Internet Application Protocol Collation Registry
RFC 4790

Network Working Group                                          C. Newman
Request for Comments: 4790                              Sun Microsystems
Category: Standards Track                                      M. Duerst
                                                Aoyama Gakuin University
                                                          A. Gulbrandsen
                                                                    Oryx
                                                              March 2007

            Internet Application Protocol Collation Registry

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   Many Internet application protocols include string-based lookup,
   searching, or sorting operations.  However, the problem space for
   searching and sorting international strings is large, not fully
   explored, and is outside the area of expertise for the Internet
   Engineering Task Force (IETF).  Rather than attempt to solve such a
   large problem, this specification creates an abstraction framework so
   that application protocols can precisely identify a comparison
   function, and the repertoire of comparison functions can be extended
   in the future.

Newman, et al.              Standards Track                     [Page 1]
RFC 4790                   Collation Registry                 March 2007

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Conventions Used in This Document  . . . . . . . . . . . .  4
   2.  Collation Definition and Purpose . . . . . . . . . . . . . . .  4
     2.1.  Definition . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  Purpose  . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.3.  Some Other Terms Used in this Document . . . . . . . . . .  5
     2.4.  Sort Keys  . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Collation Identifier Syntax  . . . . . . . . . . . . . . . . .  6
     3.1.  Basic Syntax . . . . . . . . . . . . . . . . . . . . . . .  6
     3.2.  Wildcards  . . . . . . . . . . . . . . . . . . . . . . . .  6
     3.3.  Ordering Direction . . . . . . . . . . . . . . . . . . . .  7
     3.4.  URIs . . . . . . . . . . . . . . . . . . . . . . . . . . .  7
     3.5.  Naming Guidelines  . . . . . . . . . . . . . . . . . . . .  7
   4.  Collation Specification Requirements . . . . . . . . . . . . .  8
     4.1.  Collation/Server Interface . . . . . . . . . . . . . . . .  8
     4.2.  Operations Supported . . . . . . . . . . . . . . . . . . .  8
       4.2.1.  Validity . . . . . . . . . . . . . . . . . . . . . . .  9
       4.2.2.  Equality . . . . . . . . . . . . . . . . . . . . . . .  9
       4.2.3.  Substring  . . . . . . . . . . . . . . . . . . . . . .  9
       4.2.4.  Ordering . . . . . . . . . . . . . . . . . . . . . . . 10
     4.3.  Sort Keys  . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.4.  Use of Lookup Tables . . . . . . . . . . . . . . . . . . . 11
   5.  Application Protocol Requirements  . . . . . . . . . . . . . . 11
     5.1.  Character Encoding . . . . . . . . . . . . . . . . . . . . 11
     5.2.  Operations . . . . . . . . . . . . . . . . . . . . . . . . 11
     5.3.  Wildcards  . . . . . . . . . . . . . . . . . . . . . . . . 12
     5.4.  String Comparison  . . . . . . . . . . . . . . . . . . . . 12
     5.5.  Disconnected Clients . . . . . . . . . . . . . . . . . . . 12
     5.6.  Error Codes  . . . . . . . . . . . . . . . . . . . . . . . 13
     5.7.  Octet Collation  . . . . . . . . . . . . . . . . . . . . . 13
   6.  Use by Existing Protocols  . . . . . . . . . . . . . . . . . . 13
   7.  Collation Registration . . . . . . . . . . . . . . . . . . . . 14
     7.1.  Collation Registration Procedure . . . . . . . . . . . . . 14
     7.2.  Collation Registration Format  . . . . . . . . . . . . . . 15
       7.2.1.  Registration Template  . . . . . . . . . . . . . . . . 15
       7.2.2.  The Collation Element  . . . . . . . . . . . . . . . . 15
       7.2.3.  The Identifier Element . . . . . . . . . . . . . . . . 16
       7.2.4.  The Title Element  . . . . . . . . . . . . . . . . . . 16
       7.2.5.  The Operations Element . . . . . . . . . . . . . . . . 16
       7.2.6.  The Specification Element  . . . . . . . . . . . . . . 16
       7.2.7.  The Submitter Element  . . . . . . . . . . . . . . . . 16
       7.2.8.  The Owner Element  . . . . . . . . . . . . . . . . . . 16
       7.2.9.  The Version Element  . . . . . . . . . . . . . . . . . 17