Abstract:
A telephony application architecture which allows creating programs as a set of nested routines running independently and concurrently on three different control layers. Each layer focuses on only a particular portion of the overall call processing function thus allowing that portion to be written or presented in a substantially linear fashion. This linear presentation greatly reduces the complexity of development and maintenance of the software.

Description:
TECHNICAL FIELD 
     This invention relates generally to the field of call processing and more particularly to providing service node/intelligent peripheral (SN/IP) telephony applications. 
     BACKGROUND 
     Computer-based telecommunications systems have grown exponentially over the last several years due, in part, to the ever-advancing and increasing availability of high-speed personal computers and low-cost equipment. The delivery and advancement of calling services has followed this trend of overwhelming growth. Because of rapid technological advancements, telephone service providers are now generally able to offer more complex calling services to a wider population and at a lower cost than previously possible. With this rapid advancement of technology and increasing consumer demand, telephone service providers realize the profitable potential to design, develop, and implement more sophisticated calling services. 
     During the current evolution of telephone network design, the industry developed a design architecture called Advanced Intelligent Network (AIN). AIN allowed calling service programming to finally be removed from the telephone switches. Prior to AIN, because of the complexity of telephone switches, every time a new calling service was developed, the switch vendors typically had to reprogram the switches to perform the service. This process normally delayed the introduction of new services and generally prohibited smaller telephone service providers from introducing their own calling services thereby reducing the possibility for competitive advantage. 
     AIN architecture generally works by grouping “intelligent” operations into peripheral computer systems, thereby freeing the switches to perform their core functions of call connection and call routing. AIN architecture also generally allows relatively inexpensive computer systems to provide flexible and efficient call processing. Because the intelligent peripheral computer systems are easier to update, reprogram, and maintain than switches, telephone service providers can generally offer a wider variety of calling services. 
     Calling services are typically delivered by AIN architecture through service control points (SCP). A switch sends a data package to the SCP which then manages the call processing. SCP&#39;s usually delegate many of the tasks associated with the data package to intelligent peripherals (IPs). IPs generally provide a number of processing resources such as voice prompting and data collection. The SCP will normally defer a small part of the call processing to an IP, but will regain control immediately after the IP completes the task. In this prior art system model, the IP receives and executes only primitive commands such as Play Message or Collect Digits. 
     A typical contemporary AIN architecture system includes service nodes (SN). SNs are usually stand-alone platforms which independently deliver calling services. An SN is typically connected directly to a switch and is dedicated to deliver a particular calling service such as voice mail. After receiving a call, the switch directly routes it to the SN which then processes the call without much direction from the switch or SCP. SNs also may use IPs to provide primitive resources for call processing. Communication systems or calling service applications which use SNs and IPs together are commonly referred to as SN/IP applications. 
     A recent technological advance to the AIN architecture derives from a family of patents issued to Sattar et al., U.S. Pat. Nos. 5,469,500, 5,572,581, and 5,644,631. Sattar advanced the AIN architecture by establishing more coupling routines between SNs and IPs. The Sattar IP now typically performs more of the decision-making tasks previously handled by the SN. The SN is then left to perform the general call processing and the more complex decision-making tasks. In the context of calling service processing, this generally allows the SN/IP application to lessen fragmentation of the call flow. Call flow refers to the actual call connection between the user and the calling service and the control thereof. 
     The prior art in SN/IP applications, both before and after Sattar, uses a central program located on the SN which incorporates the call flow control, data access control, and asynchronous event handler. Data access control refers to the function of obtaining data from a source other than a user in response to a user input or call signal such as automatic number identification (ANI) or dialed number identification service (DNIS). The level of data access required depends on the particular calling service being provided. In a voice mail service, the data required would typically consist of a list of valid voice mailbox addresses to check against the user&#39;s entry, a list of the user&#39;s password or personal identification number (PIN) to check against the user&#39;s entry, and the actual message(s) stored in the mailbox. 
