usefor-article-09 February 2003

6.16.  Xref

   The Xref-header is a variant header (4.2.5.3) which indicates where
   an article was filed by the last serving agent to process it.

      header            =/ Xref-header
      Xref-header       = "Xref" ":" SP Xref-content
                   *( ";" extension-parameter )
      Xref-content      = [CFWS] server-name 1*( CFWS location ) [CFWS]
      server-name       = path-identity  ; see 5.6.1
      location          = newsgroup-name ":" article-locator
      article-locator   = 1*( %x21-27 / %x29-3A / %x3C-7E )
                   ; US-ASCII printable characters
                   ; except '(' and ';'

   The server-name is included so that software can determine which
   serving agent generated the header. The locations specify what
   newsgroups the article was filed under (which may differ from those
   in the Newsgroups-header) and where it was filed under them. The
   exact form of an article-locator is implementation-specific.

        NOTE: The traditional form of an article-locator is a decimal
        number, with articles in each newsgroup numbered consecutively
        starting from 1. NNTP demands that such a model be provided, and
        much other software expects it, but it seems desirable to permit
        flexibility for unorthodox implementations.
   An agent inserting an Xref-header into an article MUST delete any
   previous Xref-header(s). A relaying agent MAY delete it before
   relaying, but otherwise it SHOULD be ignored by any relaying or
   serving agent receiving it.

   It is convenient, though not required, for a serving agent to use the
   same server-name in Xref-headers as the path-identity it uses in
   Path-headers (just so long as reading agents can distinguish it from
   other serving agents known to them).

--- ../usefor-article-08/Xref.out          August 2002
+++ ../usefor-article-09/Xref.out          February 2003
@@ -5,7 +5,7 @@
 
       header            =/ Xref-header
       Xref-header       = "Xref" ":" SP Xref-content
-                   *( ";" other-parameter )
+                   *( ";" extension-parameter )
       Xref-content      = [CFWS] server-name 1*( CFWS location ) [CFWS]
       server-name       = path-identity  ; see 5.6.1
       location          = newsgroup-name ":" article-locator
@@ -24,7 +24,6 @@
         starting from 1. NNTP demands that such a model be provided, and
         much other software expects it, but it seems desirable to permit
         flexibility for unorthodox implementations.
-
    An agent inserting an Xref-header into an article MUST delete any
    previous Xref-header(s). A relaying agent MAY delete it before
    relaying, but otherwise it SHOULD be ignored by any relaying or