Method and apparatus for reselection of data trunk upon connection failure

• US 6,370,113 B1
• Filed: 07/23/1998
• Issued: 04/09/2002
• Est. Priority Date: 07/23/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Paradiso, Mike, Gauthier, Claude
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US09/121,392
• Time in Patent Office: 1,356 Days
• Field of Search: 379/7, 379/35, 370/225, 370/227, 370/228
• US Class Current: 370/225
• CPC Class Codes: H04M 3/2281 Call monitoring, e.g. for law enforcement purposes; Call tracing; Detection or prevention of malicious calls

Abstract

A method and apparatus for monitoring voice and data telephone calls by a law enforcement agency, wherein separate monitoring connections for each party to the call are established. Upon determining that a particular call is to be monitored, the group switch attempts to establish a plurality of separate connections between each multiple point (MUP) on the group switch that receives voice or data signals from one of the parties to the call and one or more monitoring centers. If the connection associated with the primary party to be monitored fails, the group switch reroutes signals received from the primary party to a successful connection of the plurality of attempted connections.

Claims

1. A method for monitoring a telephone call connection by a law enforcement agency, comprising the steps of:

determining that a call between a plurality of parties is to be monitored;

attempting to establish, in response to said determination, a plurality of connections with a monitoring center for monitoring the plurality of parties;

detecting a failure to establish at least one of said attempted connections; and

rerouting communications received from said failed connection to a successful one of the attempted connections in response to said detection of a failed connection.

2. The method of claim 1, further comprising the step of selecting a preferred party to monitor.

3. The method of claim 2, wherein said step of detecting a failed connection comprises detecting a failure in establishing a connection between the preferred party and said monitoring center.

4. The method of claim 3, wherein the step of rerouting communications comprises rerouting communications received from said preferred party to a successful one of the attempted connections.

5. The method of claim 2, wherein said rerouting communications further comprises the steps of:

disconnecting a portion of a successfully connected trunk connecting the monitoring center and one of the parties to the call to be monitored; and

reestablishing a new path of said trunk, wherein the new path connects the monitoring center and the preferred party.

6. The method of claim 5 wherein said disconnecting of a portion of the successfully connected trunk includes disconnecting an internal connection in a group switch.

7. The method of claim 2 wherein said call to be monitored comprises a data call.

8. The method of claim 7 wherein said step of selecting comprises the step of automatically selecting as the preferred party a party that is a source of a data transmission.

9. The method of claim 2 wherein said step of selecting a preferred party further comprises the step of evaluating a set of preferred party criteria to select a preferred party from said plurality of parties.

10. The method of claim 1, wherein the plurality of attempted connections comprises a separate attempted connection for each of the plurality of parties.

11. The method of claim 1 wherein said step of attempting to establish a plurality of connections comprises transmitting a call setup request to set up a call between a switching node through which the call to be monitored is routed and the monitoring center.

12. A method for monitoring a telephone call connection by a law enforcement agency, comprising the steps of:

determining that a call between a plurality of parties is to be monitored;

attempting to establish a plurality of connections with a monitoring center for monitoring the plurality of parties;

selecting a preferred party to monitor; and

establishing a connection between said preferred party and the monitoring center over a first successful one of the attempted connections.

13. The method of claim 12, further comprising the step of establishing a connection between a second one of the plurality of parties and the monitoring center over a second successful one of the attempted connections.

14. The method of claim 12 wherein said call to be monitored comprises a data call.

15. The method of claim 14 wherein said step of selecting comprises the step of automatically selecting as the preferred party a party that is a source of a data transmission.

16. The method of claim 12 wherein said step of selecting a preferred party further comprises the step of evaluating a set of preferred party criteria to select a preferred party from said plurality of parties.

17. The method of claim 12 wherein the plurality of attempted connections comprises a separate attempted connection for each of the plurality of parties.

18. The method of claim 12 wherein said step of attempting to establish a plurality of connections comprises transmitting a call setup request to set up a call between a switching node through which the call to be monitored is routed and the monitoring center.

19. A system for monitoring a telephone call by a law enforcement agency, comprising:

at least one monitoring center for monitoring a call connection; and

a switch for establishing said call connection between a subscriber to be monitored and at least one other subscriber to a telecommunications network and for establishing a plurality of monitoring connections to said at least one monitoring center, said switch rerouting signals received from a preferred one of said subscribers to a successful monitoring connection with the at least one monitoring center upon failure of a monitoring connection between the preferred one of said subscribers and the at least one monitoring center.

20. The system of claim 19, further comprising a memory for storing information identifying said subscriber to be monitored.

21. The system of claim 19, further comprising a switch controller for selecting the preferred subscriber according to stored selection criteria.

22. The system of claim 19, wherein said switch includes a plurality of multiple points (MUPs), each subscriber in said connection associated with a particular MUP.

23. The system of claim 22, wherein each of said monitoring connections comprises:

an external connection between the switch and the monitoring center; and

an internal connection inside said switch, said internal connection connecting said external connection to a MUP associated with one of the subscribers in said call connection.

24. The system of claim 23 wherein the switch reroutes the internal connection connected to the MUP associated with the preferred subscriber upon failure of the external connection for the preferred subscriber, said rerouting to a successful external connection.

25. A system for monitoring a telephone call by a law enforcement agency, comprising:

at least one monitoring center for monitoring a call connection; and

a switch for establishing said call connection between a subscriber to be monitored and at least one other subscriber to a telecommunications network and for establishing a plurality of monitoring connections to said at least one monitoring center, said switch routing signals received from a preferred one of said subscribers to a first successful monitoring connection with the at least one monitoring center.

26. The system of claim 25, further comprising a memory for storing information identifying said subscriber to be monitored.

27. The system of claim 25 further comprising a switch controller for selecting the preferred subscriber according to stored selection criteria.

28. The system of claim 25 wherein said switch includes a plurality of multiple points (MUPs), each subscriber in said connection associated with a particular MUP.

29. The system of claim 28 wherein each of said monitoring connections comprises an external connection between the switch and the monitoring center, the system further comprising an internal connection inside said switch, said internal connection connecting said external connection to a MUP associated with one of the subscribers in said call connection.

30. The system of claim 29 wherein the internal connection connected to the MUP associated with the preferred subscriber is routed to a first successful external connection.

31. The system of claim 30 wherein the internal connection connected to a MUP associated with a second one of said subscribers is routed to a second successful external connection.