     The asynchronous event handler refers to the call processing/decision-making functions. When a user initiates a call, the asynchronous event handler generally receives the call “event code” and transfers it to the IP for interfacing with the telephony network. If an SN performs a certain function which requires data, the asynchronous event handler usually receives the “get data” command and then either forwards control to the IP if the data is required from the caller or forwards control to the data access control to get data from another source. When the data returns, an event code is typically transferred back to the asynchronous event handler to determine which piece of call flow to execute next. 
     FIG. 1 shows a typical SN/IP model of the prior art. The system will typically include multiple SNs  100 - 103 , each of which is dedicated to perform a different function. SNs of the same system will normally not be interconnected unless they are overlapped for redundancy. SNs  100 - 103  will generally be connected to multiple IPs  104 - 108  which interface with the telephone lines and, thus, also the voice path of the caller. A single SN  100  may be connected to several IPs  106 - 108 , or may just be connected to one, depending on the system configuration and calling function. SNs  100 - 103  may also be connected to data access routine  109  to perform any data collection other than from the caller. 
     In an example of pre-Sattar operation, a caller places a call to check the balance in his/her checking account. SN  100  receives the call and forwards it to IP  108  to set up the interface between the calling service and the caller. Because this SN does balance checking, SN  100  begins call flow and sends the initial instruction, Play Message, to IP  108 . When IP  108  plays the message, an event code is generated and control is forwarded back to SN  100 . SN  100  stops the call flow and then sends the instruction, Get Account Number, to IP  108 . Call flow begins again and the caller is prompted by IP  108  to enter the account number. When IP  108  gets the number entered by the caller, an event code is generated and sent back to SN  100 . Call flow stops. SN  100  sends an instruction to the data access routine  109  to return a list of valid account numbers. Data access routine  109  returns the list for SN  100  to check against the entered account number. If the number is valid, SN  100  begins call flow again and sends IP  108  the instruction, Get PIN. The process continues until the service has been completed. With all control processing elements located in the SN, the call flow is fragmented because the application must always stop the call flow to return to the SN to perform a particular task or make a particular decision. This start/stop, back and forth methodology makes control of the call flow much more complicated from the programming aspect. 
     After Sattar, because IP  108  is now able to handle more complex tasks, SN  100  is able to send a string of commands, thereby increasing the length of call flow segments. When the caller places the call, SN  100  begins call flow and sends IP  108  the instructions, Play Message, Get Account Number, Is Account Number Valid?, Get PIN, Is PIN Valid? Call flow begins. IP  108  plays the message, prompts the caller for the account number and checks that number against an internal database. IP  108  then prompts the user for the PIN and checks that number against another internal database. IP  108  then generates an event code and sends the data back to SN  100 . SN  100  stops call flow and then uses data access routine  109  to get the account balance corresponding to the account number. After obtaining the requested account balance information, SN  100  begins the call flow again and prompts IP  108  to play a message containing the account balance. In the Sattar model, the call flow presentation appears more linear than before. 
     A limitation of the prior art is that the system uses a central program to provide the call flow control, the data access control, and the asynchronous event handling. This centralization creates a complex, non-linear program. The call flow experienced by the caller is fragmented and scattered throughout the system. The Sattar patents help this by allowing larger segments of call flow to be kept together. Specifically, the IP portion of the program logic handles caller events and decisions, such as “Is Account Number Valid?” without intermixing those events and decisions with outgoing data access and asynchronous event handling program logic. However, the need for data access limits the length of the call flow segment that can be delegated to the IP. Each interaction by the caller with the data access control requires the call flow segment to end so the SN can use the caller information to retrieve more data. Only then can the SN reinitiate the next segment of call flow. This fragmentation makes programming and, therefore, maintenance of the system much more complex and expensive. 
     It would therefore be desirable to have a unified model for SN/IP applications which maintains continuous call flow as much as necessary and, thus, facilitates more linear programming of the system. 
     SUMMARY OF THE INVENTION 
     These features are achieved by a system and method for providing SN/IP applications which provide at least three distinct layers of concurrently operating control routines. This unified system comprises a first control layer, located on an SN, having an asynchronous event handler routine; a second control layer, located either on the same SN or a different one, having at least one data access routine; and a third control layer, located on an IP, having a call flow routine, wherein the third control layer is connected to the first and second control layers and wherein the IP provides the SN/IP applications with an interface to a telephony network. The present invention also provides for the asynchronous event handler routine and the call flow routine to operate concurrently. 
