Patent ID: 8254278
Filing Date: 2012-08-28
Classification: H04L,H04M

Abstract:
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 place a call to a telephone number; in response to the subscriber request, querying a cache associated with the Internet telephony service provider to check if the cache holds a record for the telephone number; if the cache holds a record for the telephone number, obtaining the record and: if the cache does not hold a record for the telephone number, sending a request to a database server, which maintains a database of records associating endpoint user terminal telephone numbers of subscribers with respective packet network addresses of the endpoint user terminal, each packet network address being uniquely associated with a subscriber, to retrieve a packet network address of the endpoint user terminal to which calls to the telephone number should be placed; if the database server holds a record of a packet network address of the endpoint user terminal telephone number, the database server notifying the Internet telephony service provider of the packet network address of the endpoint user terminal; if the database server does not hold a record of a packet network address of the endpoint user terminal telephone number, the database server notifying the Internet telephony service provider with a negative response that no record of a packet network address associated with the endpoint user terminal telephone number was found; upon receiving the notification from the database server, storing the packet network address or the negative response, as appropriate, in the cache as a record for the telephone number; after storing the record, receiving at the Internet telephony service provider a further subscriber request from an IP telephony user terminal to place a further call to the telephone number; in response to the further subscriber request, querying the cache to obtain the record and: