Network Working Group J. Welch
Request for Comments: 4445 IneoQuest Technologies
Category: Informational J. Clark
Cisco Systems
April 2006
Network Working Group J. Welch
Request for Comments: 4445 IneoQuest Technologies
Category: Informational J. Clark
Cisco Systems
April 2006
A Proposed Media Delivery Index (MDI)
建议的媒体交付指数（MDI）
Status of This Memo
关于下段备忘
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
本备忘录为互联网社区提供信息。它没有规定任何类型的互联网标准。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2006).
版权所有（C）互联网协会（2006年）。
IESG Note
IESG注释
This RFC is not a candidate for any level of Internet Standard. There are IETF standards which are highly applicable to the space defined by this document as its applicability, in particular, RFCs 3393 and 3611, and there is ongoing IETF work in these areas as well. The IETF also notes that the decision to publish this RFC is not based on IETF review for such things as security, congestion control, MIB fitness, or inappropriate interaction with deployed protocols. The RFC Editor has chosen to publish this document at its discretion. Readers of this document should exercise caution in evaluating its value for implementation and deployment. See RFC 3932 for more information.
本RFC不适用于任何级别的互联网标准。IETF标准高度适用于本文件定义的适用空间，尤其是RFCs 3393和3611，这些领域也正在进行IETF工作。IETF还指出，发布此RFC的决定并非基于IETF对安全性、拥塞控制、MIB适配性或与已部署协议的不当交互等方面的审查。RFC编辑已自行决定发布本文件。本文档的读者在评估其实施和部署价值时应谨慎。有关更多信息，请参阅RFC 3932。
Abstract
摘要
This memo defines a Media Delivery Index (MDI) measurement that can be used as a diagnostic tool or a quality indicator for monitoring a network intended to deliver applications such as streaming media, MPEG video, Voice over IP, or other information sensitive to arrival time and packet loss. It provides an indication of traffic jitter, a measure of deviation from nominal flow rates, and a data loss at-a-glance measure for a particular flow. For instance, the MDI may be used as a reference in characterizing and comparing networks carrying UDP streaming media.
本备忘录定义了媒体交付指数（MDI）测量值，该测量值可用作诊断工具或质量指示器，用于监控网络，以交付流媒体、MPEG视频、IP语音或其他对到达时间和数据包丢失敏感的信息。它提供了流量抖动指示、偏离标称流量的测量值以及特定流量的数据丢失一览测量值。例如，MDI可以用作表征和比较承载UDP流媒体的网络的参考。
The MDI measurement defined in this memo is intended for Information only.
本备忘录中定义的MDI测量仅供参考。
There has been considerable progress over the last several years in the development of methods to provide for Quality of Service (QoS) over packet-switched networks to improve the delivery of streaming media and other time-sensitive and packet-loss-sensitive applications such as [i1], [i5], [i6], [i7]. QoS is required for many practical networks involving applications such as video transport to assure the availability of network bandwidth by providing upper limits on the number of flows admitted to a network, as well as to bound the packet jitter introduced by the network. These bounds are required to dimension a receiver`s buffer to display the video properly in real time without buffer overflow or underflow.
在过去几年中，在开发通过分组交换网络提供服务质量（QoS）的方法以改进流媒体和其他时间敏感和分组丢失敏感应用（如[i1]、[i5]、[i6]、[i7]）的交付方面取得了相当大的进展。许多涉及视频传输等应用的实际网络都需要QoS，以通过提供网络允许流量的上限来确保网络带宽的可用性，并限制网络引入的数据包抖动。需要这些边界来确定接收器缓冲区的尺寸，以便在没有缓冲区溢出或下溢的情况下实时正确显示视频。
Now that large-scale implementations of such networks based on RSVP and Diffserv are undergoing trials [i3] and being specified by major service providers for the transport of streaming media such as MPEG video [i4], there is a need to diagnose issues easily and to monitor the real-time effectiveness of networks employing these QoS methods or to assess whether they are required. Furthermore, due to the significant installed base of legacy networks without QoS methods, a delivery system`s transitional solution may be composed of networks with and without these methods, thus increasing the difficulty in characterizing the dynamic behavior of these networks.
