ATM-based distributed virtual tandem switching system

• US 6,219,348 B1
• Filed: 05/01/2000
• Issued: 04/17/2001
• Est. Priority Date: 04/30/1998
• Status: Expired due to Term

• Current Assignee: SBC Technology Resources, Inc. (AT&T, Inc.)
• Original Assignee: SBC Technology Resources, Inc. (AT&T, Inc.)
• Inventors: Allen, Jr., George C., Bi, Haifeng, Partridge, Steven R., Sigarto, Samuel, Stephenson, Richard W.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): Harper, Kevin C.
• Application Number:
  US09/562,725
• Time in Patent Office: 351 Days
• Field of Search: 370/352, 370/353, 370/354, 370/384, 370/385, 370/389, 370/395, 370/396, 370/397, 370/409, 370/524, 370/466, 370/467, 379/219, 379/220, 379/230
• US Class Current: 370/354
• CPC Class Codes: H04J 2203/0048 Network termination, e.g. NT1, NT2, PBX
• CPC Class Codes: H04J 2203/0066 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04J 2203/0078 Support of N-ISDN
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5618 Bridges, gateways [GW] or interworking units [IWU]
• CPC Class Codes: H04L 2012/5626 Network management, e.g. Intelligent nets
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5653 using the ATM adaptation layer [AAL]
• CPC Class Codes: H04L 2012/5663 Support of N-ISDN
• CPC Class Codes: H04L 2012/5665 Interaction of ATM with other protocols
• CPC Class Codes: H04L 2012/5671 Support of voice
• CPC Class Codes: H04L 49/3081 ATM peripheral units, e.g. policing, insertion or extraction
• 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
• CPC Class Codes: H04M 7/06 using auxiliary connections for control or supervision , e.g. where the auxiliary connection is a signalling system number 7 link
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04Q 3/0025 Provisions for signalling

Abstract

An Asynchronous Transfer Mode (ATM)-based distributed virtual tandem switching system is provided in which a network of ATM-based devices is combined to create a distributed virtual tandem switch. The system includes an ATM switching network that dynamically sets up individual switched virtual connections. The system also includes a trunk interworking function (T-IWF) device and a centralized control and signaling interworking finction (CS-IWF) device. The trunk interworking function device converts end office voice trunks from TDM channels to ATM cells by employing a structured circuit emulation service. The centralized control and signaling interworking function device performs call control functions and interfaces narrowband signaling and broadband signaling for call processing and control within the ATM switching network. Consequently, the ATM based distributed virtual tandem switching system replaces a standard tandem switch in the PSTN.

Claims

1. An Asynchronous Transfer Mode (ATM) based distributed virtual tandem switching system, comprising:

an ATM switching network comprising a plurality of ATM switches;

a trunk interworking function (T-IWF) device adapted to receive end office voice trunks from TDM channels and convert the trunks to ATM cells; and

a centralized control and signaling interworking function (CS-IWF) device that performs call control functions for the plurality of ATM switches and is adapted to interface narrowband and broadband signaling for call processing and control within the ATM switching network.

2. The ATM based distributed virtual tandem switching system of claim 1, wherein the ATM based distributed virtual tandem switching system is adapted to comprise a virtual switch in a PSTN.

3. The ATM based distributed virtual tandem switching system of claim 1, in which the T-IWF device comprises a circuit emulation service.

4. The ATM based distributed virtual tandem switching system of claim 3, in which the T-IWF device comprises ATM adaptation layer 1.

5. The ATM based distributed virtual tandem switching system of claim 3, in which the T-IWF device comprises ATM adaptation layer 2.

6. The ATM based distributed virtual tandem switching system of claim 5, in which at least one of silence suppression and voice compression is employed.

7. The ATM based distributed virtual tandem switching system of claim 1, in which the T-IWF device and an end office switch are positioned near each other.

8. The ATM distributed virtual tandem switching system of claim 1, in which the CS-IWF device comprises a plurality of CS-IWF devices, and in which each T-IWF device is assigned to an individual CS-IWF device.

9. The ATM based distributed virtual tandem switching system of claim 1, in which the narrowband signaling is SS7 signaling.

