CA2197983A1 - A method to structure call processing and a call processing switching system for telephony - Google Patents

Abstract

The present invention demonstrates a method to structure call processing in a telecommunication system, preferably by way of software, to create a standard and generic structure, which makes it possible to extend said system with new services and data without effecting an already existing overhead operation of the system using the half-call principle, by combining this half-call principle with a generic protocol between the executing half-calls in a session with a session scope and a traffic case scope which are using memory functions in which different records are storing pointers to a local memory function, said pointers being combined with a tag element by means of which locally stored data will be uniquely identified and in spite of not being real global data may still be utilized as global data during the duration of a specific session in which period the particular records exist.

Description

2 ~ 97q~3 ~ wo~3~/os7~9 PCT/s~ss/01027 ]

~ metho~ to structure cali processing and a call processing switching system for telephony TEC~ICA~ FIELD
The present invention refers to a data structure for call processing and particularly to a data structuring in a traffic controlling process for a telecommunication application.

BAC~GROUND OF THE INVENTI~N
During processing of a call in a telecommunication system a large amount of data needs to be handled or collected. Such call related data differs a lot between calls depending on what kind of services ~re utillzed in the specific call, which protocols are used to communicate with the bU' l~u--ding networks etc. Data contains information useful for different kinds of users of the telecommunication system. One network/service provider may want to create billing records while another wants to create statis-tics of different kinds. As the vendor wants to be independent of which data the user wants to use and still be able to add new data together with a new service without having to change already existing software, this call related data record have to be handled in a new efficient way.

There exist a number of possible solutions to handle the call related data. One obvious way is to use a conventional database to collect the information, which quickly renders into capacity problems. Another solution is choose a declarative solution where a declaration of the contents is made ~e.g. compare a record in Pascal). The drawback ~f a declarative solution as a Pascal record is that it does not present the desired flexibi.lity. Yet another approach is to send around the data between the objects whenever it is needed, which creates duplication of data.

In ~he state of the art the; are found several concepts regarding objec~ oriented software structures for processing in a modern teleCOmmunication system. EP-0 524 08g Al titled "5tructure de logiciel pour système de traitement de données, amment pour Système de télecommunications" describes a logical ssructure system for processing data, specifically for tele-~Os~s729 2 1 q 7 9 8 ~ P~T1S~s1011127 ~

commw1ication systems. ~he structure particul.arly simplifie:i t.hereal tin-e commurlication between the objects according to the CCr~T'' rules X 200. ~P-0 524 077 A1 titled "Structure de logicie3 pOUI système de traitement d'informations" de.scribe a struct.ure which hi.des the hardware and software system features to the applicat,iollE~rograms.

EP-0 470 415 A2 describes a method to supply a nun~er of application processors in a telephony system access to cal~.
related information in a common database, The information is tagc,~ed and stored temporarily as a record in the database a~, long as the communic.,ation lasts. The information is particularly direc~ted for being directly viewed on a display terminal for sUperVisiOrl iII an operator controlled switching sy~tem.

SUMM~RY OF THE IN~ rIO~
Therefore there is a demand in a telecommunicat,ion system, preferably by way of software, to create a standard and generic structure, which makes it, possible to extend the system wit.h new services and data without effecting an already exist,ing operatinc3 software of a system using the half-call principle.

A first object according to the present invention is t,o co~bine the half-call principle with a generic protocol between the executing half-calls and including a session comprisi.ng a session scope and a traffic case scope which are using memory functions in which different records are storing pointers to a local memory function, the pointers being combined with a tag element by means of which locally stored data will be uniquely identified and in spite of not, being real global data may still be ut,ili~ed ar.
qlobal data duriny the duration of a specific session in wnl.ch period t..he particular records exist.

A second object: according to the present invention is that the specific session scope is using a session record for storing poi,nt.ers to executing objects of the call and from which record it will be possible to find all other objects within the session, 2 i q79~3 ~ ~ ~096/09729 PCTIS~,9SI/~1~27 if the tag elements un~er which the objects are stored are k1lowr., other data objects being stored in a transaction record refer-enced session record or of a traffic case record.

