1、BRITISH STANDARD BS 7521:1992 Specification for Electronic messaging enabling the application of BS ISO/IEC10021 in the UnitedKingdomBS7521:1992 This British Standard, having been prepared under the directionof the Information Systems Technology StandardsPolicy Committee, waspublishedunder the autho
2、rityofthe Standards Boardand comes into effecton 31January1992 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference IST/18 Draft for comment 90/64614 DC ISBN 0 580 20278 X Committees responsible for this British Standard The preparation of this British St
3、andard was entrusted by the Information Systems Technology Standards Policy Committee (IST/-) to Technical Committee IST/18, upon which the following bodies were represented: British Computer Society British Facsimile Industry Consultative Committee British Photographic Association British Printing
4、Industries Federation British Telecommunications plc Computing Services Association Department of Trade and Industry (Information Technology Division) EEA (the Association of Electronics, Telecommunications and Business Equipment Industries) HM Treasury (Central Computer and Telecommunications Agenc
5、y) Her Majestys Stationery Office Institute of Information Scientists Joint Network Team Ministry of Defence National Computer Users Forum National Computing Centre Ltd. National Health Services SGML Users Group University of London User Standards Forum for Information Technology (Institute of Data
6、Processing Management) Amendments issued since publication Amd. No. Date CommentsBS7521:1992 BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii Section 1. General 0 Introduction 1 1 Scope 1 2 Definitions and abbreviations 2 Section 2. Naming and Addressing 3 The Countr
7、y Name 4 4 The Administration Domain Name 4 5 The Private Domain Name 5 6 The Organization Name 6 7 The Organizational Unit Name 6 8 Teletex String equivalence rules 6 Section 3. UK Management Domains 9 UK Private Management Domains (UK PRMDs) 7 10 UK Administration Management Domains (UK ADMDs) 7 1
8、1 Message handling 8 12 Value added services 9 13 Responsibility for messages 9 Section 4. Conformance 14 Conformance requirements 10 Appendix A Explanation of terms 11 Appendix B The reasoning behind the national decisions 12 Appendix C Guidelines for use of conditional O/R address attributes 19 Fi
9、gure 1 Hierarchy of Naming/Registration Authorities 20 Table 1 Cross-reference to BS ISO/IEC 10021-2 1 Table 2 Cross-reference to BS ISO/IEC 10021-4 1 Publication(s) referred to Inside back coverBS7521:1992 ii BSI 12-1999 Foreword This British Standard has been produced under the direction of the In
10、formation Systems Technology Standards Policy Committee (IST/-). The multi-part International Standard ISO/IEC10021, which has been implemented in the United Kingdom as BS ISO/IEC10021:1990, leaves certain aspects of a Message Handling service open for decision by individual countries as a national
11、matter. This British Standard incorporates the decisions that have been made relating to the application of BS ISO/IEC10021 in the UnitedKingdom. ISO/IEC10021 was produced as a joint text document with the1988 CCITTX.400 series of Recommendations, and the decisions apply equally to the CCITT version
12、, except where indicated in notes to the normative text. Three appendices are included to provide background information. Appendix A explains the terms that are referenced in clause2 as defined in other standards. Appendix B discusses the reasoning behind the national decisions. Appendix C describes
13、 some aspects of O/R address attributes and the relationships between the Registration Authorities that support the United Kingdom Message Handling Services. BS 7521 will not have any explicit regulatory role unless specified by the Office of Telecommunications (Oftel), under pertinent Licence condi
14、tions. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document com
15、prises a front cover, an inside front cover, pagesi andii, pages1 to24, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS7521:1992 BSI 12-1999
16、 1 Section 1. General 0 Introduction BS ISO/IEC10021 defines a common architecture and set of protocols for an international messaging service. However, this service will be subject to differing regulatory regimes in each of the countries in which it operates, and the InternationalStandard has had t
17、o provide the means by which it can be adapted to suit local conditions. The result is a series of options on each of which the country has to make a national decision. The relationship between the clauses and subclauses in the International Standard that explicitly require a national decision, and
18、the decisions recorded in this standard is shown in Table 1 andTable 2. Table 1 Cross-reference to BS ISO/IEC10021-2 Table 2 Cross-reference to BS ISO/IEC10021-4 In the UK, the Department of Trade and Industry (DTI) is the telecommunications Administration and thus the CCITT Administration for Messa
