Abstract:
A scalable call management system. The system can include at least one voice server hosting one or more voice browsers, the voice server having a single communications port through which voice call requests can be processed by the voice browsers, each voice browser having a port alias through which call requests can be processed. The system also can include a call processing gateway linking telephony endpoints in a public switched telephone network (PSTN) to the voice server. Finally, the system can include a translation table mapping port aliases to respective voice browsers.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The invention relates to the field of call management systems and more particularly, to Internet protocol (IP) telephony based call management systems. 
   2. Description of the Related Art 
   IP telephony provides an alternative to conventional circuit switched telephony which requires the establishment of an end-to-end communication path prior to the transmission of information. In particular, IP telephony permits packetization, prioritization and simultaneous transmission of voice traffic and data without requiring the establishment of an end-to-end communication path. As a result, IP telephony can capitalize upon Voice over IP (VOIP) technologies which advantageously provide a means by which voice traffic and data can be simultaneously transmitted across IP networks. 
   Common applications of IP telephony can include the integration of voice mail and electronic mail (e-mail). Other applications can include voice logging by financial or emergency-response organizations. Additionally, automated call distribution and interactive voice response (IVR) systems can employ IP telephony as a workflow component. Nevertheless, call management systems, have lagged in the utilization of IP telephony. In particular, call management systems operate on real-time audio signals which cannot tolerate latencies associated with traditional data communications. As such, where call management systems are implemented using an IP telephony topology, the speech processing portions of the call management systems have been closely integrated with the IP telephony portion in order to overcome the inherent latencies of traditional data communications. In consequence, the design and development of IP telephony enabled call management systems have been closely associated with the proprietary nature of IP telephony. 
   The close association between speech processing and IP telephony portions of a call management system substantially limits both the design and the extensibility of the speech processing portion of the call management system. Specifically, in the present paradigm the speech processing design can incorporate functionality directly job related to the chosen protocol for transporting packetized voice data to a speech application. As a result, the development of a superior voice transport protocol, the nature of the tight linkage between the IP telephony server and the speech processing portion of the call management system can compel the redesign of the speech application. 
   Aside from the close association between the IP telephony and speech processing portions of call management applications, IP telephony based call management systems can provide telephony support for a single voice browser session in a voice server. Both the single voice browser implementation and the proprietary nature of such call management systems, however, can substantially limit scalability. The scalability problem can be compounded where multi-vendor applications are integrated within such call management systems. While attempts have been made to standardize IP telephony interfaces, such as the Java Telephony Application Programming Interface (JTAPI), such attempts still remain limited to providing IP telephony support through single voice browsers within single voice servers. 
     FIG. 1  is a schematic depiction of a call management system configured for IP telephony which illustrates the foregoing deficiencies. Specifically, the call management system  100  can include one or more telephony end-points through which individual callers can interact with individual voice servers  120 ,  130 ,  140  over the telephony network  105 . The call management system  100  further can include a voice gateway  106  which can convert call request data configured for use in the telephony network to packet-based request data suitable for use in an IP-based network. In that regard, the gateway  106  can be configured to route individual calls between individual telephony end-points  102   a ,  102   b ,  102   c  and voice browsers  122 ,  132 ,  142  of respective voice servers  120 ,  130 ,  140 . 
