Abstract: A call forwarding parameter, which a communication network uses to control forwarding of a subscriber's incoming calls to a centralized messaging system, is varied as a function of the status of a subscriber's services within the centralized messaging system. This forwarding control may apply to a variety of different types of communication network and/or to a variety of centralized messaging systems. For example, if the messaging system provides voice mail type services, and the communication network is a public switched telephone network, the voice mail system might instruct the network to change the threshold ringing interval or the threshold number of rings before forwarding unanswered calls directed to a subscriber to the voice mail system, as a function of the status of that subscriber's mailbox.