Method and apparatus for prioritizing voice and data in a circuit-switched network

• US 6,507,648 B1
• Filed: 12/23/1998
• Issued: 01/14/2003
• Est. Priority Date: 12/23/1998
• Status: Expired due to Term

• Current Assignee: Spherix Incorporated
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Golka, Kevin W., Donak, John R., Porter, Lorne A.
• Primary Examiner(s): Hong, Harry S.
• Application Number:
  US09/219,496
• Time in Patent Office: 1,483 Days
• Field of Search: 379/221.06, 379/221.07, 379/219, 379/220.01, 379/221.01, 379/232, 379/242, 379/243, 379/271, 379/272, 379/273, 370/468
• US Class Current: 379/221.07
• CPC Class Codes: H04L 67/61 taking into account QoS or priority requirements
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 2207/203 composed of PSTN and data network, e.g. the Internet
• CPC Class Codes: H04M 2242/06 Lines and connections with preferential service
• CPC Class Codes: H04M 3/20 with means for interrupting existing connections; with means for breaking-in on conversations
• CPC Class Codes: H04M 3/42314 in private branch exchanges
• CPC Class Codes: H04Q 2213/13141 Hunting for free outlet, circuit or channel
• CPC Class Codes: H04Q 2213/1325 Priority service
• CPC Class Codes: H04Q 2213/13332 Broadband, CATV, dynamic bandwidth allocation
• CPC Class Codes: H04Q 3/66 Traffic distributors

Abstract

The invention is a novel method of processing incoming and outgoing call requests by a switching unit such as a KSU, PBX or PC server. Each established circuit and each call request is associated with a priority. For an outgoing call request, if an available external bandwidth channel of the appropriate type is found, then a circuit is established at once. However, if there is no available external bandwidth channel of the appropriate type, then the priority of the outgoing call request is checked against the priority of the established circuits. If a lower-priority circuit is found, then that circuit is torn down and a new circuit is established between the internal bandwidth channel carrying the outgoing call request and the external bandwidth channel formerly occupying the established circuit that was torn down. In the case of an incoming call request, a destination terminal device and associated internal bandwidth channels will be specified and availability thereof is verified. If all the bandwidth channels are occupied and if the incoming call request has a higher priority than at least one established circuit involving the destination terminal device, then the existing circuit is torn down and a new one is established between that internal bandwidth channel and the external bandwidth channel carrying the incoming call request.

Claims

1. A switching unit connectable to a plurality of external lines carrying a plurality of external bandwidth channels and also connectable to a plurality of internal lines carrying a plurality of internal bandwidth channels, the switch comprising:

a plurality of internal interface units connectable to the internal lines, for receiving outgoing call requests associated with respective internal bandwidth channels;

a control unit connected to the internal interface units, for receiving outgoing call requests from the internal interface units and generating respective updated circuit mappings therefrom; and

a switch connected to the control unit and to the internal interface units and connectable to the external lines, for controllably establishing circuits between the external bandwidth channels and respective ones of the internal bandwidth channels in accordance with updated circuit mappings received from the control unit;

wherein the control unit comprises means for, upon receiving an outgoing call request, determining whether there is an available external bandwidth channel and

if so;

generating an updated circuit mapping sent to the switch for establishing a circuit between the available external bandwidth channel and the internal bandwidth channel associated with said outgoing call request;

otherwise;

determining whether the outgoing call request has a higher priority than at least one currently established circuit and if so, generating an updated circuit mapping sent to the switch for interrupting a lower-priority circuit and establishing a new circuit between the external bandwidth channel formerly associated with the interrupted circuit and the internal bandwidth channel associated with said outgoing call request.

2. A switching unit according to claim 1, wherein the switch is a digital switch matrix.

3. A switching unit according to claim 1, wherein the internal interface units comprise circuitry for formatting signals leaving or entering the switching unit on the internal lines.

4. A switching unit according to claim 1, further comprising a plurality of external interface units connectable to the external lines and connected to the control unit and to the switch, for formatting the signals leaving or entering the switching unit on the external lines.

