Forced bearer routing for packet-mode interception

• US 7,436,835 B2
• Filed: 05/30/2003
• Issued: 10/14/2008
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Castleberry, Michael Ray, Eustace, Daniel Weiler
• Primary Examiner(s): Chan; Wing F.
• Assistant Examiner(s): Roberts; Brian
• Application Number:
  US10/448,909
• Publication Number:
  US 20040240439A1
• Time in Patent Office: 1,964 Days
• Field of Search: 379/213.01, 379/211.01
• US Class Current: 370/392
• CPC Class Codes: H04L 63/306 intercepting packet switched data communications, e.g. Web, Internet or IMS communications
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/1101 Session protocols
• 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 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

A method of intercepting call content in a packet-based Internet Protocol (IP) network. The method includes targeting bearer packets containing the call content via a Softswitch controlling the redirection of the targeted bearer packets through a specified Intercept Router using alias IP addresses for the targeted bearer packets.

Claims

1. A method of intercepting call content bearer packets from first and second communications terminals communicating with each other over a packet-based Internet Protocol (IP) network comprising:

a Softswitch obtaining alias IP addresses for the first and second communications terminals, the alias IP addresses corresponding to an Intercept Router in the network;

the Softswitch using the alias IP addresses in call control signaling for redirecting call content bearer packets from the first and second communications terminals through the Intercept Router for interception.

2. The method defined in claim 1 wherein a target having an IP address A communicates with an associate having an IP address B, further comprising:

the Softswitch communicating the target IP address information A to the Intercept Router; and

the Softswitch requesting Network Address Translation mappings A′

from a pool of addresses for the Intercept Router.

3. The method defined in claim 2 wherein the requesting step comprises:

the Softswitch sending the intercept Router an AddNAT message to create alias IP addresses A′

for the target address A; and

the Softswitch receiving an AddNAT Response message containing the alias IP address A′

from the Intercept Router.

4. The method defined in claim 3 further comprising:

the Softswitch sending Delete NAT messages to the Intercept Router to remove the temporary NAT mappings creating the alias address A′

after the call ends.

5. The method defined in claim 2 wherein an associate using the Public Switched Telephone Network (PSTN) communicates with a target having a forwarded IP address A via a Media Gateway having an IP address mg, wherein the step of the Softswitch communicating the target IP address information A to the Intercept Router comprises:

the Softswitch sending an Add Target message to the Intercept Router containing the Media Gateway IP address mg and UDP port number port1 associated with the target for communicating to the Intercept Router that any bearer packets to or from the target should be intercepted.

6. The method defined in claim 1 wherein a target having an IP address A communicates with an associate having an IP address B, further comprising:

the Softswitch communicating the associate IP address information B to the Intercept Router; and

the Softswitch requesting Network Address Translation mappings B′

from a pool of addresses for the Intercept Router.

7. The method defined in claim 6 wherein the requesting step comprises:

the Softswitch sending the Intercept Router an AddNAT message to create alias IP addresses B′

for the associate address B; and

the Softswitch receiving an AddNAT Response message containing the alias IP address B′

from the Intercept Router.

8. The method defined in claim 7 further comprising:

the Softswitch sending Delete NAT messages to the Intercept Router to remove the temporary NAT mappings creating the alias address B′

after the call ends.

9. The method defined in claim 1 wherein the associate using the Public Switched Telephone Network (PSTN) communicates with a target having an IP address A via a Media Gateway having an IP address mg, further comprising:

the Softswitch communicating the target IP address information A to the Intercept Router;

the Softswitch requesting Network Address Translation mappings A′

from a pool of addresses for the Intercept Router;

the Softswitch communicating the media gateway IP address information mg to the Intercept Router; and

the Softswitch requesting Network Address Translation mappings mg′

from a pool of addresses for the Intercept Router.

10. The method defined in claim 9 further comprising:

the Softswitch sending the Intercept Router an AddNAT message to create alias IP addresses A′

for the target address A;

the Softswitch receiving an AddNAT Response message containing the alias IP address A′

from the Intercept Router;

the Softswitch sending the Intercept Router an AddNAT message to create alias IP addresses mg′

for the media gateway address mg; and

the softswitch recieving an AddNAT Response message containing the alias IP address mg′

from the Intecept Router.

11. The method defined in claim 1 wherein an associate using the Public Switched Telephone Network (PSTN) calls a target, the target forwarding calls to a phone which also uses the PSTN, further comprising:

the Softswitch sending an Add Target message to the Intercept Router containing the Media Gateway IP address mg and UDP port number port1 associated with the associate;

the Softswitch requesting Network Address Translation mapping mg to mg′

from a pool of addresses for the Intercept Router.

12. The method defined in claim 11 wherein the requesting step comprises:

the Softswitch sending the Intercept Router an AddNAT message to create alias Media Gateway address mg′

for the Media Gateway address mg; and

the Softswitch receiving an AddNAT Response message containing the alias IP address mg′

from the Intercept Router.

13. The method defined in claim 12 further comprising:

Softswitch sending a control message to the Media Gateway ADD (trunk2, mg′

+port1) to arrange for the second port of the bearer path; and

the Softswitch receiving an acknowledgement including the Media Gateway second port number for the bearer path from the Media Gateway.

14. The method defined in claim 13 further comprising:

the Softswitch sending the Media Gateway a message MODIFY(mg′

+port2) propagating the Media Gateway second returned port with the alias Media Gateway address mg′

to be associated with the Media Gateway first port.

15. The method defined in claim 1 further comprising:

sending an Add Target message to the Intercept Router containing the IP address of the call content bearer packets.

16. The method defined in claim 15 wherein the Add Target message includes the port number of the target bearer packets.

17. The method defined in claim 15 wherein the Add Target message includes the IP address of the Legal Enforcement Agency to which copies of intercepted bearer packets are sent.

18. A method of intercepting call content bearer packets from first and second communications terminals communicating with each other over a packet-based Internet Protocol (IP) network comprising:

receiving call control signaling at a network node including a first IP address corresponding to the first terminal and a second IP address corresponding to the second terminal;

obtaining alias IP addresses for the first and second IP addresses, the alias IP addresses corresponding to an Intercept Router in the network; and

the network node sending call control signaling to the first and second terminals using the alias IP addresses in place of the first and second IP addresses to direct the call content bearer packets from the first and second communications terminals through the Intercept Router for interception.