Naming Authority

 

Naming Authority

In the virtual observatory context, a resource is a general term referring to an element which can be described in terms of who curates and maintains it and which can be given a name and a unique identifier. A resource can be an organization or group, a web service, a catalogue, etc.

There is a set of XML Schemas designed to describe VOResources, based on the document "Resource Metadata for the Virtual Observatory" ( RM R. Hanisch et al). These schema define the metadata which describe a VOResource. The metadata are most commonly used to pass information about VOResources to and from registries (which are themselves VOResources).

In order to distinguish between VOResources, each VOResource must have a unique IVOA identifier. (See Plante et al). The XML form of the identifier looks like:

<ResourceID>

<AuthorityID>authority.id.string</AuthorityID>

<ResourceKey>resource/key/string</ResourceKey>

</ResourceID>

There are currently two different styles of creating AuthorityIDs. The National Virtual Observatory combines the publishing organisation name with the project or archive, for example, "adil.ncsa". The AstroGrid project uses DNS names in reverse order, for example, "org.astrogrid.www". The resource key is a localized name for a resource which is unique within the namespace of the AuthorityID.

In principle, the right to create identifiers is granted to naming authorities by the IVOA. In practice, since an identifier is created by a person or organisation when registering a resource, only a recognized naming authority may register new resources.

We propose that aus-vo become a naming authority, and therefore maintain a resource registry. Further, we propose that the aus-vo follow the NVO style of assigning AuthorityIDs. An example might be "ausvo.melbourne".

-- KathieManson - 30 Sep 2004

I think a reasonable addition to the NVO approach is to create AuthorityIDs like this: {project | archive name}.{aus-vo site}.ausvo. Examples might be

  • hipass.unimelb.ausvo
  • 2dF.aao.ausvo
  • sumss.usyd.ausvo
  • generic.unimelb.ausvo

where the "aus-vo site" name is roughly the relevant piece of the top-level internet domain name for the site. I realise that this might be adding information that could be better expressed in the ResourceKey, but for a large site (eg. ATNF) that might want to have different groups publishing data it may be useful to delegate authority within the organisation. Each site could have a "generic" AuthorityID as shown in the last example above, and publish using this one by default, until a sub-project within the organisation decided they want to have their own AuthorityID.

-- DavidBarnes - 1 Oct 2004

I'm not sure I agree that we need your proposed addition. All the AuthorityID has to do is "establish a namespace within which the rest of the ID, the resource key, can be considered unique." (To quote from Plante et al) Hence even though a organisation may be quite large, you would only need a finer grained AuthorityID if you expected them to have problems with resource names clashing within the organisation. To me this seems unlikely.

-- TaraMurphy - 08 Oct 2004