I'm working on an updated draft for DCTNG, and here are some of the new
syntax, which I find more generic.
First of all, it's using mime-types, which I find as a good idea as it
allows for alot of interresting ideas. (Live video or audio streaming over
the DC protocol, anyone?).
The draft will be updated by the end of this week.

mime-types are good but the problem is to have an common mime-type database. There is lot of mysterious type (let's say application/ms-tnef (outlook) or application/proxy (netscape)) which are only know on a single platform (or even a single program) and there is even (a lot of file) file type without mime-types (let's say .ogg and .ogm files).

Eric