A third object according to the present invention is that the traffic case scope is having a similar structure as the session scope and the traffic case record being referenced from the session record and the traffic case record being created to store executing objects of a call.

A fourth object according to the present invention is that the transaction record is storing data objects belonging to the traffic case.

A fifth object according to the present invention is that the tag element is being realized by an integ~r number uniquely assigned to each ~ ut;ng object or data object being stored.

~RIEF DESCRIPTION OE~ THE DRAWINGS

The invention, together with further objects and advantages thereof, may best be understood hy making reference to the following description taken together with the accompanying drawings, in which:
~igure l is an illustration of a session having a session controller, SC, handli}lg several traffic cases including for each traffic case a respect.ive originating call, OC, in communication with other traffic cases including a respective terminatir1y 'l, TC;
~igure 2 demonstrates a session controller, SC, using, according to the method and system c.f the present invention, a session record to store references to executing objects and a transaction record to store references to data objects;

wv96~972~ 2, 9 ? ~ 8 ~ PCTISE9~101027 ~ ~

Figure 3 demonstrates collect,ions according t,o tht-~ method and system of the present invention to store a traffic case object within an ori,ginai,i,ng call, OC;
~igure 4 is an demonstration of objects controllillg ehe data flow in a session;
~igure 5 demonstrates an example when data for a charging bac;is is extracted from a session;
~igure 6 shows in a simple example the relation between created managed ob~ects;
~igure 7 shows the complete static view accor-ding to the si~ple example of Fig. 6;
~igure 8 is a simple flow chart of call data collection in a Transaction Record during call processing; and ~igure 9 is a simple flow chart of specification of dat,a t,o include in an output.

FUNDAMENTALS
To be able to handle the suhject of the present application in an efficient, way it, will be praetical to first define a number of techllical terms which will be useful throughout the follo~ing description.

A common way to structure software in a call processing switchillg system for telephony is to divide the control of tAe call into two hal~es, d Half-Call A and a Half-Call B. The softwarl, which controls a Half-Call is e~ecuting in a process called a Sess,ion.
A session can handle one or several Traffic Cases simultaneously (for example in a multi call situation). The Traffic Case defirle<.;
the funct,ionality and data that handles a call in a Session, Note also that a three party call is handled by two Traffic Cases in 2 1 ~798~
~ Wos6/~9729 PCT1~E95/01027 a Session, one for each call leg.

For the sake of simpl.icity the session is structured in different scopes and therefore is introduced the Session Scope anà the Traffic Case Sco~e. The Session Scope is controlled by the Baseflow Session Controller, SC'. The main task for the session controller is to act as a command interpreter against the Acsess Prot~ocol, ACP and make a service analysis OII these commands (Messages). This includes the-l, for instance, initiaeing and terminating new Traffic Cases, distributins infon~ation from the Access Protocol to the correct Traffic C'ase, initiating new services, etc.

Every ~'raffic Case within the Session is controlled by one baseflow. Such a baseflow may be either an Oriqinatinq Call, OC
or a Terminatinq Call, TC. The main task for this baseflow is to take care of the basic call handling. This includes for example establishing/disconnecting a call (including handling of the Telecommunication Service Protocol, TSP, between the call halves), ordering establishment/disconnection of conr1ections ~for example a speech conr1ection), and orderins address information analysis, etc.

To support the different scopes and the control logic opera~ing within those, there is a need of a similar data structure. Thus the data must be structured in a certain way to make it possible to implement and m~;n~in the applications. Correspondingly there exists two different t.ypes of objects, which in tllis descr-iption are denoted Execu~inq Objects and Data Obiects.

