John C Klensin wrote: >> Still, the draft may assure new usages compatible with each >> other. > > That is the hope. The problem is that an existing and an new usages may not be compatible. >> If we need subtypes because 16bit RRTYPE space is not enough >> (I don't think so), the issue should be addressed by itself >> by introducing a new RRTYPE (some considerations on subtype >> dependent caching may be helpful), not TXT, which can assure >> compatibilities between subtypes. > > Again, I completely agree. But it isn't an issue for this > proposed registry. With a new RRTYPE, new usages are assured to be compatible with existing TXT usages. Thanks, Masataka Ohta