S    !"#$% &'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\_]^`abcdfghejklmnopqrstuvwxyz{|}i~Z[|   `]DLT TTTT$RP ``DLT TTRP `]DLT TTTT$RP `]DLT TTTT$RP (| T V08=mGbNX_hYRBConcepts, P\ H ^^^Models and Services, were developed in close collaboration and are H. <D^^^^^technically aligned.d P Recommendations X.501 and I"ly same as COM VII-R 38PGs COM VII-R 380 ^^^^^^^  /  Melbourne, 1988Gbourne, 1988 VII-R Oc 38H. N : IXth Plenary Assembly :)d a t same as COM VII-R 38.  ^^^^^^^  .  Melbourne, 1988E  1TITLE:FINAL REPORT TO THE PLENARY ASSEMBLY - 1B .PART II.8: DRAFT NEW RECOMMENDATIONS.E -^^^^^^^^^#   4 Note by the CCITT Secretariat ^ JThe final report of Study Group VII to the IXth Plenary Assembly JZ Fconsists of the following four parts published in separate documents:Fd a t R >Part I: General report (published in AP IX-39/COM VII-R 30)>PAd PPart II: Draft new Recommendations (published in AP IX-40/COM VII-R^31 to ^^^^^P5  ! AP IX-47/COM VII-R 38)! c OPart III: Draft revised Recommendations (published in AP IX-48/COM^VII-R^39 to O5 ! AP IX-56/COM VII-R^47 ^ JRecommendation X.519: The directory - protocol specifications 227J^ JRecommendation X.520: The directory - selected attribute types 249J ^d a t JRecommendation X.521: The directory - selected object classes 281J 1Kq _d a t KRecommendation X.521: The directory - selected object classes yY Ethe Plenary Assembly it will be prepared and issued at a later date.E  P D ,CONTENTS# < ((c K PageF P <Recommendation X.500: The Directory - overview of concepts,<^cOThe name of an object will be common among all of the applications which refer O . 7.1Introduction  cO7.1.1This clause provides an overview of the service provided to users, as Oc Orepresented by their DUAs, by the Dire The name Cbject, rather than being fabricated for the purpose. The name P to it.ll be common among all of the  N:IXth PLENARY ASSEMBLY - DOCUMENT 47:< ((K 7STUDY GROUP VII - REPORT R 387K 7=============================7< ((K 7SOURCE:STUDY GROUP VII - DATA COMMUNICATION NETWORKS7 sses 15   -Note to the translators (French and Spanish),U-Series Recommendations presented in this volume all have been Mb Nfinalized by the final meeting of Study Group VII, 21-31 March 1988, of which NUa Mthe base documents are those white Contributions as published. Please check Md Pyour translated texts (except Recommendation X.51b y cendation X.509: The directory - authentication framework 1J ^ JRecommendation X.511: The directory - abstract service definition 108JU ARecommendation X.518: The directory - procedures for distributedA^ J operation 154J,U ARecommendatioY Qe Q QeZLQ Qe Q ` Lusers of the Directory, including people and computer programs, can read or Ld Pmodify the information, or parts of it, sub Syntax Notation One (ASN.1)2 ` LRecommendation X.501: Open Systems Interconnection - The Directory - ModelsL b NRecommendation X.511: Open Systems Interconnection - The Directory - Abstract N=) Service Definition) dPRecommendation X.518: Open Systems Interconnection - The Directory - Procedures PD0Pore your revision. ThankPyou! +P Recommendation X.500  bFTHE DIRECTORY - OVERVIEW OF CONCEPTS, MODELS AND SERVICESB@!`< ((T#P Introduction  c O1)This document, together with the others of the series, has been Od 9594-2. The Directory-Models, were developedPMȧ9 in close collaboration and are technically aligned.9r eCamb+- # -'Ae d-AP IX-47-E-< ((< ((; '' Pproduced to facilitate the interconnection of information processing systems to P` Lprovide directory services. The set of all such systems, together with the La Mdirectory information which they hold, can be viewed as an integrated whole, Md Pcalled the Directory. The information held by the Directory, collectively knownP] Ias the Directory Information Base (DIB), is typically used to facilitate I_ Kcommunication between, with or about objects such as application entities, K> *people, terminals and distribution lists.