Method and apparatus for providing virtual private network services over public switched telephone network

• US 6,453,035 B1
• Filed: 03/02/1998
• Issued: 09/17/2002
• Est. Priority Date: 03/02/1998
• Status: Expired due to Term

• Current Assignee: Stentor Resource Centre, Inc.
• Original Assignee: Stentor Resource Centre, Inc.
• Inventors: Carkner, R. William, Cotton, Marc, Psarras, Elias
• Primary Examiner(s): Matar, Ahmad F.
• Assistant Examiner(s): BUI, BING Q
• Application Number:
  US09/033,278
• Time in Patent Office: 1,660 Days
• Field of Search: 379/207, 379/219, 379/220, 379/225, 379/229, 379/230, 379/231, 379/234, 379/221.08, 379/207.11, 379/207.12, 379/207.02, 379/112.09, 379/221.09, 379/221.12
• US Class Current: 379/221.08
• CPC Class Codes: H04M 2207/12 intelligent networks
• CPC Class Codes: H04M 7/009 in systems involving PBX or KTS networks
• CPC Class Codes: H04Q 3/0029 Provisions for intelligent networking

Abstract

A method of providing a Private Telephone Network over a Public Telephone Network is described. A Private Network is a telecommunications service which has controlled access, and is generally provided to customers having two or more geographic locations. A Private Network is provided by embedding originating customer site identification and a Private Network Routing Code into an Initial Address Message at the originating End Office associated with the originating customer site. This Initial Address Message is routed to a Service Switching Point by the Private Network Routing Code. At the Service Switching Point, reference is made to databases defining the members of the Private Network, and a destination End Office identification and a destination customer site identification associated with the destination customer site is embedded into the Initial Address Message. The Initial Address Message is then routed to the destination End Office Switch by a Public Network Routing Number associated with the destination End Office Switch. This will permit a Private Network to be provided over a Public Telephone Network, taking advantage of the inherent redundancy and reliability of the Public Telephone Network.

Claims

1. A method of providing a Private Network on a Public Network for Customers having two or more sites, each said site having a unique customer site identification which includes a Switch Identification and a Trunk Group Identification representative of said customer'"'"'s Dedicated Access Line, and being associated with an End Office Switch of said Public Network having at least one Service Switching Point adapted to route Private Network calls, said Service Switching Point responsive to an Initial Address Message originating from one of said customer sites and destined for another of said customer sites, comprising the steps of:

embedding originating customer site identification and a Private Network Routing Code into a Called Party Number Parameter of an Initial Address Message at the originating End Office associated with the originating customer site;

said originating customer site identification including an Originating Switch Identification and an Originating Trunk Group Identification representative of said originating customer'"'"'s Dedicated Access Line;

routing said Initial Address Message to said Service Switching Point;

embedding a destination End Office identification and a destination customer site identification associated with said destination customer site into said Initial Address Message; and

routing said Initial Address Message to the destination End Office Switch associated with said destination customer site.

2. A method as claimed in claim 1, wherein said step of embedding originating customer site identification and a Private Network Routing Code into an Initial Address Message at said originating End Office further comprises the steps of:

placing said originating customer site identification and said Private Network Routing Code into a Called Party Number Parameter;

placing an originating customer business group identification into a business group Parameter; and

placing a dialled number into a General Address Parameter.

3. A method as claimed in claim 2, wherein said step of placing said originating customer site identification comprises the step of placing an originating Switch identification and an originating Trunk group identification representative of said originating Customer'"'"'s Dedicated Access Line into said Called Party Number Parameter.

4. A method as claimed in claim 1, wherein said Public Network further comprises at least one Intermediate Switch, wherein said step of routing said Initial Address Message to said Service Switching Point, further comprises the steps of:

routing said Initial Address Message to one of said at least one Intermediate Switches on said Public Network via a shared Trunk group; and

determining whether said Initial Address Message is destined for said Service Switching Point, and if so, routing said Initial Address Message to said Service Switching Point.