19、ge Handling Systems (MHS). As the responsible authority, the DTI has granted Public Telecommunications Operators (PTO) Licences to certain organizations, and has also granted the Branch Systems General Licence (BSGL), and the now obsolescent Value Added Data Services (VADS) Licences to classes of pe
20、rsons defined in those Licences. The PTO Licences and the PTO Associates Licence determine how public telecommunications operators and their associates may offer services, including message handling services. All other providers of message handling services operate under either the BSGL or the VADS
21、licence. This British Standard has therefore been produced in order to record a coherent set of national decisions within the regulatory framework imposed by the PTO Licence, the BSGL, and the VADS Licence. To provide compatibility with the style used in BSISO/IEC10021-4 the names and values of the
22、parameters of the MTS Abstract Service and the MTA Abstract Service are printed in bold. Section 2 of this British Standard specifies the rules for the assignment of originator/recipient (O/R) addresses that include a country-name identifying the United Kingdom. In association with BS7453-1, these r
23、ules ensure uniqueness of O/R addresses between Management Domains (MDs) by providing a registration scheme for Administration Management Domain (ADMD) and Private Management Domain (PRMD) names; to simplify matters, registration is performed using a single Name Space for MHS Management Domain names
24、. Section 3 specifies the roles and responsibilities of UK ADMDs and PRMDs. It should be noted that under UK legislation, any provider of message handling services may operate as an ADMD and, because of this, the definition of an ADMD in the United Kingdom contained within this standard differs from
25、 that given in the InternationalStandard (seeA.1). 1 Scope 1.1 This British Standard specifies the UnitedKingdom requirements for those matters that BS ISO/IEC 10021 leaves open for national decision, namely: a) whether UK Private Management Domain (PRMD) names are to be nationally unique, or unique
26、 only within the scope of an Administration Management Domain (see5.1); b) whether UK Organization names are to be nationally unique, or unique only within the scope of a Management Domain (see6.1); c) whether UK ADMDs are to be required to form a National Message Transfer Backbone, i.e.should they
27、be interconnected (see10.1); d) whether the users of PRMDs registered with more than one UK ADMD will have to have multiple alias O/R addresses, each relative to one of those ADMDs, or whether ADMDs will be required to recognize the reserved value of the single space (“ ”) to identify the union of a
28、ll UK ADMDs see4.2.3 b); e) whether equivalence rules are to be imposed regarding those O/R address Standard Attributes represented as Teletex Strings and their Printable String equivalents (see clause8); f) whether the Private Domain Identifier is identical with the Private Domain name (see5.2.3).
29、BS ISO/IEC10021-2:1990 clause BS 7521 clause 15 10.1 18.3.1 4.1.2 18.3.21 5.1 18.3.9 6.1 18.4, note 2 8 BS ISO/IEC 10021-4:1990 clause BS 7521 clause 8.5.2 5.2.3BS7521:1992 2 BSI 12-1999 It thereby enables the application of BS ISO/IEC10021 in the United Kingdom. NOTE 1In some cases, the need for a
30、national decision is explicitly identified by BS ISO/IEC10021, while in others, e.g.the use of the country-name standard attribute, the need is implicit. NOTE 2The background to the national decisions is described in Appendix B. 1.2 This British Standard also specifies the procedures to be followed
31、by BS ISO/IEC10021 Management Domains subordinate to the UK Name Registration Authority (see BS7453-1). NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions and abbreviations 2.1 Definitions 2.1.1 The following terms are used in this Brit
32、ishStandard and are defined in BS ISO7498-3: name; naming authority. 2.1.2 The following terms are used in this BritishStandard and are defined in BS ISO/IEC10021-2: administration-domain-name; administration management domain; attribute; country-name; conditional; delivery; distribution list; manag
33、ement domain; message; message handling; message handling system; message transfer agent; network-address; non-delivery; non-delivery report; O/R address; optional; organization-name; organizational-unit-names; originator; P1; private-domain-name; private management domain; probe; receipt; recipient
34、; report; routing; transfer; user; user agent. 2.1.3 The following terms are used in this BritishStandard and are defined in BS ISO/IEC10021-4: criticality; global-domain-identifier. 2.1.4 The following terms are used in this BritishStandard and are defined in BS ISO/IEC9834-1: registration; registr