*ed Z F2)The Directory plays a significant role in Open Systems FbByNInterconnection, whose aim is to allow, with a minimum of technical agreement N`RecLoutside of the interconnection standards themselves, the interconnection of L4d y information processing systems:  prAbas--from different manufacturers;- @ ,-under different managements;, J 6-of different levels of complexity; and6 6"-of different ages." a M3)This Recommendation introduces and models the concepts of the Md PDirectory and of the DIB and overviews the services and capabilities which they P] Iprovide. Other Recommendations make use of these models in defining the I`Labstract service provided by the Directory, and in specifying the protocols LN :through which this service can be obtained or propagated.:T@(1.Scope and field of application  _ K1.1The Directory provides the directory capabilities required by OSI KZ Fapplications, OSI management processes, other OSI layer entities, and Fd Ptelecommunication services. Among the capabilities which it provides are those Pd Pof "user-friendly naming" whereby objects can be referred to by names which are P^ Jsuitable for citing by human users (though not all objects need have user-Jd Pfriendly names); and "name-to-address mapping" which allows the binding between Pa Mobjects and their locations to be dynamic. The latter capability allows OSI M` Lnetworks, for example, to be "self-configuring" in the sense that addition, Lded Premoval and the changes of object location do not affect OSI network operation.P dByP1.2The Directory is not intended to be a general-purpose data base system,P base systemthough it may be built on such systems. It is assumed, for instance, that, asP_d yKis typical with communications directories, there is a considerably higher Kc prOfrequency of "queries" than of updates. The rate of updates is expected to be OdbasPgoverned by the dynamics of people and organizations, rather than, for example, P^ Jthe dynamics of networks. There is also no need for instantaneous global Jc Ocommitment of updates: transient conditions where both old and new versions of ON :the same information are available, are quite acceptable.: c O1.3It is a characteristic of the Directory that, except as a consequence OaMof differing access rights or unpropagated updates, the results of directory Md Pqueries will not be dependent on the identity or location of the enquirer. ThisP` Lcharacteristic renders the Directory unsuitable for some telecommunications LE 1applications, for example some types of routing.1 ,2.References  _TKRecommendation X.200: Open Systems Interconnection - Basic Reference ModelK    c ORecommendation X.208: Open Systems Interconnection - Specification of Abstract OF2 for Distributed Operation0 bByNRecommendation X.519: Open Systems Interconnection - The Directory - Protocol N9% Specifications%d yb prNRecommendation X.520: Open Systems Interconnection - The Directory - Selected N:& Attribute Types& b NRecommendation X.521: Open Systems Interconnection - The Directory - Selected N9 % Object Classes% d PRecommendation X.219: Remote Operations: Model, Notation and Service DefinitionPU ARecommendation X.229: Remote Operations: Protocol Specification.Apecification.+basAttribute Types ibute ( ( Recommendation X.229? +Remote Operations: Protocol Specification.+@+( Recommendation X.229'perations: Protocol Specification.?  p+odel, Notation and Service DefinitionNAS ?Recommendation X.229Remote Operations: Protocol Specification.? - 3.Definitions  dPThe definitions contained in this clause make use of the abbreviations P) defined in clause 4.TA )3.1OSI Reference Model Definitions  W CThis Recommendation is based on the concepts developed in C` LRecommendation^X.200, and makes use of the following terms therein defined:L 7 #a)application-entity;# 6 "b)Application Layer;" 8$c) application process;$ed C /d)application protocol data unit;/By@Rec,e)application service element.,d y=P pr%3.2Basic Directory Definitions bas ^ Ja)The Directory: a collection of open systems cooperating to J? +provide directory services;+ d Pb)Directory Information Base (DIB): the set of information managed P5 !by the Directory;!d Pc)(Directory) user: the end user of the Directory, i.e. the entity PK 7or person which accesses the Directory.7 = %3.3Directory Model Definitions ] IThis Recommendation makes use of the following terms defined in I*TRecommendation^X.501. O ;a) Administration Directory Management Domain;; * b)alias; . c)attribute; 3 d)attribute type;4  e)attribute value;  E 1f)Directory Information Tree (DIT);1 F 2g)Directory Management Domain (DMD);2 A -h)Directory System Agent (DSA);- ?+i)Directory User Agent (DUA);+ 7 #j)distinguished name;# * k)entry;) l)name; 9 %m)object (of interest);% >*n)Private Management Domain;* )To)root; + p)schema; 7 #q)subordinate object;# 3 r)superior entry; 4  s)superior object; ) t)tree.  