Network Working Group O. Aboul-Magd
Request for Comments: 4115 S. Rabie
Category: Informational Nortel Networks
July 2005
Network Working Group O. Aboul-Magd
Request for Comments: 4115 S. Rabie
Category: Informational Nortel Networks
July 2005
A Differentiated Service Two-Rate, Three-Color Marker with Efficient Handling of in-Profile Traffic
一种高效处理配置文件内流量的区分服务双速率三色标记
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 (2005).
版权所有（C）互联网协会（2005年）。
IESG Note
IESG注释
This RFC is not a candidate for any level of Internet Standard. The IETF disclaims any knowledge of the fitness of this RFC for any purpose and in particular notes that the decision to publish is not based on IETF review for such things as security, congestion control, 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不承认本RFC适用于任何目的的任何知识，特别注意到，发布决定并非基于IETF对安全、拥塞控制或与已部署协议的不当交互等事项的审查。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 document describes a two-rate, three-color marker that has been in use for data services including Frame Relay services. This marker can be used for metering per-flow traffic in the emerging IP and L2 VPN services. The marker defined here is different from previously defined markers in the handling of the in-profile traffic. Furthermore, this marker doesn't impose peak-rate shaping requirements on customer edge (CE) devices.
本文档描述了一种用于数据服务（包括帧中继服务）的双速率三色标记。此标记可用于计量新兴IP和L2 VPN服务中的每流流量。此处定义的标记与之前定义的标记在处理配置文件内流量方面不同。此外，该标记不会对客户边缘（CE）设备施加峰值速率成形要求。
The differentiated service defines a quality-of-service (QoS) architecture for the Internet [RFC2475]. Two integral components of this architecture are traffic metering and marking. This document describes a two-rate, three-color metering/marker algorithm that is
区分服务定义了互联网的服务质量（QoS）体系结构[RFC2475]。该体系结构的两个组成部分是流量计量和标记。本文档描述了一种双速率三色测光/标记算法
suitable for the differentiated service applications such as IP and L2 VPNs. This algorithm has been in use for data services including Frame Relay Service.
适用于IP和L2 VPN等区分服务应用。该算法已用于数据业务，包括帧中继业务。
The metering/marker defined here is different from those in [RFC2697] and [RFC2698]. It is different from [RFC2697] in that it is a two-rate, three-color marker. In contrast, [RFC2697] is a single-rate marker. It is different from [RFC2698] in the way its parameters are defined, which allows a better handling of in-profile traffic for predominant service scenarios over a wider range of traffic parameters.
此处定义的计量/标记与[RFC2697]和[RFC2698]中的计量/标记不同。它与[RFC2697]的不同之处在于它是一个双速率三色标记。相反，[RFC2697]是一个单一的速率标记。与[RFC2698]不同的是，其参数的定义方式允许在更大范围的流量参数上更好地处理主要服务场景的配置文件内流量。
Furthermore, the algorithm described here eliminates the need for the CE to shape its traffic to a certain peak information rate (PIR), as might be the case for the marker defined in [RFC2698] when the value for the peak burst size (PBS) is smaller than that for the committed burst size (CBS).
此外，这里描述的算法消除了CE将其业务塑造成特定峰值信息速率（PIR）的需要，当峰值突发大小（PBS）的值小于提交突发大小（CBS）的值时，[RFC2698]中定义的标记可能就是这种情况。
The marker described here operates for both color-blind and color-aware modes, as defined in [RFC2698].
如[RFC2698]中所定义，此处描述的标记可用于色盲和颜色感知模式。
The operation of the marker is described by two rate values. The committed information rate (CIR) and the excess information rate (EIR). CIR and EIR define the token generation rate of a token bucket with size that is equal to committed burst size (CBS) and excess burst size (EBS), respectively.
标记器的操作由两个速率值描述。提交信息速率（CIR）和超额信息速率（EIR）。CIR和EIR分别定义大小等于提交突发大小（CBS）和超出突发大小（EBS）的令牌桶的令牌生成速率。
The CBS and EBS are measured in bytes and must configure to be greater than the expected maximum length of the incoming PDU. The CIR and EIR are both measured in bits/s. The CIR and EIR can be set independently of each other. Alternatively, the CIR and EIR can be linked together by defining a burst duration parameter, T, where T=CBS/CIR=EBS/EIR.
