1、BRITISH STANDARD BS ISO/IEC 15773:1998 Information technology Telecommunications and information exchange between systems Broadband Private Integrated Services Network Inter-exchange signalling protocol Transit counter additional network feature ICS 33.040.40; 35.110BSISO/IEC 15773:1998 This British
2、 Standard, having been prepared under the directionof the DISC Board, was published under the authority of the Standards Board and comes into effect on 15 October1998 BSI04-1999 ISBN 0 580 30312 8 National foreword This British Standard reproduces verbatim ISO/IEC15773:1998 and implements it as the
3、UK national standard. The UK participation in its preparation was entrusted to Technical Committee IST/6, Data communications, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or pr
4、oposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement int
5、ernational or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to in
6、clude 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 comprises a front cover, an inside front cover, pag
7、es i and ii, theISO/IEC title page, pagesii toiv, pages1 to7 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. Amendments issued since publication Amd. No. Date Comm
8、entsBSISO/IEC15773:1998 BSI 04-1999 i Contents Page National foreword Inside front cover Foreword iii Text of ISO/IEC15773 1ii blankBSISO/IEC 15773:1998 ii BSI 04-1999 Contents Page Foreword iii Introduction 1 1 Scope 1 2 Conformance 1 3 Normative references 1 4 Definitions 2 4.1 External definition
9、s 2 5 List of acronyms 2 6 Signalling protocol for the support of ANF-TC 2 6.1 ANF-TC description 2 6.2 ANF-TC operational requirements 3 6.2.1 Requirements on the Originating PINX 3 6.2.2 Requirements on the Terminating PINX 3 6.2.3 Requirements on a Transit PINX 3 6.3 ANF-TC coding requirements 3
10、6.3.1 Transit counter information element 3 6.3.2 Messages 4 6.4 ANF-TC signalling procedures 4 6.4.1 Actions at the Originating PINX 4 6.4.2 Actions at the Terminating PINX 4 6.4.3 Actions at a Transit PINX 4 6.4.4 Actions at an Incoming Gateway PINX 4 6.4.5 Actions at an Outgoing Gateway PINX 4 An
11、nex A (normative) Protocol Implementation Conformance Statement (PICS)proforma 5 Annex B (informative) Guidelines for interworking with ATM Forum PNNI1.0 7 Figure 1 Transit counter information element 3 Table 1 Transit counter information element 4 Descriptors: Data processing, information interchan
12、ge, telecommunications, telecommunication network, network interconnection, ISDN, private network, data transmission, signal processing, protocols.BSISO/IEC15773:1998 BSI 04-1999 iii Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commiss
13、ion) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO a
14、nd IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/I
15、EC JTC1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least75% of the national bodies casting a vote. International Standard ISO/IEC15773 was prepared by ECMA (as
16、ECMA-252) and was adopted, under a special “fast-track procedure”, by Joint Technical Committee ISO/IEC JTC1, Information technology, in parallel with its approval by national bodies of ISO and IEC. Annex A forms an integral part of this International Standard. Annex B is for information only.iv bla
17、nkBSISO/IEC15773:1998 BSI 04-1999 1 Introduction This International Standard is one of a series of standards defining services and signalling protocols applicable to Broadband Private Integrated Services Networks. The series uses the B-ISDN concepts as developed by ITU-T and is also within the frame
18、work of standards for open systems interconnection as defined by ISO. This International Standard specifies the signalling protocol for use at the Q reference point in support of the Transit Counter additional network feature. This International Standard is based upon the practical experience of ECM
19、A member companies and the results of their active and continuous participation in the work of ISO/IEC JTC1, ITU-T, ETSI and other international and national standardization bodies. It represents a pragmatic and widely based consensus. 1 Scope This International Standard specifies the signalling pro
20、tocol for the support of the Transit Counter additional network feature (ANF-TC) at the Q reference point between Private Integrated Services Network Exchanges (PINXs) connected together within a Broadband Private Integrated Services Network(B-PISN). ANF-TC is a feature that limits the number of Tra
