Abstract:
Systems and methods are disclosed for enabling an embedded media terminal adapter (EMTA) with included MIB objects to redirect a received telephone call. Based on the MIB objects, the EMTA communicates with a cable modem termination system (CMTS) to set up two service flows where one flow is set up between two EMTAs and one flow is set up between the endpoint EMTA and the NOC.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates in general to voice over Internet Protocol systems over broadband, more specifically broadband over coaxial cable, and more particularly, to the field of enabling a media terminal adapter to redirect a telephone call to a second endpoint. 
       BACKGROUND OF THE INVENTION 
       [0002]    Multiple services operators (MSOs) are now capable of providing many services in addition to broadcast audio/video signals over their existing systems. Some advanced services in a broadband communications system provide conventional cable television signals along with other telephony services, such as high-speed data and telephone. To support these additional services, cable modems and media terminal adapters (MTAs), which is also known as embedded media terminal adapters (EMTAs) when the cable modem is included in an MTA, are used in the subscriber&#39;s premises and have typically been coupled with coaxial cable to a communications network. U.S. Pat. No. 6,161,011 to Loveless, the disclosure and teachings of which are incorporated herein by reference, shows an example of a hybrid fiber/coaxial (HFC) communications network that could be used to implement the present invention. 
         [0003]    Public switched telephone networks (PSTNs) traditionally carry voice signals using a circuit-switched infrastructure. This infrastructure lends itself easily to a Network Operation Center (NOC) intercepting a call that is in progress at multiple points throughout the network to assess the voice quality. On the other hand, a Voice over Internet Protocol (VoIP) network in a broadband communications system uses IP packets to route telephone calls. Due to the nature of IP packet routing, which can take many different paths in the system, it is extremely difficult to intercept a call and determine possible problems. 
         [0004]    Thus, there exists a need for a more efficient system and method of intercepting a telephone call in a VoIP communications system. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. In the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0006]      FIG. 1  is a block diagram of a PSTN and a VoIP communications system that are suitable for transmitting voice and data signals. 
           [0007]      FIG. 2  is a block diagram of the VoIP communications system of  FIG. 1  including call routing equipment that is suitable for use in the present invention. 
           [0008]      FIG. 3  is a block diagram of a subscriber&#39;s premise including an EMTA coupled to telephones and a computer that is suitable for use in the system of  FIG. 2 . 
           [0009]      FIG. 4  is a block diagram of the EMTA of  FIG. 3 . 
           [0010]      FIG. 5  is a table illustrating management information base (MIB) objects table in accordance with the present invention. 
           [0011]      FIG. 6  is a block diagram illustrating a conventional call flow throughout the VoIP communications system of  FIG. 2 . 
           [0012]      FIG. 7  is an abridged illustration of steps included in the conventional call flow of  FIG. 6 . 
           [0013]      FIG. 8  is a block diagram illustrating a redirected call flow throughout the VoIP communications system of  FIG. 2  in accordance with the present invention. 
           [0014]      FIG. 9  is an abridged illustration of steps included in the redirected call flow of  FIG. 8  in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Preferred embodiments of the invention can be understood in the context of a broadband communications system. Note, however, that the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. All examples given herein, therefore, are intended to be non-limiting and are provided in order to help clarify the description of the invention. 
         [0016]    The present invention is directed towards enabling a destination EMTA, i.e., an endpoint EMTA, to redirect a received telephone call in a VoIP communication system. MIB objects are downloaded to the endpoint EMTA specifying a redirected endpoint address, e.g., a NOC or other customer service department, and a control function, which enables the redirect mode. Accordingly, a technician in the NOC is able to receive the redirected voice packets of a phone call. In this manner, a technician is able to troubleshoot the call in order to determine any quality problems. 
         [0017]      FIG. 1  is a block diagram of a PSTN  105  and a VoIP communications system  110  that are suitable for transmitting voice and data signals. The VoIP communications system  110  typically includes a managed Internet Protocol (IP) network  115  and a plurality of HFC networks, where only one HFC network  120  is shown. A headend facility  125  transmits, receives, and manages video, audio, and data signals with a plurality of headend equipment. In a VoIP communications system  110 , voice packets are routed throughout the IP network  115  to various HFC networks via a connected hub  130  depending upon a destination address(es). Optical fiber  135  transports the voice packets to an optical node  140  for conversion into electrical signals. Coaxial cable  145  then delivers the converted electrical signal containing voice packets to an intended subscriber  150   a - d . As mentioned, operators are generally able to intercept voice packets at multiple points throughout the PSTN  105  due to the nature of the circuit-switched environment. In contrast, operators are not able to intercept voice packets as readily in a VoIP system  110  due to the many different routes voice packets may take throughout the system  110 , as well as far-end echo that prohibits proper analyzing of the voice packets. 