现在，基于RSVP和Diffserv的此类网络的大规模实现正在进行试验[i3]，并由主要服务提供商指定用于传输流媒体，如MPEG视频[i4]，需要轻松诊断问题，并监控采用这些QoS方法的网络的实时有效性，或评估是否需要这些方法。此外，由于没有QoS方法的传统网络的大量安装基础，交付系统的过渡解决方案可能由使用和不使用这些方法的网络组成，因此增加了描述这些网络动态行为的难度。
The purpose of this memo is to describe a set of measurements that can be used to derive a Media Delivery Index (MDI) that indicates the instantaneous and longer-term behavior of networks carrying streaming media such as MPEG video.
本备忘录的目的是描述一组可用于推导媒体交付指数（MDI）的测量值，该指数指示承载流媒体（如MPEG视频）的网络的瞬时和长期行为。
While this memo addresses monitoring MPEG Transport Stream (TS) packets [i8] over UDP, the general approach is expected to be applicable to other streaming media and protocols. The approach is applicable to both constant and variable bit rate streams though the variable bit rate case may be somewhat more difficult to calculate. This document focuses on the constant bit rate case as the example to describe the measurement, but as long as the dynamic bit rate of the encoded stream can be determined (the "drain rate" as described below in Section 3), then the MDI provides the measurement of network-induced cumulative jitter. Suggestions and direction for calculation of MDI for a variable bit rate encoded stream may be the subject of a future document.
虽然本备忘录涉及通过UDP监控MPEG传输流（TS）数据包[i8]，但一般方法预计适用于其他流媒体和协议。该方法适用于恒定和可变比特率流，尽管可变比特率情况可能更难计算。本文档以恒定比特率情况为例来描述测量，但只要可以确定编码流的动态比特率（如下文第3节所述的“漏比特率”），则MDI提供网络诱导累积抖动的测量。对于可变比特率编码流的MDI的计算的建议和方向可能是未来文档的主题。
Network packet delivery time variation and various statistics to characterize the same are described in a generic approach in [i10]. The approach is capable of being parameterized for various purposes with the intent of defining a flexible, customizable definition that can be applied to a wide range of applications and further
[i10]中的通用方法描述了网络数据包交付时间变化和表征该变化的各种统计数据。该方法能够为各种目的进行参数化，目的是定义一个灵活的、可定制的定义，该定义可应用于广泛的应用程序和其他应用程序
experimentation. Other approaches to characterizing jitter behavior are also captured such as in [i12]. A wide-ranging report format [i11] has been described to convey information including jitter for use with the RTP Control Protocol (RTCP) [i12]. The MDI is instead intended to specifically address the need for a scalable, economical-to-compute metric that characterizes network impairments that may be imposed on streaming media, independent of control plane or measurement transport protocol or stream encapsulation protocol. It is a targeted metric for use in production networks carrying large numbers of streams for the purpose of monitoring the network quality of the flows or for other applications intended to analyze large numbers of streams susceptible to IP network device impairments. An example application is the burgeoning deployments of Internet Protocol Television (IPTV) by cable and telecommunication service providers. As described below, MDI provides for a readily scalable per-stream measure focused on loss and the cumulative effects of jitter.
实验。描述抖动行为的其他方法也被捕获，如[i12]。已经描述了一种广泛的报告格式[i11]，用于传送信息，包括用于RTP控制协议（RTCP）[i12]的抖动。相反，MDI旨在专门解决对可伸缩、经济的计算度量的需求，该度量表征可施加在流媒体上的网络损伤，独立于控制平面或测量传输协议或流封装协议。它是一个目标指标，用于承载大量流的生产网络中，用于监控流的网络质量，或用于分析易受IP网络设备损害的大量流的其他应用。一个示例应用是电缆和电信服务提供商新兴的互联网协议电视（IPTV）部署。如下文所述，MDI提供了一种易于扩展的每流度量，其重点是丢失和抖动的累积效应。
The MDI provides a relative indicator of needed buffer depths at the consumer node due to packet jitter as well as an indication of lost packets. By probing a streaming media service network at various nodes and under varying load conditions, it is possible to quickly identify devices or locales that introduce significant jitter or packet loss to the packet stream. By monitoring a network continuously, deviations from nominal jitter or loss behavior can be used to indicate an impending or ongoing fault condition such as excessive load. It is believed that the MDI provides the necessary information to detect all network-induced impairments for streaming video or voice-over-IP applications. Other parameters may be required to troubleshoot and correct the impairments.
