The mapping of x500 names onto URLs is not defined here.  A
      decision is required as to whether "distinguished names" or "user
      friendly names" (ufn), or both, should be allowed.  If any
      punctuation conversions are needed from the adopted x500
      representation (such as the use of slashes between parts of a ufn)
      they must be defined.  This is a subject for study.

   WHOIS

      This prefix describes the access using the "whois++" scheme in the
      process of definition.  The host name part is the same as for
      other IP based schemes.  The path part can be either a whois
      handle for a whois object, or it can be a valid whois query
      string. This is a subject for further study.







 
RFC 1630                      URIs in WWW                      June 1994


   NETWORK MANAGEMENT DATABASE

      This is a subject for study.

   NNTP

      This is an alternative form of reference for news articles,
      specifically to be used with NNTP servers, and particularly those
      incomplete server implementations which do not allow retrieval by
      message identifier.  In all other cases the "news" scheme should
      be used.

      The news server name, newsgroup name, and index number of an
      article within the newsgroup on that particular server are given.
      The NNTP protocol must be used.

      Note 1.

         This form of URL is not of global accessability, as typically
         NNTP servers only allow access from local clients.   Note that
         the article numbers within groups vary from server to server.

         This form or URL should not be quoted outside this local area.
         It should not be used within news articles for wider
         circulation than the one server.  This is a local identifier
         for a resource which is often available globally, and so is not
         recommended except in the case in which incomplete NNTP
         implementations on the local server force its adoption.

Prospero

   The Prospero (Neuman, 1991) directory service is used to resolve the
   URL yielding an access method for the object (which can then itself
   be represented as a URL if translated).  The host part contains a
   host name or internet address.  The port part is optional.

   The path part contains a host specific object name and an optional
   version number. If present, the version number is separated from the
   host specific object name by the characters "%00" (percent zero
   zero), this being an escaped string terminator (null).  External
   Prospero links are represented as URLs of the underlying access
   method and are not represented as Prospero URLs.

Registration of naming schemes

   A new naming scheme may be introduced by defining a mapping onto a
   conforming URL syntax, using a new prefix.  Experimental prefixes may
   be used by mutual agreement between parties, and must start with the




 
RFC 1630                      URIs in WWW                      June 1994


   characters "x-".  The scheme name "urn:" is reserved for the work in
   progress on a scheme for more persistent names.

   It is proposed that the Internet Assigned Numbers Authority (IANA)
   perform the function of registration of new schemes. Any submission
   of a new URI scheme must include a definition of an algorithm for the
   retrieval of any object within that scheme. The algorithm must take
   the URI and produce either a set of URL(s) which will lead to the
   desired object, or the object itself, in a well-defined or
   determinable format.

   It is recommended that those proposing a new scheme demonstrate its
   utility and operability by the provision of a gateway which will
   provide images of objects in the new scheme for clients using an
   existing protocol. If the new scheme is not a locator scheme, then
   the properties of names in the new space should be clearly defined.
   It is likewise recommended that, where a protocol allows for
   retrieval by URL, that the client software have provision for being