Abstract:
A method of conducting covert surveillance of a subject is provided for within a telecommunications network. The surveillance includes surveillance of a monitored call connected over the network, the monitored call being between the subject and an associate and including circuit-switched or packet-switched call content, i.e., bearer traffic exchanged between the subject and the associate. The method includes: clandestinely receiving the circuit-switched or packet-switched call content; converting the received circuit-switched call content into a packet-switched format; and, delivering the call content in the packet-switched format to a designated law enforcement agency over a packet-switched data network.

Description:
FIELD  
       [0001]     The present inventive subject matter relates to the telecommunication arts. Particular application is found in conjunction with class 5 telecommunications switches, and the specification makes particular reference thereto. However, it is to be appreciated that aspects of the present inventive subject matter are also amenable to other like applications.  
       BACKGROUND  
       [0002]     As is known in the art, the Communications Assistance for Law Enforcement Act (CALEA) prescribes the statutory obligations of a telecommunications carrier to assist a Law Enforcement Agency (LEA) in executing electronic surveillance pursuant to a court order or other lawful authorization. Under CALEA, the telecommunications carrier is generally obliged to provide a suitable means for LEAs to monitor the calls of telephone subscribers when the LEAs are duly authorized under the law to engage in such surveillance of the subscribers. CALEA simply seeks to ensure that after an LEA obtains the appropriate legal authority, the telecommunications carrier will have appropriate capability, and sufficient capacity, to assist the LEA regardless of their specific systems or services. Accordingly, various implementations have been developed to accommodate CALEA compliance.  
         [0003]     In certain instances, for example, to achieve CALEA compliance, an Application Server Complex (ASC) or the like is implemented as an adjunct to a class  5  telecommunications switch, commonly maintained at a Central Office (CO) of the telecommunications network. That is to say, the ASC provides for the electronic surveillance and/or call monitoring by the LEA. The ASC and/or like facilities typically provide this surveillance in accordance with the technical specifications set forth in what is known as Standard J-STD-25, “Lawfully Authorized Electronic Surveillance,” developed jointly by the Telecommunications Industry Association (TIA) and Standards Committee T1-Telecommunications.  
         [0004]     In general, the CALEA ASC is capable of receiving and immediately retransmitting to a designated LEA, two kinds of call information, namely: (i) call progress data and/or call identifying information; and (ii) call content. The call progress data/call identifying information refers to the dialling and/or signalling information that relates to and/or identifies the origin, direction, destination or termination of a call and other such information. The call content refers to the bearer traffic or information being transmitted via a call, e.g., the audio signal (such as speech) being transmitted via a circuit-switched communication or the data packets being transmitted via a packet-switched communication. For simplicity herein, the first type of information shall be referred to using the abbreviation CPD for call progress data, and the second type of information shall be referred to using the abbreviation CC for call content.  
         [0005]      FIG. 1  shows an exemplary CALEA implementation in accordance with a commonly used network connection architecture. For the purpose of this example, a class  5  switch  10  provides service to a subject  20  that is properly under surveillance. The class  5  switch  10  incorporates a CALEA ASC  12 . The ASC  12  selectively receives and retransmits to the LEA  30 , call information related to the subject  20 . In the case of packet-switch calls (e.g., data calls and the like), the packet data CC is transmitted to the LEA  30  over a packet-switched data network (PSDN)  40 . Notably, in the case of circuit-switched calls (e.g., voice calls and the like), the circuit-switched CC is transmitted to the LEA  30  over a public switch telephone network (PSTN)  50 , i.e., a circuit-switched network. In the case of both circuit and packet-switched calls, the CPD is transmitted to the LEA  30  over the PSDN  40  (as shown) or over the PSTN  50  using a packet-switched protocol over a dedicated channel. Typically, the CPD and packet data CC are delivered to the LEA  30  using a data channel (DC) arranged as a permanent virtual circuit (PVC), and circuit-switched CC is delivered to the LEA  30  using dedicated call content channels (CCCs). Generally, for a given surveillance, at least two dedicated CCCs are employed for retransmission of the circuit-switched CC, one for the transmitting leg and the other for the receiving leg of the subject under surveillance.  
         [0006]     For surveillance of circuit-switch CC, the J-STD-25 specifies that circuit-switched CC is to be intercepted and delivered using only circuit-switched delivery. Accordingly, the connections between the ASC and the LEA commonly include dedicated circuit-switched facilities. In general, these connections are nailed connections going through one or more CO switches to telephone lines that terminate in the LEA&#39;s offices or monitoring facility. The connections are typically set up at the time the surveillance is established, and they remain dedicated exclusively to the surveillance of a given subject (for a given LEA) as long as the surveillance remains in effect. For example, these connections are kept open continually, even when the subject is not engaged in any calls. As can be appreciated by those skilled in the art, such an approach to the implementation of CALEA functionality tends to result in an inefficient allocation of resources because the facilities are dedicated full time but are typically used only a fraction of the time.  
         [0007]     Accordingly, a new and improved CALEA architecture is disclosed that overcomes the above-referenced problems and others.  