MDI提供由于数据包抖动而在消费者节点处所需的缓冲区深度的相对指示符以及丢失数据包的指示。通过在不同节点和不同负载条件下探测流媒体服务网络，可以快速识别对分组流引入显著抖动或分组丢失的设备或区域设置。通过连续监测网络，偏离标称抖动或损耗行为可用于指示即将发生或正在发生的故障状况，如过载。据信，MDI提供了必要的信息来检测流式视频或IP语音应用的所有网络诱导损伤。可能需要其他参数来排除故障并纠正损坏。
The MDI is updated at the termination of selected time intervals spanning multiple packets that contain the streaming media (such as transport stream packets in the MPEG-2 case). The Maximums and Minimums of the MDI component values are captured over a measurement time. The measurement time may range from just long enough to capture an anticipated network anomaly during a troubleshooting exercise to indefinitely long for a long-term monitoring or logging application. The Maximums and Minimums may be obtained by sampling the measurement with adequate frequency.
MDI在跨越包含流媒体的多个分组（例如MPEG-2情况下的传输流分组）的选定时间间隔终止时更新。在测量时间内捕获MDI分量值的最大值和最小值。测量时间的范围可能从刚好足以捕获故障排除过程中预期的网络异常到无限长的长期监视或日志应用程序。最大值和最小值可通过以适当频率对测量值进行取样获得。
The MDI consists of two components: the Delay Factor (DF) and the Media Loss Rate (MLR).
MDI由两部分组成：延迟因子（DF）和介质丢失率（MLR）。
The Delay Factor is the maximum difference, observed at the end of each media stream packet, between the arrival of media data and the drain of media data. This assumes the drain rate is the nominal constant traffic rate for constant bit rate streams or the piece-wise computed traffic rate of variable rate media stream packet data. The "drain rate" here refers to the payload media rate; e.g., for a typical 3.75 Mb/s MPEG video Transport Stream (TS), the drain rate is 3.75 Mb/s -- the rate at which the payload is consumed (displayed) at a decoding node. If, at the sample time, the number of bytes received equals the number transmitted, the instantaneous flow rate balance will be zero; however, the minimum DF will be a line packet's worth of media data, as that is the minimum amount of data that must be buffered.
延迟因子是在每个媒体流分组结束时观察到的媒体数据到达和媒体数据排出之间的最大差值。这假设漏失率是恒定比特率流的标称恒定业务率或可变速率媒体流分组数据的分段计算业务率。这里的“漏失率”是指有效负载介质速率；e、 例如，对于典型的3.75 Mb/s MPEG视频传输流（TS），漏失率为3.75 Mb/s——解码节点消耗（显示）有效负载的速率。如果在采样时，接收的字节数等于传输的字节数，则瞬时流量平衡为零；然而，最小DF将是线路数据包的媒体数据值，因为这是必须缓冲的最小数据量。
The DF is the maximum observed value of the flow rate imbalance over a calculation interval. This buffered media data in bytes is expressed in terms of how long, in milliseconds, it would take to drain (or fill) this data at the nominal traffic rate to obtain the DF. Display of DF with a resolution of tenths of milliseconds is recommended to provide adequate indication of stream variations for monitoring and diagnostic applications for typical stream rates from 1 to 40 Mb/s. The DF value must be updated and displayed at the end of a selected time interval. The selected time interval is chosen to be long enough to sample a number of TS packets and will, therefore, vary based on the nominal traffic rate. For typical stream rates of 1 Mb/s and up, an interval of 1 second provides a long enough sample time and should be included for all implementations. The Delay Factor indicates how long a data stream must be buffered (i.e., delayed) at its nominal bit rate to prevent packet loss. This time may also be seen as a measure of the network latency that must be induced from buffering, which is required to accommodate stream jitter and prevent loss. The DF`s max and min over the measurement period (multiple intervals) may also be displayed to show the worst case arrival time deviation, or jitter, relative to the nominal traffic rate in a measurement period. It provides a dynamic flow rate balance indication with its max and min showing the worst excursions from balance.
