Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
1999-08-18
2002-12-31
Chin, Wellington (Department: 2735)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S395640
Reexamination Certificate
active
06501752
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to surveillance of telephone calls over a public communications link and is particularly concerned with providing assistance for such surveillance to law enforcement agencies. It particularly concerns surveillance of voice over IP (i.e., cable) networks.
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 emerging communication technologies such as IP telephony. These new technologies are plural and will exist side by side with other new technologies as well as traditional technologies. They will be plurally encountered along all stages of the network. It is important that surveillance techniques be able to operate in these combined pluralities of technologies.
SUMMARY OF THE INVENTION
A monitoring network, embodying the principals of the invention, is able to provide surveillance of IP phone calls, which span plural backbone networks, which may embody different transmission techniques.
An agent connected through a monitor center to one backbone network enters a request for surveillance (i.e. wiretapping) of a particular network connected to another backbone network. A WatchDog program is associated with each backbone network. These WatchDogs all communicate with other watchdogs associated with other backbone networks. All these watchdogs interact with one another to set up the surveillance connections.
The watchdog of the requester's backbone network receives the surveillance request and flows/transmits the request to a watchdog function of the terminating backbone network of the specific caller to be monitored establishing a point-to-point connection, through as many backbone networks as needed. The terminating WatchDog of the termination backbone network flows/transmits the request to a destination WatchDog associated with an IP Address Mapping Check Point of the target telephone number to be surveillanced. The destination watchdog communicates with the requesting watchdog using predefined protocols spanning the intervening backbone networks. The destination watchdog replicates the packets of the target telephone and transmits them to the originating monitor center.
In an aspect of the invention the target IP telephone being monitored is connected to the network through a hybrid fiber coax (HFC). HFC is a local connection medium in which a cable connection to the subscriber location is joined to a fiber connection to a backbone network.
In the instant embodiment flowing/transmitting is indicative of proper rate control and protocol control a well as connection. Hence the WatchDogs are a dynamic control element as well as a “direction of packets” routing interface element to/from and joining backbone networks. A backbone network may connect to a local device or network or to another backbone and is normally considered a long haul heavily trafficked network element.
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Kung Fen-Chung
Russell Jesse Eugene
Sankalia Anish
Wang Spencer C.
AT&T Corp.
Chin Wellington
Pham Brenda
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