I like the terms "Aggregate Master", "Master Pool", and "Public Access".

Some Feedback on the term "Tier":

The term "Tier 0-2" is used to refer to a Server that is authoritative for a particular Zones.

It is important to understand the subtle difference between a ".zone" and a "domain.name". see: http://www.bind9.net/manual/bind/9.3.1/Bv9ARM.ch01.html#AEN107


www.example.TLD. can be broken down into 3 "zones" and a "stub zone".

Both the Primary and Secondary for a zone, according to the Bind manual, are authoritative servers for the zone.

The first zone is the root, ".", and for those who remember that the "0" was conceived of/created to represent the "point of origin" and not "nothingness", it will make perfect sense why a rootserver (both type master or slave) is referred to as a "Tier 0 server".

The next Zone is the Top-Level zone, ".TLD", and any server that is authoritative for any of these zones is a Tier 1 server.

The next zone is what could be arguably called a Domain zone ".example.TLD." and any server that is authoritative for any of these zones is a Tier 2.

and then there is what is called a "stub zone", "www" (or "ftp", "https", "bob", "sftp", "lists", etc..) It is called a "stub zone" because there is no "." to the left of the "name" to complete the zone. (note: There won't be a zone configured in named.conf for stub zones.)

A name server that is authoritative for all 3 zones would be a Tier 0/1/2 server, or if only an authority for 2 zones, Tier 1/2, etc..

In the legacy root, most Tier 2 servers (if not all) are "not" type master or slave for "." or a ".TLD". They are configured as a "cache"/"resolver"/"forwarder" server and use "type hint" for "." and would then setup a Primary/Secondary zone IN "domain.TLD." { ...; }; for any number of domain zones.

They function a both a Tier 2 (for example.com) and as a cache server.

In the OpenNIC, the Primary Masters of the TLD's are both Tier 0/1 servers.