DF是计算间隔内流量不平衡的最大观测值。以字节为单位的缓冲媒体数据表示为以标称流量消耗（或填充）该数据以获得DF所需的时间（以毫秒为单位）。建议以十分之一毫秒的分辨率显示DF，以便为监测和诊断应用程序提供足够的流变化指示，典型流速率为1到40 Mb/s。DF值必须在选定的时间间隔结束时更新和显示。所选择的时间间隔被选择为足够长以对多个TS分组进行采样，并且因此将基于标称业务速率而变化。对于1 Mb/s及以上的典型流速率，1秒的间隔提供了足够长的采样时间，并且应该包括在所有实现中。延迟因子指示数据流必须以其标称比特率缓冲（即延迟）多长时间以防止数据包丢失。这段时间也可以被视为必须由缓冲引起的网络延迟的度量，缓冲是适应流抖动和防止丢失所必需的。还可以显示测量周期（多个间隔）内的DF最大值和最小值，以显示相对于测量周期内标称流量的最坏情况到达时间偏差或抖动。它提供了动态流量平衡指示，其最大和最小值显示了与平衡的最差偏差。
The Delay Factor gives a hint of the minimum size of the buffer required at the next downstream node. As a stream progresses, the variation of the Delay Factor indicates packet bunching or packet
延迟因子给出了下一个下游节点所需的最小缓冲区大小的提示。随着流的进行，延迟因子的变化指示分组聚束或分组
gaps (jitter). Greater DF values also indicate that more network latency is necessary to deliver a stream due to the need to pre-fill a receive buffer before beginning the drain to guarantee no underflow. The DF comprises a fixed part based on packet size and a variable part based on the buffer utilization of the various network component switch elements that comprise the switched network infrastructure [i2].
间隙（抖动）。更大的DF值还表明，由于需要在开始排放之前预填充接收缓冲区以确保无下溢，因此需要更多的网络延迟来交付流。DF包括基于分组大小的固定部分和基于构成交换网络基础设施的各种网络组件交换元件的缓冲器利用率的可变部分[i2]。
To further detail the calculation of DF, consider a virtual buffer VB used to buffer received packets of a stream. When a packet P(i) arrives during a calculation interval, compute two VB values, VB(i,pre) and VB(i,post), defined as:
为了进一步详述DF的计算，考虑用于缓冲流的接收分组的虚拟缓冲器VB。当数据包P（i）在计算间隔期间到达时，计算两个VB值，VB（i，pre）和VB（i，post），定义为：
VB(i,pre) = sum (Sj) - MR * Ti; where j=1..i-1
VB(i,post) = VB(i,pre) + Si
VB(i,pre) = sum (Sj) - MR * Ti; where j=1..i-1
VB(i,post) = VB(i,pre) + Si
where Sj is the media payload size of the jth packet, Ti is the relative time at which packet i arrives in the interval, and MR is the nominal media rate.
其中Sj是第j个分组的媒体有效负载大小，Ti是分组i到达间隔的相对时间，MR是标称媒体速率。
VB(i,pre) is the Virtual Buffer size just before the arrival of P(i). VB(i,post) is the Virtual Buffer size just after the arrival of P(i).
VB（i，pre）是P（i）到达之前的虚拟缓冲区大小。VB（i，post）是P（i）到达后的虚拟缓冲区大小。
The initial condition of VB(0) = 0 is used at the beginning of each measurement interval. A measurement interval is defined from just after the time of arrival of the last packet during a nominal period (typically 1 second) as mentioned above to the time just after the arrival of the last packet of the next nominal period.
VB（0）=0的初始条件用于每个测量间隔的开始。测量间隔定义为从如上所述的标称周期（通常为1秒）内最后一个分组的到达时间之后到下一个标称周期的最后一个分组的到达时间之后的时间。
During a measurement interval, if k packets are received, then there are 2*k+1 VB values used in deriving VB(max) and VB(min). After determining VB(max) and VB(min) from the 2k+1 VB samples, DF for the measurement interval is computed and displayed as:
在测量间隔期间，如果接收到k个数据包，则在推导VB（max）和VB（min）时使用2*k+1 VB值。从2k+1 VB样本中确定VB（最大）和VB（最小）后，计算测量间隔的DF并显示为：
DF = [VB(max) - VB(min)]/ MR
DF = [VB(max) - VB(min)]/ MR
As noted above, a measurement interval of 1 second is typically used. If no packets are received during an interval, the last DF calculated during an interval in which packets did arrive is displayed. The time of arrival of the last previous packet is always retained for use in calculating VB when the next packet arrives (even if the time of the last received packet spans measurement intervals). For the first received measurement interval of a measurement period, no DF is calculated; however, packet arrival times are recorded for use in calculating VB during the following interval.
