Addressing
URLs (e.g. http://www.bristol-poly .ac.uk/depts/music/) have limitations:
- Lack of long-term persistency
- Organisation changes name
- Department shut down or merged
- Directory structure reorganised
- Inability to support multiple versions of resources (mirroring)
URNs (Uniform Resource Names):
- Proposed as solution
- Difficult to implement (no W3C activity in this area)