Hello, At OGF 33 in Lyon we discussed the potential problem that urn:ogf:network identifiers are somewhat volatile. The IETF requires that URN must never be re-assigned or re-used. The currently proposed syntax (and prior practice) uses domain names to identify the organisation that assigned a URN. Domain names may be re-assigned, so there is a risk that URNs in the proposed syntax may be re-assigned or re-used. I personally consider identifier collisions unlikely, but possible in archives with historic measurement data. The participants in the OGF 33 discussion generally agreed that we should look into fixing this. The usual solution to prevent identifier collisions is to set up a registry that assigns prefixes. E.g. IANA has a registry for URN namespaces, ICANN for top level domain names, CNRI has a registry for the Handle system, etc. Most of the discussion was aimed how to create a registry within the OGF. A few possible identifiers that identify the organisation that assigns URNs were discussed: - DNS name - the current syntax. e.g. "sara.nl" - organisation name - e.g. "SARA" - DNS + version - e.g. "sara.nl:1" - DNS + year - e.g. "sara.nl:2011" I personally hope it is possible to re-use an existing registry, so that the OGF does not need to create a registry on its own. Examples of current registries are AS-numbers and DNS. - DNS can be used, but is consider volatile. (RFC 3406 explicitly states that domain names "makes a poor URN namespace in practice") - AS-number do not work, since not all organisations that want to assign urn:ogf:network identifiers have a AS number (e.g. many Dutch universities do not have their own AS number as they only have one upstream provider, SURFnet). Of the above examples, - organisation name - e.g. "SARA" - DNS + version - e.g. "sara.nl:1" require a new registry within the OGF - DNS name - e.g. "sara.nl" is considered volatile I claim that using a domain name + year 1) is not volatile 2) does not require a new registry within the OGF A domain name is volatile because it can be reassigned. However, a domain name is typically not re-assigned within a year (if only because registration fees are usually paid per year, not per month). Hence, the combination of year and domain name is a unique identifier for an organisation. Hence, I propose the following syntax for urn:ogf:network identifiers (in ABFR format): "urn:ogf:network:" DOMAINNAME ":" ASSIGNINGYEAR ":" SNSS where DOMAINNAME = a FQDN that is administratively owned by the organisation that assigns the URN ASSIGNINGYEAR = year (gregorian calendar) whent he URN is first assigned (note that once a URN is assigned, this number does not change for that URN.) SNSS = subnamespace specific string. The remainder of the URN that only has meaning for the assigning organisation and should not be interpreted by other organisations. Regards, Freek