Network Working Group Y. Bernet
Request for Comments: 2996 Microsoft
Category: Standards Track November 2000
Network Working Group Y. Bernet
Request for Comments: 2996 Microsoft
Category: Standards Track November 2000
Format of the RSVP DCLASS Object
RSVP DCLASS对象的格式
Status of this Memo
本备忘录的状况
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
本文件规定了互联网社区的互联网标准跟踪协议，并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态，请参考当前版本的“互联网官方协议标准”（STD 1）。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2000). All Rights Reserved.
版权所有（C）互联网协会（2000年）。版权所有。
Abstract
摘要
Resource Reservation Protocol (RSVP) signaling may be used to request Quality of Service (QoS) services and enhance the manageability of application traffic's QoS in a differentiated service (diff-serv or DS) network. When using RSVP with DS networks it is useful to be able to carry carry Differentiated Services Code Points (DSCPs) in RSVP message objects. One example of this is the use of RSVP to arrange for the marking of packets with a particular DSCP upstream from the DS network's ingress point, at the sender or at a previous network's egress router.
资源预留协议（RSVP）信令可用于请求服务质量（QoS）服务，并增强区分服务（区分服务或DS）网络中应用流量的QoS的可管理性。在DS网络中使用RSVP时，能够在RSVP消息对象中携带区分服务代码点（DSCP）非常有用。这方面的一个例子是使用RSVP来安排在发送方或先前网络的出口路由器处使用来自DS网络的入口点的上游的特定DSCP标记分组。
The DCLASS object is used to represent and carry DSCPs within RSVP messages. This document specifies the format of the DCLASS object and briefly discusses its use.
DCLASS对象用于表示和携带RSVP消息中的DSCP。本文档指定了DCLASS对象的格式，并简要讨论了其用法。
This section describes the mechanics of using RSVP [RSVP] signaling and the DCLASS object for effecting admission control and applying QoS policy within a Differentiated Service network [DS]. It assumes standard RSVP senders and receivers, and a diff-serv network somewhere in the path between sender and receiver. At least one RSVP aware network element resides in the diff-serv network. This network element may be a policy enforcement point (PEP) [RAP] or may simply act as an admission control agent for the network, admitting or denying resource requests based on the availability of resources. In either case, this network element interacts with RSVP messages arriving from outside the DS network, accepting resource requests
本节描述了使用RSVP[RSVP]信令和DCLASS对象在区分服务网络[DS]中实现接纳控制和应用QoS策略的机制。它假设标准的RSVP发送方和接收方，以及发送方和接收方之间路径中的某个位置的diff-serv网络。至少一个RSVP感知网络元素驻留在区分服务网络中。该网元可以是策略实施点（PEP）[RAP]，或者可以简单地充当网络的接纳控制代理，基于资源的可用性接纳或拒绝资源请求。在任何一种情况下，该网元都与来自DS网络外部的RSVP消息交互，接受资源请求
from RSVP-aware senders and receivers, and conveying the DS network's admission control and resource allocation decisions to the higher-level RSVP. The network element is typically a router and will be considered to be so for the purpose of this document. This model is described fully in [INTDIFF].
从感知RSVP的发送方和接收方，并将DS网络的准入控制和资源分配决策传送给更高级别的RSVP。网元通常是一个路由器，在本文件中被视为路由器。该模型在[INTDIFF]中有详细描述。
1.1 Use of the DCLASS Object to Carry Upstream Packet Marking Information
1.1 使用DCLASS对象携带上行数据包标记信息
A principal usage of the DCLASS object is to carry DSCP information between a DS network and upstream nodes that may wish to mark packets with DSCP values. Briefly, the sender composes a standard RSVP PATH message and sends it towards the receiver. At some point the PATH message reaches the DS network. The PATH message traverses one or more network elements that are PEPs and/or admission control agents for the diff-serv network. These elements install appropriate state and forward the PATH message towards the receiver. If admission control is successful downstream of the diff-serv network, then a RESV message will arrive from the direction of the receiver. As this message arrives at the PEPs and/or admission control agents that are RSVP enabled, each of these network elements must make a decision regarding the admissibility of the signaled flow to the diff-serv network.
