INTERNET-DRAFT Kurt D. Zeilenga Intended Category: Experimental OpenLDAP Foundation Expires in six months 16 June 2002 LDAPv3 Transactions Status of Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. This document is intended to be, after appropriate review and revision, submitted to the RFC Editor as an Experimental document. Distribution of this memo is unlimited. Technical discussion of this document will take place on the IETF LDAP Extension Working Group mailing list . Please send editorial comments directly to the author . Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as ``work in progress.'' The list of current Internet-Drafts can be accessed at . The list of Internet-Draft Shadow Directories can be accessed at . Copyright 2002, The Internet Society. All Rights Reserved. Please see the Copyright section near the end of this document for more information. Abstract Lightweight Directory Access Protocol (LDAP) update operations have atomic properties upon individual entries. However, it is often desirable to update two or more entries as one atomic action, a transaction. Transactions are necessary to support a number of applications including resource provisioning and information replication. This document defines an LDAP extension to support Zeilenga LDAP Transactions [Page 1] INTERNET-DRAFT draft-zeilenga-ldap-txn-04 16 June 2002 transactions. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119]. Protocol elements are described using ASN.1 [X.680]. The term "BER-encoded" means the element is to be encoded using the Basic Encoding Rules [X.690] under the restrictions detailed in Section 5.1 of [RFC2251]. 1. Overview This document extends LDAP [LDAPTS] to allow clients to group a number of related update operations and have them preformed as one atomic action, a transaction. The mechanism uses the grouping mechanism provided by [GROUP] to relate operations of the transaction. The createGrouping operation is used to obtain a group cookie which is used to identify operations which are apart of the transaction. The group cookie can be viewed as a transaction identifier. The endGrouping operation is used to settle (commit or abort) the transaction. This specification will likely be significantly enhanced before it progressed. In particular, clarification of transaction semantics and better error handling will likely be added. A ''prepare'' capability may also be added. Editor's Note: The object identifiers appearing in this draft are fictious. The top-level OID 1.1 is be replaced before this draft is published as an RFC. 2. Specification of a Transaction Servers implementing this specification SHOULD publish the transactionGroupingType as a value of the supportedGroupingTypes attribute contained within the Root DSE. transactionGroupingType ::= 1.1.1 ;; fictious A client wishing to preform a transaction MUST issue a createGroupingRequest with a createGroupType of transactionGroupingType and no createGroupValue. A server which is Zeilenga LDAP Transactions [Page 2] INTERNET-DRAFT draft-zeilenga-ldap-txn-04 16 June 2002 willing and able to support transactions SHALL return a createGroupingResponse with a success result code, a createGroupCookie, and no createGroupValue. Otherwise the server SHALL return a non-success result code, no createGroupCookie, and no createGroupValue. The client MAY then attach a GroupingControl to subsequent update operations (modify or moddn) to indicate that they are to be processed as part of the transaction per [GROUP], Section 3.5. If the server is willing and able to attempt to process operation as part of the transaction, the server SHALL return success. If the server is unwilling or unable to attempt to process the operation as part of the transaction, the server SHALL return a non-successful result code. If the server becomes unwilling or unable to continue the specification of a transaction, the server SHOULD issue a endGroupNotice. Any future use of cookie by the client SHALL result in a response containing a non-success result code. Upon receipt of a endGroupingNotice, the client SHOULD discontinue all use of the grouping cookie. The client SHOULD NOT issue an endGroupingRequest for the grouping cookie as the transaction is null and void. A client requests settling of transaction by issuing an endGroupingRequest where the groupingCookie is the group cookie identify the transaction. The absence of any endGroupingValue indicates a commit request. The presence of an empty endGroupValue indicates an abort request. The endGroupValue MUST be empty if provided. The endGroupingResponse of success indicates the settle action was successfully. No endGroupingValue is provided with the endGroupingResponse. 