Call Routing system and method

• US 20040042605A1
• Filed: 08/27/2002
• Published: 03/04/2004
• Est. Priority Date: 08/27/2002
• Status: Active Grant

• Current Assignee: ITXC IP Holdings SARL (Tata Sons Pvt Ltd.)
• Original Assignee: ITXC IP Holdings SARL (Tata Sons Pvt Ltd.)
• Inventors: Evslin, Tom
• Granted Patent: US 7,031,450 B2
• Time in Patent Office: Days
• US Class Current: 379/220.01
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 65/1043 Gateway controllers, e.g. media gateway control protocol [MGCP] controllers
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1106 Call signalling protocols; H.323 and related
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04M 7/1245 where a network other than PSTN/ISDN interconnects two PSTN/ISDN networks
• CPC Class Codes: H04M 7/1285 Details of finding and selecting a gateway for a particular call

Abstract

A method and system is provided wherein routing information is obtained from previously cached information or from a gatekeeper. An originating gateway in a network receives a request for a connection and determines whether pertinent routing information is cached. If available, the cached routing is used to attempt to establish a connection. If no previously established routing is available, the originating gateway requests preferred routing from a gatekeeper, including prioritized selections of terminating gateways through which to make a connection to a designated call recipient.

Claims

1. A method for determining call routing from an originating gateway to one of a plurality of terminating gateways in a network, comprising the steps of:

(a) the originating gateway sending to a gatekeeper a request for routing to a call recipient via one of the plurality of terminating gateways;

(b) the gatekeeper determining routing from the originating gateway to the call recipient;

(c) the gatekeeper transmitting to the originating gateway routing to a priority terminating gateway;

(d) the originating gateway caching the routing priority; and

(e) the originating gateway initiating a connection to the priority gateway.

2. The method for determining call routing as described in claim 1 further comprising the gatekeeper determining whether the originating gateway is an authorized user of the system.

3. The method for determining call routing as described in claim 2, further comprising the gatekeeper transmitting an authorizing token to the originating gateway.

4. The method for determining call routing as described in claim 1, wherein before sending a request to the gatekeeper, the originating gateway verifies whether routing priority information to a call recipient is in a cache.

5. The method for determining a call routing priority as described in claim 4, further comprising the originating gateway determining whether the routing priority information in the cache is stale.

6. The method for determining a call routing priority as described in claim 5, wherein if the routing priority is stale, the originating gateway sends a request to the gatekeeper for routing priority.

7. The method for determining a call routing priority as described in claim 5, wherein if the routing priority is not stale, the originating gateway initiates a connection to the priority terminal gateway.

8. The method for determining call routing as described in claim 1, wherein routing to one of the plurality of terminating gateways comprises designating a first selected gateway to which to first attempt connection and a second selected terminating gateway to which to subsequent attempt connection.

9. The method for determining call routing as described in claim 1, further comprising the gatekeeper communicating an instruction to the originating gateway to delete selected prior routing information.

10. The method for determining call routing as described in claim 1, wherein the gatekeeper determines the routing according to pre-established criteria.

11. The method for determining call routing as described in claim 10, wherein the pre-established criteria include indicia of the intended call recipient, service quality, service cost and connective speed of the priority terminating gateway.

12. The method for determining call routing as described in claim 11, wherein an authorization token is also sent to the gateway.

13. The method for determining call routing as described in claim 9, wherein the gatekeeper sends updates to routing information to the originating gateway.

14. The method for determining call routing as described in claim 13, wherein the updates comprise deletion instructions for previously provided routing information.

15. The method for determining call routing as described in claim 13, wherein the updates comprise modification instructions for previously provided routing information.

16. A system for determining call routing, comprising:

(a) an originating gateway in communication with a first client device through a PSTN;

(b) the originating gateway being in communication with a network;

(c) a gatekeeper in communication with the originating gateway;

(d) a cache for storing routing instructions from the gatekeeper;

(e) a terminating gateway in communication with the network; and

(f) the terminating gateway in communication with a second client device through a PSTN;

(g) wherein the gatekeeper is configured for establishing routing for a call from the first client device to the second client device, the routing dependent upon pre-established criteria.

17. The system as described in claim 16, wherein the cache is located proximate to the originating gateway.

18. The system as described in claim 16, wherein the cache is located proximate to the gatekeeper.

19. The system as described in claim 16, wherein the cache is located substantially between the originating gateway and the gatekeeper.

20. An originating gateway for routing traffic to a terminating gateway, said originating gateway comprising a means for examining parameters of a phone call, means for ascertaining if an intelligent node needs to be contacted to ascertain the terminating gateway to which the call should be routed, and means for contacting said intelligent node only if such intelligent node needs to be contacted.