10. The ATM based distributed virtual tandem switching system of claim 9, in which the broadband signaling is PNNI.

11. The ATM based distributed virtual tandem switching system of claim 9, in which the broadband signaling is B-ISUP.

12. The ATM based distributed virtual tandem switching system of claim 9, in which the broadband signaling is UNI.

13. The ATM distributed virtual tandem switching system of claim 1, wherein an individual switched virtual connection is provided in the ATM switching network to dynamically setup each voice trunk.

14. A method for transporting voice from an originating location to a destination across an Asynchronous Transfer Mode (ATM) network via an originating trunk interworking function (T-IWF) device and a terminating T-IWF device, the method comprising:

transmitting the voice from the originating location to an originating trunk that leaves an end office switch;

converting the originating trunk to ATM cells;

interfacing between narrowband and broadband signaling at a centralized control and signaling interworking function (CS-IWF) device for call processing and control within the ATM network;

transmitting the voice within the ATM cells across the ATM network utilizing the broadband signaling;

converting the ATM cells to a destination trunk; and

transmitting the voice from the destination trunk to the destination.

15. The method for transporting voice according to claim 14, in which the transporting is enabled by emulating a circuit by employing a circuit emulation service.

16. The method for transporting voice according to claim 15, in which the voice is converted to ATM cells utilizing ATM adaptation layer 1.

17. The method for transporting voice according to claim 15, in which the voice is converted to ATM cells utilizing ATM adaptation layer 2.

18. The method for transporting voice according to claim 17, in which at least one of silence suppression and voice compression is employed.

19. The method for transporting voice according to claim 14, in which each voice trunk is setup dynamically as an individual switched virtual connection in the ATM network.

20. The method for transporting voice according to claim 14, in which converting the originating trunk to ATM cells occurs in the originating T-IWF device within an originating end office and converting the ATM cells to a destination trunk occurs in the terminating T-IWF device within a destination end office.

21. The method for transporting voice according to claim 14, in which the narrowband signaling is SS7 signaling.

22. The method for transporting voice according to claim 21, in which the broadband signaling is PNNI.

23. The method for transporting voice according to claim 21, in which the broadband signaling is B-ISUP.

24. The method for transporting voice according to claim 21, in which the broadband signaling is UNI.

25. An Asynchronous Transfer Mode (ATM) based distributed virtual tandem switching system in which a network of ATM-based devices is combined to create a distributed virtual tandem switch, the system comprising:

an ATM switching network that dynamically sets up individual switched virtual connections, the ATM switching network comprising a plurality of switches;

a trunk interworking function (T-IWF) device that converts end office voice trunks from TDM channels to ATM cells by employing a circuit emulation service; and

a centralized control and signaling interworking function (CS-IWF) device that performs call control functions for the plurality of ATM switches and interfaces narrowband signaling and broadband signaling for call processing and control within the ATM switching network;

wherein the ATM based distributed virtual tandem switching system is adapted to comprise a virtual switch in a PSTN.

26. An Asynchronous Transfer Mode (ATM) distributed virtual tandem switch comprising:

a centralized control and signaling inter-working function (CS-IWF) device that performs call control functions for a plurality of ATM switches and converts between narrowband and broadband signaling for call processing and control within an ATM switching network comprising the plurality of ATM switches;

a first trunk inter-working function (T-IWF) device that converts trunks from end office switches to ATM cells; and

a second trunk inter-working function (T-IWF) device that converts ATM cells to trunks for end office switches;

wherein telephone calls originating and terminating within an advanced intelligent network are transmitted through the ATM switching network.

27. The ATM distributed virtual tandem switch of claim 26, wherein each T-IWF device employs a structured circuit emulation service to emulate a circuit.

28. The ATM distributed virtual tandem switch of claim 26, wherein individual switched virtual connections are provided that dynamically set up the ATM switching network.

29. The ATM distributed virtual tandem switch of claim 26, in which the CS-IWF device comprises a plurality of CS-IWF devices, wherein each T-IWF device is assigned to an individual CS-IWF device.

30. An Asynchronous Transfer Mode (ATM) distributed virtual tandem switch comprising:

a centralized control and signaling inter-working function (CS-IWF) device that performs call control functions for a plurality of ATM switches and converts between narrowband and broadband signaling for call processing and control within an ATM switching network;

wherein telephone calls originating and terminating within an advanced intelligent network are transmitted through the ATM switching network and are controlled, within the ATM switching network, by the CS-IWF device.

