1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 4 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%2-).!,G0G0%15)0-%.4G0G0!.$G0G002/4/#/,3G0G0(b) that within the X Series of Recommendations services and optional user facilities for public datanetworks are defined;(c)that the F Series of Recommendations d
2、efines telematic services and that the T Series of Recommendationsdefines terminal equipment and control procedures for telematic services;(d) that a set of Recommendations describes various aspects of message handling systems: X.400 Series,unanimously declaresthat this Recommendation describes the
3、general principles for telematic interworking.CONTENTS0 Introduction1 Scope and field of application2 References3 Definitions4 Symboles and abbreviations5 Conventions6 Telematic interworking model6.1 Overview6.2 Telematic interworking involving the MTS6.3 Telematic interworking not involving the MTS
4、6.4 Physical configuration - Definition of the telematic interworking facility (TIF)7 The telematic interworking system7.1 Definition of the TISs7.2 TIS involving the MTS7.3 TIS not involving the MTS8 Refinement of the TLMA principles of telematic access protocol2 Fascicle VII.5 - Rec. T.3000 Introd
5、uctionThis Recommendation is the first in a series of Recommendations dealing with telematic interworking.Telematic interworking is the generic name for a set of applications provided to telematic users. Each of theseapplications is called a telematic interworking application (TIA), and involves a s
6、ubset of the following:- allowing efficient interchange of information between telematic terminals which cannot interact directly;- providing additional features to standardized telematic services, such as document storage andmultiaddressing;- providing access to or participation in CCITT defined se
7、rvices such as telex, interpersonal messaging,directory services, etc.Two TIAs are defined in the present set of Recommendations, namely:- participation of telematic users in the PM service;- teletex to telex interworking.Other TIAs are for further study.Some TIAs may be defined to be operated on a
8、standalone basis, e.g. teletex to telex interworking.1 Scope and field of applicationThis Recommendation defines the general principles for telematic interworking. It defines the principles of thetelematic access protocols as the protocols used by the telematic terminal to participate in telematic i
9、nterworkingapplications.This Recommendation makes use of the concepts defined for message handling. The architectural basis andfoundation for message handling is defined in the X.400 Series of Recommendations.The other Recommendations in the T.300 Series define the telematic interworking application
10、s and theprotocols used by telematic terminals to make these applications available to their users. Only the protocols dealingwith the telematic access to CCITT-defined services are being considered.2 ReferencesThis Recommendation cites the documents listed below:- Rec. T.330: Telematic access to in
11、terpersonal messaging system- Rec. X.400: Message handling systems: System and service overview- Rec. X.402: Message handling systems: Overall architecture- Rec. X.420: Message handling systems: Interpersonal messaging system.3 DefinitionsThis Recommendation makes use of terms defined in Recommendat
12、ions X.400, X.402 and X.420.4 Symbols and abbreviationsAU Access unitC Conditional/consumerCF Conversion facilityFascicle VII.5 - Rec. T.300 3IPM Interpersonal messagingIPMS Interpersonal messaging systemIPM-UA Interpersonal messaging user agentM MultipleMS Message storeMTA Message transfer agentMTS
13、 Message transfer systemPDS Physical delivery systemPTTXAU Public teletex access unitTIA Telematic interworking applicationTIAS Telematic interworking abstract serviceTIU Telematic interworking unitTLM TelematicTLMA Telematic agentTLMAU Telematic access unitTLM-TER Telematic terminalTTX TeletexUA Us
14、er agent5 ConventionsThis Recommendation makes use of no specific convention.6 Telematic interworking model6.1 OverviewThe telematic interworking model serves as a tool to aid in the development of Recommendations ontelematic interworking. It depicts different interworking scenarios, and the use of
15、the message handling model fortelematic interworking.The model is applicable in two cases, the first one involving the MTS, the second one not involving the MTS.The model provides only a functional description and does not mandate any specific implementation or interfaces.6.2 Telematic interworking
16、involving the MTSFigure 1/T.300 depicts the telematic interworking model when the MTS is involved.It allows:a) telematic to telematic interworking, through the use of the MTS for relaying the telematic information;b) participation of a telematic user in the IPM service (telematic to IPM-UA interwork
17、ing through the MTS);c) participation of a telematic user in any other CCITT-defined application in the field of message handling(telematic to other UA interworking);d) telematic to other CCITT-defined services interworking through the MTS and the appropriate access units.4 Fascicle VII.5 - Rec. T.3