C +3.4Distributed Operation Definitions ! ] IThis Recommendation makes use of the following terms defined in I* Recommendation X.519: -a)chaining; 1 b)multicasting; - c)referral./ 4.Abbreviations  H 4ADDMDAdministration Directory Management Domain47 #DAPDirectory Access Protocol#8$DIBDirectory Information Base$8 $DITDirectory Information Tree$9T%DMDDirectory Management Domain%4  DSADirectory System Agent 7 #DSPDirectory System Protocol#2 DUADirectory User Agent: &OSIOpen Systems Interconnection&A -PRDMDPrivate Directory Management Domain-? +PSAPPresentation Service Access Point+9 %RDNRelative Distinguished Name% ;#5.Overview of the Directory  d P5.1The Directory is a collection of open systems which cooperate to hold aPd Plogical data base of information about a set of objects in the real world. The Pal world. The C the Dir  logical data WCbase of information about a set of objects in the real world. The C`ject to having permission to do so. Pb NEach user is represented in accessing the Directory by a Directory User Agent Na M(DUA), which is considered to be an application-process. These concepts are M- illustrated in Figure^1.e ONote - This series of Recommendations refers to the Directory in the singular, Kd Pand reflects the intention to create, through a single, unified, name space, oneP_ Klogical directory composed of many systems and serving many applications. Kd PWhether or not these systems choose to interwork will depend on the needs of thePdPapplications they support. Applications dealing with non-intersecting worlds ofP] Iobjects, may have no such need. The single name space facilitates later I: &interworking should the needs change.&   T      @ ,FIGURE 1,< ((L 4Access to the Directory ` L5.2The information held in the Directory is collectively known as the Ld PDirectory Information Base (DIB). Clause 6 of this Recommendation overviews itsP  structure.  d P5.3The Directory provides a well-defined set of access capabilities, knownPd Pas the abstract service of the Directory, to its users. This service, which is Pd Poverviewed in clause 7 of this Recommendation provides a simple modification andPd Pretrieval capability. This can be built on with local DUA functions to provide P@,the capabilities required by the end-users.,k by the end-users.BIt is likely that the Directory will be distributed, perhaps widely Md Pdistributed, both along functional and organizational lines. Clause 8 overviewsPc Othe corresponding models of the0the capabilities require2& by the end-users. for the cooperation of the various components to provide P) an integrated whole. c O5.5The provision and consumption of the Directory services requires that O_ Kthe users (actually the DUAs) and the various functional components of the KbNDirectory should cooperate with one another. In many cases this will require Nb Ncooperation between application processes in different open systems, which in NaTMturn requires standardized application protocols, overviewed in clause^9, to M- govern this cooperation. d P5.6The Directory has been designed so as to support multiple applications,P] Idrawn from a wide range of possibilities. The nature of the application Ia Msupported will govern which objects are listed in the Directory, which users Ma Mwill access the information, and which kinds of access they will carry out. Mc OApplications may be very specific, such as the provision of distribution lists O` Lfor electronic mail, or generic, such as the "inter-personal communications L_ Kdirectory" application. The Directory provides the opportunity to exploit K: &commonalities among the applications:& a M-a single object may be relevant to more than one application; Md Pperhaps even the same piece of information about the same object P7 #may be so relevant.# a MTo support this, a number of object classes and attribute types are Md Pdefined, which will be useful across a range of applications. These definitionsPF2are contained in Recommendations X.520 and X.521.2 d P-certain patterns of use of the Directory will be common across a P] Irange of applications: this area is overviewed further in I, Annex^A.F .6.The Directory Information Base (DIB) $ ^ HNote - The DIB, and its structure, are defined in Recommendation^X.501. D aM6.1The DIB is made up of information about objects. It is composed of Mb N(directory) entries, each of which consists of a collection of information on NbTNone object. Each entry is made up of attributes, each with a type and one or Nd Pmore values. The types of attribute which are present in a particular entry arePP <dependent on the class of object which the entry describes.