An Executing Object will execute in the session, e. g., control objects, protocol objects, resource objects etc. A pure ~ata Object will contain data received for example from a Teleservice Protocol Message. It shall also be possible to make an output of this type of data for charging or statistic purposes. The two types of Objects have different semantics and are stored in different records in the Session. Such a record is referred to as 2 1 ~7~3 W0~6/0~729 PC~1'/SEg~/0102 a Session Recol-d and i.s used to store point:ers to protocc)l objects and resource objects instantiated b~ control and resource objects within the Session. The Objects storecd in a Session Record are common for the whole Session. Por st.oring pure Data Objec.ts is used a Transactior, Record. In a similar way as the SessiGn Record stores pointer to objects the Transaction Record (also named call record) is used to store pointers to pure Data Objects instantiated by control., protocol, and resource object.s within the Session or a Traffic Case exec-.uting in the Session A users view of a Session Record is referred to a Session Record ~iew and gives the user an interface to the Session Record on a high abstraction level Similarly a users view of a Transacti.on Record is referred to as the Transaction Record View and gives t.he user an interface to the Transaction Recprd on a high abstraction level.

Finally there is also found a Traffic Case Record which is a rec.ord where pointers to Objects belonging to a T~affic Case are stored. Only pointers to Protocol Objects and Resource Objects are stored in this record. Por storing pure Data Objects a Transaction Record should be used. A users view of a ~'raffic Case Record is referred to a Traffic Case Record View and g1ves the user an interface to the Session Record on a high abstractio level.

DETAILr~ r~ESCRIPTION OF T~E PREFERRED EMBODIME~T
'I'o support t.he different scopes and correspondiny control logic for a c.all processing in a telecommunication sys~.em we ne~ec~ a suit.ab1e data structure. Data must. be~ structured to ma~.:e it possible to implement and m~jnt~in the applications WL~ there~ore introduce two different types of objects, the executi.ng objects and data objects, respectively, to keep track in an session These two terms, which were. already defined above, do have different semant..ics and are stored in different records in the created session. ~hen storing an object in a collection it is only a questlon of storing a pointer t.o the object that is to be 2 ~ ~79~3 ~ ~ W096/09729 PCTISE!~/01027 stored and consequently no ciuplication of the object ltselL is made in such a step. This also implies that for such a pointer storage there is actually no need to know the size of t~ie particular object.

Figure l is a generalized view of a session scope, which is controlled by the session controller SC. The session controller is acting as a command interpreter against the access protocol ACP, which is the generic term used for the subsc.riber or network accesses. As is evident from figure l, the session contains one or several traffic cases, and here the particular session contains two traffic cases which are both of the OC type (originating call~. Eac.h one of the two traffic cases of type OC
is established by means of the respective traffic case to another traffic case of type TC (terminating call) through a handling telecommunication service protocol, TSP.

As indicated in figure 2 there is in the session scope a session record, which shall be used for storing a pointer, PTR, to each executing object, for example to a so called session agent. The session record, SR, is by means of other pointers the root for the data structure in each session. The data objects of the w1lole session is found in the transaction record by means of their respect.ive pointers, PTR. Each entry in the session record is having a particular name or key, TAG, which makes it possible to locate any object within the session scope if the particular sysl-em operator knows the particular name or TAG.

Figure 3 is a generalized view of a traffic case scope, here ccnt~ining an originating call t..ype, OC, but a terminating c.all type, TC, would have the corre ~nding structure. This scope has to be introduced if the appl ition has a need to execute an arbitrary number of parallel traffic cases in the session. The structure of the traffic case scope is thus similar to that of the session scope. For each traffic case in a session there is created a traffic case record to store executing objects. ~ike in the session record is used a name or TAG and a pointel- PTP.. The 21 q~q~3 ~~096rog729 PC~S~.s~ 2 traffic case record i.s accordingly referenced fro~ the sessio record. 'I'o store data objects belonging to the traffic case is consequently used a transaction record, TR, creating a table for the data objects a~. this traffic case level.

Every user of a session or traffic case record has an own view object through which the stored executing objects or data objects 7nay be accessed.

.?igure ~ demonstrates in greater detail the data flow through a session executing an originating call, OC. The data flow starts when some data is received by an access agent or the input a7ent.
The received dat.a is converted to an AXE internal representation.
The converted data is then stored in the transaction record, 'ï'R.
The data object is stored with a tag. The tag is an integer that is reserved for this particular data object. Other users, e.g. an Application Analysis, needing the data object can ~etch it from the transaction record by means of the tag and by utili~ing a transaction record view object, TR_View. The above exa~ple also illustrates wherl ~ata is sent by the output agent to the other Half-Call via the telecommunication service protocol, ~rsP r~ata is sent in a parameter which besides the data ~nt~i7~ the tag which identifies it.

