the domain name space. The shorter term "domain name" is not formally
>defined; in common usage it may be the shorthand equivalent of "fully
>qualified domain name" (FQDN) or refer to any non-empty subset of the
>sequence of labels formally identified by a fully qualified domain name.

A clarifying question - (is) this definition specific to names in the DNS?

The reason I ask is that I believe that only within the DNS is the name
space finite and that is because the DNS is defined for a 1980's-era code
base.  (I.e., fixed widths, static limits on space.)

>In this formulation, the term "domain name space" refers to the complete
>graph consisting of all possible vertices and edges - not just those with
>which a specific meaning has been associated (what we might call
>"allocated" labels). It is a finite graph because the length of the
>longest possible FQDN is finite. At any point in time, there is another
>labelled directed rooted tree - a sub-graph of the domain name space -
>containing only vertices that represent allocated labels.
>
>-------------------------------
>
>So mathematically, a domain name is simply a sequence of labels. In most
>of the contexts in which we talk about, write about, or use domain names
>we add representational elements like "top to bottom" or "separating
>character," but those are not properties of a domain name.
>
>Not terribly pragmatic, I know; but it might have a place in your draft -

I completely agree.  With all of that - sequence/separating character/not
pragmatic.

A question rolling in my mind is - do we want to offer something a few
steps away from mathematic towards pragmatic?  Like - are IETF(tm) Domain
Names things that have ... dots between labels and other constraining
elements?  (Using "dots between labels" as an example.)