< \P H6.2The entries of the DIB are arranged in the form of a tree, the H` LDirectory Information Tree (DIT) where the vertices represent the entries. Lc OEntries higher in the tree (nearer the root) will often represent objects such Oa Mas countries or organizations while entries lower in the tree will represent M^will represent Gr application processes.!  Note - The services defined in this Recommendation operate only on a tree- F` Lstructured DIT. This Recommendation does not preclude the existence in the LE 1future of other structures (as the need arises).1 d P6.3Every entry has a distinguished name, which uniquely and unambiguously Pb Nidentifies the entry. These properties of the distinguished name are derived Nd Pfrom the tree structure of the information. The distinguished name of an entry P^ Jis made up of the distinguished name of its superior entry, together with JdPspecially nominated attribute values (the distinguished values) from the entry.P d P6.4Some of the entries at the leaves of the tree are alias entries, while Pb Nall other entries are object entries. Alias entries point to object entries, N_ Kand provide the basis for alternative names for the corresponding objects.Kb N6.5The Directory enforces a set of rules to ensure that the DIB remains Nc Owell-formed in the face of modifications over time. These rules, known as the Oc ODirectory schema, prevent entries having the wrong types of attributes for its Oc Oobject class, attribute values being of the wrong form for the attribute type, OT@and even entries having subordinate entries of the wrong class.@rong class.<TP6.6Figure 2 illustrates the above concepts of the DIT and its components.P        anP <even entries having subordinate entries of the wrong class. *using network information.* d PThe Directory allows users to obtain a variety of information about thePa Mnetwork, and provides for the maintenance, distribution and security of that M!  information.  B *A.3Patterns of use of the Directory  f PNote - This subclause is concerned only with Directory retrieval: it is assumed Ld Pthat the Directory modification services are used solely to maintain the DIB in PF 2the form necessary for the application over time.2 . A.3.1Introduction ] IThe Directory service is defined in these standards in terms of I\ Hparticular requests that a DUA can make and the parameters of them. An Hb Napplication designer is likely, however, to think in more goal-oriented terms Nd Pwhen considering the information retrieval requirements of the Directory in thatPdPapplication. Accordingly, this clause describes a number of high-level patternsP] Iof use of the Directory service, which are likely to be relevant to many I" applications. ) A.3.2Look-up  c OThe straight Directory look-up is likely to be the most frequent type Od Pof query of the Directory. It involves the DUA supplying the distinguished namePbNof an object, together with an attribute type. The Directory will return any Na Mvalue(s) corresponding that attribute type. This is a generalization of the Md Pclassic directory function, which is obtained when the attribute type requested Pd Pcorresponds to a particular type of address. Attribute types for various kinds Pb Nof address are standardized, including OSI PSAP address, Message Handling O/R N> *address, and telephone and telex numbers.* _ KLook-up is supported by the read service, which also provides the K7 #following further generalizations:# d P-look-up can be based upon names other than the distinguished nameP@ ,of the object, e.g. aliases;, d P-the values from a number of attribute types can be requested withPc Oa single request: the extreme case being that the values of all OO ;attributes in the entry are to be returned.; 6A.3.3User-friendly naming  d PNames can be given to objects in such a way as to maximize the chances Pd Pthat these names can be predicted (or perhaps remembered) by human users. NamesP` Lwhich have this property would typically be made up of attributes which are Lc Osomehow inherent to the object, rather than being fabricated for the purpose. OCoperty would typically be made 1t somehow cations which refer to it.M    * A.3.4Browsing  b NIn many human-oriented uses of the Directory, it may not be possible Nd Pfor the user (or DUA) to directly quote a name, user-friendly or otherwise, for Pb Nthe object about which information is sought. However, perhaps the user will NcO"know it when he sees it". The browsing capability will allow a human user to ON :wander about the DIB looking for the appropriate entries.: ] IBrowsing is accomplished by combinations of the list and search I] Iservices, possibly in conjunction with read (although the search service I6 "includes the capability of read)." 