35、ation authority; registration procedures. 2.1.5 The following term is used in this BritishStandard and is defined in BS ISO/IEC8824: object identifier. 2.1.6 For the purposes of this British Standard, the following additional definitions apply. 2.1.6.1 UK Administration management domain a Managemen
36、t Domain that has registered its MHS Management Domain name with the UK Name Registration Authority (see BS7453-1), and which has performed the procedures specified in10.3 to become part of the UK National Message Transfer Backbone 2.1.6.2 UK Private management domain a Management Domain that has re
37、gistered its MHS Management Domain name with the UK Name Registration Authority (see BS7453-1) 2.1.6.3 interconnection agreement a contract between two Management Domains that enables them to exchange messages, probes and reports 2.1.6.4 message transfer backbone a number of Management Domains that
38、together provide the facility that any Management Domain that has an interconnection agreement with at least one member of the message transfer backbone, can transfer messages, probes or reports to any other Management Domain that has an interconnection agreement with at least one member of that mes
39、sage transfer backboneBS7521:1992 BSI 12-1999 3 2.1.6.5 UK national message transfer backbone the message transfer backbone formed by UKADMDs 2.1.6.6 international message transfer backbone the message transfer backbone formed by all ADMDs NOTESee also clause 15 of BS ISO/IEC10021-2:1990. 2.1.6.7 re
40、achable the property of an MD that messages may be transferred to it either directly or indirectly 2.1.6.8 UK organization an organization owning UAs and/or DLs located in a UK PRMD and/or a UK ADMD 2.1.6.9 intermediate MD a) A Management Domain that handles a message or probe when neither the origi
41、nator, nor the recipient is located in that Management Domain. b) A Management Domain that handles a report when neither the point at which the report was generated, nor the destination of the report, is located in that Management Domain. 2.1.6.10 originating MD for a message or probe, the MD in whi
42、ch the originator of that message or probe is located; for a report, the MD in which the report was generated 2.1.6.11 delivering MD for a recipient of a message or probe, the MD in which that recipient is located; for a report, the MD in which the originator of the corresponding message or probe is
43、 located 2.1.6.12 MHS management domain name a name registered by the UK Name Registration Authority (see BS7453-1) for use as either an administration-domain-name or a private-domain-name 2.1.6.13 organizational-unit-name an identifier that identifies an organizational unit relative to a superior o
44、rganizational unit, or the organization as a whole. It is a component of the organizational-unit-names standard attribute 2.2 Abbreviations The following abbreviations are used in this BritishStandard. ADMD Administration Management Domain DL Distribution List MD Management Domain MHS Message Handli
45、ng System MS Message Store MTA Message Transfer Agent MTS Message Transfer System O/R Originator/Recipient PRMD Private Management Domain UA User AgentBS7521:1992 4 BSI 12-1999 Section 2. Naming and addressing 3 The Country Name 3.1 National implementation Implementations shall be capable of recogni
46、zing any of the following values of the country-name standard attribute as a country-name identifying the United Kingdom. a) Alphabetic form: the combination of the two BS4730 (identical with ISO646) characters4/7 (or6/7) and4/2 (or6/2) encoded as an ASN.1 PRINTABLE STRING (see BS ISO/IEC8824), i.e.
47、“GB” in any combination of upper or lower case as specified by BS5374 (identical with ISO3166). b) Numeric form: the following combinations of three BS4730 characters encoded as an ASN.1 NUMERIC STRING (see BS ISO/IEC8824). 1) 3/2,3/3 and3/4 (i.e.CCITT Recommendation X.121 DCC value “234”). 2) 3/2,
48、3/3 and 3/5 (i.e.CCITT Recommendation X.121 DCC value “235”). 3) 3/2, 3/3 and 3/6 (i.e.CCITT Recommendation X.121 DCC value “236”). 4) 3/2, 3/3 and 3/7 (i.e.CCITT Recommendation X.121 DCC value “237”). NOTE 1The alphabetic form is recommended. NOTE 2The values of the Data Country Codes (DCC) shown a
49、re those currently allocated to the United Kingdom. This places no limitation on the use of further DCCs that may be allocated to the United Kingdom in the future. 3.2 Use 3.2.1 Restrictions on use A country-name that identifies the UnitedKingdom shall be used only in names assigned to objects subordinate to the UK Name Registration Authority, whose registration procedures are described in BS7453-1. When such a name contains an administration-domain-name and/or a private-domain-name these shall be registered as MHS Management Domain names by the UK Name Registrat
