Internet Engineering Task Force (IETF) G. Fairhurst
Request for Comments: 8436 University of Aberdeen
Updates: 2474 August 2018
Category: Standards Track
ISSN: 2070-1721
Internet Engineering Task Force (IETF) G. Fairhurst
Request for Comments: 8436 University of Aberdeen
Updates: 2474 August 2018
Category: Standards Track
ISSN: 2070-1721
Update to IANA Registration Procedures for Pool 3 Values in the Differentiated Services Field Codepoints (DSCP) Registry
针对差异化服务字段代码点（DSCP）注册表中的池3值更新IANA注册程序
Abstract
摘要
The Differentiated Services (Diffserv) architecture specifies use of the DS field in the IPv4 and IPv6 packet headers to carry one of 64 distinct differentiated services field codepoint (DSCP) values. The Internet Assigned Numbers Authority (IANA) maintains a registry of assigned DSCP values.
区分服务（Diffserv）体系结构指定使用IPv4和IPv6数据包头中的DS字段来携带64个不同的区分服务字段代码点（DSCP）值之一。Internet分配号码管理局（IANA）维护分配DSCP值的注册表。
This update to RFC 2474 changes the IANA registration policy for Pool 3 of the registry (i.e., DSCP values of the form xxxx01) to Standards Action, i.e., values are assigned through a Standards Track or Best Current Practice RFC. The update also removes permission for experimental and local use of the codepoints that form Pool 3 of the DSCP registry; Pool 2 Codepoints (i.e., DSCP values of the form xxxx11) remain available for these purposes.
RFC 2474的更新将注册中心池3的IANA注册策略（即表XX01中的DSCP值）更改为标准行动，即通过标准跟踪或最佳现行做法RFC分配值。更新还删除了对构成DSCP注册表池3的代码点的实验性和本地使用权限；池2代码点（即形式为XX11的DSCP值）仍可用于这些目的。
Status of This Memo
关于下段备忘
This is an Internet Standards Track document.
这是一份互联网标准跟踪文件。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关互联网标准的更多信息，请参见RFC 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8436.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问https://www.rfc-editor.org/info/rfc8436.
Copyright Notice
版权公告
Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2018 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(https://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. The Updates to RFC 2474 . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . 6
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. The Updates to RFC 2474 . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . 6
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
The Differentiated Services (Diffserv) [RFC2475] architecture (updated by [RFC3260]) provides scalable service differentiation in the Internet. Diffserv uses the six most significant bits of the former IPv4 Type of Service (TOS) octet or the former IPv6 Traffic Class octet to convey the field, which is used to carry the DSCP. This DSCP value is used to select a Diffserv per-hop behavior (PHB).
区分服务（Diffserv）[RFC2475]体系结构（由[RFC3260]更新）在互联网上提供可扩展的服务区分。Diffserv使用前IPv4服务类型（TOS）八位字节或前IPv6流量类八位字节中的六个最高有效位来传输用于承载DSCP的字段。此DSCP值用于选择区分服务每跳行为（PHB）。
The six-bit field is capable of conveying 64 distinct codepoints, and this codepoint space has been divided into three pools for the purpose of codepoint assignment and management (as shown in Figure 1). Pool 1 comprises 32 codepoints [RFC2474]. These are assigned by Standards Action, as defined in [RFC8126]. Pool 2 comprises a pool of 16 codepoints reserved for Experimental or Local Use (EXP/LU) as defined in [RFC2474]. Pool 3 comprises 16 codepoints, which were originally specified as "initially available for experimental or local use, but which should be preferentially utilized for standardized assignments if Pool 1 is ever exhausted" by [RFC2474].
