Efficient address caching for packet telephony services

摘要

A method for telephony includes receiving at an Internet telephony service provider a subscriber request to place a call to a telephone number. A cache associated with the internet telephony service provider is queried to check if the cache holds a record for the telephone number. If the cache holds the record, the record is obtained. If the cache does not hold the record, a request is sent to a database server that maintains a database of records associating endpoint user terminal telephone numbers of subscribers with respective packet network addresses of the endpoint user terminal. The call is placed to the endpoint user terminal telephone number via a public switched telephone network while the request is sent to the database server to retrieve the packet network address of the endpoint user terminal to which calls to the telephone number should be placed.

主权项

1. A method for telephony, comprising:
receiving at an Internet telephony service provider a subscriber request from an Internet Protocol, IP, telephony user terminal which is directly connected to the Internet telephony service provider via a packet switched data link to initiate a communication to a telephone number; in response to the subscriber request, querying a first database to check if the first database holds a record for the telephone number; if the first database holds a record for the telephone number, obtaining the record and: if the record holds a URI associated with an endpoint user terminal telephone number, initiating the communication to that URI; and if the record indicates that there is no URI associated with the endpoint user terminal telephone number, initiating the communication to the endpoint user terminal telephone number via a public switched telephone network (PSTN); if the first database does not hold a record for the telephone number, sending a request to one or more subsequent databases of records associating endpoint user terminal telephone numbers of subscribers with endpoint user terminal URIs, each URI being uniquely associated with a subscriber, to retrieve a URI of the endpoint user terminal to which communications to the telephone number should be initiated; if the one or more subsequent databases holds a record of a URI of the endpoint user terminal telephone number, the one or more subsequent databases responds to or notifies the Internet telephony service provider with the URI of the endpoint user terminal; if none of the one or more subsequent databases holds a record of a URI of the endpoint user terminal telephone number, the Internet telephony service provider is notified with a negative response that no record of a URI associated with the endpoint user terminal telephone number was found; and upon receiving the notification or response from the one or more subsequent database, storing the URI or the negative response, as appropriate, in the first database in a record for the telephone number.