ALTERNATE ROUTING OF VOICE COMMUNICATION IN A PACKET-BASED NETWORK

• US 20080112327A1
• Filed: 01/21/2008
• Published: 05/15/2008
• 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: McCabe, John, McGuigan, David, Sporel, Eric, Mussman, Harry, Israel, Robert
• Granted Patent: US 7,720,084 B2
• Time in Patent Office: Days
• US Class Current: 370/238
• 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: 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 system for routing calls through a network, the system comprising:

an inbound gatekeeper operable to receive requests to setup data sessions and issue routing requests for determining routes for the requested data session;

a plurality of resource zones, wherein each zone has an associated resource management gatekeeper and a plurality of outbound gateway resources configured to terminate data sessions received by the inbound gatekeeper, wherein each outbound gateway resource is further configured to periodically report the outbound gateway resource'"'"'s availability to the resource management gatekeeper of the associated resource zone; and

a directory gatekeeper having memory storing a plurality of routes through the resource zones, each route corresponding to one of the resource management gatekeepers, and wherein, in response to a routing request received from the inbound gatekeeper, the directory gatekeeper requests an outbound gateway resource from a resource management gatekeeper associated with a selected route, and

wherein the selected resource management gatekeeper checks for an available outbound gateway resource among the plurality of outbound gateway resources in the resource zone of the selected resource management gatekeeper,

wherein if an available outbound gateway resource is identified in the resource zone, the selected resource management gatekeeper notifies the directory gatekeeper of the available outbound gateway resource, and

wherein if an available outbound gateway resource is not identified in the resource zone, the directory gatekeeper requests resources from another resource management gatekeeper in another zone by selecting another route corresponding to the other resource management gatekeeper.

2. The system of claim 1, wherein each resource management gatekeeper is operable to exclude certain outbound gateway resources during checking for available outbound gateway resources.

3. The system of claim 2, wherein each resource management gatekeeper is operable to exclude certain gateways when the associated zone is associated with a given carrier and the requested call is associated with a given area code.

4. The system of claim 1, wherein the data sessions are voice sessions.

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

receiving, at an inbound gatekeeper, a request to initiate a session for communicating data; and

in response to receiving the request to initiate the session;

sending a routing request to a directory gatekeeper to request a route for terminating the session;

determining, by the directory gatekeeper, a list of possible routes for terminating the session;

selecting a route from the list of possible routes by querying a selected resource management gatekeeper to determine availability of outbound gateway resources associated with the selected route based on outbound gateway resource availability periodically reported to the selected resource management gatekeeper;

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

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

6. The method of claim 5, further comprising selecting a route from the list of possible routes by querying another resource management gatekeeper to dynamically determine availability of outbound gateway resources associated with the selected route.

7. The method of claim 6, wherein the list of possible routes includes routes corresponding to a numbering plan area (NPA) associated with the session.

8. The method of claim 5, wherein the data is voice data.

9. The method of claim 5, wherein each route in the list of routes is associated with a resource management gatekeeper.

10. The method of claim 9, 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.

11. The method of claim 10, wherein selecting a candidate route from list of possible routes includes at least one of selecting the least cost route as the candidate route and selecting a candidate route from the list of possible routes at a predetermined ratio.

12. The method of claim 11, wherein the predetermined ratio is selected such that the likelihood of choosing each of the one or more candidate routes is substantially equal.

13. A computer-readable medium including software for performing alternate routing of data in a directory gatekeeper according to the method of claim 8.

14. A directory gatekeeper for performing alternate routing of data through a plurality of outbound gateway resources, the directory gatekeeper comprising:

one or more communication devices communicatively coupled to a plurality of resource management gatekeepers, each resource management gatekeeper associated with one or more of the plurality of outbound gateway resources, wherein each outbound gateway resource periodically reports the outbound gateway resource'"'"'s availability to the outbound gateway resource'"'"'s associated resource management gatekeeper;

another communication device communicatively coupled to an inbound gatekeeper, the inbound gatekeeper operable to send a routing request to the directory gatekeeper in response to receiving a session setup request for communicating the data and direct the session to an outbound gateway resource determined by the directory gatekeeper;

memory storing a list of routes, each route being associated with a resource management gatekeeper;

a processor operable to perform alternate routing by selecting one of the routes and sending a resource request to the resource management gatekeeper corresponding to the selected route to initiate the session through an outbound gateway resource associated with the selected resource management gatekeeper,

wherein the outbound gateway resource availability is used to determine an available outbound gateway resource among the one or more outbound gateway resources associated with the selected resource management gatekeeper, and wherein the directory gatekeeper notifies the inbound gatekeeper of the determined available outbound gateway resource to cause the inbound gatekeeper to direct the session through the available outbound gateway resource.

15. The directory gatekeeper of claim 14, wherein one of the one or more communication devices provides access to a packet-based network.

16. The directory gatekeeper of claim 15, wherein the packet-based network is an Internet protocol (IP) network.

17. The directory gatekeeper of claim 14, wherein the one or more communication devices provides access to the public switched telephone network (PSTN).

18. The directory gatekeeper of claim 14, wherein the processor selects a route by performing operations comprising:

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

for each of the one or more candidate routes,

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

19. The directory gatekeeper of claim 18, wherein selecting a candidate route from the one or more candidate routes includes at least one of selecting the least cost route as the candidate route and selecting a candidate route from the one or more candidate routes at a predetermined ratio.

20. The directory gatekeeper of claim 19, wherein the predetermined ratio is selected such that the likelihood of choosing each of the one or more candidate routes is substantially equal.