Automatic backup trunking for voice over the internet

• US 6,389,005 B1
• Filed: 12/01/1997
• Issued: 05/14/2002
• Est. Priority Date: 12/01/1997
• Status: Expired due to Term

• Current Assignee: Avaya Incorporated
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Cruickshank, Brian
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Boakye, Alexander O.
• Application Number:
  US08/980,760
• Time in Patent Office: 1,625 Days
• Field of Search: 370/351, 370/352, 370/353, 370/355, 370/356, 370/225, 370/227, 340/826, 340/827, 379/88.17, 379/221
• US Class Current: 370/352
• CPC Class Codes: H04L 12/2856 Access arrangements, e.g. Internet access asynchronous transfer mode networks H04L12/5601; broadband local area networks H04L12/2801; optical access or distribution networks H04Q11/0067; access to open networks H04L12/5691; digital subscriber line end-user equipment and bit-level processing of data on a PSTN-based network H04M11/00; home network gateways H04L12/2834; wireless access networks H04W
• CPC Class Codes: H04L 12/2898 Subscriber equipments DSL modems H04M11/062; cable modems H04L12/2801
• CPC Class Codes: H04M 7/0057 Services where the data services network provides a telephone service in addition or as an alternative, e.g. for backup purposes, to the telephone service provided by the telephone services network
• CPC Class Codes: H04Q 3/62 for connecting to private branch exchanges

Abstract

To reduce telephone toll costs to a user, a PBX preferentially establishes a call to a destination number (DN) over a WAN or the internet. The PBX determines the available connection types available by querying look-up tables for the particular DN. If no alternatives to the PSTN are available, the call is routed over the PSTN. Where a WAN or internet connection is available, the call is then routed over this alternative service. If the Quality of Service (QoS) over the computer network connection falls below a specified threshold, a second parallel connection is made over the PSTN and the call is then transferred to the PSTN. The user is notified of this change in service. During the PSTN connection, the PBX polls the alternative service and, upon the QoS rising above a specified threshold, the call is then routed back to the alternative service and the PSTN connection is torn down. The user is again notified of this change in service.

Claims

1. A method for routing a telephone call, comprising:

receiving a destination number (DN) for said call;

based on said DN, determining whether a connection is possible through an intranet;

where an intranet connection is possible, routing said call through said intranet;

where an intranet connection is not possible, determining if an internet connection is possible;

and where an intranet connection is not possible and an internet connection is possible, routing said call through said internet preferentially to routing said call through a switched telephone network; and

where neither an internet nor an intranet connection is possible, routing said call through said switched telephone network.

2. A method for routing a telephone call, comprising:

receiving a destination number (DN) for said call;

based on said DN, determining whether a connection is possible through a computer network;

where a computer network connection is not possible, routing said call through a switched telephone network;

where said call is routed on a path through said switched telephone network and a computer network connection becomes possible, (i) monitoring for a period of silence on said switched telephone network path and (ii) during a period of silence, switching said call from said switched telephone network path to said computer network connection and tearing down said switched telephone network path.

3. The method of claim 2 wherein said computer network comprises an internet and wherein said switched telephone network comprises a public switched telephone network (PSTN).

4. The method of claim 2 wherein said computer network comprises an intranet.

5. The method of claim 2 wherein said telephone call is a first call and further comprising receiving a DN for a second call;

determining, based on said DN for said second call, whether a connection is possible through said computer network; and

, where a computer network connection is possible, routing said second call through said computer network.

6. A switch for routing a telephone call comprising;

means for receiving a destination number (DN) for said call;

means for, based on said DN, determining whether a connection is possible through a computer network;

means for, where a computer network connection is not possible, routing said call through a switched telephone network and for, where said call is routed on a path through said switched telephone network and a computer network connection becomes possible, (i) monitoring for a period of silence on said switched telephone network path and (ii) during a period of silence, switching said call from said switched telephone network path to said computer network connection and tearing down said switched telephone network path.

7. The switch of claim 6 wherein said computer network comprises an internet and wherein said switched telephone network comprises a public switched telephone network (PSTN).

8. The switch of claim 6 wherein said computer network comprises an intranet.

9. A switch for routing a telephone call from a calling station to a called station, comprising:

means for receiving a destination number (DN) for said call;

means for, based on said DN, determining whether a connection is possible through an intranet;

means for, where an intranet connection is possible, routing said call through said intranet;

means for, where an intranet connection is not possible, determining if an internet connection is possible;

means for, where an intranet connection is not possible and an internet connection is possible, routing said call through said internet preferentially to routing said call through a switched telephone network; and

means for, where neither an internet nor an intranet connection is possible, routing said call through said switched telephone network.

10. A method for routing telephone calls, comprising:

receiving a destination number (DN) for each of a plurality of calls;

based on a DN for each call, determining whether a connection is possible through an intranet;

where, for a first call, an intranet connection is possible routing said call through said intranet;

where, for a second call, an intranet connection is not possible, determining if an internet connection is possible;

where, for said second call, an internet connection is possible, routing said second call through said internet preferentially to routing said second call through a switched telephone network; and

where, for a third call, an intranet connection is not possible, determining if an internet connection is possible;

where, for said third call, an internet connection is not possible, routing said third call through said switched telephone network.

11. The method of claim 10 further comprising:

where, for said second call, said internet connection becomes no longer viable, (i) sending an alert notification to a calling station and a called station associated with said second call and (ii) switching said second call from said internet to a switched telephone network.

12. The method of claim 11 wherein said switched telephone network comprises a public switched telephone network (PSTN).

13. A switch for routing a telephone call, comprising:

means for receiving a destination number (DN) for each of a plurality of calls;

means for, based on a DN for each call, determining whether a connection is possible through an intranet; and

for, for a given call for which an intranet connection is not possible, determining if an internet connection is possible;

means for, (i) where, for a first call, an intranet connection is possible, routing said call through said intranet;

(ii) where, for a second call, an intranet connection is not possible and an internet connection is possible, routing said second call through said internet; and

(iii) where, for a third call, neither an intranet connection nor an internet connection is possible, routing said third call through a switched telephone network.

14. The switch of claim 13 further comprising:

means for, where for said second call, said internet connection becomes no longer viable, (i) sending an alert notification to a calling station and a called station associated with said second call and (ii) switching said second call from said internet to a switched telephone network.

15. The switch of claim 14 wherein said switched telephone network comprises a public switched telephone network (PSTN).