1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 : TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!.G13-!#().%G0G0,!.5!%-%4(/$/,/9G0G0 what the system is supposed to do; what the user is supposed to do; the complexity of the job from the users perspective (see Note); the frequency of the job (see Note);
2、at which level in the network hierarchy the job is supposed to be performed (exchange, OMC); safety aspects.Note The following assumptions have been taken to better identify what is meant for “frequency” and“complexity” of a job.3.1.1.1 FrequencyLow: if the job is supposed to be performed weekly or
3、at longer intervals.Medium: if the job is supposed to be performed daily._1)The tools and methods may be improved on the basis of user experience leading to additions or revisions.2 Fascicle X.7 - Rec. Z.333High: if the job is supposed to be performed several times in a day.3.1.1.2 ComplexityLow: lo
4、w number of parameters (in general sense) max 0 : 3; most information associated with these parameters are not compound; there is no semantic relationship among different parameters and parameter values.Medium: the number of parameters is greater than 4 but less than 6-8; much information associated
5、 to these parameters is compound; there is no semantic relationship among parameters and/or parameter values.High: there are many parameters; most information associated to these parameters is compound; there are semantic relationships among parameters and/or parameter values.3.1.2 For Phase 4No spe
6、cific guidelines are provided for phase 2.3.1.3 For phase 3Three main categories of outputs can be identified within the MML function semantics specification, namely:1) Response outputs inside the dialogue to the operator inputs.2) Result outputs whose end-user is supposed to be the operator (e.g. r
7、esults of reporting or interrogationfunctions).3) Result outputs whose end-user is not assumed to be the operator (e.g. data collected for furtherelaborations).The partitioning of the output media to be used and its component information entities should not be pursued indetail, with the following gu
8、idelines: Output media and output characteristics to support the first category of output (output inside dialogue) willnot appear in the diagrams. Output media and output characteristics to support the second category will be as shown in Figure 1/Z.333.It is also recognized that the lower level of d
9、etail, whose definition will depend on the individualAdministrations needs, could in general include the information shown in Figure 2/Z.333.Fascicle X.7 - Rec. Z.333 3Output media to support outputs belonging to the third category will be shown if possible in the same way asthe previous point.3.1.4
10、 For phase 4To define individual menus and forms, follow the guidelines for the design of menus and forms as defined inRecommendation Z.323.To define the individual inputs and outputs:1) Consider what the system is supposed to do.2) Select options in the function information structure.3) Define the
11、information to be represented by the command code or equivalent.4) Define the information to be represented by the parameters and, if appropriate, their order.5) For each parameter, when appropriate, identify the: range of values, default values, information to be automatically supplied by the syste
12、m.6) Define the response outputs within dialogue, the interaction request outputs and outputs outside dialoguewhen applicable after considering the various mode operating sequences and the users reactions to theoutputs.4 Fascicle X.7 - Rec. Z.3337) Define the associated syntactic structure.8) Select
13、 terms and abbreviations for inputs and outputs.3.1.5 For phase 51) Define a preliminary operational procedure in functional terms.2) Finalize operational procedures.3.1.6 General guidelines1) Determine that the MML functions support the jobs to be performed.2) It will be necessary to consider: huma
14、n factor aspects; adequate allocation of authorities; adequate definition of responsibility; training of the user.3.1.7 Terminology harmonization guidelines for Phases 1-3To harmonize terminology:1) Utilize existing CCITT vocabulary.2) Select appropriate terms included in the general functional term
15、inology (Appendix I).3) Derive specific terms and their definitions pertinent to the functional area involved based on the followingconsiderations: common usage; specificity; translatability.3.2 ModellingModelling involves the use of description text and/or figures drawn either with the support of f
16、ormalsymbology and rules (formal modelling) or without such rules (informal modelling).3.2.1 The need for modelsA tool available is the construction of informal models of those parts of telecommunications systems whichhave been selected for MML control. Also the organization of the Administration co
17、uld be subject to modelling.Several models could apply when defining a job or an MML function. The use of models has the following advantages.Fascicle X.7 - Rec. Z.333 51) Models provide a means for the exchange of functional descriptions.2) The validity of the derived man-machine interface can be c
