Internet Engineering Task Force (IETF) K. Leung, Ed.
Request for Comments: 7337 Cisco
Category: Informational Y. Lee, Ed.
ISSN: 2070-1721 Comcast
August 2014
Internet Engineering Task Force (IETF) K. Leung, Ed.
Request for Comments: 7337 Cisco
Category: Informational Y. Lee, Ed.
ISSN: 2070-1721 Comcast
August 2014
Content Distribution Network Interconnection (CDNI) Requirements
内容分发网络互连（CDNI）要求
Abstract
摘要
Content delivery is frequently provided by specifically architected and provisioned Content Delivery Networks (CDNs). As a result of significant growth in content delivered over IP networks, existing CDN providers are scaling up their infrastructure. Many Network Service Providers (NSPs) and Enterprise Service Providers (ESPs) are also deploying their own CDNs. To deliver contents from the Content Service Provider (CSP) to end users, the contents may traverse across multiple CDNs. This creates a need for interconnecting (previously) standalone CDNs so that they can collectively act as a single delivery platform from the CSP to the end users.
内容交付通常由专门设计和配置的内容交付网络（CDN）提供。由于通过IP网络交付的内容显著增长，现有CDN提供商正在扩展其基础设施。许多网络服务提供商（NSP）和企业服务提供商（ESP）也在部署自己的CDN。要将内容从内容服务提供商（CSP）交付给最终用户，内容可以跨多个CDN。这就需要互连（以前）独立的CDN，以便它们可以共同充当从CSP到最终用户的单一交付平台。
The goal of the present document is to outline the requirements for the solution and interfaces to be specified by the CDNI working group.
本文件的目标是概述CDNI工作组指定的解决方案和接口的要求。
Status of This Memo
关于下段备忘
This document is not an Internet Standards Track specification; it is published for informational purposes.
本文件不是互联网标准跟踪规范；它是为了提供信息而发布的。
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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
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。并非IESG批准的所有文件都适用于任何级别的互联网标准；见RFC 5741第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7337.
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http://www.rfc-editor.org/info/rfc7337.
Copyright Notice
版权公告
Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2014 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 (http://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(http://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
1.1. Terminology ................................................3
2. CDNI Model and CDNI Interfaces ..................................4
3. Generic CDNI Requirements .......................................6
4. CDNI Control Interface Requirements .............................7
5. CDNI Request Routing Redirection Interface Requirements ........10
6. CDNI Footprint & Capabilities Advertisement Interface
Requirements ...................................................12
7. CDNI Metadata Interface Requirements ...........................14
8. CDNI Logging Interface Requirements ............................18
9. CDNI Security Requirements .....................................20
10. Security Considerations .......................................21
11. Contributors ..................................................21
12. Acknowledgements ..............................................21
13. References ....................................................22
13.1. Normative References .....................................22
13.2. Informative References ...................................22
1. Introduction ....................................................2
1.1. Terminology ................................................3
2. CDNI Model and CDNI Interfaces ..................................4
3. Generic CDNI Requirements .......................................6
4. CDNI Control Interface Requirements .............................7
5. CDNI Request Routing Redirection Interface Requirements ........10
6. CDNI Footprint & Capabilities Advertisement Interface
Requirements ...................................................12
7. CDNI Metadata Interface Requirements ...........................14
8. CDNI Logging Interface Requirements ............................18
9. CDNI Security Requirements .....................................20
10. Security Considerations .......................................21
11. Contributors ..................................................21
12. Acknowledgements ..............................................21
13. References ....................................................22
13.1. Normative References .....................................22
13.2. Informative References ...................................22
The volume of video and multimedia content delivered over the Internet is rapidly increasing and expected to continue doing so in the future. In the face of this growth, Content Delivery Networks (CDNs) provide numerous benefits: reduced delivery cost for cacheable content, improved quality of experience for end users, and increased robustness of delivery. For these reasons, CDNs are frequently used for large-scale content delivery. As a result of the significant growth in content delivered over IP networks, existing CDN providers are scaling up their infrastructure and many NSPs and ESPs are deploying their own CDNs. Subject to the policy of the Content Service Provider (CSP), it is generally desirable that a given item
通过互联网传送的视频和多媒体内容的数量正在迅速增加，预计今后还会继续增加。面对这种增长，内容交付网络（CDN）提供了许多好处：降低了可缓存内容的交付成本，提高了最终用户的体验质量，增强了交付的健壮性。由于这些原因，CDN经常用于大规模内容交付。由于通过IP网络交付的内容显著增长，现有CDN提供商正在扩展其基础设施，许多NSP和ESP正在部署自己的CDN。根据内容服务提供商（CSP）的政策，通常希望给定项目
of content can be delivered to an end user regardless of that end user's location or attachment network. This creates a need for interconnecting (previously) standalone CDNs so they can interoperate and collectively behave as a single delivery infrastructure. The Content Distribution Network Interconnection (CDNI) working group has been chartered to develop an interoperable and scalable solution for such CDN interconnections.