0 A.3.5"Yellow Pages"  Z FThere are a variety of ways to provide a "Yellow Pages" type F^ Jcapability. The simplest is based upon filtering, using assertions about J^ Jparticular attributes whose values are the categories (e.g. the "Business Jd PCategory" attribute type defined in Recommendation^X.520. This approach does Pb Nnot require any special information being set-up in the DIT, except to ensure NdPthat the requisite attributes are present. However, in the general case, it mayP_ Kbe expensive to search where there is a large population because filtering KZ Frequires the generation of the universal set which is to be filtered.F _ KAn alternative approach is possible, based upon the setting up of KbNspecial subtrees, whose naming structures are designed especially for "Yellow Na MPages" type searching. Shown in Figure^A1 is an example of a "Yellow Pages" Ma Msubtree populated by alias entries only. In reality, the entries within the Md P"Yellow Pages" subtrees may be a mixture of object and alias entries, so long asPes, so long as Bts only one object entry for e!  "Yellow Pages V Bsubtrees may be a mixture of object and alias entries, so long as BJ                  A -FIGURE A1-< ((O7An approach to "Yellow Pages" i ( A.3.6Groups  ` LA group is a set whose membership can change over time by explicit Lc Oaddition and removal of members. The group is an object, as are its members. M7An approach to "Yellow Pages"` L-indicate whether or not a particular object is a member of a L* group;C /-list the membership of a group./ ^ JGroups are supported by having the entry for the group contain a J] Imultiple valued "Member" attribute (such an attribute type is defined in Ic ORecommendation^X.520). The two capabilities mentioned can then be carried out O? +by means of compare and read respectively.+ d PA member of a group could itself be a group, if this is meaningful for Pb Nthe application. However, the necessary recursive verification and expansion Nc Oservices would have to be created by the DUA out of the non-recursive versions O  provided.  0 A.3.7Authentication c OMany applications require the objects taking part to offer some proof O_ Kof their identify before they are permitted to carry out some action. The K` LDirectory provides support for this authentication process. (As a separate Lc Omatter, the Directory itself requires its users to authenticate themselves, so O3 as to support access control).a MThe more straightforward approach to authentication, called "simple Md Pauthentication", is based upon the Directory holding a "User Password" attributePa Min the entry for any user that wishes to be able to authenticate itself to a Md PService. At the request of the Service, the Directory will confirm or deny thatPb Na particular value supplied is actually the user's password. This avoids the N] Iuser needing a different password for every Service. In cases where the Id Pexchange of passwords in a local environment that uses simple authentication is P_ Kconsidered to be inappropriate, the Directory optionally provides means to K -, the Directory optionally 5 considered to be inappropriat2 A -, the Directory optionally provides means to -Vled "strong authentication" is based uponP` Lpublic key cryptography, where the Directory acts as a repository of users' Lb Npublic encryption keys, suitably protected against tampering. The steps that Nc Ousers can take to obtain each other's public keys from the Directory, and then O[ Gto authenticate with each other using them, are described in detail in G* Recommendation^X.509. 6 A.4Generic applications  . A.4.1Introduction  a MThere are a number of generic applications which can be imagined as Mb Nimplicitly supported by the Directory: applications which are not specific to NdPany particular telecommunications service. Two such applications are described P] Iherein: the inter-personal communications directory and the inter-system I8 $communications directory (for OSI).