如上所述，通常使用1秒的测量间隔。如果在某个时间间隔内未收到任何数据包，则显示在数据包确实到达的时间间隔内计算的最后一次DF。上一个数据包的到达时间始终保留，以便在下一个数据包到达时用于计算VB（即使上一个接收数据包的时间跨越测量间隔）。对于测量周期的第一个接收测量间隔，不计算DF；但是，数据包到达时间会被记录下来，以便在接下来的时间间隔内用于计算VB。
The Media Loss Rate is the count of lost or out-of-order flow packets over a selected time interval, where the flow packets are packets carrying streaming application information. There may be zero or more streaming packets in a single IP packet. For example, it is common to carry seven 188 Byte MPEG Transport Stream packets in an IP packet. In such a case, a single IP packet loss would result in 7 lost packets counted (if those 7 lost packets did not include null packets). Including out-of-order packets is important, as many stream consumer-type devices do not attempt to reorder packets that are received out of order.
媒体丢失率是选定时间间隔内丢失或无序流分组的计数，其中流分组是承载流应用信息的分组。单个IP数据包中可能有零个或多个流数据包。例如，在IP分组中携带七个188字节的MPEG传输流分组是常见的。在这种情况下，单个IP数据包丢失将导致统计7个丢失的数据包（如果这7个丢失的数据包不包括空数据包）。包括无序数据包很重要，因为许多流消费者类型设备不会尝试对无序接收的数据包重新排序。
Combining the Delay Factor and Media Loss Rate quantities for presentation results in the following MDI:
将延迟因子和媒体丢失率数量组合在一起可生成以下MDI：
DF:MLR Where: DF is the Delay Factor MLR is the Media Loss Rate
DF:MLR，其中：DF是延迟因子，MLR是媒体丢失率
At a receiving node, knowing its nominal drain bit rate, the DF`s max indicates the size of buffer required to accommodate packet jitter. Or, in terms of Leaky Bucket [i9] parameters, DF indicates bucket size b, expressed in time to transmit bucket traffic b, at the given nominal traffic rate, r.
在接收节点上，知道其标称漏比特率后，DF's max指示容纳数据包抖动所需的缓冲区大小。或者，就漏桶[i9]参数而言，DF表示桶大小b，以给定标称流量率r下传输桶流量b的时间表示。
If a known, well-characterized receive node is separated from the data source by unknown or less well-characterized nodes such as intermediate switch nodes, the MDI measured at intermediate data links provides a relative indication of the behavior of upstream traffic flows. DF difference indications between one node and another in a data stream for a given constant interval of calculation can indicate local areas of traffic congestion or possibly misconfigured QoS flow specification(s) leading to greater filling of measurement point local device buffers, resultant flow rate deviations, and possible data loss.
如果已知的、特征化良好的接收节点被未知的或特征化程度较低的节点（例如中间交换机节点）从数据源分离，则在中间数据链路处测量的MDI提供上游业务流行为的相对指示。给定恒定计算间隔的数据流中一个节点与另一个节点之间的DF差异指示可指示局部交通拥堵区域或可能错误配置的QoS流规范，从而导致测量点本地设备缓冲区更大程度的填充、产生的流量偏差和可能的数据丢失。
For a given MDI, if DF is high and/or the DF Max-Min captured over a significant measurement period of multiple intervals is high, jitter has been detected but the longer-term, average flow rate may be nominal. This could be the result of a transient flow upset due to a coincident traffic stream unrelated to the flow of interest causing packet bunching. A high DF may cause downstream buffer overflow or underflow or unacceptable latency even in the absence of lost data.
对于给定的MDI，如果DF较高和/或在多个间隔的重要测量周期内捕获的DF Max Min较高，则已检测到抖动，但长期平均流速可能为标称值。这可能是由于与感兴趣的流无关的重合业务流导致数据包聚束而导致的瞬态流混乱的结果。即使在没有丢失数据的情况下，高DF也可能导致下游缓冲区溢出或下溢或不可接受的延迟。
Due to transient network failures or DF excursions, packets may be lost within the network. The MLR component of the MDI shows this condition.