CBS和EBS以字节为单位，必须配置为大于传入PDU的预期最大长度。CIR和EIR均以位/秒为单位进行测量。CIR和EIR可以彼此独立设置。或者，可以通过定义突发持续时间参数T将CIR和EIR链接在一起，其中T＝CBS/CIR＝EBS/EIR。
The behavior of the meter is defined in terms of its mode and two token buckets, C and E, with the rates, CIR and EIR, respectively, and maximum sizes CBS and EBS.
电表的行为根据其模式和两个令牌桶C和E来定义，速率分别为CIR和EIR，最大大小为CBS和EBS。
The token buckets C and E are initially (at time 0) full; i.e., the token count Tc(0) = CBS and Te(0) = EBS. Thereafter, the token count Tc is incremented by one CIR times per second (up to CBS), and the token count Te is incremented by one EIR times per second (up to EBS).
令牌桶C和E最初（在时间0时）已满；i、 例如，令牌计数Tc（0）=CBS，Te（0）=EBS。此后，令牌计数Tc每秒增加一次CIR（最多CBS），令牌计数Te每秒增加一次EIR（最多EBS）。
In the color-aware operation, it is assumed that the algorithm can recognize the color of the incoming packet (green, yellow, or red). The color-aware operation of the metering is described below.
在颜色感知操作中，假设算法能够识别传入数据包的颜色（绿色、黄色或红色）。计量的颜色感知操作如下所述。
When a green packet of size B arrives at time t, then
当大小为B的绿色数据包在时间t到达时，则
o if Tc(t)- B > 0, the packet is green, and Tc(t) is decremented by B; else
o 如果Tc（t）-B>0，则分组为绿色，并且Tc（t）由B递减；其他的
o if Te(t)- B > 0, the packet is yellow, and Te(t) is decremented by B; else
o 如果Te（t）-B>0，则分组为黄色，并且Te（t）由B递减；其他的
o the packet is red.
o 这个包是红色的。
When a yellow packet of size B arrives at time t, then
当大小为B的黄色数据包在时间t到达时，则
o if Te(t)- B > 0, the packet is yellow, and Te(t) is decremented by B; else
o 如果Te（t）-B>0，则分组为黄色，并且Te（t）由B递减；其他的
o the packet is red.
o 这个包是红色的。
Incoming red packets are not tested against any of the two token buckets and remain red.
传入的红包不会针对两个令牌桶中的任何一个进行测试，并保持红色。
In the color-blind operation, the meter assumes that all incoming packets are green. The operation of the meter is similar to that in the color-aware operation for green packets.
在色盲操作中，仪表假定所有传入的数据包都是绿色的。仪表的操作与绿色数据包的颜色感知操作类似。
The salient feature of the algorithm described above is that traffic within the defined CIR is colored green directly, without the need to pass additional conformance tests. This feature is the main differentiator of this algorithm from that described in [RFC2698], where traffic is marked green after it passes two conformance tests (those for PIR and CIR). In either color-blind or color-aware mode, the need to pass two conformance tests could result in packets being dropped at the PIR token bucket even though they are perfectly within their CIR (in-profile traffic). Furthermore, in the color-aware mode of operation, the need to pass two conformance tests could make yellow traffic starve incoming in-profile green packets.
