Method for establishing call state information without maintaining state information at gate controllers

• US 6,694,429 B1
• Filed: 08/04/1999
• Issued: 02/17/2004
• Est. Priority Date: 08/04/1998
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Mishra, Partho Pratim, Kalmanek, Charles Robert Jr., Marshall, William Todd, Nortz, Douglas M, Ramakrishnan, Kadangode K.
• Primary Examiner(s): Barron, Gilberto
• Assistant Examiner(s): Gurshman, Grigory
• Application Number:
  US09/366,210
• Time in Patent Office: 1,658 Days
• Field of Search: 713/201, 713/153, 713/150, 380/247, 370/410, 379/900, 88/17
• US Class Current: 713/153
• CPC Class Codes: H04L 61/2517 using port numbers
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/104 in the network
• CPC Class Codes: H04L 65/1043 Gateway controllers, e.g. media gateway control protocol [MGCP] controllers
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1106 Call signalling protocols; H.323 and related
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 7/1275 Methods and means to improve the telephone service quality, e.g. reservation, prioritisation or admission control
• CPC Class Codes: H04Q 2213/1307 Call setup
• CPC Class Codes: H04Q 2213/13091 CLI, identification of calling line
• CPC Class Codes: H04Q 2213/13095 PIN / Access code, authentication
• CPC Class Codes: H04Q 2213/13097 Numbering, addressing
• CPC Class Codes: H04Q 2213/13102 : Common translator
• CPC Class Codes: H04Q 2213/13103 : Memory
• CPC Class Codes: H04Q 2213/13106 : Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13109 : Initializing, personal profile
• CPC Class Codes: H04Q 2213/13145 : Rerouting upon failure
• CPC Class Codes: H04Q 2213/1315 : Call waiting
• 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 2213/1324 : Conference call
• CPC Class Codes: H04Q 2213/1328 : Call transfer, e.g. in PBX
• CPC Class Codes: H04Q 2213/1329 : Asynchronous transfer mode, ATM
• CPC Class Codes: H04Q 2213/13298 : Local loop systems, access network
• CPC Class Codes: H04Q 2213/13339 : Ciphering, encryption, security
• CPC Class Codes: H04Q 2213/13348 : Channel/line reservation
• CPC Class Codes: H04Q 2213/13389 : LAN, internet
• CPC Class Codes: H04Q 2213/13405 : Dual frequency signaling, DTMF
• CPC Class Codes: H04Q 3/0025 : Provisions for signalling
• CPC Class Codes: H04Q 3/0045 : involving hybrid, i.e. a mixture of public and private, or multi-vendor systems
• CPC Class Codes: H04Q 3/72 : Finding out and indicating number of calling subscriber

Abstract

State information for a call between a calling party and a called party is established without maintaining the state information at a gate controller. A setup request for the call is received at an originating gate controller. The originating gate controller is connected to a trusted network. The calling party is associated with an originating interface unit coupled to an untrusted network. The setup request for the call is authorized. The authorized setup request is sent to the called party. State information for the call is formatted based on a setup acknowledgment message received from the calling party. The state information for the call is sent from the originating gate controller to the originating interface unit without maintaining the state information at the originating gate controller.

Claims

1. A method for establishing state information for a call between a calling party and a called party, comprising:

receiving, at an originating gate controller, a setup request for a call, the originating gate controller being connected to a trusted network, the calling party being associated with an originating interface unit coupled to an untrusted network that is different from said tested network;

authorizing the setup request for the call;

sending the authorized setup request to the called party;

formatting state information for the call based on a setup acknowledgment message received from the called party; and

sending the state information for the call from the originating gate controller to the originating interface unit without maintaining the state information at the originating gate controller,

said originating gate controller and said originating interface unit communicating with one another via a telecommunications access network.

2. The method of claim 1, further comprising:

encrypting, at the originating gate controller, the state information for the call before sending the state information from the originating gate controller to the originating interface unit,

the state information being sent to the originating interface unit being in encrypted form.

3. The method of claim 1, further comprising:

performing, at the originating gate controller, a cryptographic hash function on the state information to produce a hash-value; and

sending the hash value from the originating gate controller to the originating interface unit.

