ATM-based distributed virtual tandem switching system

• US 6,389,011 B2
• Filed: 02/28/2001
• Issued: 05/14/2002
• Est. Priority Date: 04/30/1998
• Status: Expired due to Fees

• Current Assignee: SBC Technology Resources, Inc. (AT&T, Inc.)
• Original Assignee: SBC Technology Resources, Inc. (AT&T, Inc.)
• Inventors: Sigarto, Samuel, Stephenson, Richard W., Allen, Jr., George C., Bi, Haifeng, Partridge, Steven R.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): Harper, Kevin C.
• Application Number:
  US09/794,914
• Publication Number:
  US 20010017861A1
• Time in Patent Office: 440 Days
• Field of Search: 370/352-354, 370/384-385, 370/389, 370/395-397, 370/409, 370/466-467, 370/524, 379/219-220, 379/230
• US Class Current: 370/356
• 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 function (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. A method for establishing an Asynchronous Transfer Mode (ATM) connection from an originating end office to a destination end office across an ATM network via an originating trunk interworking function (T-IWF) device and a terminating T-IWF device, the method comprising:

transmitting an originating message, including a called telephone number, from the originating end office to a centralized control and signaling interworking function (CS-IWF) device;

processing the originating message to identify the originating T-IWF device and to identify the terminating T-IWF device;

forwarding a terminating message, including the called telephone number, from the CS-IWF device to the destination end office;

initially reserving a first trunk between the originating end office and the originating T-IWF device, the first trunk having a first trunk ID, the originating message further comprising the first trunk ID;

sending an ATM request via the ATM network to the terminating T-IWF device requesting a second trunk between the terminating T-IWF device and the destination end office, the second trunk having a second trunk ID;

reserving the second trunk;

forwarding a trunk ATM message via the ATM network from the terminating T-IWF device to the CS-IWF device, the trunk ATM message comprising the second trunk ID; and

establishing an ATM connection between the originating T-IWF device and the terminating T-IWF device.

2. The method of claim 1, in which the processing further comprises identifying the originating T-IWF device based upon the calling party number, and identifying the terminating T-IWF device based upon the called party number.

3. The method of claim 2, in which the identifying further comprises identifying the originating T-IWF device by an ATM address of the originating T-IWF device, and identifying the terminating T-IWF device by an ATM address of the terminating T-IWF device.

4. The method of claim 1, further comprising

sending a first ATM message, corresponding to the originating message, via the ATM network to the originating T-IWF device; and

determining, at the originating T-IWF device, a DS0 corresponding to the first trunk ID;

wherein the terminating message further comprises the second trunk ID;

reserving, at the destination end office, the second trunk based upon the received second trunk ID.

5. The method of claim 1, in which the establishing further comprises the originating T-IWF device establishing a constant bit rate (CBR) connection to the terminating T-IWF device.

6. The method of claim 1, in which the establishing further comprises the terminating T-IWF device establishing a constant bit rate (CBR) connection to the originating T-IWF device.

7. The method of claim 1, in which the establishing further comprises the originating T-IWF device establishing a variable bit rate (VBR) connection to the terminating T-IWF device.

8. The method of claim 1, in which the establishing further comprises the terminating T-IWF device establishing a variable bit rate (VBR) connection to the originating T-IWF device.

9. The method of claim 1, in which the establishing further comprises mapping the first trunk to an outgoing switched virtual connection (SVC), and mapping an incoming SVC to the second trunk.

10. A method for establishing a connection from a calling party associated with an originating end office to a called party associated with a destination end office, the connection being via an originating trunk interworking function (T-IWF) device, an Asynchronous Transfer Mode (ATM) network, and a terminating T-IWF device, the connection being established in response to the calling party dialing a called telephone number, the method comprising:

reserving a first trunk between the originating end office and the originating T-IWF device, the first trunk having a first trunk ID;

transmitting an originating message, including the called telephone number and the first trunk ID, from the originating end office to a centralized control and signaling interworking function (CS-IWF) device;

processing the originating message to identify the originating T-IWF device and to identify the terminating T-IWF device;

sending an ATM request via the ATM network to the terminating T-IWF device requesting a second trunk between the terminating T-IWF device and the destination end office, the second trunk having a second trunk ID;

reserving the second trunk;

forwarding a trunk ATM message via the ATM network from the terminating T-IWF device to the CS-IWF device, the trunk ATM message comprising the second trunk ID;

forwarding a terminating message, including the called telephone number and the second trunk ID, from the CS-IWF device to the destination end office; and

establishing an ATM connection between the originating T-IWF device and the terminating T-IWF device.

11. The method of claim 10, further comprising:

connecting a terminating line associated with the called telephone number to the second reserved trunk; and

connecting an originating line associated with the calling party to the first reserved trunk;

wherein the calling party hears a ringing tone.

12. The method of claim 11, further comprising:

sending an off-hook message from the destination end office to the CS-IWF device when the called party answers the call;

forwarding the off-hook message to the originating end office; and

starting billing measurement.

13. The method of claim 10, in which the establishing further comprises the originating T-IWF device establishing a constant bit rate (CBR) connection to the terminating T-IWF device.

14. The method of claim 10, in which the establishing further comprises the terminating T-IWF device establishing a constant bit rate (CBR) connection to the originating T-IWF device.

15. The method of claim 10, in which the establishing further comprises the originating T-IWF device establishing a variable bit rate (VBR) connection to the terminating T-IWF device.

16. The method of claim 10, in which the establishing further comprises the terminating T-IWF device establishing a variable bit rate (VBR) connection to the originating T-IWF device.

17. The method of claim 10, in which the establishing further comprises mapping the first trunk to an outgoing switched virtual connection (SVC), and mapping the second trunk to an incoming SVC.