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508 lines
18 KiB
Plaintext
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INTERNET-DRAFT Kurt D. Zeilenga
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Intended Category: Standard Track OpenLDAP Foundation
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Expires in six months 5 March 2006
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LDAP Transactions
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<draft-zeilenga-ldap-txn-07.txt>
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Status of Memo
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This document is intended to be, after appropriate review and
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revision, submitted to the IESG for consideration as a Proposed
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Standard. Distribution of this memo is unlimited. Technical
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discussion of this document will take place on the IETF LDAP
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Extensions mailing list <ldapext@ietf.org>. Please send editorial
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comments directly to the author <Kurt@OpenLDAP.org>.
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By submitting this Internet-Draft, each author represents that any
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applicable patent or other IPR claims of which he or she is aware have
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been or will be disclosed, and any of which he or she becomes aware
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will be disclosed, in accordance with Section 6 of BCP 79.
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Internet-Drafts are working documents of the Internet Engineering Task
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Force (IETF), its areas, and its working groups. Note that other
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groups may also distribute working documents as Internet-Drafts.
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Internet-Drafts are draft documents valid for a maximum of six months
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and may be updated, replaced, or obsoleted by other documents at any
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time. It is inappropriate to use Internet-Drafts as reference material
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or to cite them other than as "work in progress."
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The list of current Internet-Drafts can be accessed at
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http://www.ietf.org/1id-abstracts.html
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The list of Internet-Draft Shadow Directories can be accessed at
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http://www.ietf.org/shadow.html
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Copyright (C) The Internet Society (2006). All Rights Reserved.
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Please see the Full Copyright section near the end of this document
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for more information.
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Abstract
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Lightweight Directory Access Protocol (LDAP) update operations, such
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Zeilenga LDAP Transactions [Page 1]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
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as Add, Delete, and Modify operations, have atomic, consistency,
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isolation, durability (ACID) properties. Each of these update
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operations act upon an entry. However, It is often desirable to
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update two or more entries in a single unit of interaction, a
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transaction. Transactions are necessary to support a number of
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applications including resource provisioning and information
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replication. This document defines an LDAP extension to support
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transactions.
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1. Overview
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This document extends the Lightweight Directory Access Protocol (LDAP)
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[Roadmap] to allow clients to group a number of related update
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operations [Protocol] and have them preformed as one unit of
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interaction, a transaction. As with distinct update operations, each
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transaction has atomic, consistency, isolation, and durability
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([ACID]) properties.
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This extension consists of two extended operations, one control, and
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one unsolicited notification message. The Start Transaction operation
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is used to obtain a transaction identifier. This identifier is then
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attached to multiple update operations to indicate that they belong to
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transaction using the Transaction Specification control. The End
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Transaction is used to settle (commit or abort) the transaction. The
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Aborted Tranaction Notice is used notify the client the server is no
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longer willing or able to process an outstanding transaction.
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1.1. Conventions and Terminology
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
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document are to be interpreted as described in BCP 14 [RFC2119].
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Protocol elements are described using ASN.1 [X.680] with implicit
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tags. The term "BER-encoded" means the element is to be encoded using
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the Basic Encoding Rules [X.690] under the restrictions detailed in
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Section 5.2 of [Protocol].
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DSA stands for "Directory System Agent" (a server). DSE stands for
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"DSA-specific entry".
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2. Elements of an LDAP Transaction
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2.1. Start Transaction Request and Response
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Zeilenga LDAP Transactions [Page 2]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
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A Start Transaction Request is an LDAPMessage of CHOICE extendedReq
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where the requestName is IANA-ASSIGNED-OID.1 and the requestValue is
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absent.
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A Start Transaction Response is an LDAPMessage of CHOICE extendedRes
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sent in response to a Start Transaction Request. Its responesName is
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absent. When the resultCode is success, responseValue is present and
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contains a transaction identifier. Otherwise, the responseValue is
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absent.
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2.2. Transaction Specification Control
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A Transaction Specification Control is an LDAPControl where the
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controlType is IANA-ASSIGNED-OID.2, the criticality is TRUE, and the
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controlValue is a transaction identifer. The control is appropriate
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for update requests including Add, Delete, Modify, and ModifyDN
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requests [Protocol].
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2.3. End Transactions Request and Response
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An End Transaction Request is an LDAPMessage of CHOICE extendedReq
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where the requestName is IANA-ASSIGNED-OID.3 and the requestValue is
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present and contains a BER-encoded settlementValue.
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settlementValue ::= SEQUENCE {
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commit BOOLEAN DEFAULT TRUE,
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identifier OCTET STRING }
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A commit value of TRUE indicates a request to commit the transaction
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identified by the identifier. A commit value of FALSE indicates a
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request to abort the identified transaction.
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An End Transaction Response is an LDAPMessage sent in response to a
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End Transaction Request. Its response name is absent. The
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responseValue when present contains a BER-encoded MessageID.
