Abstract: An Internet Protocol (IP) voice telephony system constructed according to the present invention manages Gatekeeper load by redirecting calls from an assigned Gatekeeper to a servicing Gatekeeper during call setup. A Load Management Unit (LMU) processes all setup messages. In processing the setup messages, the LMU receives the message from the assigned Gatekeeper to which a requesting endpoint is registered. Upon receipt, the LMU determines which Gatekeeper of a plurality of Gatekeepers should setup and service the call. Based upon its selection, the LMU either directs the assigned Gatekeeper to setup and service the call or redirects the endpoint to a servicing Gatekeeper. Upon receipt of a redirection message, the endpoint sends a confirmation message to the assigned Gateway and then sends a setup message to the servicing Gateway. Upon receipt of the setup message, the servicing Gateway sets up and services the call.

Abstract: An Internet Protocol (IP) telephony system manages Gatekeeper subscriber load by assigning subscriber load among a plurality of Gatekeepers during the Gatekeeper discovery and registration process. A Registration Load Management Unit (RLMU) is primarily responsible for assigning subscriber load to the plurality of Gatekeepers. In one embodiment, the plurality of Gatekeepers are organized without a hierarchy structure and are made up of a plurality of Gatekeeper service nodes and a plurality of Gatekeeper Database nodes. The Gatekeeper service nodes provide the Registration, Admission, Status, Location, Call Set Up and other operating functions of the Gatekeeper while the plurality of Gatekeeper Database nodes store subscriber information. In a second embodiment, the plurality of Gatekeepers are organized in a hierarchy with a Root Gatekeeper at the top of the hierarchy and a plurality of Gatekeepers residing below the Root Gatekeeper in the hierarchy.

Abstract: An Internet Protocol (IP) telephony system cross-references transport addresses of Gatekeepers using a domain name of the IP telephony system. The IP telephony system is serviced by at least one Gatekeeper and the transport address for each Gatekeeper is stored on a Domain Name Server (DNS). An A record or other suitable record may be employed within the DNS to index the transport addresses of the Gatekeepers to the IP telephony system domain name. A calling endpoint first queries the DNS for the transport address of a Gatekeeper servicing the IP telephony system. The DNS address retrieves at least one transport address for the Gatekeeper(s) and returns the transport address(es) to the calling endpoint. When querying the DNS, the calling endpoint may use an identifier such as subscribername@Gatekeeper.ABC.domain where the user name of the called endpoint is “subscribername” and the domain name of the IP telephony system is ABC.domain.