As stated above a data object i.s stored in the transaction record la synonym for transaction record is also call record~. 'rhe transaction record, TR, is as already stated always accessecl vla a view object. The view object gives the user a high le~vel irlte.rface to TR, which will be further described below. Each clata object that is stored in the transaction record is semanticall}/
identified by a name or key referred to as the TAG. The TA~ is an integer, i.n an exemplifying embodiment a 16 bit word, whic'h hc15 been reserved for one particular data object. By using a dynamic storage such as the transacti.on record, where the data objects are stored with tags it will be possible to support a very flexible output mechanism. In other words it will be extremely easy, without influencing the general operation of the teieco~nu-2 ~ q7~83 096/09~9 PCT~E~51~1027 nicat.ion system, to at any particular time period extract anychosen data objects on demand of the user for a later analysis.
A conse~uence of this is that it will be extremely easy to add additional services into a system operating according to such a structured way of operation.

Assume that the agent receive the parameter "calling party number" on the protocol, ACP. The data will be converted to an AXE internal representation and stored in the TR together with an dedicated tag, 'lAppcallingpartyNumberTagll~ Other users oE TR that needs the calling party number can then turn to the TR and ask Eor the data object that is stored with the TA~ "AppCalling-PartyNumberTag". An interEace Applicati.on Platfonn Tags In-terface, ATI, nnn~;n~ the number of tags used by the functions.
ATI also contains the rules to follow when new tag,s are reserved.

As already mentioned the TR is always accessed via a view object.
The view object has two main tasks. The Eirst is to present a customized interface towards the TR. Each user of the TR should have a dedicated interface to the contents in the TR. The second task is to act as a handle object towards the TR, the handle ensures that TR is not removed until all handles are deleted.

View objects are also used to access the contents of the other two types of record that exist, the session record and the tra.ffic case record. As mentioned above one task of the view object is to provide the user wit,h a customized interface on a high abstraction level towards a record. The customi2ing means that the interface gives the users access only to the objects needed to be accessed, which may be only a part of the ~o~,al contents in a record.

The second major task of the view object.s t.owards the transaction record and the traffic case record is that they act a handles. As long as a record has a handle it can not be deleted. Whell the las~, handle towards a record is removed the record and all its content is also removed from the local memory storage. I~. is , .. . . . , . , .. ,, ,, ... , . ,, ,, . ,, , ... _ . _ _ _ _ _ _ _ _ _ _ _ _, ,, _ _ _ 2 1 97q~3 WO Yh~'097~9 PCrlSE9~V0102/

apparen~.that this creates a very convellierlt local. memory stoIaye management.

The call recorcd output mechanism a~ready mentioned is used to output parts of the content of a transaction record for post.-processing. It. should be kept in mind that the contents of the session record and a traffic case record and a transaction record are exist,ent only during the duration of that pa.rticular sessior and will disappear when the session is terminated. The c~utput.
mechanism is built around a nunber of managed objects corltainir,g tag lists. In the operation of a telecolnmunication system theIe is for instance a need to collect charging data to be able to correctly bill the different subscribers. In Figure 5 is exemplified what may take place in a session. A control objec~
"C'harging" has opened an object Cro_Type. This particular Cro_Type object contains a Tag list, fetched ;rom the data base, denoting the data objects to be extracted from the transaction record. Cro_Type i~ then ordered to compile a report consisting of the data objects identified by the tag list w.hi.ch is stored in t.he data base. The control object then uses the Cro_T~fpe interface t.o order ie to collect the data during the existellce of the particular se~sion. The data may be packed in a data area which then ~ill be sent to a post-processing node. C;onsequentl~
a charging basis due to increased service~ may be challged at anr moment by-simple modification of the tag list without interferillg at all with the existing system having a structure accordincJ to the present invention.