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2.5. Aborted Transaction Notice
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The Aborted Transaction Notice is an Unsolicited Notification message
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where the responseName is IANA-ASSIGNED-OID.4 and responseValue is
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present and contains a transaction identifier.
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3. An LDAP Transaction
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3.1. Extension Discovery
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Zeilenga LDAP Transactions [Page 3]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
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To allow clients to discover support for this extension, servers
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implementing this specification SHOULD publish IANA-ASSIGNED-OID.1 and
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IANA-ASSIGNED-OID.3 as values of the 'supportedExtension' attribute
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[Models] within the Root DSE, and publish the IANA-ASSIGNED-OID.2 as a
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value of the 'supportedControl' attribute [Models] of the Root DSE.
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A server MAY choose to advertise this extension only when the client
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is authorized to use it.
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3.2. Starting an Transactions
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A client wishing to preform a sequence of directory updates as an
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transaction issues a Start Transaction Request. A server which is
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willing and able to support transactions responds to this request with
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a Start Transaction Response providing a transaction identifier and
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with a resultCode of success. Otherwise, the server responds with a
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Start Transaction Response wth a result code other than success
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indicating the nature of the failure.
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The transaction identifier provided upon successful start of a
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transaction is used in subseqent protocol messages to identify this
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transaction.
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3.3. Specification of a Transaction
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The client then may issue may issue one or more update (add, delete,
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modify, modifyDN) requests, each with a Transaction Specification
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control containing the transaction identifier indicating the updates
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are to processed as part of the transaction. Each of these update
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request MUST have a different MessageId value. If the server is
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unwilling or unable to attempt to process the requested update
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operation as part of the transaction, the server immediately returns
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the approrpiate response to the request with a resultCode indicating
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the nature of the failure. Otherwise, the server immediately returns
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success and the defers further processing of the operation is then
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deferred until settlement.
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If the server becomes unwilling or unable to continue the
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specification of a transaction, the server issues an Aborted
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Transaction Notice with a non-success resultCode indicating the nature
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of the failure. All operations that were to be processed as part of
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the transaction are implicitly abandoned. Upon receipt of an Aborted
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Transaction Notice, the client is to discontinue all use of the
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transaction identifier as the transaction is null and void. Any
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future use of identifier by the client will result in a response
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containing a non-success resultCode.
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Zeilenga LDAP Transactions [Page 4]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
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3.4. Transaction Settlement
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A client requests settlement of transaction by issuing an End
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Transaction request for the transaction indicating whether it desires
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the transaction to be committed or aborted.
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Upon receipt of a request to abort the transaction, the server is to
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abort the identified transaction (abandoning all operations which are
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part of the transaction) and indicate that it has done so by returning
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an End Transaction response with a resultCode of success.
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Upon receipt of a request to commit the transaction, the server
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processes all update operations of the transaction as one atomic,
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isolated action with each requested update being processed in turn.
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Either all of the requested updates are to be successfully applied or
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none of the requested are to be applied. The server returns an End
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Transaction Response with a resultCode of success and no responseValue
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to indicate all the requested updates were applied. Otherwise, the
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server returns an End Transaction with an non-success resultCode
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indicating the nature of the failure. If the failure is associated
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with a particular update request, a responseValue containing its
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MessageID is returned. If the failure was not associated with any
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particular update request, no responseValue is returned.
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There is no requirement that a server serialize transactions, or
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updates requested outside of a transaction. That is, a server MAY
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process multiple commit requests (from one or more clients) acting
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upon different sets of entries concurrently. A server MUST avoid
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deadlock.
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4. Distributed Directory Considerations
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The LDAP/X.500 models provide for distributed directory operations
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including server-side chaining and client-side chasing of operations.
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This document does not preclude servers from chaining operations which
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are part of a transaction. However, if a server does allow such
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chaining, it MUST ensure that transaction semantics are provided.
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This mechanism defined by this document does not support client-side
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chasing. Grouping cookies used to identify the transaction are
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specific to a particular client/server session.
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The LDAP/X.500 models provide for a single-master/multiple-shadow
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replication architecture. This document states no requirement that
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changes made to the directory based upon processing a transaction be
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replicated as one atomic action. That is, the client SHOULD NOT
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Zeilenga LDAP Transactions [Page 5]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
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assume tight data consistency nor fast data convergence at shadow
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servers unless they have prior knowledge that such service is
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provided. Though this mechanism could be used to support replication,
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use in replication is not described in this document.
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The LDAP/X.500 models do not currently support a multi-master
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replication architecture and, hence, not considered by this
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specification.
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5. Security Considerations
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Transactions mechanisms may be the target of denial of service
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attacks. Implementors should provide safeguards to ensure these
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mechanisms are not abused.
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General security considerations [Roadmap], especially associated with
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update operations [Protocol], apply to this extension.
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6. IANA Considerations
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In accordance with [BCP64bis], it is requested that Internet Assigned
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Numbers Authority (IANA) make the following assignments.