4. The method of claim 1, further comprising:

encrypting, at the originating gate controller, the state information for the call before sending the state information from the originating gate controller to the originating interface unit, the state information being sent to the originating interface unit being in encrypted form;

performing, at the originating gate controller, a cryptographic hash function on the state information to produce a hash-value; and

sending the hash value from the originating gate controller to the originating interface unit.

5. A method for establishing state information for a call between a calling party and a called party, comprising:

receiving, at an originating gate controller, a setup request for a call, the originating gate controller being connected to a trusted network, the calling party being associated with an originating interface unit coupled to an untrusted network;

authorizing the setup request for the call;

sending the authorized setup request to the called party;

formatting state information for the call based on a setup acknowledgment message received from the called party;

sending the state information for the call from the originating gate controller to the originating interface unit without maintaining the state information at the originating gate controller;

receiving a call feature request for the call at the originating gate controller;

receiving the state information at the originating gate controller from the originating interface unit;

modifying the state information based on the call feature request; and

sending the modified state information for the call from the originating gate controller to the originating interface unit without maintaining the modified state information at the originating gate controller.

6. A computer-readable medium having stored thereon instructions for establishing state information for a call between a calling party and a called party, the instructions when executed by a processor cause the processor to:

receive, at an originating gate controller, a setup request for a call, the originating gate controller being connected to a trusted network, the calling party being associated with an originating interface unit coupled to an untrusted network that is different from said trusted network;

authorize the setup request for the call;

send the authorized setup request to the called party;

format state information for the call based on a setup acknowledgment message received from the called party; and

send the state information for the call from the originating gate controller to the originating interface unit without maintaining the state information at the originating gate controller,

said originating gate controller and said originating interface unit communicating with one another via a telecommunications access network.

7. The computer-readable medium of claim 6, having stored thereon instructions that when executed by the processor further cause the processor to:

encrypt, at the originating gate controller, the state information for the call before sending the state information from the originating gate controller to the originating interface unit,

the state information being sent to the originating interface unit being in encrypted form.

8. The computer-readable medium of claim 6, having stored thereon instructions that when executed by the processor further cause the processor to:

perform, at the originating gate controller, a cryptographic hash function on the state information to produce a hash value; and

send the hash value from the originating gate controller to the originating interface unit.

9. The computer-readable medium of claim 6, having stored thereon instructions that when executed by the processor further cause the processor to:

encrypt, at the originating gate controller, the state information for the call before sending the state information from the originating gate controller to the originating interface unit, the state information being sent to the originating interface unit being in encrypted form;

perform, at the originating gate controller, a cryptographic hash function on the state information to produce a hash value; and

send the hash value from the originating gate controller to the originating interface unit.

10. A computer-readable medium having stored thereon instructions for establishing state information for a call between a calling party and a called party, the instructions when executed by a processor cause the processor to:

receive, at an originating gate controller, a setup request for a call, the originating gate controller being connected to a trusted network, the calling party being associated with an originating interface unit coupled to an untrusted network;

authorize the setup request for the call;

send the authorized setup request to the called party;

format state information for the call based on a setup acknowledgment message received from the called party;

send the state information for the call from the originating gate controller to the originating interface unit without maintaining the state information at the originating gate controller;

receive a call feature request for the call at the originating gate controller;

receive the state information at the originating gate controller from the originating interface unit;

modify the state information based on the call feature request; and

send the modified state information for the call from the originating gate controller to the originating interface unit without maintaining the modified state information at the originating gate controller.

11. A method for establishing state information for a call between a calling party and a called party, comprising:

receiving, at a terminating gate controller, a setup request for a call, the terminating gate controller being connected to a trusted network, the called party being associated with a terminating interface unit coupled to an untrusted network that is different from said trusted network, the setup request being authorized for the call;

formatting state information for the call based on the setup request for the call; and

sending the state information for the call from the terminating gate controller to the terminating interface unit without maintaining the state information at the terminating gate controller;

said terminating gate controller and said terminating interface unit communicating with one another via a telecommunications access network.

12. The method of claim 11, further comprising:

encrypting, at the terminating gate controller, the state information for the call before sending the state information from the terminating gate controller to the terminating interface unit,

the state information being sent to the terminating interface unit being in encrypted form.

