Subject: Namespaces for national libraries

From: Juha Hakala <[email-masked]>
Date: Wed, 30 Aug 2000 09:09:26 +0300

Dear all,

Last week Jose Borbinha from the National Library of Portugal sent a URN
namespace registration for namespace "pt-bn", to be used by the library
for various purposes. I have a couple of comments to the document.

First, the national libraries have an international initiative for
registering a namespace "NBN", which stands for national bibliography
number. Within this namespace, there will be sub-namespaces based on ISO
country code. So, for instance Portugal can use urn:nbn:pt: for
basically all purposes Jose lists in his draft. Moreover, since
assigning national sub-namespaces within the international NBN namespace
is internal affair, you do not need to bother with the registration of
your own namespace in the IETF. On the other hand, if all national
libraries were to follow Portugal's example, IETF would need to tackle
with >150 registration requests.

You may remember that I sent an Internet draft registering the NBN
namespace to the [email-masked] in Spring. The comments were few,
and generally favorable. So, from IETF point of view the draft is OK.
However, the international working group preparing the text (or, to be
more exact, the Canadian participant in the group) wanted to make some
fine tuning to the document. Technical basis will remain untouched.
Editorial work has not yet been finalised, but I'm hoping that the final
version of the document can be delivered before the San Diego IETF
meeting. The current text is still available as Internet draft.

One major issue remains: what to do if the identifier used as URN also
has its own namespace? That is, should we stick to urn:isbn: instead of
urn:nbn:pt: or urn:bn-pt:. The answer, as I see it, depends on the
identifier system and location of the resolution services.

I sent 30 minutes ago to the IETF an Internet draft, which registers a
namespace for ISBN, International Standard Book Number. ISBN, as
intelligent code, provides good hints as to where to find a resolution
service. Since there is no global ISBN database, ISBNs need to be
resolved in national bibliography databases. Within DNS system there
needs to be a record for each ISBN group identifier (which means that
about 200 DNS records need to be created). For instance, if ISBN begins
with "951", the DNS record will point to the Finnish national
bibliography database. If ISBN starts with 972, the resolution service
will be found from Lisbon. In some cases a cascade of resolution
services is needed; for ISBNs starting with 3 it is necessary to check
Germany, Austria and Switzerland, in this order.

Therefore I do not see any need for having URNs like
urn:bn-pt:isbn:<ISBN>. In order to enable usage of Portuguese national
bibliography database for resolving ISBN-based URNs, you will only need
urn:isbn:. But things are not always as simple as this.

ISSN (International Standard Serial Number) is a dumb code. Luckily
there is also a global ISSN database, which currently contains about
million bibliographic records. The ISSN International Centre will
register a URN namespace for ISSN. For technical reasons the only
resolution service that can be used is the one built on top of the ISSN
database (as an aside, the ISSN centre has already built a URN
resolution server and WWW browser plug-in; they work fine).

Now, if the National Library of Portugal wants to replace the ISSN
database with their own national bibliography as resolution service, the
only way to do this, as far as I can see, is to define a namespace such
as urn:bn-pt:issn: or urn:nbn:pt:issn:.

For some reason not clear to me, Jose does not rely on SICI standard
(Serial Item and Contribution Identifier, see RFC2288) for
identification of journal issues and articles or sections within
articles. SICI is based on ISSN, and resolving URNs based on them can be
accomplished via using the global ISSN database as a way station. The
way this may work is that in the bibliographic record describing an
electronic journal  there will be two kinds of URL links; some pointing
to the journal's home pages, some pointing to a resolution service(s)
that can deal with the SICIs identifying articles and issues of the
journal at hand.

To sum up: Jose's proposal should be aligned with international
developments. It is also necessary to analyse more carefully how
individual identifier systems actually can be resolved within the URN
framework. Some times domestic arrangements should be avoided; some
other times they may be desirable.

Regards,

Juha
--

Juha Hakala
Helsinki University Library
[email-masked]