Architecture of the ASDD

• Architecture diagram (colour GIF in new window)
• Architecture diagram (b/w GIF in new window)

Explanatory notes to accompany diagram

• A - ASDD HTTP to Z39.50 Gateway
  • provides access to the Z39.50 world for WWW clients
  • provides search interfaces using familiar WWW pages
• B - Z39.50 Server and ASDD nodes
  • Z39.50 servers handle the search and presentation requests
  • each ASDD node is a certain custodian's metadata collection
  • many ASDD nodes can sit behind each Z39.50 server
• C - WWW browsers
  • use an HTTP-Z39.50 Gateway to search and present
• D - Metadata as document collection
  • metadata can be held as XML documents (conform to ANZMETA DTD)
  • with HTML and plain text presentation versions
• E - Metadata as relational database
  • metadata can also be stored in database
  • search and presentation is handled by the database
• F - Presentation metadata can link to other documents
  • the main metadata document can link to another other network resource (HTML further info, GIF locality and data demo, order form, online database)
• G - HTTP server can also present documents
  • direct access to the metadata reference page
• H - Other HTTP to Z39.50 Gateway
  • any number of gateways can interrogate all or some nodes
  • it is important to have many access points
• I - True Z39.50 client
  • traditional library clients can connect directly to Z39.50 servers
• J - Other Application e.g. Web Mapping
  • other applications can also interrogate the Z39.50 servers
  • e.g. Web mapping applications can automatically conduct a Z39.50 search for suitable mapping layers, then read the metadata to glean information to be automatically presented in a WWW mapping interface

URL:http://www.indexgeo.com.au/tech/asdd/arch.html
Last Modified: 11 May 2000