Jim, Thanks for the comprehensive comments. I'ld like to reply to one chunk at a time. [dns-wg-ers, sorry for the cross-posting; I'ld use enum-wg if it were populated.] On 15 Jul 2004, at 11:07, Jim Reid wrote:
So what? Is disk space and RAM expensive?
No. T1 zone-file size is indeed no big deal, mentioned for completeness only.
The T1 registry is going to be storing so much data about its registrations -- tech & admin contact details, billing info, authentication/validation tokens, whois tags, registrar data, etc, etc -- that shaving off a couple of resource records would be lost in the noise.
Only if your (unstated) assumptions about the role of the T1 Registry match the particular instance. My concept of the T1 Registry is much lighter, with delegation only at T1, payload (NAPTR of course, possibly others) at T2, and validation with the registRARs. This distributes customer-related overhead to the front-office, where it can be related directly to each registrar's business.
For the T1, adding CNAMEs instead of conventional delegations might well be an unwanted complication: ie it requires changes and on-going support to the registry database and back-end scripts and tools. IIUC some registry systems only handle the RRs needed for conventional delegation: NS records and related glue.
IMHO such registry systems are not suited to the ENUM business, and a T1 which takes this approach is unlikely to be winning many tenders for national infrastructure. Of course, that depends on the clue-level available to the local awarding agency. I'm happy to say that, here in +353-land, our trial T1 is taking a more helpful approach. Best regards, Niall O'Reilly UCD Computing Services