• There are no items in your cart

ISO/IEC 9594-1:2017

Withdrawn

Withdrawn

A Withdrawn Standard is one, which is removed from sale, and its unique number can no longer be used. The Standard can be withdrawn and not replaced, or it can be withdrawn and replaced by a Standard with a different number.

View Superseded by

Information technology Open Systems Interconnection The Directory Part 1: Overview of concepts, models and services

Available format(s)

Hardcopy , PDF , PDF 3 Users , PDF 5 Users , PDF 9 Users

Withdrawn date

03-12-2020

Superseded by

ISO/IEC 9594-1:2020

Language(s)

English

Published date

05-05-2017

€60.00
Excluding VAT

ISO/IEC 9594-1:2017 provides the directory capabilities required by OSI applications, OSI management processes, other OSI layer entities, and telecommunications services. Among the capabilities which it provides are those of "user-friendly naming", whereby objects can be referred to by names which are suitable for citing by human users (though not all objects need have user-friendly names); and "name-to-address mapping" which allows the binding between objects and their locations to be dynamic. The latter capability allows OSI networks, for example, to be "self-configuring" in the sense that addition, removal and the changes of object location do not affect OSI network operation.

ISO/IEC 9594-1:2017 is not intended to be a general-purpose database system, although it may be built on such systems. It is assumed, for instance, that, as is typical with communications directories, there is a considerably higher frequency of "queries" than of updates. The rate of updates is expected to be governed by the dynamics of people and organizations, rather than, for example, the dynamics of networks. There is also no need for instantaneous global commitment of updates; transient conditions, where both old and new versions of the same information are available, are quite acceptable.

It is a characteristic of the Directory that, except as a consequence of differing access rights or un-propagated updates, the results of directory queries will not be dependent on the identity or location of the inquirer. This characteristic renders the Directory unsuitable for some telecommunications applications, for example some types of routing. For cases where the results are dependent on the identity of the inquirer, access to directory information and updates of the Directory may be denied.

DocumentType
Standard
Pages
23
PublisherName
International Organization for Standardization
Status
Withdrawn
SupersededBy
Supersedes

Standards Relationship
NEN ISO/IEC 9594-1 : 2017 Identical
BS ISO/IEC 9594-1:2017 Identical
CSA ISO/IEC 9594-1 : 0 Similar to
NF ISO/IEC 9594-1 : 1996 Identical
CSA Z243.177.1 : 0 Similar to

