The present invention permits a network service provider to detect an operational condition--such as congestion--in a packet-switched network and to alleviate such congestion by providing customer incentives to avoid use of the network. The detection mechanism triggers an incentive such as the modification of the user's access charges and the customer can be immediately notified of either the occurrence of the congestion or of information regarding the incentive. Usage of the network during congested periods can be deterred by imposing additional access charges during such periods--similarly, customers can be given a discount to encourage usage during periods of low congestion. An incentive schedule can be tailored to dynamically change the usage patterns of the customers of the network to accommodate the operational conditions in the network. The present invention has application in the Internet, where a detection/notification mechanism, for example, can be implemented in a network node such as a router or in a network endpoint such as a client machine or a proxy or mail server.