Routing service method in voice over internet protocol system

• US 20020188755A1
• Filed: 04/30/2002
• Published: 12/12/2002
• Est. Priority Date: 05/26/2001
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yeom, Eung-Moon
• Granted Patent: US 7,519,732 B2
• Time in Patent Office: Days
• US Class Current: 709/238
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/104 in the network
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• 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: H04M 7/009 in systems involving PBX or KTS networks
• CPC Class Codes: Y10S 379/90 Internet, e.g. Internet phone, webphone, internet-based telephony

Abstract

A routing service method in a public switched telephone network (PSTN) system uses a stand-alone gateway interworking with disparate central office lines. The stand-alone gateway checks whether a call service can be provided over the Internet with reference to an internal database having periodically updated call service state information in response to a call service request from a calling private branch exchange (PBX) connected to the stand-alone gateway via a central office line. If the call service cannot be provided over the Internet, the stand-alone gateway transmits a call service request, together with a public switched telephone network (PSTN) rerouting control request, to the calling PBX. The calling PBX transfers the call to a called party over the PSTN in response to the PSTN rerouting control request.

Claims

1. A routing service method in a voice over internet protocol (VoIP) system using a stand-alone gateway interworking with disparate central office lines, comprising the steps of:

determining in the stand-alone gateway whether a call service can be provided over the Internet, with reference to an internal database having periodically updated call service state information, in response to a call service request from a calling private branch exchange (PBX) connected to the stand-alone gateway via a central office line;

transmitting the call service request, together with a public switched telephone network (PSTN) rerouting control request, to the calling PBX by means of the stand-alone gateway, when it is determined that the call service cannot be provided over the Internet; and

transferring the call to a called party over the PSTN by the calling PBX in response to the PSTN rerouting control request.

2. The routing service method of claim 1, further comprising providing a central office line interface between the stand-alone gateway and the calling PBX, said central office line interface being one of a T1/E1-T1/E1 interface, an ear and mouth tie trunk-ear and mouth tie trunk (E&

M-E&

M) interface, and a foreign exchange office-foreign exchange station (FXO-FXS) interface.

3. A routing service method in a voice over internet protocol (VoIP) system using a stand-alone gateway interworking with disparate central office lines, comprising the steps of:

determining in the stand-alone gateway whether a call service can be provided over the Internet, with reference to an internal database having periodically updated call service state information, in response to a call service request from a calling private branch exchange (PBX) connected to the stand-alone gateway via a central office line; and

transmitting the call service request, and requesting a public switched telephone network (PSTN) rerouting control to the calling PBX, between the calling PBX and the stand-alone gateway by means of the stand-alone gateway and through a central office line used for the call service request, when it is determined that the call service cannot be provided over the Internet.

4. A routing service method in a voice over internet protocol (VoIP) system using stand-alone gateways interworking with disparate central office lines, comprising the steps of:

providing a database which includes an access code table, an Internet protocol table, and a state table for remote gateways, and a PSTN rerouting setting field, to a local-stand alone gateway;

updating the state table by periodically testing links between a local stand-alone gateway and remote stand-alone gateways;

determining whether a call service over the Internet is available with reference to the state table by means of the local stand-alone gateway upon receipt of a call service request from a calling PBX connected to the local stand-alone gateway via a central office line;

inserting a PSTN central office line access code set in the PSTN rerouting setting field in the call service request, and transmitting the call service request with the PSTN central office line access code to the calling PBX, when the call service over the Internet is not available; and

requesting the call service to the PSTN using the PSTN central office line access code by means of the calling PBX.

5. A voice over internet protocol (VoIP) system which provides a routing service, said system comprising:

a stand-alone gateway interworking with disparate central office lines;

determining means in the stand-alone gateway for determining whether a call service can be provided over the Internet, with reference to an internal database having periodically updated call service state information, in response to a call service request from a calling private branch exchange (PBX) connected to the stand-alone gateway via a central office line;

transmitting means in the stand-alone gateway for transmitting the call service request, together with a public switched telephone network (PSTN) rerouting control request, to the calling PBX when it is determined that the call service cannot be provided over the Internet; and

transferring means for transmitting the call to a called party over the PSTN by the calling PBX in response to the PSTN rerouting control request.

6. The system of claim 5, further comprising a central office line interface between the stand-alone gateway and the calling PBX.

7. The system of claim 6, wherein the central office line interface comprises one of a T1/E1-T1/E1 interface, an ear and mouth tie trunk-ear and mouth tie trunk (E&

M-E&

M) interface, and a foreign exchange office-foreign exchange station (FXO-FXS) interface.

8. A voice over internet protocol (VoIP) system which provides a routing service, said system comprising:

a stand-alone gateway interworking with disparate central office lines;

determining means in the stand-alone gateway for determining whether a call service can be provided over the Internet, with reference to an internal database having periodically updated call service state information, in response to a call service request from a calling private branch exchange (PBX) connected to the stand-alone gateway via a central office line; and

transmitting means for transmitting the call service request, and requesting a public switched telephone network (PSTN) rerouting control to the calling PBX, between the calling PBX and the stand-alone gateway by means of the stand-alone gateway and through a central office line used for the call service request when it is determined that the call service cannot be provided over the Internet.

9. A voice over internet protocol (VoIP) system which provides a routing service, said system comprising:

stand-alone gateways interworking with disparate central office lines;

a database which includes an access code table, an Internet protocol table, and a state table for remote gateways, and a PSTN rerouting setting field, said state table being updated periodically by testing links between a local stand-alone gateway and remote stand-alone gateways;

determining means for determining whether a call service over the Internet is available with reference to the state table by means of the local stand-alone gateway upon receipt of a call service request from a calling PBX connected to the local stand-alone gateway via a central office line;

inserting means for inserting a PSTN central office line access code set in the PSTN rerouting setting field in the call service request;

transmitting means for transmitting the call service request with the PSTN central office line access code to the calling PBX, when the call service over the Internet is not available; and

requesting means in the calling PBX for requesting the call service to the PSTN using the PSTN central office line access code.