13. The method of claim 11, wherein:

performing, at the terminating gate controller, a cryptographic hash value on the state information to produce a hash value; and

sending the hash value from the terminating gate controller to the terminating interface unit.

14. The method of claim 11, further comprising:

encrypting, at the terminating gate controller, the state information for the call before sending the state information from the terminating gate controller to the terminating interface unit, the state information being sent to the terminating interface unit being in encrypted form;

performing, at the terminating gate controller, a cryptographic hash value on the state information to produce a hash value; and

sending the hash value from the terminating gate controller to the terminating interface unit.

16. The method of claim 11, further comprising:

receiving a call return request for the call at the terminating gate controller;

receiving the state information at the terminating gate controller from the terminating interface unit, the state information having a source address associated with the calling party;

modifying the state information based on the call return request; and

sending the modified state information for the call from the terminating gate controller to the terminating interface unit without maintaining the modified state information at the terminating gate controller.

17. The method of claim 11, further comprising:

receiving a called-party-originated trace request for the call at the terminating gate controller;

receiving the state information at the terminating gate controller from the terminating interface unit, the state information having a source address associated with the calling party;

modifying the state information based on the called-party-originated trace request; and

sending the modified state information for the call from the terminating gate controller to the terminating interface unit without maintaining the modified state information at the terminating gate controller.

15. A method for establishing state information for a call between a calling party and a called party, comprising:

receiving, at a terminating gate controller, a setup request for a call, the terminating gate controller being connected to a trusted network, the called party being associated with a terminating interface unit coupled to untrusted network, the setup request being authorized for the call;

formatting state information for the call based on the setup request for the call;

sending the state information for the call from the terminating gate controller to the terminating interface unit without maintaining the state information at the terminating gate controller;

receiving a call feature request for the call at the terminating gate controller;

receiving the state information at the terminating gate controller from the terminating interface unit;

modifying the state information based on the call feature request; and

sending the modified state information for the call from the terminating gate controller to the terminating interface unit without maintaining the modified state information at the terminating gate controller.

18. A computer-readable medium having stored thereon instructions that, when executed by a processor, cause the processor to:

receive, at a terminating gate controller, a setup request for a call, the terminating gate controller being connected to a trusted network, the called party being associated with a terminating interface unit coupled to untrusted network that is different from said trusted network, the setup request being authorized for the call;

format state information for the call based on the setup request for the call; and

send the state information for the call from the terminating gate controller to the terminating interface unit without maintaining the state information at the terminating gate controller,

said terminating gate controller and said terminating interface unit communicating with one another via a telecommunications access network.

19. The computer-readable medium of claim 18, having stored thereon instructions that when executed by the processor further cause the processor to:

encrypt, at the terminating gate controller, the state information for the call before sending the state information from the terminating gate controller to the terminating interface unit,

the state information being sent to the terminating interface unit being in encrypted form.

20. The computer-readable medium of claim 18, having stored thereon instructions that when executed by the processor further cause the processor to:

perform, at the terminating gate controller, a cryptographic hash function on the state information to produce a hash value; and

send the hash value from the terminating gate controller to the terminating interface unit.

21. The computer-readable medium of claim 18, having stored thereon instructions that when executed by the processor further cause the processor to:

encrypt, at the terminating gate controller, the state information for the call before sending the state information from the terminating gate controller to the terminating interface unit, the state information being sent to the terminating interface unit being in encrypted form;

perform, at the terminating gate controller, a cryptographic hash function on the state information to produce a hash value; and

send the hash value from the terminating gate controller to the terminating interface unit.

23. The computer-readable medium of claim 18, having stored thereon instructions that when executed by the processor further cause the processor to:

receive a call return request for the call at the terminating gate controller;

receive the state information at the terminating gate controller from the terminating interface unit, the state information having a source address associated with the calling party;

modify the state information based on the call return request; and

send the modified state information for the call from the terminating gate controller to the terminating interface unit without maintaining the modified state information at the terminating gate controller.