     The present invention produces the desired characteristics through a method for modeling SN/IP applications comprising the steps of implementing an event management function on an SN; implementing at least one data management function on an SN; implementing a call flow management function on an IP, wherein the call flow management function is connected to the event management function and to each of the data management function(s). Operating the event management function and the call flow management function concurrently. 
     It is an advantage of a preferred embodiment of the present invention to provide SN/IP applications by allowing the creation of programs as a set of nested routines running independently and concurrently on three different control layers. Because each layer focuses only on a particular portion of the overall calling service, that portion may be written or presented in a substantially linear fashion. This linear presentation generally keeps the call flow intact and greatly reduces the complexity of development and maintenance of the software. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: 
     FIG. 1 is a block diagram illustrating a prior art SN/IP application; 
     FIG. 2 is a flow diagram illustrating the three layer model of the present invention; 
     FIG. 3 is a block diagram illustrating a preferred embodiment of the present invention which includes the three control layers implemented on two layers of hardware; and 
     FIG. 4 is a flow diagram illustrating the basic operation of the present invention. 
    
    
     DETAILED DESCRIPTION 
     The present invention achieves uninterrupted call flow and facilitates nearly linear programming design by using three separate control layers which operate independently from and concurrently with each other. FIG. 2 shows the relationship between the three control layers. The asynchronous event handler routine  20  forwards an incoming call to the call flow routine  21  through link  200  which initiates the call flow. During the course of the call, call flow routine  21  can forward event handling to the asynchronous event handler routine  20  through link  200  and data requirements to the data access routine  22  through link  201  while keeping the call flow open. As the asynchronous event handler routine  20  and data access routine  22  complete their processing, the results are forwarded to the call flow routine  21  which may act on the resulting information. 
     A preferred embodiment of the present invention achieves these advantages by using three separate control layers which operate independently and concurrently on at least two separate layers of hardware. This preferred embodiment is shown in FIG.  3 . The event management function  301  and the data management function  302  are both located on SN  30 . Call flow management function  300  is located on IP  31 . Thus, the three control layers are located on two layers of hardware. 
     The control layers are connected in such a way so as to allow call flow management function  300  to pass information back and forth between event management function  301  through link  32 . Call flow management function  300  is also connected through link  33  to pass information back and forth between data management function  302 . Although not shown, in an alternative embodiment of the present invention may provide a link for information communication directly between event management function  301  and data management function  302 , if desired. Of course, such information communication may be provided in the embodiment illustrated in FIG. 3 indirectly through call flow management function  300 . In the preferred embodiment, all three control layer routines operate concurrently and are, therefore, co-routines. This co-routine relationship allows the call flow to remain open through the duration of the call and also facilitates an uninterrupted presentation to the caller. 
     In the general operation of the preferred embodiment of the present invention, as shown in the flow chart of FIG. 4, an incoming call  400  to an SN/IP application is forwarded in step  401  by asynchronous event handler routine  45  to call flow routine  40 . This initiates the call flow  402 . As events arise during the course of the call, call flow routine  40  passes the event code to asynchronous event handler routine  45 , as shown in steps  420  and  424  to process the event. Call flow routine  40  preferably maintains the call flow in steps  405 - 408  while asynchronous event handler routine  45  concurrently processes the event in steps  421 - 423 . Similarly, when a need for data arises during a call, call flow routine  40  passes a request for data to data access routine  47  as shown in step  440 . Data access routine  47  preferably concurrently processes the data request in steps  441 - 442  and returns the requested data in step  443 , while call flow routine  40  maintains the call flow as shown in steps  405 - 409 . During the time in which asynchronous event handler routine  45  is processing the event or in which data access routine  47  is processing the data request, call flow routine  40  may play pre-recorded message asking the caller to wait while the necessary information is accessed, as shown in steps  406  and  407 . This process is preferably repeated as required until the caller&#39;s business is finished, the caller hangs up, or the caller is disconnected as shown in steps  410 ,  424 , and  425 . Thus, the call flow preferably remains open during the entire call as shown in steps  402 - 410 , even while events are processed, steps  420 - 423 , and data is accessed, as in steps  440 - 443 . The constant call flow allows for a more linear program to control the system and provides a more pleasant interface with the caller. Such linear programming is easier to develop and maintain than that required for a random, disjointed call flow. 