5. A switching unit according to claim 1, further comprising a plurality of emulators connected between the control unit and respective internal interface units, wherein each emulator comprises means for receiving and processing an outgoing call request from the respective internal interface, thereby to extract the priority of the outgoing call request.

6. A switching unit according to claim 5, wherein the control unit and emulators are interconnected in a hardware bus architecture.

7. A switching unit according to claim 5, wherein the control unit and emulators are implemented in software and communicate through the exchange software parameters.

8. A switching unit according to claim 1, wherein the control unit communicates with the switch using a dedicated hardware link.

9. A switching unit according to claim 6, wherein the switch is also interconnected via the hardware bus architecture.

10. A switching unit according to claim 7, wherein the switch is also implemented in software and communicates via the exchange of software parameters.

11. A switching unit according to claim 1, wherein the control unit is a processor comprising a table stored in memory, said table containing a record of the external bandwidth channel, the internal bandwidth channel and the priority associated with each established circuit.

12. A switching unit according to claim 1, wherein the internal bandwidth channels carry a mixture of voice and data traffic.

13. A switching unit according to claim 12, wherein voice is considered to have a higher priority than data.

14. A switching unit according to claim 12, wherein data is said to have a higher priority than voice.

15. In a switching unit comprising a switch for controllably establishing circuits between a plurality of external bandwidth channels and respective ones of a plurality of internal bandwidth channels, a method of processing an outgoing call request associated with an internal bandwidth channel, said outgoing call request having a priority, the method comprising the steps of:

determining whether there is an available external bandwidth channel and

if so;

establishing a circuit between the available external bandwidth channel and the internal bandwidth channel associated with said outgoing call request;

otherwise;

determining whether the outgoing call request has a higher priority than at least one currently established circuit and if so, interrupting a lower-priority circuit and establishing a new circuit between the external bandwidth channel formerly associated with the interrupted circuit and the internal bandwidth channel associated with said outgoing call request.

16. A computer-readable storage medium containing software which, when running on a processor in a switching unit for controllably establishing circuits between a plurality of external bandwidth channels and respective ones of a plurality of internal bandwidth channels, follows a sequence of steps to process an outgoing call request associate with an internal bandwidth channel and having a priority, the steps comprising:

determining whether there is an available external bandwidth channel and

if so;

establishing a circuit between the available external bandwidth channel and the internal bandwidth channel associated with said outgoing call request;

otherwise;

determining whether the outgoing call request has a higher priority than at least one currently established circuit and if so, interrupting a lower-priority circuit and establishing a new circuit between the external bandwidth channel formerly associated with the interrupted circuit and the internal bandwidth channel associated with said outgoing call request.

17. A switching unit connectable to at least one external line carrying a plurality external bandwidth channels and also connectable to at least one internal line carrying a plurality of internal bandwidth channels, the internal lines connected to terminal devices, the terminal devices associated with at least one of the plurality of internal bandwidth channels, the switch comprising:

a plurality of external interface units connectable to the external lines, for receiving incoming call requests associated with the external bandwidth channels carried by the external lines;

a control unit connected to the external interface units, for receiving incoming call requests from the external interface units and generating respective updated circuit mappings therefrom; and

a switch connected to the control unit and to the external interface units and connectable to the internal lines, for controllably establishing circuits between the external bandwidth channels and respective ones of the internal bandwidth channels in accordance with updated circuit mappings received from the control unit;

wherein the control unit comprises means for, upon receiving an incoming call request from an external interface unit, determining the destination terminal device and determining whether there is at least one available internal bandwidth channel associated with the destination terminal device and

if so;

if the external bandwidth channel carrying said incoming call request is available, generating an updated circuit mapping sent to the switch for establishing a circuit between an available internal bandwidth channel and the external bandwidth channel associated with said incoming call request;

otherwise;

determining whether the incoming call request has a higher priority than at least one circuit currently established with the destination terminal device and if so and also if the external bandwidth channel carrying said incoming call request is available, generating an updated circuit mapping sent to the switch for interrupting a lower-priority circuit occupying an internal bandwidth channel associated with the destination terminal device and establishing a new circuit between the internal bandwidth channel formerly associated with the interrupted circuit and the external bandwidth channel associated with said incoming call request.