ISO/IEC ISP 10615-6:1998 Information technology — International Standardized Profiles ADInn — OSI Directory — Part 6: ADI32 — DSA Support for Distributed Operations
BS ISO/IEC 14608/2 : 1997 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - DIRECTORY SYSTEM PROTOCOL - PROTOCOL IMPLEMENTATION CONFORMANCE STATEMENT (PICS) PROFORMA
BS ISO/IEC 14392:1996 Information technology. Directory services. Application program interface (API) (language independent)
CSA ISO/IEC ISP 10616 : 0 INFORMATION TECHNOLOGY-INTERNATIONAL STANDARDIZED PROFILE FDI11 - DIRECTORY DATA DEFINITIONS - COMMON DIRECTORY USE (NORMAL)
INCITS/ISO/IEC 9594-4 : 2013 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: PROCEDURES FOR DISTRIBUTED OPERATION
ISO/IEC ISP 10615-5:1998 Information technology — International Standardized Profiles ADInn — OSI Directory — Part 5: ADI31— DUA Support for Distributed Operations
IEEE DRAFT 1387.4 : D9 FEB 98 INFORMATION TECHNOLOGY - POSIX SYSTEMS ADMINISTRATION - PRINTING ADMINISTRATION
08/30194076 DC : DRAFT DEC 2008 BS ISO 21091 - HEALTH INFORMATICS - DIRECTORY SERVICES FOR SECURITY, COMMUNICATIONS AND IDENTIFICATION OF PROFESSIONALS AND PATIENTS
ISO/IEC 15944-10:2013 Information technology — Business operational view — Part 10: IT-enabled coded domains as semantic components in business transactions
BS ISO/IEC 13235-3:1998 Information technology. Open distributed processing. Trading function Provision of trading function using OSI Directory service
INCITS/ISO/IEC 9594-2 : 2013 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: MODELS
CSA Z243.177.7 : 0 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - SELECTED OBJECT CLASSES
CAN/CSA-ISO/IEC 10021-4-04 (R2014) Information Technology - Message Handling Systems (MHS): Message Transfer System - Abstract Service Definition and Procedures (Adopted ISO/IEC 10021-4:2003, third edition, 2003-12-15)
ISO/IEC 9834-1:2012 Information technology — Procedures for the operation of object identifier registration authorities — Part 1: General procedures and top arcs of the international object identifier tree
CSA ISO/IEC 10021-2 : 2004 : R2009 INFORMATION TECHNOLOGY - MESSAGE HANDLING SYSTEMS (MHS): OVERALL ARCHITECTURE
CSA ISO/IEC 15816 : 2004 : R2012 INFORMATION TECHNOLOGY - SECURITY TECHNIQUES - SECURITY INFORMATION OBJECTS FOR ACCESS CONTROL
INCITS/ISO/IEC 15816 : 2002 : R2007 INFORMATION TECHNOLOGY - SECURITY TECHNIQUES - SECURITY INFORMATION OBJECTS FOR ACCESS CONTROL
INCITS/ISO/IEC 14364 : 1996 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION (OSI) ABSTRACT DATA MANIPULATION C LANGUAGE INTERFACES - BINDING FOR APPLICATION PROGRAM INTERFACE (API)
ISO/IEC 14393:1996 Information technology — Test methods for measuring conformance to directory services — Application Program Interface (API) (Language independent)
CAN/CSA-ISO/IEC 15816-04 (R2017) Information Technology - Security Techniques - Security Information Objects for Access Control (Adopted ISO/IEC 15816:2002, first edition, 2002-02-01)
INCITS/ISO/IEC 9594-5 : 2013 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: PROTOCOL SPECIFICATIONS
ISO/IEC 9594-5:2017 Information technology Open Systems Interconnection The Directory Part 5: Protocol specifications
ISO/TS 21091:2005 Health informatics Directory services for security, communications and identification of professionals and patients
CSA Z243.177.4 : 0 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - PROCEDURES FOR DISTRIBUTED OPERATION
ISO/IEC 9594-4:2017 Information technology Open Systems Interconnection The Directory Part 4: Procedures for distributed operation