     In a more specific example using the preferred embodiment shown in FIG. 3, consider a telephony application for providing calling card long distance service. A call comes in prompting event management function  301  to transfer the call to call flow management function  300  to launch the call flow. Call flow management function  300  answers the phone, plays a greeting message, prompts the user for the target phone number and the user&#39;s PIN or account number. Once the user enters the numbers, call flow management function  300  sends a request to data management function  302  to find out whether the PIN number entered is valid. While data management function  302  retrieves the requested data, call flow management function  300  preferably keeps the call flow open. Call flow management function  300  may play a message, such as an advertisement or new service announcement, to the caller while the data is being retrieved. Call flow management function  300  may also interact with the caller to provide a related service. At some point, data management function  302  returns the requested data and, in this particular example, call flow management function  300  discovers that the PIN corresponds to a stolen calling card. Call flow management function  300  returns an event code to event management function  301  which corresponds to a message that the current call needs to be taken out of the normal call flow. Event management function  301  then preferably launches two new fraud detection applications. One of these applications may be a separate call flow management function on the same or another IP (not shown) designed to keep the caller on the line. The other application preferably initiates a call to a service center with the message that a stolen card is being used. The service center application (not shown) may provide information to the service center to facilitate tracing the call. If the service center is able to trace the call before the caller hangs up, the service center application returns an event code to event management function  301  indicating that the call may now be terminated. With that event code, event management function  301  terminates the connection. In the event that the caller hangs up before the service center can complete a trace, the keep busy routine preferably returns an event code to event management function  301  indicating the caller is no longer on the line. Event management function  301  then preferably sends a message to service center application to inform service center that the caller is no longer there. Event management function  301  then terminates the service center routine. 
     In this example, the call flow advantageously remains intact because the event management function  301  and the data management function  302  preferably operate concurrently with call flow management function  300 . The only break in call flow comes when the caller is transferred to the keep busy call flow management function. This example also illustrates an embodiment wherein SN  30  is preferably connected to more than one call flow management function (call flow management function  300 , keep busy management function, and the service center application) and thus possibly more than one IP. 
     It should be noted that the preferred embodiment of the present invention is not limited to applications directed solely at voice telephone call processing. The preferred embodiment also encompasses video, data, and multimedia processing. An incoming call can be placed by a person on a land-line telephone, a wireless phone, through a low-speed connected computer, a high-speed multimedia computer, or any other device which is capable of connecting over a telecommunications system. Such an embodiment of the present invention may use a data application which conforms to the model disclosed in the above-referenced U.S. patent application, USER DEVICE-INDEPENDENT TRANSACTION MODEL. The invention of this referenced application describes a model in which the user data may be stored in one place and in a generic format. The device-independent transaction model determines the user&#39;s access format and then adapts the generic user information into the appropriate format to be viewed or received by the user. This user device-independent format streamlines the data access process while expanding the user access capabilities. 
     In an alternative embodiment, data management function  302  does not operate concurrently with event management function  301  and call flow management function  300 . Although concurrent operation of all three control layers is most desirable and produces a more powerful and flexible result, the basic model can be achieved with only call flow management function  300  and event management function  301  operating concurrently. Another alternative embodiment allows event management function  301  and data management function  302  to be located on separate SNs. 
     A further alternative contemplates data management function  302  performing a portion of the decision-making or processing of data required for the call. In this alternative, a request for data is forwarded from call flow management function  300  to data management function  302 . After the data management function  302  retrieves the requisite data, data management function  302  processes the data and returns a result of the processing for use by call flow management function  300 . Therefore, if call flow management function  300  is performing a function which checks the PIN of a caller, call flow management function  300  preferably passes the request to look up the PIN to data management function  302 . Data management function  302  looks up the table containing the list of valid PINs, checks the PIN entered by the caller against the list, and then returns a pass/fail response to call flow management function  300 . 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.