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What is name resolution?
Name resolution is the process of mapping a URN to a URL that retrieves the named resource; the URL locates the resource identified by the persistent identifier:

If a resource moves or changes the way it is accessed, the mapping between the resource's persistent identifier and URL can be updated; the persistent identifier remains unchanged and valid.

Why use persistent identifiers?
In general, important resources should never be directly identified by a URL because URLs can become invalid if the resource is moved or if the way it is accessed changes. (This is the cause of the "404 File Not Found" browser error message. ) By adding a layer of indirection into the access process, persistent identifiers URNs will never become invalid. If a resource moves, only the URL to which the persistent identifier URN resolves needs to be updated; the identifier URN itself can remain unchanged. As long as persistent identifiers URNs are properly maintained within NRS, 404 errors should never occur when accessing named resourcesthey should always point to the intended resource.

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