18、onsistently demonstrated by reference to therelevant models.3.2.2 Interpretation of modelsA model can be defined as an abstraction of a reality as seen from a certain viewpoint.In Z.300 Recommendations the viewpoint assumed is that of their users, i.e. Administration specifiers andsuppliers designer
19、s.Models should therefore be interpreted as high level specifications and are not aimed to represent, suggest orimply any particular implementation.They intend to provide only an overview in a conceptual sense of the information which is primarily relevantfor the control of each particular functiona
20、l area and of the main relationships among the various entities in the operatorperspective.Models produced expressly to determine the MML control structure are interpreted purely with that use inmind. Other models must lend themselves to the generation of MML control message sequences. CCITT feel bo
21、und toproduce models which can be linked with the methods for determining information structure of MML functions.3.3 MML function decompositionThe general MML functions are structured into component MML functions. Multiple levels of decompositionare allowed. For examples see the Annexes to this Reco
22、mmendation.3.4 Information structure meta-languageEach MML function identified at the lowest level of the MML function decomposition is structured into theinformation components needed to perform it. A top-down structuring is performed and multiple levels of informationdecomposition are allowed. The
23、 supporting tool is the meta-language presented below.An aid in understanding of information structuring is to view a MML function as an action on an object(s).Information composed may therefore relate either to objects or to actions.A general action associated with a MML function can be decomposed
24、into subsidiary actions and modifiers tothose actions. It is possible that no decomposition will take place. However, if decomposition is necessary, it should benoted that “decomposition“ with respect to actions means both determining subsidiary actions and determining anyqualifiers (modifiers, opti
25、ons, etc.) associated with the action. The latter is not a true decomposition.3.4.1 Decomposition meta-language3.4.1.1 GeneralThe representation of the information structure associated with a MML function involves the specification ofall needed information entities and their inter-relationships.This
26、 representation can be achieved in a consistent manner by means of Information Structure Diagrams, drawnusing the meta-language described below. Such meta-language consists of a set of symbols and drawing conventions.A diagram represents the information structure in a top-down approach, starting fro
27、m the identification of theMML function to be structured and ending with all the information components felt necessary in the man-machineinterworking for that function.The decomposition process is performed by the use of sequences, selections and iterations, by means of whichany type of structure ca
28、n be obtained.Unless otherwise stated, the sequence of information is not implied by the order in which different elements arepresented in the diagram.3.4.1.2 Information entities3.4.1.2.1 Composite partsA composite part is an information entity that can be further structured into smaller parts.6 Fa
29、scicle X.7 - Rec. Z.333The following symbol is used:3.4.1.2.2 ComponentA component is an information entity that is not structured further.The following symbol is used:3.4.1.3 Structuring3.4.1.3.1 SubdivisionSubdivision in Information Structure Diagrams is shown in the following way:3.4.1.3.2 Sequen
30、ceWhen the order between information entities is relevant, these are specified in sequence. A left-to-rightsequence is indicated by the use of arrowheads as follows:Fascicle X.7 - Rec. Z.333 73.4.1.3.3 SelectionWhen a composite part is structured into a number of information entities, of which one o
31、r only some arerelevant in any one case, a selection mechanism is used, represented by the following symbol:In the general selection case, m possibilities exist from which selection must be made. Of these m possibilities aspecified number, n, is to be selected, which implies n 1 This is the most com
32、mon selection case implying that one and only one of the possibilities is tobe selected.n 1, m n Multiple selection of n of m possibilities.If the number of choices to be made are variable between specified lower and upper limits, a number ofpossibilities are implied. In this case, both limits are g
33、iven in the selection symbol:The lower limit p indicates the smallest number and q the largest number of different choices to be made out ofthe m possibilities. It should be noted that each choice may be selected only once.3.4.1.3.4 OptionsIn some cases, options may be required such as default optio
