Henrik, As for the adding hierarchy to URNs, I suggest we discuss this at OGF 40. I think it is a bad idea to add a network hierarchy to an identifier, but do not necessarily object to all sorts of hierarchies. In fact, the URN:OGF:NETWORK specification already requires that the first part of a URN starts with an identifier of the assigning organization (which is somewhat akin to the NSA, but not necessarily the same as the Topology). As for dropping the date part in the URN, please read GFD 202, section 5. http://www.ogf.org/documents/GFD.202.pdf The date is there for a reason: ensuring persistent uniqueness, without creating a registry. Adding 5 bytes seems like a cheap cost compared to any alternatives. On 11-12-2013 13:56, Jeroen van der Ham wrote:
John has dug up references of use of URNs where it is allowed to analyze the structure of the identifiers and to interpret that.
It's allowed by URN specs, but quite strongly discouraged by the URN community. Subdelegations of the URN specs may add further restrictions (such as the requirement that an identifier is context-free, and may only be interpreted by the assigning organisation), and that is what GFD 202 did. The eye-opener for me was the following email: http://www.ietf.org/mail-archive/web/urn/current/msg01564.html I'll quote verbatim:
if you allow people to assign URNs as they prefer, they always tend to "invent" some semantic rules.
At the end you have your database full of Identifiers like:
[institution-name]-[division-name]-[collection-name]-[date]-[item-number]
This goes fine many years.
Till the day the collections are renamed or two divisions fusion under another name or renaming of the institution or ...
Experiences like those are the reason why many colleagues with Long Term Archiving background propagate Identifiers without semantics --meaningless strings just for machines.
I was Brainwashed too, and I now also propagate identifiers without semantics. :) Freek -- Freek Dijkstra | Group Leader & Network Expert | Infrastructure Services | SURFsara | | Science Park 140 | 1098 XG Amsterdam | +31 6 4484 7459 | | Freek.Dijkstra@surfsara.nl | www.surfsara.nl | Available on Mon | Tue | Thu | Fri |