18. A switching unit according to claim 17, wherein the control unit further comprises means for:

if the external bandwidth channel associated with said incoming call request is occupied, determining whether the incoming call request has a higher priority than the circuit occupying the external bandwidth channel associated with said incoming call request and if not, generating an updated circuit mapping sent to the switch for interrupting a lower-priority circuit occupying an internal bandwidth channel associated with the destination terminal device, interrupting the circuit occupying the external bandwidth channel carrying the incoming call request and establishing a new circuit between the internal bandwidth channel formerly associated with the interrupted lower-priority circuit and the external bandwidth channel associated with said incoming call request.

19. In a switching unit comprising a switch for controllably establishing circuits between a plurality of external bandwidth channels and respective ones of a plurality of internal bandwidth channels, a method of processing an incoming call request associated with an the external bandwidth channels, said incoming call request having a priority and associated with a destination terminal device and at least one internal bandwidth channel, the method comprising the steps of:

determining whether there is at least one available internal bandwidth channel associated with the destination terminal device and

if so;

determining whether the external bandwidth channel carrying said incoming call request is available and if so, generating an updated circuit mapping sent to the switch for establishing a circuit between an available internal bandwidth channel and the external bandwidth channel associated with said incoming call request;

otherwise;

determining whether the incoming call request has a higher priority than at least one circuit currently established with the destination terminal device and if so, determining whether the external bandwidth channel carrying said incoming call request is available and if so, generating an updated circuit mapping sent to the switch for interrupting a lower-priority circuit occupying an internal bandwidth channel associated with the destination terminal device and establishing a new circuit between the internal bandwidth channel formerly associated with the interrupted circuit and the external bandwidth channel associated with said incoming call request.

20. A method according to claim 19, further comprising the step of:

if the external bandwidth channel associated with said incoming call request is occupied, the control unit determining whether the incoming call request has a higher priority than the circuit occupying the external bandwidth channel associated with said incoming call request and if not, generating an updated circuit mapping sent to the switch for interrupting a lower-priority circuit occupying an internal bandwidth channel associated with the destination terminal device, interrupting the circuit occupying the external bandwidth channel carrying the incoming call request and establishing a new circuit between the internal bandwidth channel formerly associated with the interrupted lower-priority circuit and the external bandwidth channel associated with said incoming call request.

21. A computer-readable storage medium containing software which, when running on a processor in a switching unit for controllably establishing circuits between a plurality of external bandwidth channels and respective ones of a plurality of internal bandwidth channels, follows a sequence of steps to process an incoming call request having a priority, the steps comprising:

determining whether there is at least one available internal bandwidth channel associated with the destination terminal device and

if so;

determining whether the external bandwidth channel carrying said incoming call request is available and if so, generating an updated circuit mapping sent to the switch for establishing a circuit between an available internal bandwidth channel and the external bandwidth channel on which said incoming call request was received;

otherwise;

determining whether the incoming call request has a higher priority than at least one circuit currently established with the destination terminal device and if so, determining whether the external bandwidth channel carrying said incoming call request is available and if so, generating an updated circuit mapping sent to the switch for interrupting a lower-priority circuit occupying an internal bandwidth channel associated with the destination terminal device and establishing a new circuit between the internal bandwidth channel formerly associated with the interrupted circuit and the external bandwidth channel carrying said incoming call request.

22. A computer-readable storage medium according to claim 21, wherein the sequence of steps further comprises the step of:

if the external bandwidth channel associated with said incoming call request is occupied, determining whether the incoming call request has a higher priority than the circuit occupying the external bandwidth channel associated with said incoming call request and if not, generating an updated circuit mapping sent to the switch for interrupting a lower-priority circuit occupying an internal bandwidth channel associated with the destination terminal device, interrupting the circuit occupying the external bandwidth channel carrying the incoming call request and establishing a new circuit between the internal bandwidth channel formerly associated with the interrupted lower-priority circuit and the external bandwidth channel associated with said incoming call request.