24. The computer-readable medium of claim 18, having stored thereon instructions that when executed by the processor further cause the processor to:

receive a called-party-originated trace request for the call at the terminating gate controller;

receive the state information at the terminating gate controller from the terminating interface unit, the state information having a source address associated with the calling party;

modify the state information based on the called-party-originated trace request; and

send the modified state information for the call from the terminating gate controller to the terminating interface unit without maintaining the modified state information at the terminating gate controller.

22. A computer-readable medium having stored thereon instructions that, when executed by a processor, cause the processor to:

receive, at a terminating gate controller, a setup request for a call, the terminating gate controller being connected to a trusted network, the called party being associated with a terminating interface unit coupled to untrusted network, the setup request being authorized for the call;

format state information for the call based on the setup request for the call;

send the state information for the call from the terminating gate controller to the terminating interface unit without maintaining the state information at the terminating gate controller;

receive a call feature request for the call at the terminating gate controller;

receive the state information at the terminating gate controller from the terminating interface unit;

modify the state information based on the call feature request; and

send the modified state information for the call from the terminating gate controller to the terminating interface unit without maintaining the modified state information at the terminating gate controller.

25. A method for performing call features to a call initiated between a calling party and a called party, comprising:

sending the state information for the call from a gate controller to an associated interface unit without maintaining the state information at the gate controller, the gate controller being connected to a trusted network and the interface unit being coupled to an untrusted network that is different from said trusted network;

receiving a call feature request for the call at the gate controller after the state information was sent from the gate controller to the associated interface unit;

receiving the state information at the gate controller from the associated interface unit after the state information was sent from the gate controller to the associated interface unit;

modifying the state information based on the call feature request; and

sending the modified state information for the call from the gate controller to the associated interface unit without maintaining the modified state information at the gate controller,

said gate controller and said interface unit communicating with one another via a telecommunications access network.

26. The method of claim 25, further comprising:

encrypting, at the gate controller, the state information for the call before sending the state information from the gate controller to the associated interface unit, the state information being sent to the associated interface unit being in encrypted form; and

encrypting, at the gate controller, the modified state information for the call before sending the modified state information from the gate controller to the associated interface unit, the modified state information being sent to the associated interface unit being in encrypted form.

27. The method of claim 25, further comprising:

performing, at the gate controller, a cryptographic hash function on the state information to produce a first hash value;

sending the first hash value from the gate controller to the associated interface unit;

performing, at the gate controller, the cryptographic hash function on the modified state information to produce a second hash value; and

sending the second hash value from the gate controller to the associated interface unit.

28. The method of claim 25, further comprising:

encrypting, at the gate controller, the state information for the call before sending the state information from the gate controller to the associated interface unit, the state information being sent to the associated interface unit being in encrypted form;

encrypting, at the gate controller, the modified state information for the call before sending the modified state information from the gate controller to the associated interface unit, the modified state information being sent to the interface unit being in encrypted form;

performing, at the gate controller, a cryptographic hash function on the state information to produce a first hash value;

sending the first hash value from the gate controller to the associated interface unit;

performing, at the gate controller, the cryptographic hash function on the modified state information to produce a second hash value; and

sending the second hash value from the gate controller to the associated interface unit.

29. The method of claim 25, wherein:

the gate controller is a terminating gate controller,

the interface unit is a terminating interface unit associated with the called party,

the call feature request is a call return request,

the state information has a source address associated with the calling party, and

a second call being connected based on the source address of the calling party.

30. The method of claim 25, wherein

the gate controller is a terminating gate controller,

the interface unit is a terminating interface unit associated with the called party,

the call feature request is a called-party-originated trace request,

the state information has a source address associated with the calling party, and

reporting the source address of the calling party to a service provider.

31. A computer-readable medium having stored thereon instructions that, when executed by a processor, cause the processor to:

send the state information for the call from a gate controller to an associated interface unit without maintaining the state information at the gate controller, the gate controller being connected to a trusted network, the interface unit being coupled to an untrusted network;

receive a call feature request for the call at the gate controller after the state information was sent from the gate controller to the associated interface unit;

receive the state information at the gate controller from the associated interface unit after the state information was sent from the gate controller to the associated interface unit;

modify the state information based on the call feature request; and

send the modified state information for the call from the gate controller to the associated interface unit without maintaining the modified state information at the gate controller.