六位字段能够传输64个不同的码点，为了码点分配和管理的目的，该码点空间被划分为三个池（如图1所示）。池1包含32个代码点[RFC2474]。这些由[RFC8126]中定义的标准行动分配。池2包括一个由16个代码点组成的池，保留供[RFC2474]中定义的实验或本地使用（EXP/LU）。池3包含16个代码点，最初由[RFC2474]指定为“最初可用于实验或本地使用，但如果池1耗尽，则应优先用于标准化分配”。
+------+-----------------+
| Pool | Codepoint Space |
+------+-----------------+
| 1 | xxxxx0 |
+------+-----------------+
| 2 | xxxx11 |
+------+-----------------+
| 3 | xxxx01 |
+------+-----------------+
+------+-----------------+
| Pool | Codepoint Space |
+------+-----------------+
| 1 | xxxxx0 |
+------+-----------------+
| 2 | xxxx11 |
+------+-----------------+
| 3 | xxxx01 |
+------+-----------------+
Figure 1: Format of the Field for Codepoints Allocated in the Three IANA Pools (Where "x" Refers to Either "0" or "1")
图1：三个IANA池中分配的代码点字段格式（其中“x”表示“0”或“1”）
At the time of writing this document, 22 of the 32 Pool 1 codepoints have been assigned.
在编写本文件时，32个池1代码点中的22个已分配。
Although Pool 1 has not yet been completely exhausted, there is a need to assign codepoints for particular PHBs that are unable to use any of the unassigned values in Pool 1. This document changes the IANA registration policy of Pool 3 to assignment by Standards Action. (Section 4.9 of [RFC8126] defines this as "assigned only through Standards Track or Best Current Practice RFCs in the IETF Stream".)
尽管池1尚未完全耗尽，但需要为无法使用池1中任何未分配值的特定PHB分配代码点。本文件将池3的IANA注册政策更改为“按标准分配”行动。（RFC8126第4.9节将其定义为“仅通过IETF流中的标准跟踪或最佳现行实践RFC分配”。）
An example is the need to assign a suitable recommended default codepoint for the Lower Effort (LE) PHB [LE-PHB]. The LE PHB is designed to protect best-effort (BE) traffic (packets forwarded with the default PHB) from LE traffic in congestion situations (when resources become scarce, best-effort traffic has precedence over LE traffic and is allowed to preempt it). In deployed networks, bleaching (i.e. intentionally setting to zero) of the IP Precedence field continues to be used. (Setting the IP Precedence field to zero disables any class-based flow management by routers configured with TOS-based packet processing.) This causes the first three bits of the former TOS byte (now the upper part of the DSCP field) to become zero. Therefore, there is a need to avoid this remapping of the DSCP for the LE PHB by assigning a codepoint that already has a zero value in the first three bits [LE-PHB].
例如，需要为较低工作量（LE）PHB[LE-PHB]分配适当的推荐默认代码点。LE PHB设计用于在拥塞情况下（当资源变得稀缺时，尽力而为流量优先于LE流量，并允许抢占）保护尽最大努力（BE）流量（使用默认PHB转发的数据包）。在已部署的网络中，继续使用IP优先级字段的漂白（即故意设置为零）。（将IP优先级字段设置为零将禁用配置了基于TOS的数据包处理的路由器的任何基于类的流量管理。）这将导致前TOS字节（现在是DSCP字段的上部）的前三位变为零。因此，需要通过分配在前三位[LE-PHB]中已经具有零值的码点来避免针对LE-PHB的DSCP的这种重新映射。
Furthermore, if the LE PHB were to have been assigned one of the currently unused Pool 1 codepoints with a zero value in the first three bits, any bleaching of the IP Precedence field would result in other (higher assurance) traffic being also remapped to the assigned DSCP. This remapping could then cause Diffserv-marked traffic to receive an unintentional LE treatment for the remainder of the Internet path. Therefore, it is important to avoid the resulting priority inversion. The absence of unassigned codepoints in Pool 1 that exhibit these important properties motivates assigning a Pool 3 codepoint as the default that is recommended for use with this PHB.
此外，如果LE PHB已被分配当前未使用的池1码点之一，且前三位中的值为零，则IP优先字段的任何漂白将导致其他（更高保证）通信量也被重新映射到分配的DSCP。然后，此重新映射可能导致Diffserv标记的流量在Internet路径的其余部分接收到无意的LE处理。因此，避免由此产生的优先级反转非常重要。池1中没有显示这些重要属性的未分配代码点，这促使将池3代码点指定为推荐用于此PHB的默认值。
To allow the IETF to utilize Pool 3 codepoints, this document requests IANA to manage Pool 3 assignments for DSCP values in Pool 3 via the Standards Action policy [RFC8126].