ISO/IEC 9594-9:2017 Information technology Open Systems Interconnection The Directory Part 9: Replication
BS ISO 15782-1:2009 Certificate management for financial services Public key certificates
I.S. EN ISO 21091:2013 HEALTH INFORMATICS - DIRECTORY SERVICES FOR HEALTHCARE PROVIDERS, SUBJECTS OF CARE AND OTHER ENTITIES (ISO 21091:2013)
BS EN ISO 21091:2013 Health informatics. Directory services for healthcare providers, subjects of care and other entities
CSA ISO/IEC ISP 10615-5 : 2001(R2005) INFORMATION TECHNOLOGY - INTERNATIONAL STANDARDIZED PROFILES ADINN - OSI DIRECTORY - PART 5: ADI31 - DUA SUPPORT FOR DISTRIBUTED OPERATIONS
BS ISO/IEC 13248-2:1998 Information technology. Open systems interconnection. The directory Protocol implementation conformance statement (PICS) proforma for the directory system protocol
ISO/IEC TR 10021-11:1999 Information technology Message Handling Systems (MHS): MHS Routing Guide for messaging systems managers Part 11:
INCITS/ISO/IEC 14362 : 1996 INFORMATION TECHNOLOGY - TEST METHODS FOR MEASURING CONFORMANCE TO OPEN SYSTEMS INTERCONNECTION (OSI) ABSTRACT DATA MANIPULATION - APPLICATION PROGRAM INTERFACE (API) [LANGUAGE INDEPENDENT]
BS ISO/IEC 9594-9:2017 Information technology. Open Systems Interconnection. The Directory Replication
INCITS/ISO/IEC 13235-3 : 1998 : R2007 INFORMATION TECHNOLOGY - OPEN DISTRIBUTED PROCESSING - TRADING FUNCTION - PART 3: PROVISION OF TRADING FUNCTION USING OSI DIRECTORY SERVICE
BS ISO/IEC ISP 10615-3:1996 Information technology. International standardized profiles ADInn. OSI directory ADI21. DSA performer role
BS ISO/IEC 9594-3:2017 Information technology. Open Systems Interconnection. The Directory Abstract service definition
BS ISO/IEC 9594-4:2017 Information technology. Open Systems Interconnection. The Directory Procedures for distributed operation
BS ISO/IEC 14393:1996 Information technology. Test methods for measuring conformance to directory services. Application program interface (API) (language independent)
IEEE DRAFT 1073.1.3.5 : D0.04 DRAFT STANDARD FOR MEDICAL DEVICE COMMUNICATIONS - MEDICAL DEVICE DATA LANGUAGE (MDDL) VIRTUAL MEDICAL DEVICE, SPECIALIZED - DEFIBRILLATOR DEVICE
BS ISO/IEC 10021-9:1995 Information technology. Message handling systems (MHS) Electronic Data Interchange messaging system
BS ISO/IEC ISP 15125-7:1998 Information technology. International Standardized Profiles ADYnn. OSI Directory ADY43. DSA to DSA authentication
BS ISO/IEC 9594-7:2017 Information technology. Open Systems Interconnection. The Directory Selected object classes
CSA ISO/IEC 15816 :2004 INFORMATION TECHNOLOGY - SECURITY TECHNIQUES - SECURITY INFORMATION OBJECTS FOR ACCESS CONTROL
INCITS/ISO/IEC 10021-9 : 2009 INFORMATION TECHNOLOGY - MESSAGE HANDLING SYSTEMS (MHS): ELECTRONIC DATA INTERCHANGE MESSAGING SYSTEM
CSA ISO/IEC 10021-4:2004 INFORMATION TECHNOLOGY - MESSAGE HANDLING SYSTEMS (MHS): MESSAGE TRANSFER SYSTEM - ABSTRACT SERVICE DEFINITION AND PROCEDURES
CSA ISO/IEC 14366 : 0 INFORMATION TECHNOLOGY - TEST METHODS FOR MEASURING CONFORMANCE TO OPEN SYSTEMS INTERCONNECTION (OSI) ABSTRACT DATA MANIPULATION C LANGUAGE INTERFACES - BINDING FOR APPLICATION PROGRAM INTERFACE (API)
IEC TR 60870-6-1:1995 Telecontrol equipment and systems - Part 6: Telecontrol protocols compatible with ISO standards and ITU-T recommendations - Section 1: Application context and organization of standards
INCITS/ISO/IEC 9594-3 : 2013 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: ABSTRACT SERVICE DEFINITION
ISO/IEC ISP 10616:1995 Information technology — International Standardized Profile FDI11 — Directory data definitions — Common Directory Use (Normal)