上述算法的显著特征是，定义的CIR内的通信量直接显示为绿色，而无需通过额外的一致性测试。该特性是该算法与[RFC2698]中描述的算法的主要区别，在[RFC2698]中，流量通过两个一致性测试（PIR和CIR测试）后被标记为绿色。在色盲或颜色感知模式下，需要通过两个一致性测试可能会导致数据包在PIR令牌桶中丢弃，即使它们完全在CIR内（配置文件内流量）。此外，在颜色感知的操作模式下，需要通过两个一致性测试可能会使黄色通信量无法满足输入的配置文件绿色数据包。
The operation of the algorithm is illustrated in the flow chart below:
算法的操作如下图所示：
+---------------------------------+
|periodically every T sec. |
| Tc(t+)=MIN(CBS, Tc(t-)+CIR*T) |
| Te(t+)=MIN(EBS, Te(t-)+EIR*T) |
+---------------------------------+
+---------------------------------+
|periodically every T sec. |
| Tc(t+)=MIN(CBS, Tc(t-)+CIR*T) |
| Te(t+)=MIN(EBS, Te(t-)+EIR*T) |
+---------------------------------+
Packet of size
B arrives /----------------\
---------------->|color-blind mode|
| OR |YES +---------------+
| green packet |---->|packet is green|
| AND | |Tc(t+)=Tc(t-)-B|
| B <= Tc(t-) | +---------------+
\----------------/
|
| NO
v
/----------------\
|color-blind mode|
| OR |YES +----------------+
| NOT red packet |---->|packet is yellow|
| AND | |Te(t+)=Te(t-)-B |
| B <= Te(t-) | +----------------+
\----------------/
|
| NO
v
+---------------+
|packet is red |
+---------------+
Packet of size
B arrives /----------------\
---------------->|color-blind mode|
| OR |YES +---------------+
| green packet |---->|packet is green|
| AND | |Tc(t+)=Tc(t-)-B|
| B <= Tc(t-) | +---------------+
\----------------/
|
| NO
v
/----------------\
|color-blind mode|
| OR |YES +----------------+
| NOT red packet |---->|packet is yellow|
| AND | |Te(t+)=Te(t-)-B |
| B <= Te(t-) | +----------------+
\----------------/
|
| NO
v
+---------------+
|packet is red |
+---------------+
Figure 1: Traffic Metering/Marking Algorithm
图1：流量计量/标记算法
In Figure 1, we have X(t-) and X(t+) to indicate the value of a parameter X right before and right after time t.
在图1中，我们有X（t-）和X（t+）来表示时间t前后的参数X的值。
The described marker can be used to mark an IP packet stream in a service where different, decreasing levels of assurances (either absolute or relative) are given to packets that are green, yellow, or red. For example, a service may discard all red packets because they exceeded the service rates, forward yellow packets as best effort, and forward green packets with low drop probability. The marker could also be used for metering L2 VPN services such as the emerging Ethernet transport over IP networks.
所述标记可用于标记服务中的IP分组流，其中对绿色、黄色或红色分组给予不同的、递减的保证级别（绝对或相对）。例如，服务可以丢弃所有红包，因为它们超过了服务速率，以最大努力转发黄包，以较低的丢弃概率转发绿包。该标记还可用于计量L2 VPN服务，如新兴的IP网络以太网传输。
Security issues resulting from this document are similar to those mentioned in [RFC2697] and [RFC2698].
本文件产生的安全问题与[RFC2697]和[RFC2698]中提到的类似。
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., and W. Weiss, "An Architecture for Differentiated Service", RFC 2475, December 1998.
[RFC2475]Blake，S.，Black，D.，Carlson，M.，Davies，E.，Wang，Z.，和W.Weiss，“差异化服务架构”，RFC 24751998年12月。
[RFC2697] Heinanen, J. and R. Guerin, "A Single Rate Three Color Marker", RFC 2697, September 1999.
[RFC2697]Heinanen，J.和R.Guerin，“单速率三色标记”，RFC 26971999年9月。
[RFC2698] Heinanen, J. and R. Guerin, "A Two Rate Three Color Marker", RFC 2698, September 1999.
[RFC2698]Heinanen，J.和R.Guerin，“双速率三色标记”，RFC 26981999年9月。
[RFC3932] Alvestrand, H., "The IESG and RFC Editor Documents: Procedures", BCP 92, RFC 3932, October 2004.
[RFC3932]Alvestrand，H.，“IESG和RFC编辑文件：程序”，BCP 92，RFC 3932，2004年10月。
Authors' Addresses
作者地址
Osama Aboul-Magd Nortel Networks 3500 Carling Ave Ottawa, ON K2H8E9 EMail: osama@nortel.com
Osama Aboul Magd Nortel Networks 3500渥太华卡林大道，K2H8E9电子邮件：osama@nortel.com
Sameh Rabie Nortel Networks 3500 Carling Ave Ottawa, ON K2H8E9 EMail: rabie@nortel.com
Sameh Rabie Nortel Networks 3500渥太华卡林大道，K2H8E9电子邮件：rabie@nortel.com
Full Copyright Statement
完整版权声明
Copyright (C) The Internet Society (2005).
版权所有（C）互联网协会（2005年）。
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确认
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