         [0018]      FIG. 2  is a block diagram of the VoIP communications system  110  of  FIG. 1  including call routing equipment that is suitable for use in the present invention. Routing equipment includes a plurality of CMTSs  205   a - b  that connects to all cable modems or EMTAs in the system  110 . The CMTSs  205   a - b  are also the connectivity point between the IP network  115  and an HFC network  120   a - b . A call management server (CMS)  210 , also known as a softswitch, controls the video and audio call connections. Additionally, a NOC  215 , or other customer service organization, includes people and other technical equipment in order to service the VoIP communications system  110 . 
         [0019]      FIG. 3  is a block diagram of a subscriber&#39;s premise  150   a  including an EMTA  320  coupled to telephones  325  and a computer  330  that is suitable for use in the system of  FIG. 2 . A radio frequency (RF) splitter  310  receives the incoming signals and routes the signals to a DHCT  315  and an EMTA  320 . The DHCT  315  processes cable television packets for display subsequent display on a television. The EMTA  320  processes and routes all received voice and data packets to an appropriate endpoint telephone  325  and/or computer  330 . 
         [0020]      FIG. 4  is a more detailed block diagram of the EMTA of  FIG. 3 . A coaxial F connector  410  connects the EMTA  320  to the VoIP communications system  110 . A tuner  415  then receives and filters data intended for the EMTA  320  and routes the data to a processor  420 . If the data is intended for a coupled computer, the processor  420  routes the data to either an Ethernet connector  435  or a USB connector  440  depending upon the application. If the data is telephony data, the data is routed to a telephony digital signal processor (DSP)  445  for further processing, such as code decoding, packetization, echo cancellation, or other telephone signal processing. The telephony data is then routed to a connected telephone  325  and/or computer softphone  330  via a subscriber line interface chip (SLIC)  450 . The telephone  325  and computer  330  are typically connected to the EMTA  320  with CAT-3 or CAT-5 wiring and an RJ11 telephone jack  455 . The EMTA  320  also includes a power supply  460  for powering the telephony DSP  445  and the SLICs  450  as well as memory  425 , such as SDRAM and Flash memory, for system storage purposes. 
         [0021]      FIG. 5  is a table illustrating management information base (MIB) objects table  500  in accordance with the present invention. The MIB objects table  500  generally may be included in non-volatile memory of the EMTA  320  or it may be a downloadable configuration file. In the present invention, a subscriber  150   b  that may be experiencing audio problems may have a MIB objects downloaded to their EMTA  320 . The downloaded MIB objects and the associated operation identification number (OID)  510 , i.e., the object&#39;s numbering scheme, are stored in the MIB objects table  500 . Accordingly, a first MIB object  515  designating an EMTA redirect address is given an IP address of the NOC. A second MIB object  520  enables redirected mode. The redirect mode may be disabled by downloading another MIB object returning the control function  520  to normal call processing. 
         [0022]      FIG. 6  is a block diagram illustrating a conventional call flow throughout the VoIP communications system  110 , and  FIG. 7  is an abridged illustration of steps included in the conventional call flow of  FIG. 6 . Referencing  FIGS. 6 and 7 , when an originating subscriber  150   a  initiates placing a call from either a telephone  325  or a computer softphone in step  705 , the subscriber&#39;s EMTA  320   a  may identify and verify a dialed valid number by an included digit map. Alternatively, the CMS  210  may perform this function. Once verified, the EMTA  320   a  builds a packet that contains information about the EMTA  320   a  and the number dialed. Also included in the packet is a destination IP address of the CMS  210 . Accordingly, the packet is routed to the subscriber&#39;s CMTS  205   a  and then on to the CMS  210 . The CMS  210  searches a database to determine the CMTS that serves the destination dialed telephone and then routes the voice packets through the IP network  115  to the correct hub  130   b , which routes the voice packets to the determined CMTS  205   b . The CMS  210  then creates a connection (CRCX) in step  710  with the destination EMTA  150   b , i.e., endpoint EMTA, in step  710 . The endpoint EMTA  150   b  sets up a dynamic service add (DSA) in step  715 , which sets up a service flow with its associated CMTS  205   b . The CMTS  205   b  sends a response in step  720  that is acknowledged by the endpoint EMTA  150   b  in step  725 . The endpoint EMTA  150   b  then sends an acknowledgement of the last command in step  730  to the CMS  210 , and an open line of communication is then set up between the callers  150   a ,  150   b  allowing for the voice packets to be freely transmitted using real time protocol (RTP) in step  735 . 