ISO/IEC ISP 11189:1997 Information technology — International Standardized Profile FDI2 — Directory Data Definitions — MHS Use of the Directory
CSA ISO/IEC 14362 : 0 INFORMATION TECHNOLOGY - TEST METHODS FOR MEASURING CONFORMANCE TO OPEN SYSTEMS INTERCONNECTION (OSI) ABSTRACT DATA MANIPULATION - APPLICATION PROGRAM INTERFACE (API) [LANGUAGE INDEPENDENT]
ISO/IEC 9594-10:2008 Information technology Open Systems Interconnection The Directory: Use of systems management for administration of the Directory Part 10:
CSA ISO/IEC ISP 10615-6 : 2001(R2005) INFORMATION TECHNOLOGY - INTERNATIONAL STANDARDIZED PROFILES ADINN - OSI DIRECTORY - PART 6: ADI32 - DSA SUPPORT FOR DISTRIBUTED OPERATIONS
BS ISO/IEC 9594-5:2017 Information technology. Open Systems Interconnection. The Directory Protocol specifications
ISO/IEC 9834-7:2008 Information technology — Open Systems Interconnection — Procedures for the operation of OSI Registration Authorities — Part 7: Joint ISO and ITU-T Registration of International Organizations
INCITS/ISO/IEC 2382-26 : 1993 INFORMATION TECHNOLOGY - VOCABULARY - PART 26: OPEN SYSTEMS INTERCONNECTION
BS ISO/IEC 10021-4:1997 Information technology. Message handling systems (MHS) Message transfer system. Abstract service definition and procedures
BS ISO/IEC 9594-8:2017 Information technology. Open Systems Interconnection. The Directory Public-key and attribute certificate frameworks
IEEE DRAFT 1073.2 : SEP 95 MEDICAL DEVICES COMMUNICATIONS, APPLICATION PROFILES (MDAP) - FRAMEWORK AND OVERVIEW
17/30355482 DC : 0 BS EN 62451-12 ED.1.0 - UNIFIED ARCHITECTURE SPECIFICATION - PART 12: DISCOVERY
CSA Z243.177.3 : 0 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - PART 3: ABSTRACT SERVICE DEFINITION
CSA ISO/IEC 10021-2 : 2004 INFORMATION TECHNOLOGY - MESSAGE HANDLING SYSTEMS (MHS): OVERALL ARCHITECTURE
ISO 15764:2004 Road vehicles Extended data link security
INCITS/ISO/IEC 9594-7 : 2013 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: SELECTED OBJECT CLASSES
ISO/IEC 20248:2018 Information technology Automatic identification and data capture techniques Data structures Digital signature meta structure
ISO/IEC ISP 10615-4:1996 Information technology — International Standardized Profiles ADInn — OSI Directory — Part 4: ADI22 — DSA Invoker Role
ISO/IEC 9834-8:2014 Information technology — Procedures for the operation of object identifier registration authorities — Part 8: Generation of universally unique identifiers (UUIDs) and their use in object identifiers
ISO/IEC TR 14252:1996 Information technology — Guide to the POSIX Open System Environment (OSE)
ISO/IEC 10166-1:1991 Information technology — Text and office systems — Document Filing and Retrieval (DFR) — Part 1: Abstract service definition and procedures
ISO 15782-1:2009 Certificate management for financial services Part 1: Public key certificates
ISO/IEC 10021-9:1999 Information technology Message Handling Systems (MHS): Electronic Data Interchange Messaging System Part 9:
ISO/IEC 9594-6:2017 Information technology Open Systems Interconnection The Directory Part 6: Selected attribute types
ISO/IEC 14608-2:1997 Information technology — Open Systems Interconnection — The Directory: Directory System Protocol — Protocol Implementation Conformance Statement (PICS) proforma
EN ISO 21091:2013 Health informatics - Directory services for healthcare providers, subjects of care and other entities (ISO 21091:2013)
IEEE DRAFT 1003.0 : D18 FEB 95 GUIDE TO THE POSIX OPEN SYSTEM ENVIRONMENT
INCITS/ISO/IEC 9594-9 : 2013 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: REPLICATION