5. A method as claimed in claim 4, wherein said step of routing said Initial Address Message to said Service Switching Point, further comprises the steps of:

selecting a shared Trunk group by accessing an internal database indexed by said Called Party Number Parameter; and

transmitting said Initial Address Message to said Service Switching Point via said shared Trunk group.

6. A method as claimed in claim 5, wherein said step of determining whether said Initial Address Message is destined for said Service Switching Point comprises the step of determining whether said Initial Address Message contains a Private Network Routing Code.

7. A method as claimed in claim 6, wherein said Public Network further comprises at least one Service Control Point accessible from a Service Switching Point, and after said step of routing said Initial Address Message to said Service Switching Point, performing the steps of:

determining whether said Initial Address Message requires routing instructions from said. Service Control Point, and if so;

preparing a VDAL (Virtual Dedicated Access Line) Query at said Service Switching Point; and

transmitting said VDAL Query to said Service Control Point.

8. A method as claimed in claim 7, wherein said step of determining whether said Initial Address Message requires routing instructions from said Service Control Point further comprises detecting the presence of a business group Parameter and a Generic Address Parameter in said Initial Address Message.

9. A method as claimed in claim 1, wherein said Public Network comprises at least one Service Control Point and before said step of embedding said destination End Office identification and said destination customer site identification associated with said destination site into said Initial Address Message, performing the step of:

determining whether said originating customer and said destination customer are members of said same Virtual Private Network; and

if so;

preparing a Response Message including a destination customer business group Parameter; and

transmitting said Response Message to said Service Switching Point.

10. A method as claimed in claim 9 wherein said step of preparing a Response Message comprises the step of preparing a Response Message including said destination customer business group Parameter and said destination customer site identification.

11. A method as claimed in claim 10 wherein after said step of transmitting said Response Message to said Service Switching Point, performing the steps of:

determining whether said Service Switching Point is a Terminating Service Switching Point for said Initial Address Message, and if not, transmitting said Initial Address Message to said Terminating Service Switching Point; and

modifying said Initial Address Message by;

identifying a destination End Office identification by accessing an internal database indexed by said destination customer site identification; and

placing said destination End Office identification in said Called Party Number Parameter.

12. A method as claimed in claim 11 wherein said step of transmitting said Initial Address Message to said Terminating Service Switching Point comprises:

identifying said Terminating Service Switching Point by accessing an internal database indexed by said destination customer site identification;

placing said destination customer site identification in said Called Party Number Parameter;

placing said destination customer business group Parameter into said business group Parameter; and

transmitting said Initial Address Message to said Terminating Service Switching Point.

13. A method as claimed in claim 1 wherein said step of routing said Initial Address Message to the destination End Office Switch associated with said destination site further comprises the steps of:

routing said Initial Address Message to the destination End Office Switch; and

determining whether said Initial Address Message terminates at said destination End Office Switch by the presence of said destination End Office identification and said destination customer site identification in an internal database.

14. A system for providing a Private Network on a Public Network for customers having two or more sites, each said site having a unique customer site identification which includes a Switch Identification and a Trunk Group Identification representative of said customer'"'"'s Dedicated Access Line, and being associated with an End Office Switch of said Public Network having at least one Service Switching Point accessible from said End Offices for processing of Initial Address Messages originating from one of said customer sites, said system comprising:

each said End Office Switch associated with said Private Network customer site being responsive to a call from a Private Network customer site by;

embedding an originating customer site identification and a Private Network Routing Code into a Called Party Number Parameter of an Initial Address Message at the originating End Office associated with the originating customer site;

said originating customer site identification including an Originating Switch Identification and an Originating Trunk Group Identification representative of said originating customer'"'"'s Dedicated Access Line; and

routing said Initial Address Message to said Service Switching Point;

said at least one Service Switching Point being adapted to route Private Network calls by being responsive to Private Network information embedded in said Initial Address Message by;

embedding a destination End Office identification and a destination customer site identification associated with said destination customer site into said Initial Address Message; and

routing said Initial Address Message to the destination End Office Switch associated with said destination customer site.