   In the conventional call management system  100 , each voice server  120 ,  130 ,  140  can include a voice browser  122 ,  132 ,  142  which can moderate a caller&#39;s voice interaction with voice-configured content stored in the respective voice server  120 ,  130 ,  140 . Voice content can include markup specified content which, when interpreted by a voice browser  122 ,  132 ,  142 , can be audibly presented to callers using conventional text-to-speech technology. Additionally voice content can include markup which, when interpreted by a voice browser, can convert caller-provided speech into computer processable text using conventional speech recognition technology. An exemplary markup language which can be used to format voice content can include the well-known VoiceXML. 
   In operation, a first caller can initiate a call to a speech application using the telephony end-point  102   a . The call can include a call request that can be routed through the PSTN  105  to gateway  106 . The gateway  106  can route the call to port  121  of voice server  120 , where the call can be processed by voice browser  122 . In addition to the first call, the gateway  106  can route a second call from a second caller at telephony end-point  102   b  to port  131  of voice server  130 , where it can be processed by voice browser  132 . Finally, the gateway  106  can route yet a third call from a third caller through telephony end-point  102   c  to port  141  of voice server  140 , where it can be processed by voice browser  142 . 
   Significantly, if the gateway  106  receives a fourth call request from a fourth caller  102   d , the call request cannot be processed without adding an additional voice browser to complement the already utilized voice browsers  122 ,  132 ,  142 . In particular, each voice browser  122 ,  132 ,  142  can handle only a single call at one time because each voice browser  122 ,  132 ,  142  has but a single port  121 ,  131 ,  141  for communicating directly with voice servers  120 ,  130 ,  140 , respectively. In consequence of the single port limitation, however, it can be difficult and expensive to scale the call management system  100  to handle many call requests. 
   SUMMARY OF THE INVENTION 
   The present invention is a scalable call management system and method which overcomes the deficiencies of the prior art by providing a single port voice server able to manage calls between one or more corresponding voice browsers using a system of port aliases and a translation table mapping of the port aliases. In consequence of the call management system of the present invention, additional voice browsers can be added to the system to respond to call requests simply by creating additional instances of the voice browsers, assigning new port aliases for each additional voice browser instance, and mapping the new port aliases in the translation table. 
   In accordance with the inventive arrangements, a scalable call management system can be provided which can include at least one voice server hosting one or more voice browsers, the voice server having a single communications port through which voice call requests can be processed by the voice browsers, each voice browser having a port alias through which call requests can be processed. The system also can include a call processing gateway linking telephony endpoints in a public switched telephone network (PSTN) to the voice server. Finally, the system can include a translation table mapping port aliases to respective voice browsers. 
   Notably, the voice server can include a communications interface to the call processing gateway; and, at least one call control component communicatively linked to each of the voice browsers. In consequence, call requests received in the call processing gateway can be routed through the communications interface to selected ones of the voice browsers. Furthermore, resulting call connections can be managed by the at least one call control component. 
   In a distributed aspect of the system of the invention, a distributed call manager server can be provided which can include a communications interface to the call processing gateway and at least one call control component linking the voice servers to the distributed call manager server. In either case, however, each voice browser can execute in a separate virtual machine having a separate process address space. As such, the voice server can scale to accommodate changes in call activity by instantiating additional voice browsers in additional virtual machines and by associating a port alias for each additional voice browser in the translation table. 
   In another aspect of the invention, a call management method can be provided which can include the steps of registering a voice server with a gateway, the voice server having a plurality of registered voice browsers; and transferring telephone call data to and from each of the voice browsers using a port alias assigned to the voice browser and a port address assigned to the voice server to which each voice browser is registered. Importantly, the translating step can include inspecting a mapping of voice server ports and corresponding voice browser port aliases to identify voice servers and corresponding voice browsers which are available to process call requests; routing each received call request to an available voice browser in an available voice server; and, noting in the mapping that each available voice browser now is unavailable. 
