draft-sermersheim-ldap-csn-xx.txt [plain text]
Internet-Draft Editor: J. Sermersheim
Intended Category: Experimental Novell, Inc
Document: draft-sermersheim-ldap-csn-00.txt Dec 2003
The LDAP Change Sequence Number Syntax and Matching Rules
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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Abstract
This document defines a syntax schema element for the Lightweight
Directory Access Protocol ([LDAP]) which is used to hold a Change
Sequence Number (CSN). In general, a change sequence number
represents the place and time that a directory entity was changed. It
may be used by various attributes for various LDAP replication, and
synchronization applications.
Table of Contents
1. Introduction....................................................2
2. Conventions.....................................................2
3. Syntaxes........................................................2
3.1 ChangeSequenceNumber Syntax....................................2
3.2 UTF8String.....................................................3
4. Matching Rules..................................................3
4.1 changeSequenceNumberMatch Matching Rule........................3
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4.2 utf8CodePointMatch Matching Rule...............................4
4.3 changeSequenceNumberOrderingMatch Matching Rule................4
4.4 utf8CodePointOrderingMatch Matching Rule.......................4
5. Security Considerations.........................................5
6. Acknowledgements................................................5
7. Normative References............................................5
8. Informative References..........................................6
9. IANA Considerations.............................................6
10. Editor's Address...............................................6
1. Introduction
A number of technologies have been documented, implemented and
experimented with which in one way or another seek to replicate, or
synchronize directory data. A common need among these technologies is
to determine which of two copies of an element represents the latest
or most authoritative data. Part of meeting this need involves
associating a change sequence number to an element copy at the time
of an update to that element. When replication or synchronization
occurs, the change sequence numbers associated with directory
elements can be used to decide which element's data will be copied to
the other element(s).
2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", and "MAY" in this document are
to be interpreted as described in [Keyword].
The General Considerations in Section 3.1 of [Syntaxes] apply to the
syntax definition in this document.
The terms "directory element" and "element" refer to data held in a
directory and may apply to an attribute value, attribute, entry, or
any other identifiable directory entity.
3. Syntaxes
3.1 ChangeSequenceNumber Syntax
A value of the ChangeSequenceNumber syntax is the time of a change
along with a replicaID which represents the Directory System Agent
(DSA) holding the element when it was changed. There are also two
sequence numbers used to disambiguate directory entities that are
changed at the same time and place.
The Abstract Syntax Notation One ([ASN.1]) type corresponding to this
syntax is defined as follows:
ChangeSequenceNumber ::= SEQUENCE {
time GeneralizedTime,
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timeCount INTEGER (0 .. MaxInt),
replicaID UTF8String,
changeCount INTEGER (0 .. MaxInt)}
MaxInt INTEGER ::= 2147483647 -- (2^^31 - 1) --
GeneralizedTime is defined in [ASN.1]. Local time without a
differential SHALL NOT be used.
UTF8String is defined below.
The LDAP-specific encoding of a value of this syntax is the Generic
String Encoding Rules ([GSER]) encoding of the ASN.1 type.
Example:
{ time "196701160315-0700",
timeCount 0,
replicaID "DSA666",
changeCount 1 }
The following is an LDAP syntax description [RFC2252] suitable for
publication in the subschema.
( IANA-ASSIGNED-OID.1 DESC 'ChangeSequenceNumber' )
3.2 UTF8String
The UTF8String syntax is used to express a string of characters from
the [ISO10646] character set (a superset of [Unicode]), encoded
following the [UTF-8] algorithm. Note that Unicode characters U+0000
through U+007F are the same as ASCII 0 through 127, respectively, and
have the same single octet UTF-8 encoding. Other Unicode characters
have a multiple octet UTF-8 encoding.
UTF8String::= OCTET STRING -- UTF-8 encoded,
-- [ISO10646] characters
The LDAP-specific encoding of a value of this syntax are the UTF-8
characters themselves.
The following is an LDAP syntax description [RFC2252] suitable for
publication in the subschema.
( IANA-ASSIGNED-OID.2 DESC 'UTF8String')
4. Matching Rules
4.1 changeSequenceNumberMatch Matching Rule
The changeSequenceNumberMatch rule compares an assertion value of the
ChangeSequenceNumber syntax to a value of a syntax (e.g the
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ChangeSequenceNumber syntax) whose corresponding ASN.1 type is
ChangeSequenceNumber.