INCITS/ISO/IEC 14360 : 1996 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION (OSI) ABSTRACT DATA MANIPULATION - APPLICATION PROGRAM INTERFACE (API) [LANGUAGE INDEPENDENT]
BS ISO/IEC 15944-10:2013 Information technology. Business Operational View IT-enabled coded domains as semantic components in business transactions
BS ISO/IEC 2382-26:1993 Information technology. Vocabulary Open systems interconnection
CSA Z21091 : 2007 HEALTH INFORMATICS - DIRECTORY SERVICES FOR SECURITY, COMMUNICATIONS AND IDENTIFICATION OF PROFESSIONALS AND PATIENTS
CSA Z243.177.5 : 0 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - PROTOCOL SPECIFICATIONS
BS ISO/IEC 9594-6:2017 Information technology. Open Systems Interconnection. The Directory Selected attribute types
BS ISO/IEC 14608/1 : 1997 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - DIRECTORY ACCESS PROTOCOL - PROTOCOL IMPLEMENTATION CONFORMANCE STATEMENT (PICS) PROFORMA
ISO/IEC ISP 10615-3:1996 Information technology — International Standardized Profiles ADInn — OSI Directory — Part 3: ADI21 - DSA Performer Role
ISO/IEC 2382-26:1993 Information technology Vocabulary Part 26: Open systems interconnection
CSA Z243.177.2 : 0 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - PART 2: MODELS
04/30111391 DC : DRAFT MAR 2004 ISO/IEC 9834-7 - INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - PROCEDURES FOR OPERATION OF OSI REGISTRATION AUTHORITIES - PART 7: JOINT ISO AND ITU-T REGISTRATION OF INTERNATIONAL ORGANIZATIONS
BS ISO/IEC 9594/2 : 2014 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY - MODELS
CAN/CSA-ISO/IEC 10021-2-04 (R2014) Information Technology - Message Handling Systems (MHS): Overall Architecture (Adopted ISO/IEC 10021-2:2003, third edition, 2003-12-15)
INCITS/ISO/IEC 15816 : 2002 INFORMATION TECHNOLOGY - SECURITY TECHNIQUES - SECURITY INFORMATION OBJECTS FOR ACCESS CONTROL
ISO/IEC 10021-4:2003 Information technology Message Handling Systems (MHS): Message transfer system Abstract service definition and procedures Part 4:
ISO/IEC 10021-2:2003 Information technology Message Handling Systems (MHS): Overall architecture Part 2:
ISO/IEC 9594-2:2017 Information technology Open Systems Interconnection The Directory Part 2: Models
ISO 21091:2013 Health informatics — Directory services for healthcare providers, subjects of care and other entities
ISO/IEC 9594-7:2017 Information technology Open Systems Interconnection The Directory Part 7: Selected object classes
01/208196 DC : 0 PRENV ISO 17575 - ROAD TRANSPORT AND TRAFFIC TELEMATICS (RTTT) - ELECTRONIC FEE COLLECTION (EFC) - APPLICATION INTERFACE DEFINITION FOR GLOBAL NAVIGATION SATELLITE SYSTEMS AND CELLULAR NETWORKS (GNSS/CN)
UNI EN ISO 21091 : 2013 HEALTH INFORMATICS - DIRECTORY SERVICES FOR HEALTHCARE PROVIDERS, SUBJECTS OF CARE AND OTHER ENTITIES
INCITS/ISO/IEC 2382-26 : 1993 : R2006 INFORMATION TECHNOLOGY - VOCABULARY - PART 26: OPEN SYSTEMS INTERCONNECTION
BS ISO/IEC ISP 10616:1995 Information technology. International standardized profile FDI11. Directory data definitions. Common directory use (Normal)
ANSI INCITS TR 11 : 1992 INFORMATION PROCESSING SYSTEMS TECHNICAL REPORT - INFORMATION RESOURCE DICTIONARY SYSTEM (IRDS) SUPPORT FOR NAMING CONVENTION VERIFICATION (NCV)
ISO/IEC 9594-8:2017 Information technology Open Systems Interconnection The Directory Part 8: Public-key and attribute certificate frameworks
BS ISO/IEC ISP 10615-4:1996 Information technology. International standardized profiles ADInn. OSI directory ADI22. DSA invoker role
TS 119 122-1 : 1.0.1 ELECTRONIC SIGNATURES AND INFRASTRUCTURES (ESI); CADES DIGITAL SIGNATURES; PART 1: BUILDING BLOCKS AND CADES BASELINE SIGNATURES
BS ISO/IEC ISP 12073:2000 Information technology. International standardized profile FD16 directory data definitions. EDI use of the directory
ISO/IEC 9594-3:2017 Information technology Open Systems Interconnection The Directory Part 3: Abstract service definition
INCITS/ISO/IEC 13235-3 : 1998 INFORMATION TECHNOLOGY - OPEN DISTRIBUTED PROCESSING - TRADING FUNCTION - PART 3: PROVISION OF TRADING FUNCTION USING OSI DIRECTORY SERVICE
INCITS/ISO/IEC 9594-8 : 2013 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: PUBLIC-KEY AND ATTRIBUTE CERTIFICATE FRAMEWORKS
MIL-STD-2204 Base Document:1992 SURVIVABLE ADAPTABLE FIBER OPTIC EMBEDDED NETWORK (SAFENET)
BS ISO/IEC ISP 11189:1997 Information technology. International standardized profile FD12. Directory data definitions. MHS use of the directory
INCITS/ISO/IEC 14366 : 1996 INFORMATION TECHNOLOGY - TEST METHODS FOR MEASURING CONFORMANCE TO OPEN SYSTEMS INTERCONNECTION (OSI) ABSTRACT DATA MANIPULATION C LANGUAGE INTERFACES - BINDING FOR APPLICATION PROGRAM INTERFACE (API)
BS ISO/IEC 10021/1 : 1990 INFORMATION TECHNOLOGY. TEXT COMMUNICATION. MESSAGE-ORIENTED TEXT INTERCHANGE SYSTEMS (MOTIS) - SYSTEM AND SYSTEM OVERVIEW
ISO/IEC 14392:1996 Information technology — Directory services — Application Program Interface (API) (Language independent)
CSA ISO/IEC 14608-1 : 2001 INFORMATION TECHNOLOGY - OPEN SYSTEMS INTERCONNECTION - THE DIRECTORY: DIRECTORY ACCESS PROTOCOL - PROTOCOL IMPLEMENTATION CONFORMANCE STATEMENT (PICS) PROFORMA
ISO/IEC ISP 15125-7:1998 Information technology International Standardized Profiles ADYnn OSI Directory Part 7: ADY43 DSA to DSA Authentication
ISO/IEC ISP 12073:2000 Information technology International Standardized Profile FDI6 Directory use by EDI
BS ISO/IEC 9594-2:2017 Information technology. Open Systems Interconnection. The Directory Models
ISO/IEC 14608-1:1997 Information technology Open Systems Interconnection The Directory: Directory Access Protocol Protocol Implementation Conformance Statement (PICS) proforma Part 1:
BS ISO/IEC TR 14252:1996 Information technology. Guide to the POSIX open system environment (OSE)

ISO/IEC 7498-1:1994 Information technology Open Systems Interconnection Basic Reference Model: The Basic Model
ISO/IEC 9594-4:2017 Information technology Open Systems Interconnection The Directory Part 4: Procedures for distributed operation
ISO/IEC 9594-8:2017 Information technology Open Systems Interconnection The Directory Part 8: Public-key and attribute certificate frameworks
ISO/IEC 9594-3:2017 Information technology Open Systems Interconnection The Directory Part 3: Abstract service definition
ISO/IEC 9594-6:2017 Information technology Open Systems Interconnection The Directory Part 6: Selected attribute types
ISO/IEC 9594-7:2017 Information technology Open Systems Interconnection The Directory Part 7: Selected object classes
ISO/IEC 9594-9:2017 Information technology Open Systems Interconnection The Directory Part 9: Replication
ISO/IEC 9594-2:2017 Information technology Open Systems Interconnection The Directory Part 2: Models
ISO/IEC 9594-5:2017 Information technology Open Systems Interconnection The Directory Part 5: Protocol specifications

Access your standards online with a subscription

Features

  • Simple online access to standards, technical information and regulations.

  • Critical updates of standards and customisable alerts and notifications.

  • Multi-user online standards collection: secure, flexible and cost effective.