[DDI-SRG] URN Syntax and URN Resolution

[Joachim Wackerow]

Dear all,

We had a bug regarding an illegal DDI URN syntax in 3.0. Square brackets 
are not allowed in URN's. The bug fix is to replace square brackets [] 
with parentheses () .

In this process I looked more detailed into the URN syntax and the into 
URN resolution approaches. I looked through the related best practices 
paper, a stack of RFC's and papers on voice-over-ip services.

With this background I have now the impression that several steps would 
make sense

1.
again a change of the DDI URN syntax (within version 3.1): clearer 
hierarchical structure, only two separators, the colon as a separator 
between major parts, dot as a separator within major parts. Colon is 
anyway a separator in URN's like urn:nid:nss (nid - namespace 
identifier, nss - namespace specific string)

2.
restriction of the number of version levels of an object to a fixed 
number. Unlimited number of versions can cause processing issues in 
every resolution system. This can be especially the case when using 
latebound versions at a specific level (a proposal is using an asterisk 
for the highest version), like 7.*.5. A reasonable amount of levels 
should be defined. Would three be enough?

3.
applying for the URN namespace DDI. For this purpose a formal RFC 
document must be written.

4.
proposal of using DNS for URN-to-URL resolution

5.
application for a DNS NAPTR record for DDI below urn.arpa (for DNS names 
like *.ddi.urn.arpa.)

Topics 1 and 2 are related and time critical. This should be decided 
soon, so it can go into the published version of 3.1

Topic 4 should be discussed in relation to the approach which is 
described in the best practices paper on URN resolution. Both ways have 
some overlap. The DNS-based URN-to-URL resolution provides an additional 
level of interaction. The URN is not necessarily resolved to an metadata 
object directly. The details of the DNS would probably need some further 
clarification with an DNS expert.

Topic 3 and 5 would be a requirement for topic 4. Topic 1 und 2 would 
ease the conversion of a DDI URN into a DNS domain name.

Topic 3 should be done anyway independently from the other topics.

Attached are two documents with details regarding the proposed DDI URN 
syntax and the URN resolution.

Arofan and I would like to discuss these issues with you while the 
IASSIST conference.

I would suggest to have lunch together at Wednesday for this discussion. 
Not all of the people are at IASSIST, but they were involved in the best 
practices paper. Input for the discussion is welcome.

Achim
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DDI_URN_NewSyntax_2009-05-24.doc
Type: application/msword
Size: 36864 bytes
Desc: not available
Url : http://www.icpsr.umich.edu/pipermail/ddi-srg/attachments/20090526/b4a3a799/attachment-0002.doc 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Proposal_DNS_as_URNResolutionSystem_2009-05-18.doc
Type: application/msword
Size: 84992 bytes
Desc: not available
Url : http://www.icpsr.umich.edu/pipermail/ddi-srg/attachments/20090526/b4a3a799/attachment-0003.doc