Just require URLs

Didier PH Martin martind at netfolder.com
Tue Jun 1 13:12:00 BST 1999

Hi Jonathan,

Jonathan said:
Note that when the string "http://www.w3.org/xxx" is used as an XML
namespace URI this is a URN not a URL by definition (the scheme remains

Didier says:
Not exactly. The string http://www3.org/xxx cannot be considered a URN it is
a URL based on the HTTP scheme. The example below is a URN:


To be qualified as a URN the string should be structured as follow:

urn:<NID>:<name space>

<NID> :: Name space identifier
<name space> :: any string constructed as defined in RFC 2141 (some
characters like "/" needs to be encoded for resolution but not for human

To see the difference let's take LDAP.

URL---> LDAP://ldap.itd.umich.edu/c=us
URN---> urn:ldap:c=us

In a URN we tend not to include a domain name witch is absolutely required
for URL but not for URN. In fact, to include a location dependent context in
a name jeopardize the permanency requirement.

Didier PH Martin
mailto:martind at netfolder.com

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