32. The computer-readable medium of claim 31, having stored thereon instructions that when executed by the processor further cause the processor to:

encrypt, at the gate controller, the state information for the call before sending the state information from the gate controller to the associated interface unit, the state information being sent to the associated interface unit being in encrypted form; and

encrypt, at the gate controller, the modified state information for the call before sending the modified state information from the gate controller to the associated interface unit, the modified state information being sent to the associated interface unit being in encrypted form.

33. The computer-readable medium of claim 31, having stored thereon instructions that when executed by the processor further cause the processor to:

perform, at the gate controller, a cryptographic hash function on the state information to produce a first hash value;

send the first hash value from the gate controller to the associated interface unit;

perform, at the gate controller, the cryptographic hash function on the modified state information to produce a second hash value; and

send the second hash value from the gate controller to the associated interface unit.

34. The computer-readable medium of claim 31, having stored thereon instructions that when executed by the processor further cause the processor to:

encrypt, at the gate controller, the state information for the call before sending the state information from the gate controller to the associated interface unit, the state information being sent to the associated interface unit being in encrypted form;

encrypt, at the gate controller, the modified state information for the call before sending the modified state information from the gate controller to the associated interface unit, the modified state information being sent to the interface unit being in encrypted form;

perform, at the gate controller, a cryptographic hash function on the state information to produce a first hash value;

send the first hash value from the gate controller to the associated interface unit;

perform, at the gate controller, the cryptographic hash function on the modified state information to produce a second hash value; and

send the second hash value from the gate controller to the associated interface unit.

35. The computer-readable medium of claim 31, having stored thereon instructions that when executed by the processor further cause the processor to:

the gate controller is a terminating gate controller,

the interface unit is a terminating interface unit associated with the called party,

the call feature request is a call return request,

the state information has a source address associated with the calling party, and

a second call being connected based on the source address of the calling party.

36. The computer-readable medium of claim 31, having stored thereon instructions that when executed by the processor further cause the processor to:

the gate controller is a terminating gate controller,

the interface unit is a terminating interface unit associated with the called party,

the call feature request is a called-party-originated trace request,

the state information has a source address associated with the calling party, and reporting the source address of the calling party to a service provider.

37. A method for maintaining state information for a call between a

calling party and a called party, comprising:

sending a setup request for the call from an originating interface unit to an originating gate controller, the originating gate controller being connected to a trusted network, the originating interface unit being associated with the calling party and being coupled to an untrusted network that is different from said trusted network; and

receiving, at the originating interface unit, state information for the call from the originating gate controller without the state information being maintained at the originating gate controller,

said originating gate controller and said originating interface unit communicating with one another via a telecommunications access network.

38. The method of claim 37, wherein the received state information has been encrypted by the originating gate controller.

39. The method of claim 37, further comprising:

receiving, at the originating interface unit, a hash value from the originating gate controller,

the received hash value being based on a cryptographic hash function applied to the state information received at the originating gate controller.

40. The method of claim 37, further comprising:

receiving, at the originating interface unit, a hash value from the originating gate controller,

the received hash value being based on a cryptographic hash function applied to the state information received at the originating gate controller,

the received state information having been encrypted by the originating gate controller.

41. A method for maintaining state information for a call between a calling party and a called party, comprising:

sending a setup request for the call from an originating interface unit to an originating gate controller, the originating gate controller being connected to a trusted network, the originating interface unit being associated with the calling party and being coupled to an untrusted network;

receiving, at the originating interface unit, state information for the call from the originating gate controller without the state information being maintained at the originating gate controller;

sending a call feature request for the call from the originating interface unit to the originating gate controller, said call feature request including at least a portion of the state information received at the originating interface unit; and

receiving modified state information at the originating interface unit from the originating gate controller, the modified state information being based on the state information in the call feature request.

42. A computer-readable medium having stored thereon instructions that, when executed by a processor, cause the processor to:

send a setup request for the call from an originating interface unit to an originating gate controller, the originating gate controller being connected to a trusted network, the originating interface unit being associated with the calling party and being coupled to an untrusted network that is different from said trusted network, and;

receive, at the originating interface unit, state information for the call from the originating gate controller without the state information being maintained at the originating gate controller;

said originating gate controller and said originating interface unit communicating with one another via a telecommunications access network.