21、nsit PINXs that a call/connection setup request may be routed through e.g.,to protect the network against indefinite looping. The Q reference point is defined in ISO/IEC11579-1. Service specifications are produced in three stages and according to the method specified in CCITT Rec.I.130. This Interna
22、tional Standard contains the stage3 specification for the Q reference point and satisfies the requirements identified by the stage1 and stage2 specifications in ISO/IEC15055. The signalling protocol for ANF-TC operates in association with the signalling protocols for basic call/connection Control (a
23、s specified in ISO/IEC13247) and call independent (connection oriented) signalling connections (as specified in ECMA-254). This International Standard is applicable to PINXs that can interconnect to form a PISN. 2 Conformance In order to conform to this International Standard, a PINX shall satisfy t
24、he requirements identified in the Protocol Implementation Conformance Statement (PICS) proforma in Annex A. 3 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the e
25、ditions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of curren
26、tly valid International Standards. ISO/IEC 11579-1:1994, Information technology Telecommunications and information exchange between systems Private Integrated Services Network Part1: Reference configuration for PISN Exchanges (PINX). ISO/IEC 13247:1997, Information technology Telecommunications and
27、information exchange between systems Broadband Private Integrated Services Network Inter-exchange signalling protocol Basic call/connection control. ISO/IEC 15055:1997, Information technology Telecommunications and information exchange between systems Private Integrated Services Network Specificatio
28、n, functional model and information flows Transit counter additional network feature. ECMA-254:1996, Broadband Private Integrated Services Network (B-PISN) Inter-Exchange Signalling Protocol Generic Functional Protocol. CCITT Rec. I.112:1988, Vocabulary of terms for ISDNs. CCITT Rec. I.130:1988, Met
29、hod for the characterization of telecommunication services supported by an ISDN and network capabilities of an ISDN. BSISO/IEC15773:1998 2 BSI 04-1999 CCITT Rec. I.210:1988, Principles of telecommunication services supported by an ISDN and the means to describe them. 4 Definitions For the purposes o
30、f this International Standard, the following definitions apply. 4.1 External definitions This International Standard uses the following terms defined in other documents: 5 List of acronyms 6 Signalling protocol for the support of ANF-TC 6.1 ANF-TC description ANF-TC is invoked when it is desired to
31、limit the number of Transit PINXs that a call/connection setup request may be routed through. This additional network feature is applicable to the broadband connection oriented bearer service. ANF-TC may be used in conjunction with either a Basic call setup request or a setup request for a call inde
32、pendent (connection oriented) signalling connection. Basic Service (CCITT Rec.I.210) Call, Basic Call (ECMA-254) Call Independent Signalling Connection (ECMA-254) Incoming Gateway PINX (ISO/IEC13247) Incoming Side (ISO/IEC13247) Inter-PTNX Link (ISO/IEC13247) Originating PINX (ISO/IEC13247) Outgoing
33、 Gateway PINX (ISO/IEC13247) Outgoing Side (ISO/IEC13247) Preceding PINX (ISO/IEC13247) Private Integrated Services Network (PISN) (ISO/IEC11579-1) Private Integrated Services Network Exchange (PINX) (ISO/IEC11579-1) Signalling (CCITT Rec. I.112) Subsequent PINX (ISO/IEC13247) Supplementary Service
34、(CCITT Rec. I.210) Terminating PINX (ISO/IEC13247) Transit PINX (ISO/IEC13247) ANF Additional Network Feature ANF-TC Transit Counter Additional Network Feature B-ISDN Broadband Integrated Services Digital Network B-PISN Broadband Private Integrated Services Network PICS Protocol Implementation Confo
35、rmance Statement PINX Private Integrated Services Network Exchange PISN Private Integrated Services NetworkBSISO/IEC15773:1998 BSI 04-1999 3 Use of ANF-TC is a network option. The criteria for determining: when ANF-TC should be invoked; the number of PINXs through which a call may be routed; and, th
