Gateway carrying out routing optimization

• US 6,577,638 B1
• Filed: 11/30/1999
• Issued: 06/10/2003
• Est. Priority Date: 03/18/1999
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Suzuki, Hiroko, Ohtsu, Kazuyuki, Tashiro, Masayuki
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Qureshi, Afsar M.
• Application Number:
  US09/450,615
• Time in Patent Office: 1,288 Days
• Field of Search: 370/352, 370/356, 370/238, 370/238.1, 370/401, 370/395.6, 370/465, 709/238, 709/241, 709/245, 709/248
• US Class Current: 370/401
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Abstract

A gateway is connected to the Internet and a telephone exchange which carries out routing optimization based on a first message and accommodates a plurality of terminals. The gateway includes: a call setting means used for determining an IP (Internet Protocol) address of a second gateway serving as a called communication partner on the basis of a second message serving as a request for call setting and used for opening a control channel to the second gateway by transmitting a third message to the second gateway at the IP address by way of the Internet; a first message transmitting means for transmitting a fourth message received from the connected telephone exchange to the second gateway by using the control channel; a second message transmitting means for transmitting a fifth message to the connected telephone exchange when receiving the fifth message transmitted by another telephone exchange connected to the second gateway through the control channel by way of the second gateway; an audio-channel opening means for opening an audio channel; and a channel releasing means for releasing the control channel and the audio channel.

Claims

1. A gateway connected to the Internet and a telephone exchange accommodating a plurality of terminals and carrying out routing optimization processing based on a first message used as a request for path optimization, said gateway comprising:

a call setting means for;

determining an IP (Internet Protocol) address of a second gateway corresponding to a calling-destination special number of a called telephone exchange used as a called communication partner and connected to said second gateway on the basis of a second message which is received from said connected telephone exchange, includes said calling-destination special number of said called telephone exchange and a telephone number of a called terminal accommodated in said called telephone exchange and serves as a request for call setting; and

transmitting a third message serving as a request for said call setting to said second gateway serving as a communication partner by using said IP address by way of said Internet to open a control channel to said second gateway;

a first message transmitting means for setting a fourth message received from said connected telephone exchange in a message to be transmitted by using said control channel and transmitting said message to said second gateway serving as a communication partner by way of said Internet;

a second message transmitting means for extracting a fifth message and transmitting said fifth message to said connected telephone exchange when receiving a message coming from said control channel and including said fifth message set therein and transmitted by said called telephone exchange;

an audio-channel opening means for opening an audio channel for a conversation between a calling terminal accommodated in said connected telephone exchange and said called terminal when receiving a message including a set sixth message issued by said called telephone exchange serving as a called communication partner through said control channel in response to said second message; and

a channel releasing means for releasing said control channel and said audio channel when receiving a message including a set seventh message serving as a request for releasing of said control channel and said audio channel from said control channel.

2. A gateway according to claim 1 wherein:

said connected telephone exchange is connected to said gateway by an ISDN line; and

said first message transmitting means adds a new information element to an H323•

Q931 user information message, and sets said fourth message in said new information element prior to message transmission.

3. A gateway connected to the Internet and a telephone exchange accommodating a plurality of terminals and carrying out routing optimization processing based on a first message used as a request for path optimization, said gateway comprising:

a call setting means for;

determining an IP (Internet Protocol) address of a second gateway corresponding to a calling-destination special number of a called telephone exchange used as a called communication partner and connected to said second gateway on the basis of a second message which is received from said connected telephone exchange, includes said calling-destination special number of said called telephone exchange and a telephone number of a called terminal accommodated in said called telephone exchange and serves as a request for call setting; and

transmitting a third message serving as a request for said call setting to said second gateway serving as a communication partner by using said IP address by way of said Internet to open a control channel and a first audio channel to said second gateway;

a first message transmitting means for transmitting a fourth message received from said connected telephone exchange by using said first audio channel to said second gateway serving as a communication partner by way of said Internet;

a second message transmitting means for extracting a fifth message and transmitting said fifth message to said connected telephone exchange when receiving said fifth message transmitted by said called telephone exchange through said first audio channel;

an audio-channel opening means for opening a second audio channel for a conversation between a calling terminal accommodated in said connected telephone exchange and said called terminal when receiving a sixth message issued by said called telephone exchange serving as a called communication partner through said first audio channel in response to said second message; and

a channel releasing means for releasing said control channel, said first audio channel and said second audio channel when receiving a seventh message serving as a request for releasing of said control channel, said first audio channel and said second audio channel from said first audio channel.

4. A gateway according to claim 3 wherein:

said connected telephone exchange is connected to said gateway by an ISDN line;

said control channel is an H323 signal channel; and

said first and second audio channels are each an H323 audio channel.

