Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method for telephony includes receiving at a facility of a telephone service provider a first subscriber request to place a first call to a specified telephone number. A provider request is sent to a remote server (26), which maintains a database (28) of records associating telephone numbers with respective packet network addresses, for a record (72) indicating a packet network address to which calls to the specified telephone number should be placed. Upon receiving the record from the remote server, the record is stored in a local cache (42) at the facility of the telephone service provider. After storing the record, upon receiving at the facility of the telephone service provider a second subscriber request to place a second call to the specified telephone number, the record is read from the local cache and is used in placing the second call to the packet network address.

Abstract: A method for packet telephony includes receiving over a packet communication network (22) a first message originating from a first end-user (32A) in a first aggregating organization (28) to place a call to a second end-user (32D) in a second aggregating organization (30). Responsively to the first message, respective values are assigned to one or more security attributes that are indicative of a likelihood that the call is a spam call. A second message is transmitted over the packet communication network toward the second end-user, the second message containing at least one of the respective values that was assigned to at least one of the security attributes.

Abstract: A method for packet telephony includes receiving over a packet communication network (22) a first message originating from a first end-user (32A) in a first aggregating organization (28) to place a call to a second end-user (32D) in a second aggregating organization (30). Responsively to the first message, respective values are assigned to one or more security attributes that are indicative of a likelihood that the call is a spam call. A second message is transmitted over the packet communication network toward the second end-user, the second message containing at least one of the respective values that was assigned to at least one of the security attributes.