31. The ATM distributed virtual tandem switch of claim 30, wherein individual switched virtual connections are provided that dynamically set up the ATM switching network.

32. The ATM distributed virtual tandem switch of claim 30, in which the at least one T-IWF device converts trunks from end office switches to ATM cells.

33. The ATM distributed virtual tandem switch of claim 32, in which the at least one T-IWF device converts ATM cells to trunks for end office switches.

34. An Asynchronous Transfer Mode (ATM) distributed virtual tandem switching system comprising:

an ATM switching network comprising a plurality of ATM switches;

a first trunk inter-working function (T-IWF) device that converts trunks from end office switches to ATM cells;

a second trunk inter-working function (T-IWF) device that converts ATM cells to trunks for end office switches; and

a centralized control and signaling interworking function (CS-IWF) device that performs call control functions for the plurality of ATM switches and converts between narrowband and broadband signaling for call processing and control within the ATM switching network, wherein the ATM distributed virtual tandem system functions like a standard tandem switch.

35. The ATM distributed virtual tandem switching system of claim 34, wherein each T-IWF device includes a structured circuit emulation service to emulate a circuit.

36. The ATM distributed virtual tandem switching system of claim 34, wherein individual switched virtual connections dynamically set up the ATM switching network.

37. The ATM distributed virtual tandem switching system of claim 34, in which the CS-IWF device comprises a plurality of CS-IWF devices, wherein each T-IWF device is assigned to an individual CS-IWF device.

38. An Asynchronous Transfer Mode (ATM) distributed virtual tandem switching system comprising:

an originating end office that originates a telephone call and forwards appropriate narrowband signaling for call processing and control within an advanced intelligent network;

a signaling transfer point that receives and forwards narrowband signaling for call processing and control within the advanced intelligent network; and

a centralized control and signaling interworking function (CS-IWF) device that performs call control functions for a plurality of ATM switches and converts between narrowband and broadband signaling for call processing and control within an ATM switching network;

wherein the CS-IWF device receives narrowband signaling from the signaling transfer point and processes and controls the telephone call within the ATM switching network using broadband signaling based upon the received narrowband signaling.

39. The ATM distributed virtual tandem switching system of claim 38, in which individual switched virtual connections dynamically set up the ATM switching network.

40. The ATM distributed virtual tandem switching system of claim 38, further comprising a terminating end office that is the destination of the telephone call.

41. The ATM distributed virtual tandem switching system of claim 39, further comprising the ATM switching network.

42. An Asynchronous Transfer Mode (ATM) distributed virtual tandem switching system comprising:

an ATM switching network comprising a plurality of ATM switches;

an originating end office that originates a telephone call;

a terminating end office that is the destination of the telephone call;

a first trunk inter-working function (T-IWF) device that converts trunks from end office switches to ATM cells;

a second trunk inter-working function (T-IWF) device that converts ATM cells to trunks for end office switches;

a signaling transfer point that receives and forwards narrowband signaling for call processing and control within an advanced intelligent network; and

a centralized control and signaling interworking function (CS-IWF) device that performs call control functions for the plurality of ATM switches and converts between narrowband and broadband signaling for call processing and control within the ATM switching network;

wherein the ATM distributed virtual tandem system functions like a standard tandem switch.

43. The ATM distributed virtual tandem switching system of claim 42, in which a structured circuit emulation service is provided in each T-IWF device to emulate a circuit.

44. The ATM distributed virtual tandem switching system of claim 42, in which individual switched virtual connections dynamically set up the ATM switching network.

45. The ATM distributed virtual tandem switching system of claim 42, in which the first T-IWF device and the originating end office are positioned near each other, and the second T-IWF device and the terminating end office are positioned near each other.

46. The ATM distributed virtual tandem switching system of claim 42, in which the CS-IWF device comprises a plurality of CS-IWF devices, and in which each T-IWF device is assigned to an individual CS-IWF device.

47. A call processing and control signal embodied on a carrier wave, the signal setting up a virtual connection across an ATM switching network for voice transport, the signal comprising:

a narrowband format, transmitted from an end office via a signaling transfer point (STP) to a control and signaling interworking function (CS-IWF) [CS-IWF] device; and

a broadband format, derived from the narrowband format, transmitted from the CS-IWF device to an originating trunk interworking function (T-IWF) device and to a destination T-IWF device via the ATM switching network.