Method and apparatus for S.I.P./H. 323 interworking

• US 20010046234A1
• Filed: 04/04/2001
• Published: 11/29/2001
• Est. Priority Date: 04/10/2000
• Status: Active Grant

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Agrawal, Hemant, Palawat, Vipin, Roy, Radhika R.
• Granted Patent: US 7,002,989 B2
• Time in Patent Office: Days
• US Class Current: 370/402
• CPC Class Codes: H04L 45/741 Routing in networks with a plurality of addressing schemes, e.g. with both IPv4 and IPv6
• CPC Class Codes: H04L 61/106 across networks, e.g. mapping telephone numbers to data network addresses
• CPC Class Codes: H04L 61/30 Managing network names, e.g. use of aliases or nicknames name-to-address mapping H04L61/45
• CPC Class Codes: H04L 65/1033 Signalling gateways
• CPC Class Codes: H04L 65/1043 Gateway controllers, e.g. media gateway control protocol [MGCP] controllers
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1073 Registration or de-registration
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• CPC Class Codes: H04L 65/1106 Call signalling protocols; H.323 and related
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/1302 Relay switches
• CPC Class Codes: H04Q 2213/13034 A/D conversion, code compression/expansion
• CPC Class Codes: H04Q 2213/1304 Coordinate switches, crossbar, 4/2 with relays, coupling field
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13196 Connection circuit/link/trunk/junction, bridge, router, gateway
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13216 Code signals, frame structure
• CPC Class Codes: H04Q 2213/13389 : LAN, internet

Abstract

An interworking function (IWF) for a first and second protocol based network, for example, an H.323 protocol based network and an SIP protocol based network comprises an interworking gateway server including a state machine for defining each call processing state and a translation table for use in translating addresses formatted in each protocol. A method of interworking for use in interworking between said first protocol based network and said second protocol based network comprises the steps of receiving at said interworking gateway server serving said first and second protocol based networks a request from an endpoint in the first or second protocol based networks, establishing a state machine in memory whereby, for each state of said state machine, a message associated with that state is categorized as one of a triggering message, a non-triggering message and an error message, establishing a translation table in said memory whereby an address formatted in said first protocol has a one-for-one correspondence with an address formatted in said second protocol, processing said request in accordance with said translation table and said state machine and permitting communication between said first and second endpoints utilizing a realtime transport protocol. In the event media is terminated at said interworking gateway server, the interworking gateway server, in one embodiment, comprises a media switching fabric for switching media terminated at the gateway to an addressed endpoint capable of receiving it.

Claims

1. A method of interworking via a state machine for use in interworking between an H.323 based network and a session initiation protocol (SIP) based network comprising the steps of:

receiving at an interworking server, including a data processor for call processing and a memory for storing said state machine, a set-up request from an H.323 endpoint,

transmitting a corresponding invite message to an addressed SIP endpoint,

receiving a ringing response message from the SIP endpoint,

transmitting a corresponding alert message to the H.323 endpoint,

receiving an OK message from the SIP endpoint, transmitting a connect message to the H.323 endpoint,

negotiating said connect message utilizing an H.245 protocol,

transmitting an ACK message to the SIP endpoint, and

communicating between the H.323 endpoint and the SIP endpoint utilizing realtime transport protocol (RTP).

2. A gateway server for performing the method of

claim 1

, said interworking server comprising said gateway server.

3. A gateway server as recited in

claim 2

wherein said interworking server further includes a media switching fabric for switching media terminated at the interworking server.

4. A method of interworking as recited in

claim 1

further comprising the step of establishing a state machine table in said memory whereby, for a state of said state machine, a message associated with said state is categorized as one of a triggering message for triggering a predetermined action, a non-triggering message and an unexpected message in said state.

5. A method of interworking as recited in

claim 1

wherein said set-up request receiving step further comprises the step of translating an SIP address to an H.323 address.

6. A method of interworking as recited in

claim 5

wherein said translation step comprises the preliminary step of receiving SIP address data from an SIP server for storage in said memory.

7. A method of interworking as recited in

claim 4

, for an idle state, defining registration messages as triggering an addition of registration information, a Q.931 message as non-triggering and an H.245 message as an error message.

8. A method of interworking via a state machine for use in interworking between a session initiation protocol based network and an H.323 based network comprising the steps of:

receiving at an interworking server, including a data processor for call processing and a memory for storing said state machine, an invite message from an SIP endpoint and transmitting a corresponding setup message to an addressed H.323 endpoint,

receiving an alerting message from the H.323 endpoint and transmitting a corresponding ringing message to the SIP endpoint,

receiving a connect request message and an H.245 protocol message and transmitting an OK message to the SIP endpoint,

receiving an ACK message, and

communicating between the SIP endpoint and the H.323 endpoint utilizing realtime transport protocol.

9. A gateway server for performing the method of

claim 8

, said interworking server comprising said gateway server.

10. A gateway server as recited in

claim 9

wherein said interworking server further includes a media switching fabric for switching media terminated at the interworking server.

11. A method of interworking as recited in

claim 8

further comprising the step of establishing a state machine table in memory whereby, for a state of said state machine, a message associated with said state is categorized as one of a triggering message for a predetermined action, a non-triggering message and an unexpected message in said state.

12. A method of interworking as recited in

claim 8

wherein said set-up request receiving step further comprises the step of translating an H.323 endpoint address to an SIP endpoint address.

13. A method of interworking as recited in

claim 12

wherein said translation step comprises the preliminary step of receiving H.323 endpoint address data from an H.323 gatekeeper.

14. A method of interworking for use in interworking between a first protocol based network and a second protocol based network comprising the steps of:

receiving at an interworking gateway server serving said first and second protocol based networks a request from an endpoint in the first or second protocol based networks,

establishing a state machine in memory whereby, for each state of said state machine, a message associated with that state is categorized as one of a triggering message for a predetermined action, a non-triggering message and an error message,

establishing a translation table in said memory whereby an address formatted in said first protocol has a one-for-one correspondence with an address formatted in said second protocol,

processing said request in accordance with said translation table and said state machine and

permitting communication between said first and second endpoints utilizing a reliable transport protocol.

15. A method as recited in

claim 14

further comprising the step of switching any media terminated at said interworking gateway to an addressed endpoint.

16. An interworking gateway server for performing the method of

claim 14

, said interworking gateway server comprising said state machine, said translation table and a data processor.

17. An interworking gateway server as recited in

claim 16

further comprising a media switching fabric for switching media terminated at said interworking gateway server.

18. A method of interworking as recited in

claim 14

wherein said first protocol based network is an H.323 protocol based network and said second protocol based network is a SIP protocol based network.

19. A method of interworking as recited in

claim 14

where for an idle state a registration message is a triggering message for an action of adding registration information, a Q.931 message is non-triggering and an H.245 message is an error message.

20. A method as recited in

claim 19

wherein for said idle state, the next state comprises a WaitForSetup state.