3. Transaction Semantics Upon request to commit the transaction, the server perform the operations as one atomic action. Operations belonging to the transaction are applied in the request order. If any operation fails, the contents of target objects is left unchanged and a non-success result code is returned indicating the nature of the failure. There is no requirement that a server serialize transactions. That is, a server MAY process multiple transactions commit requests (from one or more clients) acting upon different sets of entries concurrently. A server MUST ensure concurrent processing of Zeilenga LDAP Transactions [Page 3] INTERNET-DRAFT draft-zeilenga-ldap-txn-04 16 June 2002 transactions provides the atomic properties described above. A server MUST avoid deadlock. 4. Distributed Directory Considerations The LDAP/X.500 models provide for distributed directory operations including server-side chaining and client-side chasing of operations. This document does not disallow servers from chaining operations which are part of a transaction. However, if a server does allow such chaining, it MUST ensure that transaction semantics detailed above are provided. This mechanism defined by this document does not support client-side chasing. Grouping cookies used to identify the transaction are specific to a particular client/server session. The LDAP/X.500 models provide for a single-master/multiple-slave replication architecture. This document states no requirement that changes made to the directory based upon processing a transaction be replicated as one atomic action. That is, the client SHOULD NOT assume tight data consistency nor fast data convergence at slave servers unless they have a priori knowledge that such is provided. Though this mechanism could be used to support replication, such use is not described in this document. The LDAP/X.500 models do not currently support a multi-master replication architecture and, hence, not considered by this specification. 5. Security Considerations Transactions mechanisms and related grouping operations may be the target of denial of service attacks. Implementors should provide safeguards to ensure these mechanisms are not abused. 6. IANA Considerations No IANA assignments are required. The OID was assigned [ASSIGN] by OpenLDAP Foundation under its IANA assigned private enterprise allocation [PRIVATE] for use in this specification. Zeilenga LDAP Transactions [Page 4] INTERNET-DRAFT draft-zeilenga-ldap-txn-04 16 June 2002 7. Acknowledgments The author gratefully acknowledges the contributions made by members of the Internet Engineering Task Force. 8. Author's Address The author may be contacted as follows: Kurt D. Zeilenga OpenLDAP Foundation 9. Normative References [RFC2119] S. Bradner, "Key Words for use in RFCs to Indicate Requirement Levels", BCP 14 (also RFC 2119), March 1997. [RFC2251] M. Wahl, S. Kille, T. Howes, "Lightweight Directory Access Protocol (v3)", RFC 2251, December 1997. [LDAPIANA] K. Zeilenga, "IANA Considerations for LDAP", draft-ietf-ldapbis-iana-xx.txt, a work in progress. [LDAPTS] J. Hodges, R. Morgan, "Lightweight Directory Access Protocol (v3): Technical Specification", draft-ietf-ldapbis-ldapv3-ts-00.txt. [GROUP] K. Zeilenga, "LDAPv3: Grouping of Related Operations", draft-zeilenga-ldap-grouping-xx.txt, a work in progress. [X.680] ITU-T, "Abstract Syntax Notation One (ASN.1) - Specification of Basic Notation", X.680, 1994. [X.690] ITU-T, "Specification of ASN.1 encoding rules: Basic, Canonical, and Distinguished Encoding Rules", X.690, 1994. 10. Informative References [X.500] ITU-T, "The Directory: Overview of Concepts, Models, and Services", X.500, 1993. [X.501] ITU-T, "The Directory: Models", X.501, 1993. [ASSIGN] OpenLDAP Foundation, "OpenLDAP OID Delegations", http://www.openldap.org/foundation/oid-delegate.txt. Zeilenga LDAP Transactions [Page 5] INTERNET-DRAFT draft-zeilenga-ldap-txn-04 16 June 2002 [PRIVATE] IANA, "Private Enterprise Numbers", http://www.iana.org/assignments/enterprise-numbers. Copyright 2002, The Internet Society. All Rights Reserved. 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