18、00FIGURE 1/T.300Telematic interworking model involving the MTS6.3 Telematic interworking not involving the MTSFigure 2/T.300 depicts the telematic interworking model when the MTS is not involved.TLM Telematic terminalTLMAU Telematic access unitTLXAU Telex access unitTIU Telematic interworking unitAU
19、 Access unitFIGURE 2/T.300Telematic interworking model not involving the MTSFascicle VII.5 - Rec. T.300 5In this case, TLMAUs and AUs are the same as in 6.2. The ITU may provide the appropriate subset of theMTS service that will enable information to be conveyed between TLMAUs, or between TLMAUs and
20、 AUs. The TIUperforms, when necessary, the relevant conversion and dispatching functions.6.4 Physical configurations - Definition of the telematic interworking facility (TIF)A telematic interworking facility (TIF) is a real system incorporating a valid combination of functional unitswithin telematic
21、 interworking. The present clause defines the valid combinations.6.4.1 TIF involving the MTSIn the case of telematic interworking involving the MTS, valid combinations of functional units are depictedin Table 1/T.300.TABLE 1/T.300Physical configurations of a TIF involving the MTSFunctional unitsTLMA
22、U MTA MS UA TLX AU PDAU Other AUTIF M 1 M M M 1 MM Multiple OptionalMS Message storeTwo rules apply to define a TIF in this case:- At least one TLMAU is present.- TLMAUs are necessarily co-resident with the MTA they are in relation with.The definition of other entitles present in a TIF (UAs, MSs. TL
23、XAUs, PDAUs, other AUs) and their relationswith the MTA is outside the scope of the T.300 Series of Recommendations.6.4.2 TIF not involving the MTSThis case corresponds to a stand-alone TIF, that is a real-system interacting with telematic terminals, andoptionally with other CCITT-defined systems (e
24、.g. telex system), but not with MHS nor with other TIFs.The valid combinations of functional units are depleted in Table 2/T.300.TABLE 2/T.300Physical configurations of a TIF not involving the MTSFunctional unitsTLMAU TIU TLXAU Other AUTIF M 1 M MM Multiple Optional6 Fascicle VII.5 - Rec. T.3007 The
25、 telematic interworking systemEvery TIA is provided to the user by a system called telematic interworking system (TIS). This clauseprovides an abstract model of the TIS.7.1 Definition of the TISsThe TIS and associated users are modelled as objects, as depicted in Figure 3/T.300.FIGURE 3/T.300Definit
26、ion of the TISA user and the TIS are paired through the use of one or more ports. At each of these ports, one or moreabstract operations are made available to the user. The collection of these abstract operations will define the abstract-service (called telematic interworking abstract service TIAS)
27、provided by the TIS.All ports and operations are application-dependent, and thus are described in appropriate (application-specific) Recommendations.One application of TIS that is defined is the IPMS. IPM-ports and operations are described inRecommendations X.420 and T.330.The refinement of the TISs
28、 leads to two cases, the first one involving the MTS, the second one not involvingthe MTS.7.2 TIS involving the MTSThe TIS may be refined according to Figure 4/T.300.Fascicle VII.5 - Rec. T.300 7FIGURE 4/T.300TIS involving the MTSThe refinement or the TIS exposes the following component objects:- Th
29、e MTS, as defined in Recommendations X.402 and X.411.- The TLMA, providing the user of a telematic terminal with the telematic interworking abstract service(TIAS).- The UA, which provide TIAS to users not using a telematic terminal. One application is the IPM-UA, inRecommendation X.420.- The AUs, wh
30、ich allow intercommunication with other CCITT-defined services. An example of such anAU is the PDAU, defined in the X.400 Series of Recommendations.The description of UAs and AUs is outside the scope of the T.300 Series of Recommendations.The ports and operations between the MTS and the other object
31、s listed above are defined in the X.400 Seriesof Recommendations.7.3 TIS not involving the MTSThis case is for further study.8 Refinement of the TLMA principles of telematic access protocolsThe refinement of a TLMA exposes two component objects: the telematic terminal (TLM) and the telematicaccess u
32、nit (TLMAU).A TLM is functional object corresponding to a terminal as defined in the relevant T Series ofRecommendations.The TLMAU is defined in Recommendation T.330 in the case of telematic access to IPMS.8 Fascicle VII.5 - Rec. T.300The TLM and TLMAU are linked together through one or more port an
33、d a set of operations describing them.Ports and operations are application-dependent and thus are described in appropriate (application-specific)Recommendations.The realization of these operations involves some transfer of information between the TLM and the TLMAU.It is called a telematic access protocol (see Figure 5/T.300).FIGURE 5/T.300Refinement of the TLMA