36、e means by which the feature is activated or deactivated are network dependent and outside the scope of this International Standard. 6.2 ANF-TC operational requirements 6.2.1 Requirements on the Originating PINX Call/connection establishment procedures for the outgoing side of an inter-PINX link and
37、 call/connection release procedures, as specified in ISO/IEC13247, shall apply. If the PINX supports connection-oriented APDU transport, then the generic procedures for the call independent control (connection oriented) of supplementary services, as specified in ECMA-254 for an Originating PINX, sha
38、ll apply. 6.2.2 Requirements on the Terminating PINX Call/connection establishment procedures for the incoming side of an inter-PINX link and call/connection release procedures, as specified in ISO/IEC13247, shall apply. If the PINX supports connection-oriented APDU transport, then the generic proce
39、dures for the call independent control (connection oriented) of supplementary services, as specified in ECMA-254 for a Terminating PINX, shall apply. 6.2.3 Requirements on a Transit PINX Basic call procedures for call/connection establishment and call/connection clearing at a Transit PINX, as specif
40、ied in ISO/IEC13247, shall apply. If the PINX supports connection-oriented APDU transport, then the generic procedures for the call independent control (connection oriented) of supplementary services, as specified in ECMA-254 for a Transit PINX, shall apply. 6.3 ANF-TC coding requirements 6.3.1 Tran
41、sit counter information element ANF-TC shall be encoded as a discrete information element (called Transit counter) within codeset4 (ISOcodeset), according to the rules for the general format and coding of variable length information elements defined in8.5.1 of ISO/IEC13247. The Transit counter infor
42、mation element shall be a variable length category1 (see12.1.9.2 of ISO/IEC13247) information element with the format shown in Figure 1 and coded as shown in Table 1. 8 7 6 5 4 3 2 1 Octet Transit counter 0 0 1 1 0 0 0 1 1 Information element identifier 1 Coding IE compatibility instr. indicator 2 e
43、xt standard Flag Pass along IE Action Ind. Length of transit counter contents 3 4 1 0 0 Transit count 5 ext Reserved (binary value) Figure 1 Transit counter information elementBSISO/IEC15773:1998 4 BSI 04-1999 Table 1 Transit counter information element 6.3.2 Messages If used, the Transit counter in
44、formation element shall be conveyed in a SETUP message. One of the shift information elements (see8.5.3 and8.5.4 of ISO/IEC13247) shall precede the Transit counter information element in the SETUP message. 6.4 ANF-TC signalling procedures The signalling protocol for Transit counter functionality ope
45、rates in association with the signalling protocols for basic call/connection control (as specified in ISO/IEC13247) and call independent (connection oriented) signalling connections (as specified in ECMA-254). NOTE 1The actions specified in the following subclauses are applicable to both cases. Wher
46、e a reference is made to procedures specified in ISO/IEC13247 and ECMA-254, the interpretation of such reference should be made according to whether the call concerned is a basic call or a call independent signalling connection. 6.4.1 Actions at the Originating PINX An Originating PINX may include a
47、 Transit counter information element in the SETUP message sent across an inter-PINX link. The value of the transit count field shall be set to zero. 6.4.2 Actions at the Terminating PINX A Terminating PINX shall ignore the Transit counter information element if it is contained in any received SETUP
48、message. 6.4.3 Actions at a Transit PINX 6.4.3.1 Normal procedures On receipt of a SETUP message from the Preceding PINX, the call/connection request shall be processed according to the procedures specified in ISO/IEC13247 and ECMA-254. If the received SETUP message contains a Transit counter inform
49、ation element in which the transit count field has a value that is less than the acceptable (network dependent) limit, that information element shall be included in the SETUP message sent to the Subsequent PINX. The value of the transit count field in the outgoing Transit counter information element shall be set to one greater than the value received. If the received SETUP message does not contain a Transit counter information element, the Transit PINX may include a Transit counter information elemen