Thf' ef~ective result of this is that even if the rollten:s c.,~ the different sessions are defined as local data, it is pc,,ssihle ~.o simultaneously make use of desired parts of the cont.erlt as lf i~
constit.ut.es global data. A difference between local and globa]
data is for example that the }atter by necessity has normally ~o be allocated in predetermined memory locations to l)e able~ ~.o be accessed by other users.

In the illustrativf~ embodiment Wfe use tnree types of managed W09G/09729 PCT~SE95/0l027 objects to effectuate the flexible OUtpllt tlleChanism desCI'i.beCi here. They are denoted as CroServiceTemplate, Cro~pe and Cro-CustomerTemplate. The first managed object type, the CroService-Template is used for specification of what data objects are possible to extract for a specific basic or supplementary service. CroServiceTemplate contains one attribute, possible TAGs, denoting which data is possible to extract from the transaction record, TR, for a particular service, for example in this context a "Basic Call~ or a "Three Party Call".

The second managed object type is CroType, which is used for specification of a certain output tyl?e. Every instance of Cro~ype is connected to one or more instances of CroServiceTemplate. The union of data in these CroServiceTemplates determines what data is possible to output for a specific CroType.

The third and last management object type is CroCustomerTemplate, which is a managed object holding the information of which data to extract ~or a specific customer in a specific output type, Cro~ ype .

Figure 6 demonstrates a small example having the conditions:
- There are two customers, A and B.
- There are two services, "Basic Call" and "Three Party Call~.
- There are two CroTypes, CroType 1 and CroType 2.

Because there are two services we need two CroServiceTemplates:
- CroServiceTemplate Basic C'all, c~n~;ning the Tags 1, 2, 5 and 8.
- CroServiceT.emplate Three Party Call, c~n~inlng the Tags 1, 2, 6 and 9.

This means that for the "Basic Call" we can output the data stored in TR having the Tags 1, 2, 5, and 8, while for the serl~ice "Three Party Call" we may output the data stored under the Tags 1, 2, 6, and 9.

_ _ _ _ _ _ , 2 1 ~7~3 ~096/097~9 P~'ISE9~01027 We ~,hen define two output, t,ypes, CroType I designecl such that i t will be able to output data related to both services and CroType 2 designed such that it will be able to output dat,a related to the Basic Call. In Figure 6 is visuali~.ed the basic structure and the relation between the created rnanaged object.

One CroCustomerTemp,lat,e is required for each customer and Cro~ype to make the output mechanism "Call Record Output", CRO, able to perform outputs of all CroTypes to all customers. This resu3,ts in thir, example in a total of four CroCustorr1erTemplates In Figure is demonstratecl the resulting structure. Customer A recluire.s all possible Tags from CroType l and Tag no. l and 2 from ~rol~e 2 and customer B requires all Tags with lower rlumber than 8 from all CroTypes. We then ha~e a final structure that the output mechanism CRO needs to make a proper distrib~tion. We have specified which data fie.lds all different custc3mersrleecl frorr all different CroTypes A fillal part of the data flow in Figure 4 describes when the data shall be sent to the other ~al~-Call. The Half-Calls cornrnunicat:e by meanr, of the Telecommunication Service Protocol, TSP. The l'SP
carrie.s self-ider1tifying parameters. A parameter ~nt~lnrT a data object and is identified by a Tag. The receiver can determir~.e what data is recei~ed by loo~ing at the Tag. The Tag whic.h is used to identify a parameter on the TSP is the same 'l'ag used to identify a da~a stored in TR.

In E'igure 8 is summarized by a nurroer of steps in a simple~ flow chart of a call data collection in a Transactiol1 Rec~ord durirlg call processing. Such a processing is st,arted iII a step l00 In the first real step l0l of the process a message is received ovec-an exter1lal protocol IL is received in a protc.col age1lt wi~,hin a dynamic process within the s-ystem. NeAt in a step 102 the data is converted from an externa representation to an interIIal representation. A Dat,a Object, is created withi1l this dy1lar1lic process This Data Or~ect then contains tne internal reprer;enta-i,ion of the received data.

