Lawful interception of multimedia calls

• US 20060264200A1
• Filed: 04/09/2003
• Published: 11/23/2006
• Est. Priority Date: 04/09/2003
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Valassi, Paolo, Laiho, Keijo
• Granted Patent: US 7,577,422 B2
• Time in Patent Office: Days
• US Class Current: 455/410
• CPC Class Codes: H04L 63/306 intercepting packet switched data communications, e.g. Web, Internet or IMS communications
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1076 Screening of IP real time communications, e.g. spam over Internet telephony [SPIT]
• CPC Class Codes: H04M 3/2281 Call monitoring, e.g. for law enforcement purposes; Call tracing; Detection or prevention of malicious calls
• CPC Class Codes: H04M 7/00 Arrangements for interconnection between switching centres
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/1307 Call setup
• CPC Class Codes: H04Q 2213/13096 Digital apparatus individually associated with a subscriber line, digital line circuits
• CPC Class Codes: H04Q 2213/13176 Common channel signaling, CCS7
• CPC Class Codes: H04Q 2213/13196 Connection circuit/link/trunk/junction, bridge, router, gateway
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13209 ISDN
• CPC Class Codes: H04Q 2213/13248 Multimedia
• CPC Class Codes: H04Q 2213/13292 Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/13348 Channel/line reservation
• CPC Class Codes: H04Q 2213/13372 Intercepting operator
• CPC Class Codes: H04Q 2213/13389 LAN, internet

Abstract

A method of performing lawful interception of a multimedia call between two or more terminals. The method comprises detecting the initiation of said call at monitoring equipment located in the call path, and forwarding from the monitoring equipment to a gateway, parameters defining at least one of the forward and reverse channels of said call. At least one multimedia call is set up from said gateway to a monitoring terminal in dependence upon the received parameters. Following the setting up of the first mentioned multimedia call, forward and/or reverse channel data is intercepted at said monitoring equipment, the intercepted data routed to said gateway, and the data transmitted to the monitoring terminal over the forward channel of the or each second mentioned multimedia call.

Claims

1. A method of performing lawful interception of a multimedia call between two or more terminals, the method comprising:

detecting the initiation of said call at monitoring equipment located in the call path;

forwarding from the monitoring equipment to a gateway, parameters defining at least one of the forward and reverse channels of said call;

emulating a multimedia terminal at said gateway and setting up at least one multimedia call between the emulated terminal and a monitoring terminal, the properties of the call being negotiated in dependence upon the received parameters; and

following the setting up of the first mentioned multimedia call, intercepting forward and/or reverse channel data at said monitoring equipment, routing the intercepted data to said gateway, and transmitting the data to the monitoring terminal over the forward channel of the or each second mentioned multimedia call.

2. The method according to claim 1, said gateway performing a mapping between protocols used in the network connecting the terminals involved in the call being intercepted, to protocols used in the network connecting the gateway to the monitoring terminal.

3. The method according to claim 1, wherein the monitoring terminal communicates with said gateway via a broadband IP network.

4. The method according to claim 1, said monitoring equipment forwarding to said gateway, signalling messages exchanged between the terminals involved in the call being intercepted.

5. The method according to claim 1, said gateway performing transcoding of intercepted channel data.

6. The method according to claim 1 and comprising setting up a call from said gateway to the monitoring terminal for each of the forward and reverse channels of the intercepted call.

7. The method according to claim 1 and comprising multiplexing/mixing the intercepted forward and reverse channel data onto the forward channel of a single call established between said gateway and the monitoring terminal.

8. The method according to claim 1 and comprising establishing two calls between the gateway and respective terminals at the monitoring centre, forward channel data from the intercepted call being placed on the forward channel of one of these two calls, whilst reverse channel data is placed on the forward channel of the other one of the calls.

9. The method according to claim 1, wherein the terminals participating in the first mentioned multimedia call are H. 324 terminals, and said monitoring terminal is an H. 323 terminal.

10. The method according to claim 1, wherein the terminals participating in the first mentioned multimedia call are SIP terminals, and said monitoring terminal is also a SIP terminal

11. Apparatus for intercepting a multimedia call between two or more terminals, the apparatus comprising:

means for receiving from monitoring equipment located within the call path, parameters defining at least one of the forward and reverse channels of said call, following detection of the initiation of said call by the monitoring equipment;

means for emulating a multimedia terminal and means for setting up at least one multimedia call between the emulated terminal and to a monitoring terminal, this means negotiating the properties of the call in dependence upon the received parameters; and

means for receiving intercepted forward and/or reverse channel data from said monitoring equipment, and for transmitting the data to a monitoring terminal over the forward channel (s) of the second mentioned multimedia call (s).