5. A gateway connected to the Internet and a telephone exchange accommodating a plurality of terminals and carrying out routing optimization processing based on a first message used as a request for path optimization, said gateway comprising:

a first table for storing relations between calling-destination special numbers identifying telephone exchanges and IP (Internet Protocol) addresses of second gateways connected to said telephone exchanges identified by said calling-destination special numbers;

a call setting means for transmitting second messages each serving as a request for call setting to said second gateways identified by said IP addresses stored in said first table by using said IP addresses by way of said Internet to open in advance a control channel to each of said second gateways;

a second table for storing relations between said second gateways each with an opened control channel and said opened control channels;

a first message transmitting means for;

searching said first table for one of said IP addresses corresponding to a calling-destination special number of a called telephone exchange connected to one of said second gateways and used as a called communication partner on the basis of a third message which is received from said connected telephone exchange, includes said calling-destination special number of said called telephone exchange and a telephone number of a called terminal accommodated in said called telephone exchange and serves as a request for call setting;

searching said second table for one of said opened control channels associated with a third gateway, that is, one of said second gateways identified by said IP address found from said first table; and

setting said third message in a message to be transmitted by using said opened control channel found from said second table and transmitting said message to said third gateway serving as a communication partner by using said IP address found from said first table by way of said Internet;

a second message transmitting means for setting a fourth message received from said connected telephone exchange in a message to be transmitted by using said opened control channel found from said second table and transmitting said message to said third gateway serving as a communication partner by way of said Internet;

a third message transmitting means for extracting a fifth message and transmitting said fifth message to said connected telephone exchange when receiving a message coming from said opened control channel found from said second table and including said fifth message set therein and transmitted by said called telephone exchange;

an audio-channel opening means for opening an audio channel for a conversation between a calling terminal accommodated in said connected telephone exchange and said called terminal when receiving a message including a set sixth message issued by said called telephone exchange serving as a called communication partner through said opened control channel found from said second table in response to said third message; and

a channel releasing means for releasing said audio channel when receiving a message including a set seventh message serving as a request for releasing of said audio channel from said opened control channel found from said second table.

6. A gateway according to claim 5 wherein:

said connected telephone exchange is connected to said gateway by an ISDN line; and

said first message transmitting means adds a new information element to an H323•

Q931 user information message, and sets said third message in said new information element prior to message transmission; and

said second message transmitting means adds a new information element to an H323•

Q931 user information message, and sets said fourth message in said new information element prior to message transmission.

7. A gateway according to claim 5 wherein:

said audio-channel opening means stores a relation between said opened audio channel and a call number set in said third message in a third table; and

said channel releasing means searches said third table for an audio channel corresponding to a call number set in said seventh message and releases said audio channel.

8. A gateway according to claim 5 wherein:

a fourth table is further provided for storing an ISDN control determination flag for each of said second gateways with an IP address thereof stored in said first table;

said ISDN control determination flag indicates whether or not an ISDN message can be transferred to one of said second gateways associated with said ISDN control determination flag; and

said call setting means makes an Internet call based on said ISDN control determination flag stored in said fourth table.

9. A gateway connected to the Internet and a telephone exchange accommodating a plurality of terminals and carrying out routing optimization processing based on a first message used as a request for path optimization, said gateway comprising:

a first table for storing relations between calling-destination special numbers identifying telephone exchanges and IP (Internet Protocol) addresses of second gateways connected to said telephone exchanges identified by said calling-destination special numbers;

a call setting means for transmitting a second message serving as a request for call setting to said second gateways identified by said IP addresses stored in said first table by using said IP addresses by way of said Internet to open in advance a control channel and a first audio channel to each of said second gateways;

a second table for storing relations between said second gateways each with an opened control channel and an opened first audio channel and said opened control channels and said opened first audio channel;

a first message transmitting means for;

searching said first table for one of said IP addresses corresponding to a calling-destination special number of a called telephone exchange used as a called communication partner and connected to one of said second gateways on the basis of a third message which is received from said connected telephone exchange, includes said calling-destination special number of said called telephone exchange and a telephone number of a called terminal accommodated in said called telephone exchange and serves as a request for call setting;

searching said second table for one of said opened first audio channels associated with a third gateway, that is, one of said second gateways identified by said IP address found from said first table; and

setting said third message in a message to be transmitted by using said opened first audio channel found from said second table and transmitting said message to said third gateway serving as a communication partner by using said IP address found from said first table by way of said Internet;

a second message transmitting means for setting a fourth message received from said connected telephone exchange in a message to be transmitted by using said opened first audio channel found from said second table and transmitting said message to said third gateway serving as a communication partner by way of said Internet;

a third message transmitting means for extracting a fifth message and transmitting said fifth message to said connected telephone exchange when receiving a message coming from said opened first audio channel found from said second table and including said fifth message set therein and transmitted by said called telephone exchange;

an audio-channel opening means for opening a second audio channel for a conversation between a calling terminal accommodated in said connected telephone exchange and said called terminal when receiving a message including a set sixth message issued by said called telephone exchange serving as a called communication partner through said opened first audio channel found from said second table in response to said third message; and

a channel releasing means for releasing said second audio channel when receiving a message including a set seventh message serving as a request for releasing of said second audio channel from said opened first audio channel found from said second table.

10. A gateway according to claim 9 wherein:

said connected telephone exchange is connected to said gateway by an ISDN line;

said control channel is an H323 signal channel; and

said first and second audio channels are each an H323 audio channel.