US 7,577,422 B2
Lawful interception of multimedia calls
Keijo Laiho, Masala (Finland); and Paolo Valassi, Voghera (Italy)
Assigned to Telefonaktiebolaget L M Ericsson (PUBL), Stockholm (Sweden)
Appl. No. 10/551,913
PCT Filed Apr. 09, 2003, PCT No. PCT/EP03/50098
§ 371(c)(1), (2), (4) Date Oct. 03, 2005,
PCT Pub. No. WO2004/091250, PCT Pub. Date Oct. 21, 2004.
Prior Publication US 2006/0264200 A1, Nov. 23, 2006
Int. Cl. H04M 1/66 (2006.01); H04M 1/68 (2006.01); H04M 3/16 (2006.01); H04L 29/08 (2006.01); H04J 3/22 (2006.01)
U.S. Cl. 455—410  [455/414.1; 370/270] 8 Claims
OG exemplary drawing
 
1. A method of performing lawful interception of a first multimedia call between first and second terminals, the method comprising:
detecting the initiation of the first multimedia call at monitoring equipment located in a call path of the first multimedia call;
forwarding from the monitoring equipment to a gateway, parameters defining at least one of a forward channel and a reverse channel of the first multimedia call;
emulating a multimedia terminal at said gateway and setting up a second multimedia call between the emulated terminal and a monitoring terminal, said gateway performing the complete media control protocol transactions with the monitoring terminal based upon the received parameters and wherein said gateway maps protocols utilized in the first multimedia call to protocols used in the second multimedia call; and
following the initiation of the first multimedia call, intercepting forward 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 second multimedia call;
wherein the second multimedia call includes a first gateway call between the gateway and the monitoring terminal and a second gateway call between the gateway and the monitoring terminal, and the step of transmitting the data to the monitoring terminal includes forwarding channel data from the intercepted call on a forward channel of the first gateway call and reverse channel data on a forward channel of the second gateway call.