This Recommendation describes traffic control and congestion control procedures for IP-based networks. Such control procedures are necessary in order to support services with quality of service (QoS)@ where the QoS is negotiated between a user and the network. Traffic control refers to all network actions aiming to meet the negotiated performance objectives in an IP-based network and to allow the avoidance of congested conditions. Congestion control refers to all network actions to minimize the intensity@ spread and duration of congestion. This Recommendation provides a general description@ as well as objectives and procedures@ for traffic control and congestion control. In particular@ it describes the concepts of the traffic contract between a user and the network. It specifies the IP transfer capabilities (IPTCs) including@ for each IPTC@ the service model@ the associated traffic patterns and conformance definition.