ISO IEC 11570-1992 Information technology telecommunications and information exchange between systems Open System Interconnection transport protocol identificat.pdf

1、INTERNATIONAL STANDARD ISO/IEC 11570 First edition 1992-12-15 Information technology - Telecommunications and information exchange between Systems - Open Systems Interconnection - Transport protocol identification mechanism Technologies de I in for-ma tion - T6l6communications et echange d in forma

2、tion en tre sys temes - Interconnexion de systemes ouverts - Mkanisme didentification du protocole de transport Reference number - - v- ISO/IEC 11570:1992(E) ISOAEC 11570 : 1992 (E) Contents Page Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ill Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5、 . . 1 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Symbols and abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7、. . . . 1 Use of the network Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Protocol functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Structure and encoding of the UN TPDU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Conformance . . . . . . . . . . . . . . . .

9、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Annex A PICS Proforma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 0 ISO/IEC 1992 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permissio

11、n in writing from the publisher. lSO/IEC Copyright Office l Case postale 56 l CH-1211 Geneve 20 . Switzerland Printed in Switzerland ii 0 ISOAEC ISOAEC 11570 : 1992 (E) Foreword ISO (the International Organization for Standardization) and IEC (the Inter- national Electrotechnical Commission) form th

12、e 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 and IEC techn

13、ical com- mittees collaborate in fields of mutual interest. Other international organ- izations, 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, lSO/lEC JTC 1

14、. Draft International Standards adopted by the joint technical committee are circulated to national bodies for vot- ing. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. International Standard ISO/IEC 11570 was prepared by Joint Techn

15、ical Committee ISO/IEC JTC 1, Information technology. Annex A forms an integral part of this International Standard. ISOAEC 11570 : 1992 (E) Introduction This International Standard is one of a set of International Standards produced to facilitate the interconnection of information processing System

16、s. This set of International Standards covers the Services and protocols required to achieve such interconnection. The identification mechanism of transport protocols is positioned with respect to other related International Standards by the layer defined in the reference model for open System inter

17、connection (ISO 7498). lt allows identification of protocols (both OSI and non-OSI) used on a given network connection. The initiating transport entity of a network connection may indicate to the accepting transport entity, what transport protocol is to be used on the network connection. 0 ISOAEC IN

18、TERNATIONAL STANDARD o SCMX ISOhEC 11570 : 1992 (E) Information technology - Telecommunications and information exchange between Systems - Systems Interconnection Open identification mechanism - Transport protocol 1 Scope The procedures specified in this International Standard do not prevent communi

19、cation between transport entities conforming to ISO/IEC 8073 only and those conforming to ISO/IEC 8073 as weil as to this International Standard. The use of a protocol identification procedure allows transport entities to be implemented which tan support both the OSI transport protocols and non-OS1

20、protocols above the OSI network layer. NOTE - The use of NSAP addresses as it is defined in ISO/IEC 7498-3 provides another possibility in distinguishing between OSI and non-OS1 users of the network Service. If however the use of NSAPs incurs unacceptable penalties, for example where each NSAP is ch

21、arged for by the network provider, then the transport protocol identification mechanism is available. ISO/1 EC 8348: 1992, Information processing Systems - Data communications - Network Service definition. ISO 8602:1986, Information processing Systems - Open Systems lnterconnection - Protocol for pr

22、oviding the connectionless-mode transport Service. ISO/IEC 10736: 1992, Information technology - Telecommunications and information exchange between Systems - Transpott layer security protocol. CCITT Recommendation X.25, Interface between data terminal equipment (DTE) and data circuit-terminating eq

23、uipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit. CCITT Recommendation X.244, Procedure for the exchange of pro tocol iden tifica tion during virtual cal/ establishment on packet switched public data networks. 2 Normative references

24、3 Definitions The following Standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this Internat

25、ional Standard are encouraged to investigate the possibility of applying the most recent editions of the Standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. The following terms are used by this International Standard and are defined by ISO 74

26、98: Open Systems Interconnection (OSI); network connection; transport entity. ISO 7498:1984, Information processing Systems - Open Systems Interconnection - Basic eference Model. 4 Symbols and abbreviations ISO 7498-3:1989, Information processing Systems - Open Systems interconnection - Basic eferen

27、ce Model - Part 3: Naming and addressing. ISO 8072:1986, Information processing Systems - Open Systems lnterconnection - Transpott Service definition. ISO/IEC 8073:1992, Information technology - Telecommunications and information exchange between Systems - Open Systems lnterconnection - Protocol for

28、 providing the connection-mode transpott Service. 4.1 Transport protocol data unit UN TPDU Use of network connection TPDU 4.2 TPDU f ields LI Length indicator (field) SHARE Sharing Option (field) ISOAEC 11570 : 1992 (E) 0 ISO/IEC PRT-ID Protocol identifier (field) 7 Structure and encoding of the UN

29、TPDU 5 Use of the network Service Transport protocol identification makes use of the network Service defined in ISO 8348. lt uses the NS-User data Parameter of the N-CONNECT request and indication primitive only. 6 Protocol f unctions The length of the UN TPDU shall not exceed 32 octets. NOTE - This

30、 is a restriction imposed on future enhancements to this TPDU by constraints within the Network Layer. This restriction on the length of the Parameter is due to the desire not to conflict with the protocol identifier field carried by X.25 CALL requests. This is a Single octet located at the same Pos

31、ition as the length indicator of the UN TPDU when the latter is carried in an X.25 CALL request. CCITT have already Chosen value for this Parameter and thus it is important not to use those values (see CCITT Recommendation X.244). 6.1 Default identification 7.1 Structure When using default identific