   Significantly, the call management system of the present invention can scale in accordance with changing call processing requirements. In particular, the call management system method of the invention further can include adding additional voice browsers to the voice server and assigning additional port aliases to each of the additional voice browsers in response to detecting increased levels of call activity in the voice server. Alternatively, in response to detecting increased levels of call activity in the gateway, additional voice servers can be registered to the gateway, each additional voice server including one or more voice browsers. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     There are shown in the drawings embodiments which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown, wherein: 
       FIG. 1  illustrates a conventional call management system of the prior art; 
       FIG. 2  is a schematic illustration of a call management system which has been configured in accordance with the inventive arrangements; and, 
       FIG. 3  is a schematic illustration of a distributed call management system in accordance with the inventive arrangements. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention is a scalable call management system which overcomes the deficiencies of the prior art. Unlike conventional call management systems which are limited to providing IP telephony connectivity to single voice browsers within individual voice servers, in the scalable call management system of the present invention, IP telephony support can be extended to multiple voice browsers in individual voice servers, thus overcoming the limitations of the prior art. In particular, the scalable call management system of the present invention can cure deficiencies of the conventional call management system despite the single port configuration of individual voice servers. 
   In accordance with the present invention, a scalable call management system can include one or more voice servers communicatively linked to a VoIP gateway. Within each voice server, one or more voice browsers can be configured to receive and process calls from telephony endpoints despite the single port limitation of the voice server. Specifically, in the present invention, each voice browser can be assigned a different port identifier which can be associated with the voice server port of the respective voice server. During the transfer of call data between the gateway and a voice browser, the port identifier of the voice browser can be used by the voice server to resolve the identity of the voice browser, though the gateway need only maintain an awareness of the identity of the voice server. Advantageously, voice browsers can be distributed in the call management system of the present invention to facilitate scalability. 
     FIG. 2  is a schematic illustration of a scalable call management system which has been configured in accordance with the present invention. Referring to  FIG. 2 , there is shown multiple voice servers  320 , each having a single port  325  respectively. Each of the voice servers  320  can include an voice communications interface  330  that can facilitate communication with a VoIP gateway  306 . In one aspect of the invention, the voice communications interface  330  can be a Java implementation of a H.323 stack, referred to in the art as J.323. Notwithstanding, the voice communications interface  330  can incorporate other voice protocol compatible interfaces such as a SIP compatible interface. 
   A call media server (MS) component  335  and a call control server (CS) component  340  also can be provided in each voice server  320  for facilitating communication between the voice communications interface  330  and one or more voice browsers  350 . In particular, as will be apparent to one skilled in the art, the MS  335  and CS  340  components can be JTAPI applications which utilize an H.323 stack. Similar to the voice servers  320 , each of the voice browsers  350  can be configured to include a call control client (CC) component  360  and a call media client (MC) component  355 . The CS component  340  can facilitate call control for each of the voice browsers  350  managed by the voice server  320 . In particular, the CC component  360  can manage call control between an associated voice browser  350  and the CS component of the parent voice server  320 . 
   In order to overcome the inherent limitations of a single port voice server, in the present invention, each voice server  320  can include a translation table or map (not shown) which can be utilized to facilitate the transfer of call data between the gateway  306  and the voice browsers  350 . An exemplary translation table is illustrated below. 
   
