DOIs, OpenURL, and link resolvers

DOIs point to the authoritative version of content on the publisher's web site and to publisher-designated resources. Yet for the user working in an institutional context, it is often useful to be directed to other resources via their institution's link resolver.

The Crossref system serves as a source of metadata to enhance OpenURL-based local link resolvers and supports DOI re-direction for the purposes of localized linking within library holdings.

How the DOI System and OpenURL work together

DOIs and OpenURL work together in several ways. First, the DOI directory itself—where link resolution occurs in the Crossref system—is OpenURL-enabled. This means that it can recognize a user with access to a local resolver. When the user clicks a DOI, the Crossref system allows the DOI to be used as a key to pull the metadata needed to create the OpenURL targeting the local link resolver out of the Crossref database and redirects that DOI back to the user's local resolver. The institutional user is then directed to appropriate resources. By using the Crossref DOI system to identify their content, publishers in effect make their products OpenURL aware.

It works this way:

1. A library user clicks a DOI link within a link resolver-enabled resource.
2. A cookie on the user’s machine alerts the DOI proxy server to redirect this DOI to the local linking server.
3. The local linking server receives the metadata needed for local resolution, either from the source of the link or from Crossref via OpenURL.