ITU-T Y.1221 PDF

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.