     
       
             
             
             
             
             
           
         
             
                 
             
             
               Gateway 
               Voice Server 
               Voice Server 
               Voice Browser 
               Voice Browser 
             
             
               Port 
               Port 
               Port Status 
               Port 
               Port Status 
             
             
                 
             
           
           
             
               P:400 
               P:410 
               0 
               P:410.410a 
               0 
             
             
               P:400 
               P:410 
               0 
               P:410.410b 
               1 
             
             
               P:400 
               P:410 
               0 
               P:410.410c 
               1 
             
             
               P:400 
               P:420 
               1 
               P:420.420a 
               1 
             
             
               P:400 
               P:420 
               1 
               P:420.420b 
               1 
             
             
               P:400 
               P:420 
               1 
               P:420.420c 
               1 
             
             
               P:400 
               P:430 
               0 
               P:430.430a 
               0 
             
             
               P:400 
               P:430 
               0 
               P:430.430b 
               0 
             
             
               P:400 
               P:430 
               0 
               P:430.430c 
               0 
             
             
                 
             
           
        
       
     
   
   Referring to the translation table above, each of the voice servers can be assigned a port number or identifier. For example, port  410  of one voice server can be assigned a port number P: 410 . By comparison, port  420  of another voice server can be assigned port number P: 420  and so forth. Since each voice server has but a single port, individual voice browsers can be given an alias address, for example voice browsers  430   a ,  430   b  and  430   c  which are associated with the voice server having port  430  can be assigned respective port addresses of P: 430 : 430   a , P: 430 : 430   b  and P: 430 : 430   c . Similarly, voice browsers  410   a ,  410   b  and  410   c  which are associated with the voice server having port  410  can be assigned respective port addresses of P: 410 : 410   a , P: 410 : 410   b  and P: 410 : 410   c . Finally, the availability of each voice server and browser can be maintained in the translation table, for instance, a “1” denoting an unavailable port and a “0” denoting an available port. 
   In operation, when a call request is received by a gateway, the call request can be forwarded through gateway port P: 400  to an available voice browser. Specifically, by consulting the translation table, a determination can be made as to which voice browser is available to process the call request. Once an available voice browser in an available voice server has been detected, the translation table can be consulted to determine the port number of the available voice browser. Once an available voice browser has been selected, the selected voice browser can process the call request. 
   As one skilled in the art will recognize, by providing individual alias port addresses for each voice browser in a server, and a corresponding translation table, the scalable call management system of the present invention can provide an efficient means for load balancing call requests received in a call processing gateway. Specifically, as call requests are received in the gateway, available voice servers having available voice browsers can be identified and the call requests can be passed therethrough. Additionally, as each voice server can host multiple voice browsers in separate virtual machines, the configuration of voice browsers can be changed dynamically to accommodate changing load requirements. Specifically, voice browsers can be loaded and unloaded as the case may be in each voice server. Hence, the call management system of the present invention can be scaled. 
   Importantly, the scalable call management system of the present invention can support telephony calling features such as automatic number identification/dialed name identification service (ANI/DNIS). As one skilled in the art will recall, ANI permits the billing number of a party as opposed to the directory number (DN) of the originating party to be transmitted through the network during call setup. By comparison, DNIS permits the authorization of a call attempt based on the called party&#39;s or billing party&#39;s DN. In the present invention, a voice browser  350  can be configured to register with a voice server  320  for an incoming call, during which process the voice browser  350  can instruct the CS  340  and MS  335  components to only route calls satisfying certain ANI and/or DNIS criteria to be processed by the voice browser  350 . 
   Notably, in one aspect of the present invention, the functionality of the MS  335  and CS  340  components of each voice server can be provided within a single component, for example the distributed call management server (DCMS)  470  shown in  FIG. 3 . Referring now to  FIG. 3 , advantageously, the DCMS  470  can include a call control server  440 , a call media server  445 , and a voice browser  450  in order to provide a distributed interface that permits individual voice server  420  to register for incoming calls. In consequence, each voice server  420  can execute on remote or local systems and can be platform, including machine and operating system (OS), independent. 
   A VoIP gateway  406  can be communicatively linked to a port  475  of the DCMS server  470  through a communications interface  430 , such as an H.323 compatible stack. In particular, the communications interface  430  can facilitate communication between the DCMS  470  and the gateway  406 . Notably, like each voice server  420 , the DCMS  470  can execute within a process address space which is separate and independent of each of the voice servers  420 . For example, in a Java based implementation, the DCMS  470  can executed in its own JVM. Since each of the voice servers  420  also can have a call control client interface  440  and call media client interface  435 , each voice server  420  also can execute within separate JVMs. Each voice server  420  can further include a call control (CC) component  460  and a call media client (MC) component  455 . Advantageously, this distributed architecture con permit great flexibility in scaling the call management system of the present invention. 
   The present invention can be realized in hardware, software, or a combination of hardware and software. A distributed call management system according to the present invention can be realized in a centralized fashion in one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system, or other apparatus adapted for carrying out the methods described herein, is suited. A typical combination of hardware and software could be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. 
   The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which, when loaded in a computer system, is able to carry out these methods. Computer program or application in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following a) conversion to another language, code or notation; b) reproduction in a different material form. Significantly, this invention can be embodied in other specific forms without departing from the spirit or essential attributes thereof, and accordingly, reference should be had to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.