32、ation, no NS-User data Parameter shall be placed in the N-CONNECT request primitive. ISO/IEC 8073 is then identified. 6.2 Explicit identification When using explicit identification, an UN TPDU shall be placed in the NS-User data Parameter of the N-CONNECT request primitive. This UN TPDU may be follo

33、wed by other PDUs, which are recognizable by the identified protocol, in the NS-User data Parameter of the N-CONNECT request primitive. The sending transport entity shall a) set the PRT-ID field of the UN TPDU to the value assigned in 7.3 to the protocol used; b) set the SHARE field of the UN TPDU t

34、o the value 0000 0000 (no sharing); The structure of the UN TPDU shall be as follows: 1 2 3 4 5 to p LI UN PRT-ID SHARE Variable 0000 0001 Part 7.2 Length indicator (LI) field The field is contained in the first octet of the TPDUs. The length is indicated by a binary number, with a maximum value of

35、254 (1111 1110). The length indicated shall be the header length in octets including Parameters, but excluding the length indicator field and user data, if any. The value 255 (1111 1111) is reserved for possible extensions. If the length indicated exceeds or i s equal to the size of the NS-User data

36、 which is present, this is a pro tocol e rror. c) not use the variable part of the UN TPDU; 7.3 Fixed part NOTE - This International Standard does not include procedures for sharing a network connection between different protocols. The following strategies could be used in the future: a) sequenti al

37、 reuse of a network connection by protocols (i.e . consecutive sharing); b) concurrent use of a network connection by several protocols (i.e. concurrent sharing). Inclusion of these strategies will use other values of the SHARE field and may make use of the 1 variable part of the UN T PDU. 6.3 Proto

38、col Operation The receiving transport entity shall operate the protocol, identified either by default or explicitly, if it is claimed that this protocol is supported. Otherwise the network connection shall be refused. The fixed part shall be as follows: a) UN: UN TPDU Code: 0000 0001; b) PRT-ID: pro

39、tocol identifier; 0000 0000 Reserved 0000 0001 ISO/IEC 8073 0000 0010 So8602 0000 0011 ISO/IEC 10736 in conjunction with ISO/IEC 8073 0000 0100 ISO/IEC 10736 in conjunction with So8602 0 ISO/IEC ISO/lEC 11570 : 1992 (E) 0000 0101 through Reserved for other OSI protocols 0111 1111 1000 0000 through R

40、eserved for private use 1111 1111 c) SHARE: sharing strategy. Values: 0000 0000 No sharing 7.4 Variable part The variable part consists of one optional Parameter. This Parameter is only present when SHARE is different from 0000 0000. 1 2 3 to p PRT-ID LIST 11011111 LENGTH VALUES 1 to 26 TYPE = PRT-I

41、D LIST(llO1 llll), Length = number of PRT-IDs, Value = list of PRT-IDs, one per octet. 8 Conformance A System claiming to conform to this International Standard shall comply with the requirements of 8.1 and 8.2. 81 When initiating a network connection a transport entity shall either a) not use the N

42、S-User data Parameter of N-CONNECT request primitive and operate using the protocol of ISO/IEC 8073 on this network connection; or b) include a UN TPDU in the NS-User data Parameter of the N-CONNECT request primitive and operate using the transport protocol specified in the PRT-ID Parameter of the U

43、N TPDU. 82 When processing an N-CONNECT indication, a transport entity shall a) regard ISO/IEC 8073 as being identified if no UN TPDU is present; or b) accept the PRT-ID field of the UN TPDU if the UN TPDU is present; and operate the identified protocol if it is claimed that this protocol is support

44、ed, otherwise reject the network connection. 3 ISO/IEC 11570 : 1992 (E) Annex Al) (normative) Protocol Implementation Conformance Statement (PICS) Proforma Al . General A-l.1 Symbols used Status Symbols: M Mandatory. 0 Optional to implement. If implemented the feature may or may not be used. Support

45、 Symbols: Yes Supported. No N/A Not supported. Not applicable. A.1.2 lnstructions for completing the PICS proforma The main part of the PICS proforma is a fixed-format questionaire divided into a number of clauses. Answers to the questionnaire are to be provided in the rightmost column either by sim

46、ply marking an answer to indicate a restricted choice (such as Yes or No) or by entering a value of a range of values or entering what action is taken. A2 . Supported TPDU / Index 1 TPDU References Status r Support ST1 / / UN supported on transmission 6.2 PI :o Yes No NOT P1:M ST2 / / UN transmitted

47、, when identifying 1 6.2, 6.1 / ST1:O / Yes No N/A ISO/IEC 8073 1 ST3 I UN supported on receipt 6.3 M Yes Pl: The only transport protocol claimed to be supported is ISO/IEC 8073. l) Copyright release for PICS proforma Users of this International Standard may freely reproduce the PICS proforma in thi

48、s annex so that it tan be used for its intended purpose and may further publish the completed PICS. ISO/lEC 11570 : 1992 (E) A3 . Supported Parameters of issued UN TPDU Index 1 Supported Parameters 1 References 1 Allowed values Supported values 7.3 b) ISO/IEC 8073; lS08602; ISO/IEC IO736 in conjunct

49、ion with ISO/1 EC 8073; ISO/IEC IO736 in conjunction with ISO8602; Private: 1000 0000, . . . . 1111 1111 IU2 1 Sh aring strategy 7.3 c) No sharing A4 . Supported Parameters for received UN TPDU 1 Index 1 Supported Parameters References RU Protocol identifier 7.3 b) / RU2 / Sharing strategy 7.3 c) A5 . Actions on protocol identification Index PI Pl2 Pl3 Event Absence of a UN TPDU in an N- CONNECT indication is regarded as identifying ISO/IEC 8073 Operate the identified protocol Refuse the network connection References 6.1 6.1, 6.3 6.3 Allowed values ISO/IEC 8073; IS08602; Support