2 1 97~83 ~09610~729 PCT/S~95/1~1027 In a third step 103 the ~ata Object is stored under a uni~ue tag element in a transaction record. During call processing data lS
fetched in a fourth step l0~ from the transactio}l record using a transaction record view object then utilizing the tag element to get the correct poirter PTR to retrieve the specified data.

When the call ends or when an output of call data is wanted for statistical or charging purposes the function call record output is cal].ed in a fifth step 105. This function accesses the database to find out which data to output. As a result the function gets a list of tag elements. The wanted data is collected from TR in step 104 and put into an output buffer. This buffer may then be output to an external media. The data may later be post-processed in order to for instance produce billing information etc.

Flnally in Figure 9 is shown by means of three steps a simple flow chart a specification of data to be included in an output.
The procedure starts in a step 200. In a step 201. the service provider or any other operator administrating the system decides which data to output for different call types. These different output types are specified in a second step 202 by filling in templates with lists of tags to output. In a final step 203 these templates are stored in the database by for example entering the list, of tags by means of a separate terminal and/or a keyboard.
These entered list of tags are later accessed during the call processi,ng. ~ntering of the list of tags will 110t interfere h~ith the general ca].l processing in the telecommunication syst.e1o for init,iating and terminating traffic cases, distributing informa-tion from the access protocol to the correct traffic case, init.iating new servic~eC;~ etc., but when entered it will decide which data to be stored in the database for post-processing.

It. will be understood by t,hose skilled in the art that varlous modi.fications and changes may be made to the prese1lt invention withou~. departure from the spirit and scope thereof, which i.s defined by the appended cl.aims.

Claims (10)

1. A method to structure call processing in a telecommunication system, preferably by way of software, to create a standard and generic structure, which makes it possible to extend said system with new services and data without effecting an already existing main operating software of the system using the half-call principle, characterized by combining this half call principle with a generic protocol between the executing half-calls and including a session comprising a session scope and a traffic case scope which use memory functions in which different records are storing pointers (PTR) to a local memory function, said pointers being combined with a tag element (TAG) by means of which locally stored data will be uniquely identified and in spite of not being real global data may still be utilized as global data during the duration of a specific session in which period a particular record exists.

2. The method according to claim 1, characterized in that the specific session scope uses a session record (SR) for storing pointers to executing objects of the call and from which record it will be possible to find all other objects within the session, if the tag elements (TAG) under which the objects are stored are known, said other data objects are being stored in a transaction record (TR) of a session record (SR) or of a traffic case record.

3. The method according to claim 2, characterized in that said traffic case scope has a similar structure as said session scope and said traffic case record being referenced from said session record (SR) and said traffic case record being created to store executing objects of a call.

4. The method according to claim 2, characterized in that said transaction record (TR) stores data objects belonging to said traffic case.

5. The method according to any of claims 1 to 4, characterized in that said tag element (TAG) is realized by an integer number uniquely assigned to each executing object or data object being stored.

6. A call processing switching system for telephony, which makes it possible to extend said system with new services and data without effecting an already existing main operating software of the system using the half-call principle, characterized in that the half-call principle is combined with a generic protocol between the executing half-calls and including a session comprising a session scope and a traffic case scope, which use memory functions in which different records are storing pointers (PTR) to a local memory, said pointers being combined with a tag element (TAG) by means of which locally stored data are uniquely identified and in spite of not being real global data will be usable as global data, during the duration of a specific session in which period a particular record exists.

7. The system according to claim 6, characterized in that the specific session scope uses a session record (SR) for storing pointers (PTR) to executing objects of the call, and from which record it is practicable to find any other objects within the session, if the tag elements (TAG) under which the objects are stored are known, whereby other data objects are being stored in a transaction record (TR) of a session record (SC) or of a traffic case record.

8. The system according to claim 7, characterized in that the traffic case scope has a similar structure as said session scope and said traffic case record is referenced from said session record (SR) and said traffic case record is created to store executing objects of a call.

9. The system according to claim 8, characterized in that said transaction record (TR) stores data objects belonging to said traffic case.

10. The system according to any one of claims 6 to 9, characterized in that said tag element (TAG) is constituted by an integer number uniquely assigned to each executing object or data object being stored.