DCLASS对象的主要用途是在DS网络和可能希望用DSCP值标记数据包的上游节点之间传输DSCP信息。简而言之，发送方编写一个标准RSVP路径消息并将其发送给接收方。在某个点，路径消息到达DS网络。路径消息穿过作为区分服务网络的pep和/或接纳控制代理的一个或多个网络元件。这些元素安装适当的状态，并将路径消息转发给接收方。如果允许控制在diff serv网络下游成功，则将从接收器的方向到达RESV消息。当该消息到达启用RSVP的pep和/或接纳控制代理时，这些网络元件中的每一个都必须作出关于到区分服务网络的信号流的可容许性的决定。
If the network element determines that the request represented by the PATH and RESV messages is admissible to the diff-serv network, the appropriate diff-serv service level (or behavior aggregate) for the traffic represented in the RSVP request is determined. Next, a decision is made to mark arriving data packets for this traffic locally using MF classification, or to request upstream marking of the packets with the appropriate DSCP(s). This upstream marking could occur anywhere before the DS network's ingress point. Two likely candidates are the originating sender and the egress boundary router of some upstream (DS or non-DS) network. The decision about where the RSVP request's packets should be marked can be made by agreement or through a negotiation protocol; the details are outside the scope of this document.
如果网元确定路径和RESV消息表示的请求可被diff-serv网络接受，则确定RSVP请求中表示的业务的适当diff-serv服务级别（或行为聚合）。接下来，决定使用MF分类在本地为该业务标记到达的数据分组，或者请求使用适当的DSCP对分组进行上游标记。此上游标记可能发生在DS网络入口点之前的任何位置。两个可能的候选者是一些上游（DS或非DS）网络的发起发送者和出口边界路由器。关于RSVP请求的数据包应标记在何处的决定可以通过协议或协商协议作出；这些细节不在本文件的范围之内。
If the packets for this RSVP request are to be marked upstream, information about the DSCP(s) to use must be conveyed from the RSVP-aware network element to the upstream marking point. This information is conveyed with the DCLASS object. To do this, the network element adds a DCLASS object containing one or more DSCPs corresponding to the behavior aggregate, to the RESV message. The RESV message is then sent upstream towards the RSVP sender.
如果要将此RSVP请求的数据包标记为上游，则必须将有关要使用的DSCP的信息从感知RSVP的网元传送到上游标记点。此信息通过DCLASS对象传递。为此，网元向RESV消息中添加一个DCLASS对象，该对象包含一个或多个与行为聚合相对应的DSCP。然后将RESV消息向上游发送到RSVP发送方。
If the network element determines that the RSVP request is not admissible to the diff-serv network, it sends a RESV error message
如果网元确定区分服务网络不允许RSVP请求，则发送RESV错误消息
towards the receiver. No DCLASS is required.
对着听筒。不需要DCLASS。
The DCLASS object is intended to be a general tool for conveying DSCP information in RSVP messages. This may be useful in a number of situations. We give one further example here as motivation.
DCLASS对象旨在成为在RSVP消息中传递DSCP信息的通用工具。这在许多情况下可能很有用。我们在这里再举一个例子作为动机。
In this example, we assume that the decision about the appropriate behavior aggregate for a RSVP-mediated traffic flow is made at the DS network egress router (or a related Policy Decision Point) by observing RSVP PATH and RESV messages and other necessary information. However, the actual packet marking must be done at the ingress of the network. The DCLASS object can be used to carry the needed marking information between egress and ingress routers.
在本例中，我们假设通过观察RSVP路径和RESV消息以及其他必要信息，在DS网络出口路由器（或相关策略决策点）处做出关于RSVP介导的业务流的适当行为聚合的决策。然而，实际的数据包标记必须在网络入口进行。DCLASS对象可用于在进出路由器之间传送所需的标记信息。
The DCLASS object has the following format:
DCLASS对象具有以下格式：
0 | 1 | 2 | 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (>= 8) | C-Num (225) | 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused | 1st DSCP | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused | 2nd DSCP | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused | . . . . | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 | 1 | 2 | 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (>= 8) | C-Num (225) | 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused | 1st DSCP | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused | 2nd DSCP | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused | . . . . | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The first word contains the standard RSVP object header (the Class Num for the DCLASS object is 225). The length field indicates the total object length in bytes. The object header is followed by one or more 32-bit words, each containing a DSCP in the six high-order bits of the least significant byte. The length field in the object header indicates the number of DSCPs included in the object. Specifically, the number of DCLASS objects present is equal to (Length - 4) / 4.