         [0023]    In step  740 , when the call is over, a notify hang up signal is sent from the endpoint EMTA  150   b  to the CMS  210 . The CMS  210  in steps  745  and  750  acknowledges the command and deletes the connection (DLCX). The endpoint EMTA  150   b  acknowledges the DLCX command in step  755  and, in step  760 , sends a dynamic service delete (DSD) to the CMTS  250   b  deleting the service. The CMTS  250   b  responds in step  765 , and the endpoint EMTA  150   b  acknowledges in step  770 , thereby ending the call. 
         [0024]      FIG. 8  is a block diagram illustrating a redirected call flow throughout the VoIP communications system of  FIG. 2 , and  FIG. 9  is an abridged illustration of steps included in the redirected call flow of  FIG. 8  in accordance with the present invention. Referencing  FIGS. 8 and 9 , an originating subscriber  150   a  initiates a call in step  905 . After verifying the dialed number, the subscriber&#39;s EMTA  320   a  builds a packet that contains information about the EMTA  320   a  and the number dialed. Also included in the packet is a destination IP address of the CMS  210 . Accordingly, the packet is routed to the subscriber&#39;s CMTS  205   a  and then on to the CMS  210 . The CMS  210  searches a database to determine the CMTS that serves the destination dialed telephone and then routes the voice packets through the IP network  115  to the correct hub  130   b , which routes the voice packets to the determined CMTS  205   b . The CMS  210  then creates a connection (CRCX) in step  910  with the endpoint EMTA  150   b  in step  710 . 
         [0025]    In accordance with the present invention, MIB object enabling the redirected mode along with the NOC address are downloaded to the endpoint EMTA  150   b . Accordingly, the endpoint EMTA  150   b  relays the CRCX command to the NOC  215  in step  915 , and the NOC sends an acknowledgement in step  920 . The endpoint EMTA  150   b  then sets up two dynamic service adds (DSAs) in step  925 , which sets up two separate service flows with its associated CMTS  205   b  first with the calling endpoint  150   a  and a second service flow with the NOC  215 . The CMTS  205   b  sends a response for the two service flows in step  930  that is acknowledged by the endpoint EMTA  150   b  in step  935 . The endpoint EMTA  150   b  then sends an acknowledgement of the last command in step  940  to the CMS  210 . In steps  945  and  950 , an open line of communication is then set up between the endpoint EMTA  150   b  and the NOC  215  to route RTP voice packets; in addition, a relay is set up allowing for the voice packets to be relayed between the endpoint EMTA  150   b  and the originator  150   a . In this manner, the NOC  215  receives all voice packets for analyzing. 
         [0026]    In step  960 , when the call is over, a notify hang up signal is sent from the endpoint EMTA  150   b  to the CMS  210 . The CMS  210  in steps  965  and  970  acknowledges the command and deletes the connection (DLCX). The endpoint EMTA  150   b  acknowledges the DLCX command in step  975  and, in step  980 , the NOC  215  sends an acknowledgement signal. The endpoint EMTA  150   b  sends a dynamic service delete (DSD) to the CMTS  250   b  deleting the two services in step  985 . The CMTS  250   b  responds in step  990 , and the endpoint EMTA  150   b  acknowledges in step  995 , thereby ending the call. 
         [0027]    It will be appreciated that a solution to redirecting a call cannot be accomplished with conventional call forwarding. Call forwarding instructions are handled with the CMS  210 , not with the EMTA  150   a - d . Accordingly, a call initiated by a subscriber with an initiating EMTA  150   a  is routed to the appropriate endpoint by the CMS  210 . The CMS  210  determines that the desired endpoint subscriber  150   b  has enabled call forwarding and immediately responds to the initiating EMTA  150   a  to route the call to the forwarded number not the endpoint EMTA  150   b . At this point, the NOC  215  cannot determine any issues that the endpoint EMTA  150   b  may be experiencing since the call is not routed to that point. 
         [0028]    Accordingly, systems and methods have been provided that enables an EMTA to redirect calls in order for reasons such as testing and troubleshooting. It is understood that though the examples described in the description are directed towards an on-net call, i.e., calls within the VoIP communications system  110 , the system and methods described also apply to an off-net call, i.e., a call received from the PSTN  105 . Additionally, careful attention to security should be required due to the redirecting of telephone calls. It will be appreciated that further embodiments are envisioned that implement the invention, for example, using all software or adding modes for additional features and services.