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6.1. Object Identifier
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Assignment of an LDAP Object Identifier to identify the protocol
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elements specified in this document this document is requested.
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Subject: Request for LDAP Object Identifier Registration
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Person & email address to contact for further information:
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Kurt Zeilenga <kurt@OpenLDAP.org>
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Specification: RFC XXXX
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Author/Change Controller: IESG
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Comments: Identifies protocol elements for LDAP Transactions
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6.2. LDAP Protocol Mechanism
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Registration of the protocol mechanisms specified in this document is
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requested.
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Subject: Request for LDAP Protocol Mechanism Registration
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Object Identifier: see table
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Description: see table
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Person & email address to contact for further information:
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Zeilenga LDAP Transactions [Page 6]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
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Kurt Zeilenga <kurt@openldap.org>
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Specification: RFC XXXX
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Author/Change Controller: IESG
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Comments:
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Object Identifier Type Description
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------------------- ---- -----------------------------------------
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IANA-ASSIGNED-OID.1 E Start Transaction Extended Request
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IANA-ASSIGNED-OID.2 C Transaction Specification Control
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IANA-ASSIGNED-OID.3 E End Transaction Extended Request
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7. Acknowledgments
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The author gratefully acknowledges the contributions made by members
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of the Internet Engineering Task Force.
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8. Author's Address
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Kurt D. Zeilenga
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OpenLDAP Foundation
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Email: Kurt@OpenLDAP.org
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9. References
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[[Note to the RFC Editor: please replace the citation tags used in
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referencing Internet-Drafts with tags of the form RFCnnnn where
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possible.]]
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9.1. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
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Requirement Levels", BCP 14 (also RFC 2119), March 1997.
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[Roadmap] Zeilenga, K. (editor), "LDAP: Technical Specification
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Road Map", draft-ietf-ldapbis-roadmap-xx.txt, a work in
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progress.
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[Protocol] Sermersheim, J. (editor), "LDAP: The Protocol",
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draft-ietf-ldapbis-protocol-xx.txt, a work in progress.
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[Models] Zeilenga, K. (editor), "LDAP: Directory Information
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Models", draft-ietf-ldapbis-models-xx.txt, a work in
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progress.
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Zeilenga LDAP Transactions [Page 7]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
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[X.680] International Telecommunication Union -
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Telecommunication Standardization Sector, "Abstract
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Syntax Notation One (ASN.1) - Specification of Basic
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Notation", X.680(2002) (also ISO/IEC 8824-1:2002).
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[X.690] International Telecommunication Union -
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Telecommunication Standardization Sector, "Specification
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of ASN.1 encoding rules: Basic Encoding Rules (BER),
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Canonical Encoding Rules (CER), and Distinguished
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Encoding Rules (DER)", X.690(2002) (also ISO/IEC
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8825-1:2002).
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9.2. Informative References
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[ACID] Section 4 of ISO/IEC 10026-1:1992.
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[BCP64bis] Zeilenga, K., "IANA Considerations for LDAP",
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draft-ietf-ldapbis-bcp64-xx.txt, a work in progress.
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[X.500] International Telecommunication Union -
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Telecommunication Standardization Sector, "The Directory
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-- Overview of concepts, models and services,"
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X.500(1993) (also ISO/IEC 9594-1:1994).
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[X.501] International Telecommunication Union -
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Telecommunication Standardization Sector, "The Directory
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-- Models," X.501(1993) (also ISO/IEC 9594-2:1994).
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Intellectual Property Rights
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The IETF takes no position regarding the validity or scope of any
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Intellectual Property Rights or other rights that might be claimed to
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pertain to the implementation or use of the technology described in
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this document or the extent to which any license under such rights
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might or might not be available; nor does it represent that it has
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made any independent effort to identify any such rights. Information
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on the procedures with respect to rights in RFC documents can be found
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in BCP 78 and BCP 79.
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Copies of IPR disclosures made to the IETF Secretariat and any
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assurances of licenses to be made available, or the result of an
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attempt made to obtain a general license or permission for the use of
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such proprietary rights by implementers or users of this specification
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can be obtained from the IETF on-line IPR repository at
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http://www.ietf.org/ipr.
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Zeilenga LDAP Transactions [Page 8]
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INTERNET-DRAFT draft-zeilenga-ldap-txn-07 5 March 2006
|
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|
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|
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The IETF invites any interested party to bring to its attention any
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copyrights, patents or patent applications, or other proprietary
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rights that may cover technology that may be required to implement
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this standard. Please address the information to the IETF at
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ietf-ipr@ietf.org.
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Full Copyright
|
||
|
||
Copyright (C) The Internet Society (2006).
|
||
|
||
This document is subject to the rights, licenses and restrictions
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contained in BCP 78, and except as set forth therein, the authors
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retain all their rights.
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|
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This document and the information contained herein are provided on an
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||
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
|
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OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
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||
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
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INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
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WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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Zeilenga LDAP Transactions [Page 9]
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