第一个单词包含标准的RSVP对象头（DCLASS对象的Class Num为225）。长度字段以字节为单位指示对象的总长度。对象头后面是一个或多个32位字，每个字在最低有效字节的六个高位中包含一个DSCP。对象标头中的长度字段表示对象中包含的DSCP数。具体来说，存在的DCLASS对象的数量等于（长度-4）/4。
The network may return multiple DSCPs in the DCLASS object in order to enable the host to discriminate sub-flows within a behavior aggregate. For example, in the case of the AF PHB group [AF], the network may return the DSCPs 001010, 001100, and 001110 corresponding to increasing levels of drop precedence within Class 1 of the AF PHB group. Note that this document makes no statements regarding the significance of the order of the returned DSCPs. Further interpretation of DSCP sets is dependent on the specific service
网络可以在DCLASS对象中返回多个DSCP，以便使主机能够区分行为聚合中的子流。例如，在AF PHB组[AF]的情况下，网络可以返回DSCPs 001010、001100和001110，对应于AF PHB组的类1内的丢弃优先级的增加。请注意，本文件未对退回的DSCP订单的重要性做出任何说明。DSCP集的进一步解释取决于特定服务
requested by the host and is beyond the scope of this document.
由主机请求，不在本文件范围内。
Note that the Class-Num for the DCLASS object is chosen from the space of unknown class objects that should be ignored and forwarded by nodes that do not recognize it. This is to assure maximal backward compatibility.
请注意，DCLASS对象的Class Num是从未知类对象的空间中选择的，不识别它的节点应该忽略并转发这些未知类对象。这是为了确保最大的向后兼容性。
From a black-box perspective, admission control and policy functionality amounts to the decision whether to accept or reject a request and the determination of the DSCPs that should be used for the corresponding traffic. The specific details of admission control are beyond the scope of this document. In general the admission control decision is based both on resource availability and on policies regarding the use of resources in the diff-serv network. The admission control decision made by RSVP aware network elements represents both considerations.
从黑盒的角度来看，接纳控制和策略功能相当于决定是否接受或拒绝请求，以及确定应用于相应流量的DSCP。准入控制的具体细节超出了本文件的范围。通常，接纳控制决策基于资源可用性和关于区分服务网络中资源使用的策略。由RSVP感知的网络元件做出的接纳控制决策代表了这两个考虑。
In order to decide whether the RSVP request is admissible in terms of resource availability, one or more network elements within or at the boundary of the diff-serv network must understand the impact that admission would have on specific diff-serv resources, as well as the availability of these resources along the relevant data path in the diff-serv network.
为了确定RSVP请求在资源可用性方面是否可接受，diff-serv网络内或边界处的一个或多个网元必须理解接纳对特定diff-serv资源的影响，以及区分服务网络中相关数据路径上这些资源的可用性。
In order to decide whether the RSVP request is admissible in terms of policy, the network element may use identity objects describing users and/or applications that may be included in the request. The router may act as a PEP/PDP and use data from a policy database or directory to aid in this decision.
为了确定RSVP请求在策略方面是否可接受，网元可以使用描述可能包括在请求中的用户和/或应用的身份对象。路由器可以充当PEP/PDP，并使用来自策略数据库或目录的数据来帮助做出此决策。
See Appendix A for a simple mechanism for configurable resource based admission control.
有关可配置的基于资源的准入控制的简单机制，请参见附录A。
The DCLASS object conveys information that can be used to request enhanced QoS from a DS network, so inappropriate modification of the object could allow traffic flows to obtain a higher or lower level of QoS than appropriate. Particularly, modification of a DCLASS object by a third party inserted between the DS network ingress node and the upstream marker constitutes a possible denial of service attack. This attack is subtle because it is possible to reduce the received QoS to an unacceptably low level without completely cutting off data flow, making the attack harder to detect.
DCLASS对象传递的信息可用于从DS网络请求增强的QoS，因此对该对象的不适当修改可能会使业务流获得高于或低于适当水平的QoS。特别地，由插入DS网络入口节点和上游标记之间的第三方修改DCLASS对象构成可能的拒绝服务攻击。这种攻击很微妙，因为在不完全切断数据流的情况下，可以将接收到的QoS降低到不可接受的低水平，从而使攻击更难检测。
The possibility of raising the received level of QoS by inappropriate
通过不适当的方式提高QoS接收级别的可能性
modification of the DCLASS object is less significant because it a subclass of a larger class of attacks that must already be detected by the system. Protection must already be in place to prevent a host raising its received level of QoS by simply guessing "good" DSCP's and marking packets accordingly. If this protection is at the boundary of the DS network, it will detect inappropriate marking of arriving packets caused by modified DCLASS objects as well. If, however, the protection function as well as the marking function has been pushed upstream (perhaps to a trusted third party or intermediate node), correct transmission of the DCLASS object must be ensured to prevent a possible theft of service attack.
