What sort of persistent identifiers does DSpace use?
DSpace requires that a persistent identifier is assigned to each digital object (Item, Collection, Community). Because the developers wanted a solution which will work for a very long time, the identifier system had to be independent of any underlying network protocols, such as HTTP.
DSpace uses the Handle System from CNRI (Corporation for National Research Initiatives) as the persistent identifier for each digital object. Handles are resolved to actual URLs via a resolution service. The Handle resolver is an open-source system. Handles in DSpace (and elsewhere) are currently implemented as HTTP URIs, but can also be modified to work with future protocols. The Handle system is also able to support existing bibliographic identifiers such as ISBN or ISSN.
In the current version of DSpace, Handles are used as internal identifiers. By default, DSpace utilizes a 'dummy' (non-external) Handle prefix of '123456789' when assigning Handles to new objects. If an organization wishes to obtain a valid Handle prefix (which can be resolved from external locations), one can be purchased from the Handle System site for a small annual service fee.
It should be noted that if an organization has a policy requiring the use of another persistent identifier system, it is possible to use it as the public or external persistent identifier to the resource. In such a case, the public identifier - for instance, a URN - could resolve to a DSpace-generated page which contains metadata about the resource - including the Handle-based persistent link to the resource itself.
Future versions of DSpace may support multiple internal persistent identifiers. However, this work is still under investigation, and we are looking for developers and institutions willing to volunteer to help with this project.