       SUMMARY  
       [0008]     In accordance with one preferred embodiment, a method of conducting covert surveillance of a subject is provided for within a telecommunications network. The surveillance includes surveillance of a monitored call connected over the network, the monitored call being between the subject and an associate and including circuit-switched call content, i.e., bearer traffic exchanged between the subject and the associate. The method includes: clandestinely receiving the circuit-switched call content; converting the received circuit-switched call content into a packet-switched format; and, delivering the call content in the packet-switched format to a designated law enforcement agency over a packet-switched data network.  
         [0009]     In accordance with another preferred embodiment, a system is provided within a telecommunications network for conducting covert surveillance of a subject. The surveillance includes surveillance of a monitored call connected over the network, the monitored call being between the subject and an associate and including circuit-switched call content, i.e., bearer traffic exchanged between the subject and the associate. The system includes: monitoring means for clandestinely receiving the circuit-switched call content; translation means for converting the received circuit-switched call content into a packet-switched format; and, transmission means for delivering the call content in the packet-switched format to a designated law enforcement agency.  
         [0010]     Numerous advantages and benefits of the inventive subject matter disclosed herein will become apparent to those of ordinary skill in the art upon reading and understanding the present specification. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Preferred embodiments may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting. Further, it is to be appreciated that the drawings are not to scale.  
         [0012]      FIG. 1  is diagrammatic illustration showing an exemplary CALEA implementation in accordance with a commonly used network connection architecture.  
         [0013]      FIG. 2  is diagrammatic illustration showing a network connection architecture of a CALEA implementation in accordance with aspects of an exemplary embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0014]     For clarity and simplicity, the present specification shall refer to structural and/or functional network elements, entities and/or facilities, relevant communications standards, protocols and/or services, and other components that are commonly known in the telecommunications art without further detailed explanation as to their configuration or operation except to the extent they have been modified or altered in accordance with and/or to accommodate the preferred embodiment(s) presented.  
         [0015]     With reference to  FIG. 2 , an exemplary telecommunications system is illustrated in accordance with a preferred embodiment. A CALEA ASC  120  or other like facility is incorporated as an adjunct to a telecommunications switch  100 , which is suitably a class  5  switch or other similar telecommunications switch and/or including packet-switching equipment, e.g., located at a CO of a telecommunications carrier. The switch  100  serves as the originating and/or terminating switch (i.e., at a local CO or end office) providing telephone service to a subscriber or subject  200 , e.g., using a telephone or other customer premises equipment (CPE) to make calls. For illustrative purposes herein, the subject  200  shall be considered the subject under surveillance in accordance with CALEA by a duly authorized LEA  300 . While only one such subject and one such LEA are illustrated, it is to be appreciated that one or more LEAs may be similarly situated, and each LEA may be conducting similar surveillance on one or more similarly situated subjects at any given time, and each subject may likewise be under surveillance by one or more LEAs at a given time.  
         [0016]     Circuit-switched calls (e.g., voice calls) between the surveillance subject  200  and an associate or second party  550  (e.g., also a subscriber using a telephone or other CPE to communicate with the subject  200 ) are connected through the switch  100  and over the PSTN  500  in the usual manner. The surveillance subject&#39;s calls are monitored via the CALEA ASC  120  for so long as the surveillance remains in effect. Suitably, the call monitoring and/or surveillance conducted by the ASC  120  is substantially undetectable or unperceivable by the principals (i.e., the subject  200  and associate  550 ) engaged in the call. That is to say, from the perspective of the principals engaged in the call, the call appears to be the same regardless of whether the surveillance is being conducted or not.  
         [0017]     Generally, there are two levels of surveillance which may selectively be carried out via the CALEA ASC  120 , nominally termed level 1 and level 2. For level 1 surveillance, the CPD is obtained for calls to and/or from the surveillance subject  200 . For level 2 surveillance, the CPD and CC are both obtained for calls to and/or from the surveillance subject  200 .  
         [0018]     Suitably, the ASC  120  is equipped or provisioned with a Internet Protocol (IP) gateway  122  or other equipment to convert the CC to packet-switched format. The gateway  122  converts and/or translates the circuit-switched CC into a packet-switched format. For example, the circuit-switched CC captured, intercepted or otherwise received by the ASC  120  is converted and/or translated by the gateway  122  into a Voice over IP (VOIP) format. That is to say, the ASC  120  captures, intercepts or otherwise receives the circuit-switched CC from a call between the subject  200  and the associate  550 . The received circuit-switched CC is converted into a VolP format or other like packet-switched call format by the gateway  122 . It is then deliverable to the LEA  300  over a PSDN  400 . Optionally, the ASC  120  is also equipped or provisioned with a database (DB) or similar storage device  124 , e.g., implemented via a memory, hard drive, magnetic or optical storage, etc. The CPD and/or CC obtained by the ASC- 120  is selectively stored and/or maintained in the CALEA DB  124 . On the LEA end, the LEA facilities are optionally provisioned with an interface  310  that provides suitable access to the CALEA ASC  120 , and in particular, the CALEA DB  124 .  
