Requirements on URNs are discussed in [S&M]. These may be divided into requirements on URNs themselves (global scope, location independence, global uniqueness, and persistence), requirements on URN schemes (scalability, legacy support, extensibility, independence of naming authorities, resolvability), and requirements on URN encodings (single encoding, simple comparison, transcribability, transportability, parsability).
To these requirements could be added the necessity not to make any URN scheme into a straitjacket for future Internet development. Fulfillment of this requirement will clearly only be possible if the issues relating to URN construction are separated from those relating to resolution of URNs into other classes of Uniform Resources.
The next few sections discuss the existing proposals and documents in the light of the considerations derived in this section.
Converted from text 17 Nov 1995 by <msm@ansa.co.uk>