34、ns or general options.In these cases, the type of option is indicated by the appropriate capital letter only within the selection symbol,i.e. D for default options, G for general options. Only one outlet from the symbol is allowed:8 Fascicle X.7 - Rec. Z.333The use of a default option implies that t
35、he value taken by an information entity will be provided automaticallyif the user does not supply a value in the input.A general option is to be used for various reasons reflecting the needs of manufacturers and the needs ofAdministrations. The information entities that can be deduced from the outle
36、t of this box can optionally be part of theman-machine interworking. This means either that the information exists in the system in a predetermined manner orthat it is not needed. If this distinction must be made an annotation to the information structure diagrams should bemade.3.4.1.3.5 IterationWh
37、en a composite part is structured into a number of information entities that can be repeated an arbitrarynumber of times, an iteration mechanism is used, represented by the following symbol, which has only one outlet:If a number of interactions can vary within a range, the number of times a part is
38、to be repeated is given as thelower limit p and the upper limit q.3.4.1.4 Drawing conventions3.4.1.4.1 Flow lines and connectorsEvery symbol is connected to the symbol it follows by a solid flow line.A solid flow line may be broken by a pair of associated connectors, with the flow assumed to be from
39、 the out-connector to its associated in-connector. Several out-connectors can be associated with the same in-connector.Crossed flow lines should be avoided wherever possible.Fascicle X.7 - Rec. Z.333 9.4.1.4.2 Connectivity rulesEach information structure diagram begins with a composite part symbol a
40、nd each path of a diagram ends witha component symbol. The drawing of diagrams must follow the connectivity rules represented below.3.4.1.4.3 AnnotationsAnnotations are denoted by the following symbol, where n is a number referencing a note providing descriptiveand/or explanatory information.Annotat
41、ion nAnnotations may be connected by a dashed line to any symbol or flow line.3.4.1.4.4 Special NotationsInstead of the normal structuring symbology where the structuring is shown horizontally, a vertical symbologymay be used where this is advantageous, i.e. for saving of space. This vertical symbol
42、ogy may be used with all types ofstructuring.10 Fascicle X.7 - Rec. Z.333For the selection symbol, in case of a high number of possibilities, the following drawing conventions are alsoallowed:Fascicle X.7 - Rec. Z.333 11Where the number of information entities in a structure is undetermined, this co
43、uld be shown asdepending on the type of structuring used.3.5 Procedure description methodMan-machine dialogue may be considered a feature of an SPC system and may be represented by means of twoprocesses: one related to the user, the other related to the system. These two processes exchange informati
44、on by meansof signals that for MML purposes are intended to be mostly inputs and outputs.In particular, the description of MML operational procedures may be made by focusing the attention on one ofthe machine logic functions, the associated MML function, and describing the process that performs this
45、 function.To reduce the complexity of drawings, it seems useful to limit the description to the main signals between userand system, i.e. inputs and outputs, and to omit showing features such as timing, error reporting, editing procedures,etc., that may be described elsewhere by means of SDL if need
46、ed. For an example see Appendix II.3.5.1 Features to be used in the descriptionA MML operational procedure can be considered as a process whose behaviour may be specified in terms ofinputs, states, transitions, decisions, outputs and tasks.In the following paragraphs, basic concepts of SDL are inter
47、preted in the context of MML applications.3.5.1.1 InputAn input is a set of data which is input by the user and which is recognized by the MML operational procedure.Input may be, e.g commands in direct information entry, or other types of data.3.5.1.2 StateA state is a condition in which the action
48、of the MML procedure is suspended awaiting an input.3.5.1.3 TransitionA transition is a sequence of actions which occurs when a MML operational procedure changes from one stateto another as a reaction to an input.3.5.1.4 DecisionA decision is an action within a transition which asks a question to wh
49、ich the answer can be obtained at thatinstant and chooses one of several possible paths to continue the transitions.3.5.1.5 OutputOutput is a set of data which is output by the MML operational procedure and which in turn is used as an inputto the operational process.3.5.1.6 TaskA task is any action within a transition that is neither a decision nor an output.3.5.1.7 Symbols and rulesSymbols and rules are those defined in the SDL Z.100 series Recommendations.12 Fascicle X.7 - Rec. Z.3333.6 Formal representation of the syntactic