         [0019]     In general, the ASC&#39;s system and network architecture has been enhanced to provide a packet-switched communication and/or interface for CC between the ASC  120  and the LEA  300 . The packet interface supports delivery of both the CPD and CC to the LEA  300 , even for circuit-switched calls. Optionally, it is provided as either a dedicated packet-switched network interface or, with suitable security arrangements, a connection via a shared or public packet network (e.g., the Internet) or a virtual private network (VPN). For analog or circuit-switched CC (e.g., voice), the CC is packetized and retransmitted over this packet interface via standard protocols, e.g., those commonly used for VolP services.  
         [0020]     As will be appreciated by those of ordinary skill in the art, the present architecture has the potential of providing significant savings in the costs of surveillance for at least two reasons: 
        i) the transmission capacity on this packet-switched interface is preferably used intermittently only when desired—i.e., when a surveillance subject is engaged in a telephone call—thus, the capacity is shared among many subjects and LEAs; and,     ii) due to the technologies involved (e.g., Ethernet, fiber optics, etc.), the costs of packet-switched transmission facilities, per unit of capacity, are generally significantly lower than those of comparable circuit-switched facilities.        
 
         [0023]     Optionally, the retransmission of digitalized analog CC (such as speech) via the packet-switched interface between the ASC  120  and the LEA  300  is implemented using data compression and streaming techniques, thereby enhancing the bandwidth efficiency even further.  
         [0024]     Suitably, as already mentioned, the ASC  120  is provisioned with a DB  124  that provides local storage, within the ASC  120 , of surveillance data (e.g., the CPD, the CC or both). A secure mechanism is also provided (via the interface  310 ) whereby authorized LEA personnel are able to retrieve this stored surveillance data over the PSDN  400 . The LEA  300  is therefore given an option to obtain the surveillance data in real-time (i.e., as monitored calls occur) or at a later time (e.g., either a designated time or on demand). This provides additional potential cost savings for the LEA  300  because monitoring personnel will not have to be on duty continually to monitor all the calls in real-time, and because LEA personnel will be able to handle more surveillance operations per individual. Suitably, the local storage within the ASC  120  also serves as a back-up to surveillance data storage at the LAE facilities. That is to say, the ASC&#39;s local storage capability selectively acts as a backup or fail-safe mechanism, so that if the transmission facilities to the LEA  300  fail or become overloaded, or the monitoring equipment within the LEA&#39;s offices fails (e.g., due to equipment problems or a power outage), the ASC  120  can still retain a copy of the surveillance data for later retrieval by, and/or delivery to, the LEA  300 .  
         [0025]     As an optional addition to the architecture, a mechanism for the LEA  300  to access stored surveillance data in the DB  124  via a traditional circuit-switched network interface is also included. For example, to use this circuit-switched interface, the LEA personnel (or collection equipment) dials a specified access phone number, and then interacts with an Integrated Voice Response (IVR) interface. Suitably, the IVR prompts the caller to logon (e.g., by entering a user ID and security code or password), and to select the stored surveillance data to be accessed (e.g., via the entry of DTMF digits). Optionally, to hear the stored CC over the circuit-switched interface, the packetized data from the DB  124  is reverse routed through the gateway  122  to restore it to the circuit-switch CC originally received by the ASC  120 .  
         [0026]     Suitably, the ASC  120  is also enhanced to provide access via a standard, Internet-like interface  310  employed by the LEA personnel and/or their monitoring equipment. The interface  310  is preferably implemented with security features (e.g., user IDs, passwords, encryption, etc.) to prevent unauthorized access. It optionally enables the LEA  300  to use inexpensive and readily available equipment (e.g., personal computers) and software (e.g., VPN tools, web browsers, etc.) to monitor the subject  200  in real-time as well as to download or access stored surveillance-data from the DB  124 . Alternatively, a customized LEA surveillance software application is readily deployable for use by the LEA personnel over the interface  310 . The customized application optionally support both the real-time monitoring and downloading functions, and potentially provides a safer and less error-prone human interface for LEA personnel than standard, publicly available software packages, e.g., such as web browsers.  
         [0027]     It is to be appreciated that in connection with the particular exemplary embodiments presented herein certain structural and/or function features are described as being incorporated in defined elements and/or components. However, it is contemplated that these features may, to the same or similar benefit, also likewise be incorporated in other elements and/or components where appropriate. It is also to be appreciated that different aspects of the exemplary embodiments may be selectively employed as appropriate to achieve other alternate embodiments suited for desired applications, the other alternate embodiments thereby realizing the respective advantages of the aspects incorporated therein.  
         [0028]     It is also to be appreciated that particular elements or components described herein may have their functionality suitably implemented via hardware, software, firmware or a combination thereof. Additionally, it is to be appreciated that certain elements described herein as incorporated together may under suitable circumstances be stand-alone elements or otherwise divided. Similarly, a plurality of particular functions described as being carried out by one particular element may be carried out by a plurality of distinct elements acting independently to carry out individual functions, or certain individual functions may be split-up and carried out by a plurality of distinct elements acting in concert. Alternately, some elements or components otherwise described and/or shown herein as distinct from one another may be physically or functionally combined where appropriate.  
         [0029]     In short, the present specification has been set forth with reference to preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the present specification. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.