The present method and system relate to monitoring a subscriber base in an IP data network. The method and system receive at a subscriber base system information extracted from collected data of IP data sessions. The extracted information comprises at least a unique identifier and a timestamp. The subscriber base system queries a subscriber database with the extracted information to correlate with a corresponding subscriber record. If the extracted information is correlated to the corresponding subscriber record, the extracted information is used to update the subscriber database. If the extracted information cannot be correlated to an existing subscriber record, the extracted information is used to create a new subscriber record in the subscriber database.