$  _ INote - Authentication, described in the previous subclause as an "access EcOpattern" could alternatively be thought of as a generic Directory application.O ? 'A.4.2Inter-personal communications  a MThe intent of this application is to provide humans or their agents Ma Mwith information on how to communicate with other humans, or groups thereof.M ^ JThe following classes of objects are certainly involved: person, Jd Porganizational role and group. Many other classes are involved too, perhaps in P^ Ja less direct way, including: country, organization, organizational unit.Ja MThe attribute types concerned, other than those used in naming, are M_ Kgenerally the addressing attributes. Typically the entry for a particular K^ Jperson will have the addresses corresponding to each of the communication Jb Nmethods by which that person can be reached, selected from an open-ended list Nd Pwhich includes at least the following: telephony, electronic mail, telex, ISDN, P telex, ISDN, cal delivery (e.g. the postal system), facsimile. In some cases, such as Oa Melectronic mail, the entry will have some additional information such as the Mc Otypes of information which the user's equipment can handle. If authentication O^ Jis to be supported, then User Password and/or Credentials will be needed.J c OThe naming schemes used for the various object classes should be user-Od Pfriendly, with aliases being set up as appropriate to provide alternative names,PA -provide continuity after a name change, etc.-c OThe following access patterns will be manifested in this application: Od Plook-up, user-friendly naming, browsing, "Yellow Pages", and groups. To varyingP? +degrees, authentication will also be used.+ G /A.4.3Inter-system communications (for OSI) %_ KAccording to the OSI Reference Model, two Directory functions are KY Erequired in OSI, one, operating in the application layer, which maps Ea Mapplication-titles onto PSAP-addresses, and one, in the network layer, which Md Pmaps NSAP-addresses onto SNPA-addresses (SNPA = Subnetwork Point of Attachment).P e ONote - For the remainder of this subclause, only the application layer case is K  dealt with.  ]IThis function is carried out by consulting the Directory if the Id Pinformation required to accomplish the mapping is not conveniently available by P conveniently availaL 4information required to accomplish the mapping is no-2. conveniently available by Z 6are also application-entities, or subclasses thereof.6 d PThe main attribute type concerned, other than those used for naming, isP^ Jthe PSAP-address. Other attribute types, not viewed as necessary for the JZ Fdirectory function itself, could support verifying or finding out the F\ Happlication entity type, or the lists of application contexts, abstract Hd Psyntaxes, etc. supported. The authentication-related attribute types could alsoP!  be relevant.  W CThe main access pattern to be manifested will be look-up.C  endation X.501 ((< ((<(() S ?has the same geographical attribute in his distinguished name.?       T        @OInternational Telegraph and Telephone Document AP IX-47-E;( P gD@@ ,CONTENTS# < ((c K PageF P <Recommendation X.500: The Directory - overview of concepts,<^ J models and services 3J ^ JRecommendation X.501: The directory - models 24Jd a t ^ JRecommendation X.509: The directory - authentication framework 64J _ KRecommendation X.511: The directory - abstract service definition 1KU ARecommendatioT ks, for example, to be "self-configuring" in the sense that addition, Lded Premoval and the changes of object location do not affect OSI network operation.P 4By1.2The Directory is no2F 2intended to be a general-purpose database system, 2.WByC1.2The Directory is not intended to be a general-purpose dataC=!  base system, dRecPal rZ FThere are a va?+the capabilities rquired by the end-users.+v a M5.4It is likely that the Directory will be distributed, perhaps widely Md Pdistributed, both along functional and organizational lines. Clause 8 overviewsPc Othe corresponding models of the Directory. These have been developed in order OdPto provide a framework` A.4Generic applications  .  dTP6.6Figure 2 illustrates the above concepts of the DIT and its components.P             iid Pattributes are to be returned, the DUA suupplies the list of attribute types of P  interest.  ) 7.3.2Compare  b NA compare request is aimed at a particular attribute of a particular N` Lentry, and causes the Directory to check whether a supplied value matches a L- value of that attribute. eg Qks, for example, to be "self-configuring" in the sense that addition, Lded Premoval and the changes of object location do not affect OSI network operation.P 4By1.2The Directory is no2F 2intended to be a general-purpose database system, 2. 6 8.2Organizational model a M8.2.1A set of one or moK 5   5 7.2.2Security parameters c OEach request may be accompanied^ Jconsidered to be inappropiate, the Directory optionally provides means to J\ Hprotect those passwords against replay or misuse by a one way function.Hd PThe more complex approach, cal 7.3.4Search  d PA search request causes the Directory to return information from all ofPd Pthe entries within a certain portion of the DIT which satisfy some filter. The PcOinformation returned from each entry consists of s. which includes at leas2kL 8the following: telephony, electronic mial, telex, ISDN, 8c OphysiO 9left in a state consistent with the schema. The Mc Ochanges allowed include the addition, removal, or replacement of attributes or O& attribute values. c Oinformation required to accomplish the mapping isnot conveniently available by O!  other means.  c OThe users are application-entities and the object classes of interest OJlustrated in Figure^8.     @ ,FIGURE 8,< ((BN6H 4as countries or organizations while entries lower in4, the tree will represent e5 !people or application processes.! ` JlLqDrz{    ccitt\ap-ix\doc\47e01.txsCCITTo\c Cuevas`XDLRKpages 1-23y amanda LLO YLb NMost abnormal outcomes are common to several requests. The possibilities are Nyosed for the next study period (published P> *in AP IX-57/COM VII-R^48).* c OThe report of the final meeting of Study Group VII, 21-31 March 1988, Oc+ specific to the requestoL 8Most abnormal outcomes are common to several requests. 8- describedg@OInternational Telegraph and Telephone Document AP IX-47-E; Z F Consultative Committee April 1988F3] Iaccess point to the Directory. At the time of binding, the User and the IG3Directory optionally verify each other's identity.3 7 7.2Service qualification  2 7.2.1SYstems:  prAbas--from different manufacturers;- @ ,-under different managements;, J 6-of different levels of complexity; and6*7.4.2Remove entry d PA remove entry request causes a leaf entry to be removed from the DIT.P dgh it may be built on such systems. It is assumed, for instance, that, asP_d yKis typical with communications directories, there is a considerably higher Kc prOfrequency of "q(cOreported. Besides the above-mentioned example of problems with the parameters O\ Hsupplied by the user (particularly invalid names for entries or invalid Hb Nattribute types), errors may arise from violations of security policy, schec * k)entry;) l)name; 9 %m)object (of interest);% >*n)Private Management Domain;* )Td Poperation and configuration of private DMDs is not within the scope of envisagedP+ CCITT Recommendations.% the ROS notation.P                   t, together with information to assist the correct party to K7An approach to "Yellow Pages"7s ( A.3.6Groups  ` LA group is a set whose membership can change over time by explicit Lc Oaddition and removal of members. The group is an object, as are its members. O7 #The Directory can be requested to:# -56/COM VII-R^47)) d PPart IV:Texts of Questions proposed for the next study perioyQ.1AND(3188)dP Recommendation X.500 and ISO 9594-1, The Directory - Overview of Concepts, P\ H ^^^Models and Services, were developed in close collaboration and are H. <D^^^^^technically aligned.d P Recommendations X.501 and ISO d  PPart IV: Texts of Questions proposed for the next study period (published in APP   OM VII-R^48).L c OThe report of the final meeting of Study Group VII, 21-31 March 1988, OcOcovering aspects which have not been included in the above four parts, will be Od Pissued in another report (COM VII-R^29). Since this report is not requested forP)! d  PPart IV: Texts of Questions proposed for the next study period (published in ^^P6  " AP IX-57/COM VII-R^48)."= b  NPart IV: Texts of Questions proposed for the next study per |  AP  c OPart III: Draft revised Recommendations (published in AP IX-48/COM^VII-R^39 to O5 !!   AP