为了允许IETF利用池3代码点，本文件要求IANA通过标准行动策略[RFC8126]管理池3中DSCP值的池3分配。
This document assumes familiarity with the terminology used in [RFC2475] updated by [RFC3260].
本文件假设熟悉[RFC2475]中使用的术语，并由[RFC3260]更新。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“建议”、“不建议”、“可”和“可选”在所有大写字母出现时（如图所示）应按照BCP 14[RFC2119][RFC8174]所述进行解释。
This document updates Section 6 of [RFC2474] in the following ways.
本文件以以下方式更新了[RFC2474]第6节。
It updates the following text concerning the assignment policy:
它更新了有关派遣政策的以下文本：
OLD: which are initially available for experimental or local use, but which should be preferentially utilized for standardized assignments if Pool 1 is ever exhausted.
旧：最初可供实验或本地使用，但如果池1耗尽，则应优先用于标准化作业。
NEW: which are utilized for standardized assignments (replacing the previous availability for experimental or local use).
新：用于标准化作业（取代以前的实验或本地使用）。
It removes the footnote in RFC 2474 relating to Pool 3:
它删除了RFC 2474中与池3相关的脚注：
DELETE: "(*) may be utilized for future Standards Action allocations as necessary"
删除：“（*）可根据需要用于未来的标准行动分配”
The new registry assignment policy is shown in Figure 2.
新的注册表分配策略如图2所示。
Pool Codepoint Space Assignment Policy
---- --------------- ------------------
1 xxxxx0 Standards Action
2 xxxx11 EXP/LU
3 xxxx01 Standards Action
Pool Codepoint Space Assignment Policy
---- --------------- ------------------
1 xxxxx0 Standards Action
2 xxxx11 EXP/LU
3 xxxx01 Standards Action
Note for Pool 2: "Reserved for Experimental or Local Use"
池2注释：“保留供实验或本地使用”
Figure 2: Updated Assignment Policy for the DSCP Registry
图2:DSCP注册表的更新分配策略
Security considerations for the use of DSCP values are described in the RFCs that define their usage. This document does not present new security considerations.
DSCP值使用的安全注意事项在定义其用法的RFC中描述。本文档没有提出新的安全注意事项。
IANA has changed the use of Pool 3 in the "Differentiated Services Field Codepoints (DSCP)" registry and will manage this pool using Standards Action, as defined as Section 4.9 of [RFC8126].
IANA已更改了“差异化服务领域代码点（DSCP）”注册表中池3的使用，并将使用[RFC8126]第4.9节定义的标准行动管理该池。
IANA has made the following changes to the "Differentiated Services Field Codepoints (DSCP)" registry, made available at [Registry].
IANA已对“差异化服务现场代码点（DSCP）”注册表进行了以下更改，可在[注册表]上查阅。
IANA has referenced RFC 2474 and Section 4 of RFC 3260 for the overall format of this registry.
IANA已参考RFC 2474和RFC 3260第4节了解该注册表的总体格式。
IANA has referenced RFC 2474 and Section 4 of RFC 3260 for Pool 1.
IANA参考了RFC 2474和RFC 3260第4节中的池1。
This document does not modify the IANA registry text for Pool 2. This pool continues to preserve the note shown in Figure 2.
本文档不修改池2的IANA注册表文本。此池继续保留图2中所示的注释。
The previous registry text for Pool 3:
池3的上一个注册表文本：
3 xxxx01 Experimental or local use may be utilized for future Standards Action allocations as necessary.
3 XX01如有必要，可在未来的标准行动分配中使用试验性或本地使用。
is replaced with the following registry text:
将替换为以下注册表文本：
3 xxxx01 Standards Action.
3 XX01标准行动。
To manage codepoints in Pool 3, IANA has created and will maintain the "DSCP Pool 3 Codepoints" subregistry. Pool 3 of the registry has been created initially empty, with a format identical to that used for "DSCP Pool 1 Codepoints".
为了管理池3中的代码点，IANA已创建并将维护“DSCP池3代码点”子区。注册表的池3最初为空，格式与“DSCP池1代码点”相同。
IANA has referenced RFC 2474, Section 4 of RFC 3260, and the current document for Pool 3.