无论最终用户的位置或附件网络如何，都可以向该最终用户交付大量内容。这就需要互连（以前）独立的CDN，以便它们可以互操作，并作为一个单一的交付基础设施共同工作。内容分发网络互连（CDNI）工作组已获得特许，为此类CDN互连开发可互操作和可扩展的解决方案。
The CDNI Problem Statement [RFC6707] outlines the problem area that the CDNI working group is chartered to address. The Use Cases for CDNI document [RFC6770] discusses the use cases for CDN Interconnection. The Framework for CDN Interconnection [RFC7336] discusses the technology framework for the CDNI solution and interfaces.
CDNI问题声明[RFC6707]概述了CDNI工作组特许解决的问题领域。CDNI的用例文档[RFC6770]讨论了CDN互连的用例。CDN互连框架[RFC7336]讨论了CDNI解决方案和接口的技术框架。
The goal of the present document is to document the requirements for the CDNI solution and interfaces. In order to meet the time lines defined in the working group charter, the present document categorizes the CDNI requirements as "High Priority", "Medium Priority", and "Low Priority".
本文件的目标是记录CDNI解决方案和接口的要求。为了满足工作组章程规定的时限，本文件将CDNI要求分类为“高优先级”、“中优先级”和“低优先级”。
This document uses the terminology defined in [RFC6707]. In addition, the key words "High Priority", "Medium Priority", and "Low Priority" in this document are to be interpreted as follows:
本文件使用[RFC6707]中定义的术语。此外，本文件中的关键词“高优先级”、“中优先级”和“低优先级”的解释如下：
o "High Priority": When a requirement is tagged as "{HIGH}", it is considered by the working group as an essential function for CDNI and necessary to a deployable solution. This requirement has to be met even if it causes a delay in the delivery by the working group of a deployable solution.
o “高优先级”：当一项需求被标记为“{High}”时，工作组将其视为CDNI的一项基本功能，是可部署解决方案所必需的。即使这导致工作组延迟交付可部署解决方案，也必须满足这一要求。
o "Medium Priority": When a requirement is tagged as "{MED}", it is considered by the working group as an important function for CDNI. This requirement has to be met, unless it is established that attempting to meet this requirement would cause a delay in the delivery by the working group of a deployable solution.
o “中等优先权”：当一项要求被标记为“{MED}”时，工作组将其视为CDNI的一项重要职能。必须满足这一要求，除非确定试图满足这一要求会导致工作组延迟交付可部署解决方案。
o "Low Priority": When a requirement is tagged as "{LOW}", it is considered by the working group as a useful function for CDNI. The working group will attempt to meet this requirement as long as it does not prevent meeting the "High Priority" and "Medium Priority" requirements and does not cause a delay in the delivery by the working group of a deployable solution.
o “低优先级”：当一项需求被标记为“{Low}”时，工作组将其视为CDNI的一项有用功能。只要不妨碍满足“高优先级”和“中优先级”要求，并且不会导致工作组延迟交付可部署解决方案，工作组将尝试满足这一要求。
The "CDNI Expanded Model and CDNI Interfaces" figure and brief descriptions of the CDNI interfaces in [RFC7336] are replicated below for convenience. That document contains the definitive reference model and descriptions for the CDNI interfaces.