The rule evaluates to TRUE if and only if each of the components of
the two values evaluate to true using the following rules:
- The time component uses generalizedTimeMatch.
- The timeCount and changeCount components use integerMatch.
- The replicaID component uses utf8CodePointMatch.
The following is a LDAP matching rule description [RFC2252] suitable
for publication in the subschema.
( IANA-ASSIGNED-OID.3 NAME changeSequenceNumberMatch
SYNTAX IANA-ASSIGNED-OID.1 )
4.2 utf8CodePointMatch Matching Rule
The utf8CodePointMatch rule compares an assertion value of the
UTF8String syntax to a value of a syntax (e.g the UTF8String syntax)
whose corresponding ASN.1 type is UTF8String. The rule evaluates to
TRUE if and only if the code points [Unicode] of each of the
characters is equal.
The following is a LDAP matching rule description [RFC2252] suitable
for publication in the subschema.
( IANA-ASSIGNED-OID.4 NAME utf8CodePointMatch
SYNTAX IANA-ASSIGNED-OID.2 )
4.3 changeSequenceNumberOrderingMatch Matching Rule
The changeSequenceNumberOrderingMatch rule compares the
ChangeSequenceNumber ordering of an assertion value of the
ChangeSequenceNumber syntax to a value of a syntax (e.g the
ChangeSequenceNumber syntax) whose corresponding ASN.1 type is
ChangeSequenceNumber.
The rule evaluates to TRUE if and only if each of the components of
the two values evaluate to true using the following rules:
- The time component uses GeneralizedTimeOrderingMatch.
- The timeCount and changeCount components use integerOrderingMatch.
- The replicaID component uses utf8CodePointOrderingMatch.
The following is a LDAP matching rule description [RFC2252] suitable
for publication in the subschema.
( IANA-ASSIGNED-OID.5 NAME changeSequenceNumberOrderingMatch
SYNTAX SYNTAX IANA-ASSIGNED-OID.1 )
4.4 utf8CodePointOrderingMatch Matching Rule
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The utf8CodePointOrderingMatch rule compares the ordering of an
assertion value of the UTF8String syntax to a stored value of a
syntax (e.g the UTF8String syntax) whose corresponding ASN.1 type is
UTF8String.
The rule evaluates to TRUE if, and only if, in the code point
collation order, the stored value character string appears earlier
than the assertion value character string, i.e., the stored value is
"less than" the assertion value.
The following is a LDAP matching rule description [RFC2252] suitable
for publication in the subschema.
( IANA-ASSIGNED-OID.6 NAME utf8CodePointOrderingMatch
SYNTAX IANA-ASSIGNED-OID.2 )
5. Security Considerations
6. Acknowledgements
7. Normative References
[ABNF] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997.
[ASN.1] ITU-T Recommendation X.680 (07/2002) | ISO/IEC 8824-1:2002
"Information Technology - Abstract Syntax Notation One
(ASN.1): Specification of basic notation"
[Keyword] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[Syntaxes] Legg, S., and K. Dally, "LDAP: Syntaxes and Matching
Rules", draft-ietf-ldapbis-syntaxes-xx.txt, (a work in
progress).
[Models] Zeilenga, K., "LDAP: Directory Information Models", draft-
ietf-ldapbis-models-xx.txt (a work in progress).
[ISO10646] Universal Multiple-Octet Coded Character Set (UCS) -
Architecture and Basic Multilingual Plane, ISO/IEC 10646-1
: 1993.
[Unicode] The Unicode Consortium, "The Unicode Standard, Version
3.2.0" is defined by "The Unicode Standard, Version 3.0"
(Reading, MA, Addison-Wesley, 2000. ISBN 0-201-61633-5),
as amended by the "Unicode Standard Annex #27: Unicode
3.1" (http://www.unicode.org/reports/tr27/) and by the
"Unicode Standard Annex #28: Unicode 3.2"
(http://www.unicode.org/reports/tr28/).
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[RFC2252] Wahl, M., Coulbeck, A., Howes, T. and S. Kille,
"Lightweight Directory Access Protocol (v3): Attribute
Syntax Definitions", RFC 2252, December 1997.
8. Informative References
9. IANA Considerations
10. Editor's Address
Jim Sermersheim
Novell, Inc.
1800 South Novell Place
Provo, Utah 84606, USA
jimse@novell.com
+1 801 861-3088
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