43. The computer-readable medium of claim 42, wherein the received state information has been encrypted by the originating gate controller.

44. The computer-readable medium of claim 42, having stored thereon instructions that when executed by the processor further cause the processor to:

receive, at the originating interface unit, a hash value from the originating gate controller,

the received hash value being based on a cryptographic hash function applied to the state information received at the originating gate controller.

45. The computer-readable medium of claim 42, having stored thereon instructions that when executed by the processor further cause the processor to:

receive, at the originating interface unit, a hash value from the originating gate controller,

the received hash value being based on a cryptographic hash function applied to the state information received at the originating gate controller,

the received state information having been encrypted by the originating gate controller.

46. A computer-readable medium having stored thereon instructions that, when executed by a processor, cause the processor to:

send a setup request for the call from an originating interface unit to an originating gate controller, the originating gate controller being connected to a trusted network, the originating interface unit being associated with the calling party and being coupled to an untrusted network;

receive, at the originating interface unit, state information for the call from the originating gate controller without the state information being maintained at the originating gate controller;

send a call feature request for the call from the originating interface unit to the originating gate controller, said call feature request including at least a portion of the state information received at the originating interface unit; and

receive modified state information at the originating interface unit from the originating gate controller, the modified state information being based on the state information in the call feature request.

47. A method for maintaining state information for a call between a calling party and a called party, comprising:

receiving an authorized setup request at a terminating interface unit from a terminating gate controller;

sending a setup acknowledgment message based on the authorized setup request from the terminating interface unit to the terminating gate controller; and

receiving, at the terminating interface unit, state information for the call from the terminating gate controller without the state information being maintained at the terminating gate controller;

said terminating interface unit and said terminating gate controller communicating over a telecommunications access network.

48. The method of claim 47, wherein the received state information has been encrypted by the terminating gate controller.

49. The method of claim 47, further comprising:

receiving, at the terminating interface unit, a hash value from the terminating gate controller,

the received hash value being based on a cryptographic hash function being applied on the state information received at the terminating gate controller.

50. The method of claim 47, further comprising:

receiving, at the terminating interface unit, a hash value from the terminating gate controller,

the received hash value being based on a cryptographic value being applied on the state information received at the terminating gate controller,

the received state information has been encrypted by the terminating gate controller.

51. A method for maintaining state information for a call between a calling party and a called party, comprising:

receiving an authorized setup request at a terminating interface unit from a terminating gate controller;

sending a setup acknowledgment message based on the authorized setup request from the terminating interface unit to the terminating gate controller;

receiving, at the terminating interface unit, state information for the call from the terminating gate controller without the state information being maintained at the terminating gate controller;

sending a call feature request for the call from the terminating interface unit to the terminating gate controller, said call feature request including at least a portion of the state information received at the terminating interface unit; and

receiving modified state information at the terminating interface unit from the terminating gate controller, the modified state information being based on the state information in the call feature request.

52. A computer-readable medium having stored thereon instructions that, when executed by a processor, cause the processor to:

receive an authorized setup request at a terminating interface unit from a terminating gate controller;

send a setup acknowledgment message based on the authorized setup request from the terminating interface unit to the terminating gate controller;

receive, at the terminating interface unit, state information for the call from the terminating gate controller without the state information being maintained at the terminating gate controller;

said terminating interface unit and said terminating gate controller communicating over a telecommunications access network.

53. The computer-readable medium of claim 52, wherein the received state information has been encrypted by the terminating gate controller.

54. The computer-readable medium of claim 52, having stored thereon instructions that when executed by the processor further cause the processor to:

receive, at the terminating interface unit, a hash value from the terminating gate controller,

the received hash value being based on a cryptographic hash function being applied on the state information received at the terminating gate controller.

55. The computer-readable medium of claim 52, having stored thereon instructions that when executed by the processor further cause the processor to:

receive, at the terminating interface unit, a hash value from the terminating gate controller,

the received hash value being based on a cryptographic hash function being applied on the state information received at the terminating gate controller,

the received state information has been encrypted by the terminating gate controller.

