Alternate routing of voice communication in a packet-based network

• US 20030012178A1
• Filed: 04/06/2001
• Published: 01/16/2003
• Est. Priority Date: 04/06/2001
• Status: Active Grant

• Current Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Original Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Inventors: Mussman, Harry Edward, McCabe, John Joseph, Israel, Robert Kellar, Sporel, Eric Richard, McGuigan, David Frederick
• Granted Patent: US 7,339,934 B2
• Time in Patent Office: Days
• US Class Current: 370/352
• 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: H04L 65/1106 Call signalling protocols; H.323 and related
• CPC Class Codes: H04M 15/00 Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

A method for performing alternate and therefore least cost routing in distributed H.323 Voice over IP (VoIP) networks is provided. With this method, the VoIP network consists of a hierarchy of gatekeeper (GK) functions to provide alternate routing, network element redundancy, and scalability. The alternate routing function is performed by a directory gatekeeper with route selection advancing from a first route to a second route by either of two conditions: (1) there are no resources available to terminate the call in the first zone; and (2) a lack of response to the directory GK request for such resources.

Claims

1. A directory gatekeeper for performing alternate routing of calls through a plurality of gateway resources, the directory gatekeeper comprising:

one or more communication devices providing access to a plurality of resource management gatekeepers, each resource management gatekeeper associated with one or more of the plurality of gateway resources;

a memory device storing a list of routes wherein each route is associated with one of the plurality of resource management gatekeepers; and

a processor operable to receive a request through the one or more communication devices,

wherein in response to a received request, the processor performs alternate routing by selecting a route from the list of routes using the corresponding resource management gatekeeper to determine resource availability.

2. The directory gatekeeper of claim 1, wherein one of the one or more communication devices provides access to a packet-based network.

3. The directory gatekeeper of claim 2, wherein the packet-based network is an Internet protocol (IP) network.

4. The directory gatekeeper of claim 1, wherein the one or more communication devices provides access to the public switched telephone network (PSTN).

5. The directory gatekeeper of claim 1, wherein performing alternate routing of calls includes:

identifying one or more candidate routes based on the received request; and

for each of the one or more candidate routes,

selecting a candidate route from the one or more candidate routes;

determining if the selected candidate route is available; and

if the selected candidate route is available, sending a response to the received request indicating that the candidate route is available.

6. The directory gatekeeper of claim 5, wherein performing alternate routing of calls further includes:

if none of the candidate routes are available, sending a response to the received request indicating that the request can not be completed.

7. The directory gatekeeper of claim 5, wherein selecting a candidate route from the one or more candidate routes includes selecting the least cost route as the candidate route.

8. The directory gatekeeper of claim 5, wherein selecting a candidate route from the one or more candidate routes includes selecting a candidate route from the one or more candidate routes at a predetermined ratio.

9. The directory gatekeeper of claim 8, wherein the predetermined ratio is selected such that the likelihood of choosing each of the one or more candidate routes is substantially equal.

10. A method for performing alternate routing of calls in a directory gatekeeper, the method comprising:

receiving a request to initiate a call;

determining a list of possible routes for terminating the call;

if a route is available, selecting a route from the list of possible routes by querying one or more resource management gatekeepers;

if a route is available, sending a response to the received request to initiate a call indicating the selected route; and

if a route is not available, sending a response to the received request to initiate a call indicating that the request will not be completed.

11. The method of claim 10, wherein the request includes a telephone number.

12. The method of claim 11, wherein the number includes a numbering plan area (NPA).

13. The method of claim 10, wherein the request to initiate a call is an H.323 admission request (ARQ) message.

14. The method of claim 10, wherein each route in the list of routes is associated with a resource management gatekeeper.

15. The method of claim 14, wherein the step of selecting a route from the list of possible routes by querying one or more resource management gatekeepers includes:

for each route in the list of possible routes,

selecting a candidate route from the list of possible routes; and

determining if the selected candidate route is available.

16. The method of claim 15, wherein selecting a candidate route from list of possible routes includes selecting the least cost route as the candidate route.

17. The method of claim 15, wherein selecting a candidate route from the list of possible routes includes selecting a candidate route from the list of possible routes at a predetermined ratio.

18. The method of claim 17, wherein the predetermined ratio is selected such that the likelihood of choosing each of the one or more candidate routes is substantially equal.

20. The computer-readable medium of claim 19, wherein the request includes a telephone number.

21. The computer-readable medium of claim 20, wherein the number includes a numbering plan area (NPA).

22. The computer-readable medium of claim 19, wherein the request to initiate a call is an H.323 admission request (ARQ) message.

23. The computer-readable medium of claim 19, wherein each route in the list of routes is associated with a resource management gatekeeper.

19. A computer-readable medium including software for performing alternate routing of calls through a plurality of gateway resources, the software configuring a computer to performing a method, the method including:

receiving a request to initiate a call;

determining a list of possible routes for terminating the call;

if a route is available, selecting a route from the list of possible routes by querying one or more resource management gatekeepers;

if a route is available, sending a response to the received request to initiate a call indicating the selected route; and

if a route is not available, sending a response to the received request to initiate a call indicating that the request will not be completed.