21. The originating gateway of claim 20 wherein said intelligent node needs to be contacted if previously cached information is determined to be stale.

22. The originating gateway of claim 20 wherein said intelligent node needs to be contacted if previously cached information is inoperative.

23. The originating gateway of claim 20 further comprising software to compare prescribed parameters of a call to stored parameters of previous calls and for, in response to said comparison, determining whether previously stored information is sufficient to route a call.

24. An intelligent node for routing packet telephony information comprising a processor for executing routing rules and for transmitting the results of said routing rules and the parameters upon which said routing rules operate to an entity requesting such results;

and

Memory for storing a list of plural entities requesting routing results; and

software to operate on said memory and determine when said routing results need to be updated, and for sending said updated routing rules to said entities.

25. The intelligent node of claim 24 wherein said software is capable of selectively sending updated routing information to selected gateways while not sending updated routing information to other gateways.

26. The intelligent node of claim 25 further comprising software for authenticating said entities.

27. The intelligent node of claim 26 wherein a token is sent to said entity for the purpose of allowing said entity to use said token for authentication by a terminating gateway.

28. A method comprising checking local memory to determine if routing information sufficient to route a phone call over a packet switched data network is present, if so, routing said phone call based upon said information over said packet switched data network, and if not, contacting a remote node over said packet switched data network to obtain said routing information.

29. The method of claim 28 wherein said checking includes determining that said information is not present if the information present is too old, or has been used for too many prior calls.

30. The method of claim 28 wherein said contacting includes intercepting a communication to said remote node and rerouting it to a different node.

31. The method of claim 28 wherein said remote node is a gatekeeper operating in compliance with H.323.

32. The method of claim 28 further comprising altering routing rules or information within said remote node, and updating said routing information stored in local memory when said routing rules are altered.

33. The method of claim 28 wherein said remote node, in response to being contacted, contacts one or more other nodes to ascertain the routing information.

34. A method of routing a phone call over a packet data network comprising:

a) signaling a gateway that the phone call is to be routed;

b) communicating from the gateway to a remote node to obtain routing information;

c) caching the routing information; and

d) utilizing said cached routing information to route a subsequent call.

35. The method of claim 34 wherein the cached routing information is only utilized if it is not timed out.

36. The method of claim 34 wherein said cached routing information is stored along with an authentication token and an indicator of which parameters of a phone call are determinative of an outcome of a routing algorithm implemented at said remote node.

37. The method of claim 36 wherein said cached routing information is stored along with an indicator of under what conditions said cached routing information is valid.

38. The method of claim 37 wherein said caching information is updated periodically.

39. Apparatus for routing a call over a data network comprising means for determining whether to route the call based upon cached routing information or upon noncached routing information and means for routing said call based upon said routing information and in response to said means for determining making such determination.

40. Apparatus of claim 39 connected via a data network to a remote node that generates said noncached and said cached routing information.

41. Apparatus of claim 40 wherein said cached routing information is generated by a remote node during a prior call and stored at said apparatus, and said noncached routing information is generated by said remote node during said call.

42. Apparatus of claim 41 wherein said cached routing information includes data network addresses of one or more terminating gateways.

43. Apparatus of claim 42 wherein said cached routing information includes an authentication token for said terminating gateways to process.

44. An originating gateway for conveying calls to a data network comprising an interface to receive said calls, a processor to route said calls based upon routing information generated remotely during a previous call with similar parameters to said call, and a network interface to route said call based upon said routing information.

45. The gateway of claim 44 wherein said routing information is cached locally.

46. The gateway of claim 44 wherein said routing information is cached on a remote server.

47. The gateway of claim 44 wherein said routing information is cached and time stamped.

48. The gateway of claim 44 wherein said routing information is a list of terminating gateways in prioritized order.

49. The routing information of claim 44 wherein said gateway may selectively also route said calls by initiating the generation of said routing information remotely during said call.

50. Apparatus for routing calls to a data network comprising an interface to receive the calls and software to determine whether (1) routing information generated after initiation of said call should be used to route said call (2) routing information generated during a prior call should be used to route said call.

51. Apparatus of claim 50 further comprising means, if (1) applies, to override said decision at a subsequent time.

52. Apparatus of claim 51 wherein said means to override overrides in response to updating of routing information on a remote server and a notification of said updating being sent to said apparatus.

53. Apparatus of claim 51 wherein said routing information generated after initiation of said call is used to route future calls, and routing information generated during a prior call is used to route said prior call.