为了方便起见，下面复制了[RFC7336]中的“CDNI扩展模型和CDNI接口”图以及CDNI接口的简要说明。该文件包含CDNI接口的最终参考模型和说明。
o CDNI Control interface (CI): Operations to bootstrap and parameterize the other CDNI interfaces, as well as operations to pre-position, revalidate, and purge both metadata and content. The latter subset of operations is sometimes collectively called the "Trigger interface."
o CDNI控制接口（CI）：引导和参数化其他CDNI接口的操作，以及预定位、重新验证和清除元数据和内容的操作。后一个操作子集有时统称为“触发器接口”
o CDNI Request Routing interface: Operations to determine what CDN (and optionally what Surrogate within a CDN) is to serve an end user's requests. This interface is actually a logical bundling of two separate but related interfaces:
o CDNI请求路由接口：用于确定哪一个CDN（以及可选的CDN中的哪一个代理）将为最终用户的请求提供服务的操作。该接口实际上是两个独立但相关的接口的逻辑捆绑：
* CDNI Footprint & Capabilities Advertisement interface (FCI): Asynchronous operations (as defined in [RFC7336]) to exchange routing information (e.g., the network footprint and capabilities served by a given CDN) that enables CDN selection for subsequent user requests; and
* CDNI示意图和功能广告接口（FCI）：异步操作（定义见[RFC7336]），用于交换路由信息（例如，网络示意图和给定CDN提供的功能），从而为后续用户请求选择CDN；和
* CDNI Request Routing Redirection interface (RI): Synchronous operations (as defined in [RFC7336]) to select a delivery CDN (Surrogate) for a given user request.
* CDNI请求路由重定向接口（RI）：为给定用户请求选择交付CDN（代理）的同步操作（定义见[RFC7336]）。
o CDNI Metadata interface (MI): Operations to communicate metadata that governs how the content is delivered by interconnected CDNs. Examples of CDNI Metadata include geo-blocking directives, availability windows, access control mechanisms, and purge directives. It may include a combination of:
o CDNI元数据接口（MI）：用于传递元数据的操作，该元数据控制互连CDN交付内容的方式。CDNI元数据的示例包括地理阻止指令、可用性窗口、访问控制机制和清除指令。它可以包括以下组合：
* Asynchronous operations to exchange metadata that govern subsequent user requests for content; and
* 用于交换元数据的异步操作，这些元数据控制后续用户对内容的请求；和
* Synchronous operations that govern behavior for a given user request for content.
* 控制给定用户内容请求行为的同步操作。
o CDNI Logging interface (LI): Operations that allow interconnected CDNs to exchange relevant activity logs. It may include a combination of:
o CDNI日志接口（LI）：允许互连CDN交换相关活动日志的操作。它可以包括以下组合：
* Real-time exchanges, suitable for runtime traffic monitoring; and
* 实时交换，适用于运行时流量监控；和
* Offline exchanges, suitable for analytics and billing.
* 离线交换，适用于分析和计费。
--------
/ \
| CSP |
\ /
--------
*
*
* /\
* / \
---------------------- |CDNI| ----------------------
/ Upstream CDN \ | | / Downstream CDN \
| +-------------+ | | CI | | +-------------+ |
|******* Control |<======|====|=======>| Control *******|
|* +------*----*-+ | | | | +-*----*------+ *|
|* * * | | | | * * *|
|* +------*------+ | | LI | | +------*------+ *|
|* ***** Logging |<======|====|=======>| Logging ***** *|
|* * +-*-----------+ | | | | +-----------*-+ * *|
|* * * * | | | | * * * *|
.....*...+-*---------*-+ | | RI | | +-*---------*-+...*.*...