对DCLASS对象的修改不太重要，因为它是系统必须检测到的更大类攻击的子类。保护必须已经到位，以防止主机通过猜测“良好”DSCP并相应地标记数据包来提高其接收的QoS级别。如果此保护位于DS网络的边界，它也将检测由修改的DCLASS对象引起的到达数据包的不适当标记。但是，如果保护功能和标记功能已被推到上游（可能推到受信任的第三方或中间节点），则必须确保DCLASS对象的正确传输，以防止可能的服务盗窃攻击。
Simple observation of the DCLASS object in a RSVP message raises several issues which may be seen as security concerns. Correlation of observed DCLASS object values with RSVP requests or MF classification parameters allows the observer to determine that different flows are receiving different levels of QoS, which may be knowledge that should be protected in some environments. Similarly, observation of the DCLASS object can allow the observer to determine that a single flow's QoS has been promoted or demoted, which may signal significant events in the life of that flow's application or user. Finally, observation of the DCLASS object may reveal information about the internal operations of a DS network that could be useful to observers interested in theft-of-services attacks.
在RSVP消息中对DCLASS对象的简单观察会引发几个安全问题。观察到的DCLASS对象值与RSVP请求或MF分类参数的相关性允许观察者确定不同的流正在接收不同级别的QoS，这可能是某些环境中应该保护的知识。类似地，对DCLASS对象的观察可以允许观察者确定单个流的QoS已被提升或降级，这可能表示该流的应用程序或用户生命周期中的重大事件。最后，对DCLASS对象的观察可能会揭示有关DS网络内部操作的信息，这些信息可能对对服务盗窃攻击感兴趣的观察者有用。
[INTDIFF] Bernet, Y., Yavatkar, R., Ford, P., Baker, F., Zhang, L., Speer, M., Braden, R., Davie, B. and J. Wroclawski, "A Framework for Integrated Services Operation over Diffserv Networks", RFC 2998, November 2000.
[INTDIFF]Bernet，Y.，Yavatkar，R.，Ford，P.，Baker，F.，Zhang，L.，Speer，M.，Braden，R.，Davie，B.和J.Wroclawski，“区分服务网络上的综合服务运营框架”，RFC 29982000年11月。
[DS] Blake, S., Carlson, M., Davies, D., Wang, Z. and W. Weiss, "An Architecture for Differentiated Services", RFC 2475, December 1998.
[DS]Blake，S.，Carlson，M.，Davies，D.，Wang，Z.和W.Weiss，“差异化服务架构”，RFC 24751998年12月。
[RSVP] Braden, R., Zhang, L., Berson, S., Herzog, S. and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997.
[RSVP]Braden，R.，Zhang，L.，Berson，S.，Herzog，S.和S.Jamin，“资源预留协议（RSVP）——第1版功能规范”，RFC 22052997年9月。
[RAP] Yavatkar, R., Pendarakis, D. and R. Guerin, "A Framework for Policy Based Admission Control", RFC 2753, January 2000.
[RAP]Yavatkar，R.，Pendarakis，D.和R.Guerin，“基于政策的准入控制框架”，RFC 2753，2000年1月。
[AF] Heinanen, J., Baker, F., Weiss, W. and J. Wroclawski, "Assured Forwarding PHB Group", RFC 2597, June 1999.
[AF]Heinanen，J.，Baker，F.，Weiss，W.和J.Wroclawski，“保证货运PHB集团”，RFC 25971999年6月。
Thanks to Fred Baker and Carol Iturralde for reviewing this document. Thanks to Ramesh Pabbati, Tim Moore, Bruce Davie and Kam Lee for input.
感谢弗雷德·贝克和卡罗尔·伊图拉尔德审阅本文件。感谢Ramesh Pabbati、Tim Moore、Bruce Davie和Kam Lee的投入。
Yoram Bernet Microsoft One Microsoft Way, Redmond, WA 98052
Yoram Bernet Microsoft One Microsoft Way，华盛顿州雷德蒙，邮编：98052
Phone: (425) 936-9568 EMail: yoramb@microsoft.com
电话：（425）936-9568电子邮件：yoramb@microsoft.com
Appendix A - Simple Configurable Resource Based Admission Control
附录A-基于资源的简单可配置准入控制
Routers may use quite sophisticated mechanisms in making the admission control decision, including policy considerations, various intra-domain signaling protocols, results of traffic monitoring and so on. It is recommended that the following basic functionality be provided to enable simple resource based admission control in the absence of more sophisticated mechanisms. This functionality can be used with configurable, standalone routers. It applies to standard RSVP/Intserv requests. This minimal functionality assumes only a single DSCP is included in the DCLASS object, but may readily be extended to support multiple DSCPs.
