No, I think he means longer. IN-ADDR.ARPA can only be delegated on octet boundaries, so IN-ADDR for /16 and shorter prefixes will be delegated in /16 chunks. IN-ADDR for prefixes longer than /16 must still be maintained by the root, since they cannot be delegated.
For example, assume an ISP has been allocated the prefix 204.160/14. Along with this, the InterNIC will delegate the corresponding IN-ADDR domains:
160.204.IN-ADDR.ARPA 161.204.IN-ADDR.ARPA 162.204.IN-ADDR.ARPA 163.204.IN-ADDR.ARPA
If the ISP were instead only assigned 204.160.0/17, the associated IN-ADDR range would be:
0.160.204.IN-ADDR.ARPA ... 127.160.204.IN-ADDR.ARPA
which is not octet-aligned and therefore cannot be delegated.
Well, you can delegate these as 128 individual zones. With a little bit of automation to help, it may approach practical. You can delegate a single domain name in the limiting case. Louis A. Mamakos, Manager of Network Engineering louie@uu.net, uunet!louie UUNET Technologies, Inc. Voice: +1 703 206 5823 3060 Williams Drive Fax: +1 703 206 5908 Fairfax, VA 22031