. |* * | |<======|====|=======>| | * *| .
. |* * | Req-Routing | | |FCI | | | Req-Routing | * *| .
. |* * *** |<======|====|=======>| |** * *| .
. |* * * +-------------+.| | | | +-------------+ * * *| .
. |* * * . | | | * * *| .
. |* * * +-------------+ |. | MI | | +-------------+ * * *| .
. |* * * | Distribution|<==.===|====|=======>| Distribution| * * *| .
. |* * * | | | . \ / | | | * * *| .
. |* * * |+---------+ | | . \/ | | +---------+| * * *| .
. |* * ***| +---------+| | ...Request......+---------+ |*** * *| .
. |* *****+-|Surrogate|***********************|Surrogate|-+***** *| .
. |******* +---------+| | Acquisition | |+----------+ *******| .
. | +-------------+ | | +-------*-----+ | .
. \ / \ * / .
. ---------------------- ---------*------------ .
. * .
. * Delivery .
. * .
. +--*---+ .
...............Request............................| User |..Request..
| Agent|
+------+
--------
/ \
| CSP |
\ /
--------
*
*
* /\
* / \
---------------------- |CDNI| ----------------------
/ Upstream CDN \ | | / Downstream CDN \
| +-------------+ | | CI | | +-------------+ |
|******* Control |<======|====|=======>| Control *******|
|* +------*----*-+ | | | | +-*----*------+ *|
|* * * | | | | * * *|
|* +------*------+ | | LI | | +------*------+ *|
|* ***** Logging |<======|====|=======>| Logging ***** *|
|* * +-*-----------+ | | | | +-----------*-+ * *|
|* * * * | | | | * * * *|
.....*...+-*---------*-+ | | RI | | +-*---------*-+...*.*...
. |* * | |<======|====|=======>| | * *| .
. |* * | Req-Routing | | |FCI | | | Req-Routing | * *| .
. |* * *** |<======|====|=======>| |** * *| .
. |* * * +-------------+.| | | | +-------------+ * * *| .
. |* * * . | | | * * *| .
. |* * * +-------------+ |. | MI | | +-------------+ * * *| .
. |* * * | Distribution|<==.===|====|=======>| Distribution| * * *| .
. |* * * | | | . \ / | | | * * *| .
. |* * * |+---------+ | | . \/ | | +---------+| * * *| .
. |* * ***| +---------+| | ...Request......+---------+ |*** * *| .
. |* *****+-|Surrogate|***********************|Surrogate|-+***** *| .
. |******* +---------+| | Acquisition | |+----------+ *******| .
. | +-------------+ | | +-------*-----+ | .
. \ / \ * / .
. ---------------------- ---------*------------ .
. * .
. * Delivery .
. * .
. +--*---+ .
...............Request............................| User |..Request..
| Agent|
+------+
<==> interfaces inside the scope of CDNI
<==> interfaces inside the scope of CDNI
**** and .... interfaces outside the scope of CDNI
**** and .... interfaces outside the scope of CDNI
Figure 1: CDNI Expanded Model and CDNI Interfaces
图1:CDNI扩展模型和CDNI接口
This section identifies generic requirements independent of the individual CDNI interfaces. Some of those are expected to affect multiple or all interfaces. Management is an important aspect of CDN operation. The fault and performance management is covered in CDNI Logging interface requirements. The other types of management are specific to the CDN provider and not needed for interoperability between CDN providers.
本节确定了独立于单个CDNI接口的通用需求。其中一些可能会影响多个或所有接口。管理是CDN运营的一个重要方面。故障和性能管理包含在CDNI日志记录接口要求中。其他类型的管理是特定于CDN提供商的，CDN提供商之间的互操作性不需要这些管理。
GEN-1 {MED} Wherever possible, the CDNI interfaces should reuse or leverage existing IETF protocols.