15. A system as claimed in claim 14, wherein said End Office Switch associated with each said Private Network customer site being further operable to:

place said originating customer site identification and said Private Network Routing Code into a Called Party Number Parameter of said Initial Address Message;

place an originating customer business group identification into a Business Group Parameter of said Initial Address Message; and

place a dialled number into a General Address Parameter of said Initial Address Message.

16. A system as claimed in claim 15, wherein said End Office Switch associated with each said site being operable to place an originating Switch identification and an originating Trunk group identification representative of said originating Customer'"'"'s Dedicated Access Line into said Called Party Number Parameter.

17. A system as claimed in claim 14, said Public Network further comprising at least one Intermediate Switch accessible from said originating end office and having access to either one of said at least one Service Switching Points, or another of said at least one Intermediate Switches, each said Intermediate Switch being operable to:

receive said Initial Address Message from said originating end office, and be responsive to said Private Network Routing Code by routing said Initial Address Message to said Service Switching Point.

18. A system as claimed in claim 17, said Intermediate Switch further including an internal database for storing a plurality of Trunk Groups:

select a shared Trunk Group by accessing a internal database indexed by said Called Party Number; and

route said Initial Address Message to said Service Switching Point via said shared Trunk Group.

19. A system as claimed in claim 17, said Intermediate Switch being operable to:

select a shared Private Network Trunk group by accessing a internal database indexed by said Called Party Number Parameter; and

route said Initial Address Message to said Service Switching Point via said shared Private Network Trunk group.

20. A system as claimed in claim 18, wherein said Public Network further includes a Service Control Point containing information databases and being accessible from one of said at least one Service Switching Points, said system comprising:

said Service Control Point being operable to determine authorized members of a Private Network;

said at least one Service Switching Point being operable to determine whether said Initial Address Message requires routing instructions from said Service Control Point, and if so;

prepare a VDAL (Virtual Dedicated Access Line) Query at said Service Switching Point; and

transmit said VDAL Query to said Service Control Point.

21. A system as claimed in claim 20, said Service Switching Point being responsive to the presence of a business group Parameter and a Generic Address Parameter in said Initial Address Message by requesting routing instructions from said Service Control Point.

22. A system as claimed in claim 14, wherein said Public Telephone System comprises at least one Service Control Point operable to determine whether said originating customer and said destination customer are members of a same said Private Network, and if so, prepare a Response Message including a destination customer Business Group Parameter and transmit said Response Message to said Service Switching Point.

23. A system as claimed in claim 22, said Service Control Point being operable to prepare a Response Message including said destination customer business group Parameter and said destination customer site identification.

24. A system as claimed in claim 23 wherein:

said Service Switching Point is further operable to determine whether said Service Switching Point is a Terminating Service Switching Point for said Initial Address Message, and if not, transmit said Initial Address Message to said Terminating Service Switching Point; and

said Terminating Service Switching Point is further operable to modify said Initial Address Message by;

identifying a destination End Office identification by accessing an internal database indexed by said destination customer site identification; and

placing said destination End Office identification in said Called Party Number Parameter.

25. A system as claimed in claim 24 wherein said Service Switching Point is further operable to:

identify said Terminating Service Switching Point by accessing an internal database indexed by said destination customer site identification;

place said destination customer site identification in said Called Party Number Parameter;

place said destination customer Business Group into said Business Group Parameter; and

transmit said Initial Address Message to said Terminating Service Switching Point.

26. A system as claimed in claim 14 wherein said End Office Switch associated with said each said site being further operable to determine whether said Initial Address Message terminates at said End Office by the presence of said destination End Office identification and said destination customer site identification in an internal database.