Resolving Unique and Persistent Identifiers for Digital Objects Why Worry About Identifiers? Individuals and organizations, including governments and businesses, need to manage increasing amounts of primary and secondary data and increasingly complex and fluid data relationships over long periods of time. Identifiers are essential to this process. Identifiers are a key component of the Digital Object Architecture, a system for managing digital information and other resources in a global context. They allow for effective management of Digital Objects of all kinds. Why is Resolution Important? The resolution system enables client software to go from a digital object’s identifier to current state information about the object. Such identifiers can persist over changes to the identified object, such as changes in its location(s), ownership, and other attributes. What is the Handle System? The Handle System, a principle component of the Digital Object Architecture, is a general purpose resolution system that has been deployed for many years. Identifiers in the Handle System are made up of a prefix and a suffix separated by a slash, e.g., /bio or /5030. The prefix is used by client software to find specific servers within the widely distributed resolution system that can resolve the identifier. Existing identifiers can be easily structured as handles in order to take advantage of the resolution system. How Would the Resolution Capability Be Managed in the Future? Thousands of groups around the world currently use CNRI’s Handle System* for resolution services on a daily basis. This includes many academic and national libraries, scholarly journal publishers, scientific institutes, motion picture studios and others. Global administration of the system is now provided by CNRI, in its role as primary prefix administrator, through the Global Handle Registry (GHR). CNRI would make the Handle System technology, including the GHR capability, available under a new global management framework ― the Digital Object Numbering Authority (DONA). A Multi-primary Global Registry (MP-GR) that can accommodate multiple primary prefix administrators would be deployed under DONA. Each such administrator will be able to determine its own local policies as permitted under the anticipated DONA structure. International Telecommunications Union Corporation for National Research Initiatives *An overview of the current operation of the Handle System is shown on the reverse side. May 2011

Both people and systems use the Handle System to resolve identifiers. They submit identifiers to the system and get back the most recent state information about the identified object that has been recorded by the object owner or administrator. This process is illustrated below The client software receives the current resolution information and acts accordingly. Most users will not see this information at all but will simply see the end result of the resolution, such as a journal article. Software developers can build new applications that take advantage of the Handle System capabilities, which include security, identity management, and many other features that cannot be summarized in this brief description; some of these can be found on the Handle System web site. Current resolution information about digital objects is recorded in the Handle System in a systematic and structured fashion, so that software clients can be built to use that information to manage interactions with the objects, e.g., send a user to the right location, deliver the appropriate portion of an object, or update the information in the handle if permitted. 2 HDL:10123/ABC Where is this? Who owns this? Any services? When was this changed? Can I see this? Can I change this? Other data? DATASET XML Any client software, such as a mobile phone app, a web browser, or some completely automated process, that needs to resolve the handle 10123/ABC will first ask the Global Handle Registry (not shown here) for the location of the local handle service responsible for identifiers beginning with the prefix There are thousands of such local handle services around the globe. Each is responsible for handles that start with one or more prefixes that have been allotted to them. The Global Handle Registry knows where those services are located and who is responsible for each of them. Once the client software knows which service is responsible for resolving the handle, it sends it to that service and gets back the resolution information associated with that handle /ABC