路由器可以使用相当复杂的机制来做出接纳控制决策，包括策略考虑、各种域内信令协议、流量监控结果等。建议提供以下基本功能，以便在没有更复杂机制的情况下实现简单的基于资源的准入控制。此功能可用于可配置的独立路由器。它适用于标准RSVP/Intserv请求。此最小功能假定DCLASS对象中只包含一个DSCP，但可以很容易地扩展以支持多个DSCP。
It must be possible to configure two tables in the router. These are described below.
必须能够在路由器中配置两个表。下文对这些问题进行了说明。
One table provides a mapping from the intserv service-type specified in the RSVP request to a DSCP that can be used to obtain a corresponding service in the diff-serv network. This table contains a row for each intserv service type for which a mapping is available. Each row has the following format:
一个表提供了从RSVP请求中指定的intserv服务类型到DSCP的映射，DSCP可用于在diff serv网络中获得相应的服务。此表包含映射可用的每个intserv服务类型的一行。每行的格式如下：
Intserv service type : DSCP
Intserv服务类型：DSCP
The table would typically contain at least three rows; one for Guaranteed service, one for Controlled Load service and one for Best-Effort service. (The best-effort service will typically map to DSCP 000000, but may be overridden). It should be possible to add rows for as-yet-undefined service types.
该表通常至少包含三行；一个用于保证服务，一个用于控制负载服务，一个用于尽力而为服务。（尽力服务通常会映射到DSCP 000000，但可能会被覆盖）。应该可以为尚未定义的服务类型添加行。
This table allows the network administrator to statically configure a DSCP that the router will return in the DCLASS object for an admitted RSVP request. In general, more sophisticated and likely more dynamic mechanisms may be used to determine the DSCP to be returned in the DCLASS object. Also, it is likely that a real mapping for some services would use more than one DSCP, with the DSCP depending on the invocation parameters of a specific service request. In this case, these mechanisms may override or replace the static table based mapping described here.
此表允许网络管理员静态配置一个DSCP，路由器将在DCLASS对象中返回该DSCP，以供允许的RSVP请求。通常，可以使用更复杂且可能更动态的机制来确定要在DCLASS对象中返回的DSCP。此外，某些服务的实际映射可能会使用多个DSCP，DSCP取决于特定服务请求的调用参数。在这种情况下，这些机制可以覆盖或替换此处描述的基于表的静态映射。
Standard intserv requests are quantitative in nature. They include token bucket parameters describing the resources required by the traffic for which admission is requested. The second table enables the network administrator to statically configure quantitative
标准intserv请求本质上是定量的。它们包括令牌桶参数，用于描述请求准入的流量所需的资源。第二个表使网络管理员能够静态配置定量数据
parameters to be used by the router when making an admission control decision for quantitative service requests. Each row in this table has the following form:
路由器在为定量服务请求做出接纳控制决策时使用的参数。此表中的每一行具有以下形式：
DSCP : Token bucket profile
DSCP：令牌桶配置文件
The first column specifies those DSCPs for which quantitative admission control is applied. The second column specifies the token bucket parameters which represent the total resources available in the diff-serv network to accommodate traffic in the service class specified by the DSCP.
第一列指定应用定量准入控制的DSCP。第二列指定令牌桶参数，这些参数表示diff-serv网络中可用于容纳DSCP指定的服务类别中的流量的总资源。
Full Copyright Statement
完整版权声明
Copyright (C) The Internet Society (2000). All Rights Reserved.
版权所有（C）互联网协会（2000年）。版权所有。
This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.
本文件及其译本可复制并提供给他人，对其进行评论或解释或协助其实施的衍生作品可全部或部分编制、复制、出版和分发，不受任何限制，前提是上述版权声明和本段包含在所有此类副本和衍生作品中。但是，不得以任何方式修改本文件本身，例如删除版权通知或对互联网协会或其他互联网组织的引用，除非出于制定互联网标准的需要，在这种情况下，必须遵循互联网标准过程中定义的版权程序，或根据需要将其翻译成英语以外的其他语言。
The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.
上述授予的有限许可是永久性的，互联网协会或其继承人或受让人不会撤销。
This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
本文件和其中包含的信息是按“原样”提供的，互联网协会和互联网工程任务组否认所有明示或暗示的保证，包括但不限于任何保证，即使用本文中的信息不会侵犯任何权利，或对适销性或特定用途适用性的任何默示保证。
Acknowledgement
确认
Funding for the RFC Editor function is currently provided by the Internet Society.
RFC编辑功能的资金目前由互联网协会提供。