zero level domain

[Simon Waters]

vietanh1977 wrote:
> 
> I read some IDNS document and found there is a term "zero level domain"
> i wonder what does this term mean? and if there is any document about it?

I've only seen the term used to refer to the "." zone, which
quietly lives at the top of the DNS structure.

This is the zone where the top level domains like "com","net"
and "uk" are delegated. i.e. When your nameserver needs to find
out who servers "com." domains, who does it ask?

If they want to use Internationalised versions of domain names
like "tw" (Taiwan) they would need to redefine these root
servers, or persuade the powers that be to add some rather
perculiar looking top level domains to the "." domains.