usefor-article-12 November 2003

5.6.1.  Format

      header          =/ Path-header
      Path-header     = "Path" ":" SP Path-content
                 *( ";" extension-parameter )
      Path-content    = [FWS]
                 *( path-identity [FWS] path-delimiter [FWS] )
                 tail-entry [FWS]
      path-identity   = ( ALPHA / DIGIT )
                 *( ALPHA / DIGIT / "-" / "." / ":" / "_" )
      path-delimiter  = "/" / "?" / "%" / "," / "!"
      tail-entry      = path-identity

        NOTE: A Path-content will inevitably contain at least one path-
        identity, except possibly in the case of a proto-article that
        has not yet been injected onto the network.

        NOTE: Observe that the syntax does not allow comments within the
        Path-header; this is to simplify processing by relaying and
        injecting agents which have a requirement to process this header
        extremely rapidly.

   A relaying agent SHOULD NOT pass an article to another relaying agent
   whose path-identity (or some known alias thereof) already appears in
   the Path-content. Since the comparison may be either case sensitive
   or case insensitive, relaying agents SHOULD NOT generate a name which
   differs from that of another site only in terms of case.

   A relaying agent MAY decline to accept an article if its own path-
   identity is already present in the Path-content or if the Path-
   content contains some path-identity whose articles the relaying agent
   does not want, as a matter of local policy.

        NOTE: This last facility is sometimes used to detect and decline
        control messages (notably cancel messages) which have been
        deliberately seeded with a path-identity to be "aliased out" by
        sites not wishing to act upon them.

--- ../usefor-article-11/Format.out          June 2003
+++ ../usefor-article-12/Format.out          November 2003