56. A computer-readable medium having stored thereon instructions that, when executed by a processor, cause the processor to:

receive an authorized setup request at a terminating interface unit from a terminating gate controller;

send a setup acknowledgment message based on the authorized setup request from the terminating interface unit to the terminating gate controller;

receive, at the terminating interface unit, state information for the call from the terminating gate controller without the state information being maintained at the terminating gate controller;

send a call feature request for the call from the terminating interface unit to the terminating gate controller, said call feature request including at least a portion of the state information received at the terminating interface unit; and

receive modified state information at the terminating interface unit from the terminating gate controller, the modified state information being based on the state information in the call feature request.

57. A method for establishing state information for a call between a calling party and a called party, comprising:

receiving, at an originating gate controller, a setup request for a call, the originating gate controller being connected to a trusted network, the calling party being associated with an originating interface unit coupled to an untrusted network that is different from said trusted network;

authorizing the setup request for the call;

sending the authorized setup request to the called party;

formatting state information for the call based on a setup acknowledgment message received from the called party; and

sending the state information for the call from the originating gate controller to the originating interface unit;

said originating gate controller and said originating interface unit communicating with one another via a telecommunications access network.

58. The method of claim 57, wherein the state information for the call is sent from the originating gate controller to the originating interface unit without the state information for the call being accessed subsequently from the originating gate controller.

59. The method of claim 57, further comprising:

sending the state information for the call from the terminating gate controller to the terminating interface unit.

60. The method of claim 57, further comprising:

sending the state information for the call from the terminating gate controller to the terminating interface unit without the state information for the call being accessed subsequently from the terminating gate controller.

61. A method for use in an originating gate controller in a packet-carrying network, the method comprising

receiving a setup request for a call from an originating interface unit on a customer premises, said setup request being received over a telecommunications access network that interconnects said customer premises to said packet-carrying network;

and

sending state information for the call to the originating interface unit over said telecommunications access network without maintaining the state information at the originating gate controller.

62. The invention of claim 61 wherein said state information for the call includes information identifying a destination for the call.

63. The invention of claim 61 wherein said state information for the call includes billing information for the call.

64. The method of claim 61 wherein said state information for the call is sent to the originating interface unit in encrypted form.

65. A method for use by a gate controller in a packet-carrying network, the method comprising

receiving, from an originating interface unit on a customer premises, call request messages requesting setup of calls through the network, each of said call request messages including information identifying a destination for a respective one of the calls, and

sending at least one message to said originating interface unit subsequent to receipt of each said call request message, ones of the sent messages including network addresses corresponding to the identified destinations and others of the sent messages including network addresses corresponding to call-forwarded destinations associated with the identified destinations,

said gate controller not maintaining information about said network addresses after sending said messages to said originating interface unit, and the network addresses corresponding to at least the call-forwarded destinations being encrypted,

each said message being communicated over a telecommunications access network that interconnects said customer premises with said packet-carrying network.

66. The invention of claim 65 wherein the network addresses corresponding to the identified destinations are encrypted.

67. The invention of claim 65 wherein said others of said sent messages are call transfer messages.

68. A method for use by a gate controller in a packet-carrying network of a type in which originating interface units on customer premises send to said gate controller call setup requests that include information identifying requested destinations for the respective calls;

in which, subsequent to receipt of each call setup request from an individual one of the originating interface units, said gate controller sends to that originating interface unit at least one message that includes a network address; and

in which said originating interface units provide, for transport over said network, packets that include network addresses included in said messages, the method comprising

including in individual ones of the messages sent by said gate controller network addresses corresponding to said requested destinations, and

including in other ones of the messages sent by said gate controller network addresses corresponding to call-forwarded destinations that had been specified for ones of said requested destinations,

said gate controller not maintaining information about said network addresses after sending said messages to said originating interface units, and the network addresses corresponding to at least the call-forwarded destinations being encrypted,

each said message being communicated over a telecommunications access network that interconnects said customer premises with said packet-carrying network.

69. The invention of claim 68 wherein said other ones of said messages are call transfer messages, whereby a call that was set up to a requested destination is caused to be transferred to a call-forwarded destination.

70. The invention of claim 68 wherein the network addresses corresponding to the identified destinations are encrypted.

71. The invention of claim 70 wherein said other ones of said messages are call transfer messages.