Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
1999-08-18
2003-04-22
Chin, Wellington (Department: 2735)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S351000
Reexamination Certificate
active
06553025
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to surveillance and monitoring of telephone calls over a public communications link and is particularly concerned with providing assistance for such surveillance and monitoring to law enforcement agencies. It particularly concerns surveillance of voice over IP (i.e., cable) networks for both IP-to-IP and off net (IP-PSTN) telephone calls.
BACKGROUND OF THE INVENTION
Requirements for enabling surveillance of electronic communications have been enacted into public law (e.g., Public Law 103-414 enacted Oct. 25, 1994; CALEA Communications Assistance for Law Enforcement Act) reciting requirements for assuring law enforcement access to electronic communications. Such access is required to be in real time, have full time monitoring capabilities, simultaneous intercepts, and feature service descriptions. The requirements specifically include capacity requirements and function capability. It is incumbent upon communication carriers to provide such capability and capacity.
While initially limited in scope, at present, to certain communications technology it is almost assured that it will be extended to new technologies of communications.
With present technology surveillance and monitoring is limited to one monitoring location whose location may be static. It would be desirable to permit monitoring of multiple subscriber locations by more than one monitoring location and to permit dynamic changes to such locations and to subscriber data.
SUMMARY OF THE INVENTION
Monitored voice calls, of a targeted monitored IP subscriber are intercepted and rerouted to selected multiple monitoring stations connected to a available intervening communication networks each using different transmission technologies (e.g., PSTN networks, Packet cable telephony networks, etc.), in accord with the principles of the invention, by intervention of an IP Address-Mapping checkpoint (IP-AMCP) which duplicates the voice to a monitoring location and automatically identifying the types of networks to be traversed and adapting the voice message to such a network type to communication with monitoring stations connected to these networks. Surveillance is, therefor, enabled to be conducted at more than one monitoring location each of which many are widely separated from the other. According to the invention, selected monitoring stations connected to different type communication networks are all enabled to be connected to monitor the designated monitored target IP subscriber.
In a particular illustrative embodiment an authorized surveillance agent transmits a valid request to an IP-AMCP which in response intercepts voice packets to and from the targeted IP phone. The monitored IP phone directory number (DN) is logged in the IP Phone Intercept List (IP-PIL) database at the IP-AMCP location. When a call is made to/from the monitored IP phone and detected by the WatchDog program using the IP-PIL database at the IP-AMCP, the duplicated voice packets are transmitted to the designated monitoring location. The IP-AMCP determines the type of voice signal to be transmitted to the terminal monitoring station. The IP-PIL contains information for the network types servicing the monitoring locations. If the monitoring location is serviced by an IP telephony network the monitored traffic is duplicated by the IP-AMCP in IP format to an IP DN as programmed by the IP-PIL. If the monitoring location is serviced by a PSTN network a PSTN check point (PSTN-CP) establishes a trunk connection with the Local Digital Switch (LDS) and receives incoming voice packets from the IP-AMCP which the PSTN-CP converts to voice trunk (i.e., T
1
) to communicate with the LDS.
While the terminal monitoring station is a ported DN, the IP-AMCP generates a query to the corresponding Local Number Portability (LNP) database. This database is particularly concerned with transferring processes to accommodate changes of systems. It normally resides in an SS
7
network or its equivalent. In particular, if the monitoring location is in the IP telephony, the IP-AMCP requests an updated routing number from the IP-LNP database. For a PSTN monitoring location, the PSTN-CP requests an updated routing number from the SS
7
LNP database.
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patent: 6415027 (2002-07-01), Malik
Kung Fen-Chung
Russell Jesse Eugene
Sankalia Anish
Wang Spencer C.
AT&T Corp.
Chin Wellington
Pham Brenda
Steinmetz Alfred G.
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