信息技术.增强通信传输协议:单工多点传送用QoS管理规范

[中文适用范围]： 此建议|国际标准是 ITU-T X.606.X 建议书的组成部分 | ISO/IEC 14476“ECTP：增强型通信传输协议”，它是旨在支持多播传输服务的协议规范系列。 ITU-T 建议书。 X.606 | ISO/IEC 14476-1 提供了单工多播传输的各种协议操作的规范。 这些协议操作包括连接管理（例如连接创建/终止和连接暂停/恢复）、成员管理（例如延迟加入、用户离开和成员跟踪）以及多播数据传输的错误控制（例如错误检测和恢复）。 这部分建议|国际标准提供了 QoS 管理规范，用于在单工多播传输连接中实现理想的服务质量。 本规范描述了以下 QoS 管理操作： a) QoS 协商 对于 QoS 协商，本规范假设多播应用服务所需的 QoS 级别可以用一组 QoS 参数来表示。 QoS 协商是通过发送方和接收方之间交换控制数据包来执行的。 发送方提出从应用要求获得的QoS参数的目标值，然后每个接收方可以基于其系统和/或网络容量提出修改值。 发送方对接收方提出的修改值进行仲裁。 QoS参数的目标值可以用作网络资源预留的输入参数。 b) QoS 监控 ECTP 中的 QoS 控制基于来自接收器的控制数据包的反馈。 来自接收器的反馈消息使发送器能够跟踪活动接收器的数量，并监视多播数据传输的连接状态。 QoS 监控旨在允许发送方根据 QoS 参数值诊断连接状态，从而采取必要的操作将连接状态维持在所需的 QoS 级别。 监控到的连接状态将报告给发送方的应用程序。 例如，所传达的信息可以提供对计费目的有用的统计数据。 c) QoS维护基于来自接收者的反馈信息，发送者采取一项或多项行动以将连接状态维持在期望的QoS水平。 这些QoS维护操作包括调整数据传输速率、连接暂停和恢复、麻烦者弹出和连接终止操作。 这些 QoS 监控和维护功能基于监控的参数状态，提供基于速率的拥塞控制。 此建议|国际标准是 ITU-T X.606.X 建议书的组成部分 | ISO/IEC 14476，有 6 个部分。 所有协议组件，包括 ITU-T Rec. 中指定的数据包格式和协议程序。 X.606 | ISO/IEC 14476-1 在本建议书中也有效国际标准。 [外文原描述]： ISO/IEC 14476-2:2003 is an integral part of ITU-T Recommendation X.ectp | ISO/IEC 14476 having the main title of Enhanced communications transport protocol, which is a family of protocol specifications designed to support multicast transport services. ISO/IEC 14476-1 provides a specification of various protocol operations for simplex multicast transport. Those protocol operations include connection management such as connection creation/termination and connection pause/resume, membership management such as late join, user leave and membership tracking, and error control for multicast data transport such as error detection and recovery. ISO/IEC 14476-2:2003 provides a specification of QoS management for accomplishing desirable quality of service in simplex multicast transport connection. ISO/IEC 14476-2:2003 describes the following QoS management operations: a) QoS negotiation For QoS negotiation, this specification assumes that a desired QoS level for multicast application service can be expressed in terms of a set of QoS parameters. QoS negotiation is performed via exchange of control packets between sender and receivers. Sender proposes the target values of QoS parameters obtained from the application's requirements, and then each receiver can propose modified values based on its system and/or network capacity. Sender arbitrates the modified values proposed by receivers. Target values for QoS parameters can be used as input parameters for reservation of network resources.b) QoS monitoring QoS control in ECTP is based on feedback of control packets from receivers. The feedback messages from receivers enable the sender to keep track of the number of active receivers and also to monitor the connection status for multicast data transport. QoS monitoring is designed to allow the sender to diagnose the connection status in terms of QoS parameter values, and thus to take the necessary actions for maintaining the connection status at a desired QoS level. The monitored connection status will be reported to the application at the sender side. The information conveyed could provide statistics useful for billing purposes, for example.c) QoS maintenance Based on feedback information from receivers, the sender takes one or more actions so as to maintain the connection status at a desired QoS level. These QoS maintenance actions include adjustment of the data transmission rate, connection pause and resume, troublemaker ejection and connection termination operations. These QoS monitoring and maintenance functions, based on monitored parameter status, provide rate-based congestion control. ISO/IEC 14476-2:2003 is an integral part of ITU-T draft Recommendation X.ectp | ISO/IEC 14476, which has 6 parts. All the protocol components, including packet formats and protocol procedures specified in ITU-T draft Recommendation X.606 | ISO/IEC 14476-1, are also valid in ISO/IEC 14476-2:2003.