由于瞬时网络故障或测向偏移，数据包可能在网络中丢失。MDI的MLR组件显示此情况。
Through automated or manual flow detection and identification and subsequent MDI calculations for real-time statistics on a flow, the DF can indicate the dynamic deterioration or increasing burstiness of a flow, which can be used to anticipate a developing network operation problem such as transient oversubscription. Such statistics can be obtained for flows within network switches using available switch cpu resources due to the minimal computational requirements needed for small numbers of flows. Statistics for all flows present on, say, a gigabit Ethernet network, will likely require dedicated hardware facilities, though these can be modest, as buffer requirements and the required calculations per flow are minimal. By equipping network switches with MDI measurements, flow impairment issues can quickly be identified, localized, and corrected. Until switches are so equipped with appropriate hardware resources, dedicated hardware tools can provide supplemental switch statistics by gaining access to switch flows via mirror ports, link taps, or the like as a transition strategy.
通过自动或手动流量检测和识别以及随后的MDI计算来实时统计流量，DF可以指示流量的动态恶化或突发性增加，这可用于预测正在发展的网络运行问题，如瞬时超额订阅。由于少量流所需的计算要求最低，因此可以使用可用的交换机cpu资源获得网络交换机内流的此类统计信息。对于（比如）千兆以太网网络上存在的所有流的统计数据，可能需要专用的硬件设施，尽管这些硬件设施可能是适度的，因为每个流的缓冲要求和所需的计算是最小的。通过为网络交换机配备MDI测量，可以快速识别、定位和纠正流量损坏问题。在交换机配备适当的硬件资源之前，专用硬件工具可以通过镜像端口、链路抽头等获取交换机流的访问权限，作为一种过渡策略，从而提供补充的交换机统计信息。
The MDI figure can also be used to characterize a flow decoder's acceptable performance. For example, an MPEG decoder could be characterized as tolerating a flow with a given maximum DF and MLR for acceptable display performance (acceptable on-screen artifacts). Network conditions such as Interior Gateway Protocol (IGP) reconvergence time then might also be included in the flow tolerance DF resulting in a higher-quality user experience.
MDI图也可用于描述流解码器的可接受性能。例如，MPEG解码器可以被描述为容忍具有给定最大DF和MLR的流以获得可接受的显示性能（可接受的屏幕上伪影）。网络条件，如内部网关协议（IGP）再聚合时间，也可能包含在流量容差DF中，从而产生更高质量的用户体验。
The MDI combines the Delay Factor, which indicates potential for impending data loss, and Media Loss Rate as the indicator of lost data. By monitoring the DF and MLR and their min and max excursions over a measurement period and at multiple strategic locations in a network, traffic congestion or device impairments may be detected and isolated for a network carrying streaming media content.
MDI将延迟因子（表示即将发生的数据丢失的可能性）和介质丢失率（表示丢失的数据）结合起来。通过监视DF和MLR及其在测量周期内和在网络中的多个战略位置的最小和最大偏移，可以检测并隔离承载流媒体内容的网络的流量拥塞或设备损伤。
The measurements identified in this document do not directly affect the security of a network or user. Actions taken in response to these measurements that may affect the available bandwidth of the network or the availability of a service is out of scope for this document.
本文件中确定的测量不会直接影响网络或用户的安全。为响应这些可能影响网络可用带宽或服务可用性的测量而采取的措施不在本文档的范围内。
Performing the measurements described in this document only requires examination of payload header information (such as MPEG transport stream headers or RTP headers) to determine nominal stream bit rate and sequence number information. Content may be encrypted without affecting these measurements. Therefore, content privacy is not expected to be a concern.
执行本文档中描述的测量仅需要检查有效负载报头信息（如MPEG传输流报头或RTP报头），以确定标称流比特率和序列号信息。内容可以在不影响这些测量的情况下进行加密。因此，内容隐私预计不会受到关注。
[i1] Braden, R., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997.
[i1] Braden，R.，Zhang，L.，Berson，S.，Herzog，S.，和S.Jamin，“资源预留协议（RSVP）——版本1功能规范”，RFC 22052997年9月。
[i2] Partridge, C., "A Proposed Flow Specification", RFC 1363, September 1992.
[i2] 帕特里奇，C.，“拟定流量规范”，RFC 1363，1992年9月。
[i3] R. Fellman, `Hurdles to Overcome for Broadcast Quality Video Delivery over IP` VidTranS 2002.