IANA参考了RFC 2474、RFC 3260第4节以及池3的当前文件。
The registration procedure for use of Pool 3 is Standards Action, as defined as Section 4.9 of [RFC8126]. IANA is expected to normally make assignments from Pool 1, until this Pool is exhausted, but it MAY make assignments from Pool 3 when the format of the codepoint has properties that are needed for a specific PHB. The required characteristics for choosing a requested DSCP value MUST be explained in the IANA Considerations section of the document that requests any assignment from Pool 3.
根据[RFC8126]第4.9节的定义，池3使用的注册程序为标准行动。IANA通常会从池1进行分配，直到该池耗尽，但当代码点的格式具有特定PHB所需的属性时，IANA可能会从池3进行分配。选择请求的DSCP值所需的特征必须在文件的IANA注意事项部分解释，该部分要求从池3进行任何分配。
[Registry] IANA, "Differentiated Services Field Codepoints (DSCP)", <https://www.iana.org/assignments/dscp-registry/>.
[Registry]IANA，“差异化服务领域代码点（DSCP）”<https://www.iana.org/assignments/dscp-registry/>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，DOI 10.17487/RFC2119，1997年3月<https://www.rfc-editor.org/info/rfc2119>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474, DOI 10.17487/RFC2474, December 1998, <https://www.rfc-editor.org/info/rfc2474>.
[RFC2474]Nichols，K.，Blake，S.，Baker，F.，和D.Black，“IPv4和IPv6报头中区分服务字段（DS字段）的定义”，RFC 2474，DOI 10.17487/RFC2474，1998年12月<https://www.rfc-editor.org/info/rfc2474>.
[RFC3260] Grossman, D., "New Terminology and Clarifications for Diffserv", RFC 3260, DOI 10.17487/RFC3260, April 2002, <https://www.rfc-editor.org/info/rfc3260>.
[RFC3260]Grossman，D.，“区分服务的新术语和澄清”，RFC 3260，DOI 10.17487/RFC3260，2002年4月<https://www.rfc-editor.org/info/rfc3260>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, <https://www.rfc-editor.org/info/rfc8126>.
[RFC8126]Cotton，M.，Leiba，B.，和T.Narten，“在RFC中编写IANA考虑事项部分的指南”，BCP 26，RFC 8126，DOI 10.17487/RFC8126，2017年6月<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8174]Leiba，B.，“RFC 2119关键词中大写与小写的歧义”，BCP 14，RFC 8174，DOI 10.17487/RFC8174，2017年5月<https://www.rfc-editor.org/info/rfc8174>.
[LE-PHB] Bless, R., "A Lower Effort Per-Hop Behavior (LE PHB)", Work in Progress, draft-ietf-tsvwg-le-phb-05, July 2018.
[LE-PHB]Bless，R.，“较低的每跳努力行为（LE-PHB）”，正在进行的工作，草稿-ietf-tsvwg-LE-PHB-052018年7月。
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., and W. Weiss, "An Architecture for Differentiated Services", RFC 2475, DOI 10.17487/RFC2475, December 1998, <https://www.rfc-editor.org/info/rfc2475>.
[RFC2475]Blake，S.，Black，D.，Carlson，M.，Davies，E.，Wang，Z.，和W.Weiss，“差异化服务架构”，RFC 2475，DOI 10.17487/RFC2475，1998年12月<https://www.rfc-editor.org/info/rfc2475>.
Acknowledgments
致谢
Godred Fairhurst received funding from the European Union's Horizon 2020 research and innovation program 2014-2018 under grant agreement No. 644334 (NEAT).
Godred Fairhurst根据第644334（NEAT）号赠款协议接受了欧盟地平线2020研究与创新计划2014-2018的资助。
Author's Address
作者地址
Godred Fairhurst University of Aberdeen Department of Engineering Fraser Noble Building Aberdeen AB24 3UE United Kingdom
GoRead FelHurt阿伯丁大学工程系弗雷泽贵族大厦阿伯丁A24 24英国
Email: gorry@erg.abdn.ac.uk
URI: http://www.erg.abdn.ac.uk/
Email: gorry@erg.abdn.ac.uk
URI: http://www.erg.abdn.ac.uk/