[i3] R.Fellman，`通过IP进行广播质量视频传输需要克服的障碍'，VidTranS 2002。
[i4] CableLabs `PacketCable Dynamic Quality-of-Service Specification`, PKT-SP-DQOS-I06-030415, 2003.
[i4] CableLabs“PacketCable动态服务质量规范”，PKT-SP-DQOS-I06-030415，2003年。
[i5] Shenker, S., Partridge, C., and R. Guerin, "Specification of Guaranteed Quality of Service", RFC 2212, September 1997.
[i5] Shenker，S.，Partridge，C.和R.Guerin，“保证服务质量规范”，RFC 2212，1997年9月。
[i6] Wroclawski, J., "Specification of the Controlled-Load Network Element Service", RFC 2211, September 1997.
[i6] Wroclawski，J.，“受控负荷网元服务规范”，RFC2211，1997年9月。
[i7] Braden, R., Clark, D., and S. Shenker, "Integrated Services in the Internet Architecture: an Overview", RFC 1633, June 1994.
[i7] Braden，R.，Clark，D.，和S.Shenker，“互联网体系结构中的综合服务：概述”，RFC16331994年6月。
[i8] ISO/IEC 13818-1 (MPEG-2 Systems)
[i8] ISO/IEC 13818-1（MPEG-2系统）
[i9] V. Raisanen, "Implementing Service Quality in IP Networks", John Wiley & Sons Ltd., 2003.
[i9] V.Raisanen，“在IP网络中实施服务质量”，John Wiley&Sons有限公司，2003年。
[i10] Demichelis, C. and P. Chimento, "IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)", RFC 3393, November 2002.
[i10]Demichelis，C.和P.Chimento，“IP性能度量的IP数据包延迟变化度量（IPPM）”，RFC 3393，2002年11月。
[i11] Friedman, T., Caceres, R., and A. Clark, "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, November 2003.
[i11]Friedman，T.，Caceres，R.，和A.Clark，“RTP控制协议扩展报告（RTCP XR）”，RFC 3611，2003年11月。
[i12] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003.
[i12]Schulzrinne，H.，Casner，S.，Frederick，R.，和V.Jacobson，“RTP：实时应用的传输协议”，STD 64，RFC 35502003年7月。
The authors gratefully acknowledge the contributions of Marc Todd and Jesse Beeson of IneoQuest Technologies, Inc., Bill Trubey and John Carlucci of Time Warner Cable, Nishith Sinha of Cox Communications, Ken Chiquoine of SeaChange International, Phil Proulx of Bell Canada, Dr Paul Stallard of TANDBERG Television, Gary Hughes of Broadbus Technologies, Brad Medford of SBC Laboratories, John Roy of Adelphia Communications, Cliff Mercer, PhD of Kasenna, Mathew Ho of Rogers Cable, and Irl Duling of Optinel Systems for reviewing and evaluating early versions of this document and implementations for MDI.
作者衷心感谢IneoQuest Technologies，Inc.的Marc Todd和Jesse Beeson、时代华纳有线电视公司的Bill Trubey和John Carlucci、Cox Communications公司的Nishith Sinha、SeaChange International公司的Ken Chiquoine、加拿大贝尔公司的Phil Proulx、坦堡电视公司的Paul Stallard博士以及，Broadbus Technologies的Gary Hughes、SBC实验室的Brad Medford、Adelphia Communications的John Roy、Kasena的Cliff Mercer博士、Rogers Cable的Mathew Ho以及Optinel Systems的Irl Duling，用于审查和评估本文件的早期版本以及MDI的实施。
Authors' Addresses
作者地址
James Welch IneoQuest Technologies, Inc 170 Forbes Blvd Mansfield, Massachusetts 02048
马萨诸塞州曼斯菲尔德福布斯大道170号詹姆斯·韦尔奇IneoQuest Technologies，Inc.02048
Phone: 508 618 0312 EMail: Jim.Welch@ineoquest.com
电话：5086188312电子邮件：吉姆。Welch@ineoquest.com
James Clark Cisco Systems, Inc 500 Northridge Road Suite 800 Atlanta, Georgia 30350
James Clark Cisco Systems，Inc.乔治亚州亚特兰大市北岭路500号800室30350
Phone: 678 352 2726 EMail: jiclark@cisco.com
电话：678352726电子邮件：jiclark@cisco.com
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