GEN-1{MED}只要可能，CDNI接口应该重用或利用现有的IETF协议。
GEN-2 {HIGH} The CDNI solution shall not require a change, or an upgrade, to the User Agent to benefit from content delivery through interconnected CDNs.
GEN-2{HIGH}CDNI解决方案不需要对用户代理进行更改或升级，以从通过互联CDN的内容交付中获益。
GEN-3 {HIGH} The CDNI solution shall not require a change, or an upgrade, to the Content Service Provider delivering content through a single CDN, to benefit from content delivery through interconnected CDNs.
GEN-3{HIGH}CDNI解决方案不需要对通过单个CDN交付内容的内容服务提供商进行更改或升级，以从通过互联CDN交付的内容中获益。
GEN-4 {HIGH} The CDNI solution shall not depend on intra-CDN information to be exposed to other CDNs for effective and efficient delivery of the content. Examples of intra-CDN information include Surrogate topology, Surrogate status, cached content, etc.
GEN-4{HIGH}CDNI溶液不得依赖于CDN内部信息暴露于其他CDN，以有效和高效地交付内容。CDN内信息的示例包括代理拓扑、代理状态、缓存内容等。
GEN-5 {HIGH} The CDNI solution shall support CDN interconnection when delivery to the User Agent is based on HTTP [RFC7230]. (Note that while delivery and acquisition "data plane" protocols are out of the CDNI solution scope, the CDNI solution "control plane" protocols are expected to participate in enabling, selecting or facilitating operations of such acquisition and delivery protocols. Hence, it is useful to state requirements on the CDNI solution in terms of specifying which acquisition and delivery protocols are to be supported).
GEN-5{HIGH}当交付给用户代理时，CDNI解决方案应支持CDN互连，基于HTTP[RFC7230]。（请注意，虽然交付和采集“数据平面”协议不在CDNI解决方案范围内，但CDNI解决方案“控制平面”协议预计将参与启用、选择或促进此类采集和交付协议的操作。因此，说明CDNI解决方案在指定支持哪些采集和交付协议方面的要求非常有用）。
GEN-6 {HIGH} The CDNI solution shall support acquisition across CDNs based on HTTP [RFC7230]. (The note above applies to this requirement, too.)
GEN-6{HIGH}CDNI解决方案应支持基于HTTP的CDN间的收购[RFC7230]。（上述注释也适用于此要求。）
GEN-7 {LOW} The CDNI solution may support delivery to the User Agent based on protocols other than HTTP.
GEN-7{LOW}CDNI解决方案可能支持基于HTTP以外的协议向用户代理交付。
GEN-8 {LOW} The CDNI solution may support acquisition across CDNs based on protocols other than HTTP.
GEN-8{LOW}CDNI解决方案可支持基于HTTP以外的协议跨CDN进行采集。
GEN-9 {MED} The CDNI solution should support cascaded CDN redirection (CDN1 redirects to CDN2 that redirects to CDN3) to an arbitrary number of levels beyond the first level.
GEN-9{MED}CDNI解决方案应支持级联CDN重定向（CDN1重定向到CDN2，再重定向到CDN3）到第一级之外的任意级别。
GEN-10 {MED} The CDNI solution should support an arbitrary topology of interconnected CDNs (i.e., the topology of interconnected CDNs cannot be restricted to a tree, ring, star, etc.).
GEN-10{MED}CDNI解决方案应支持互连CDN的任意拓扑（即，互连CDN的拓扑不能限制为树、环、星等）。
GEN-11 {HIGH} The CDNI solution shall prevent looping of any CDNI information exchange.
GEN-11{高}CDNI解决方案应防止任何CDNI信息交换的循环。
GEN-12 {HIGH} When making use of third-party reference, the CDNI solution shall consider the potential issues associated with the use of various format of third-party references (e.g., NAT or IPv4/IPv6 translation potentially breaking third-party references based on an IP addresses such as URI containing IPv4 or IPv6 address literals, split DNS situations potentially breaking third-party references based on DNS FQDNs) and wherever possible avoid, minimize or mitigate the associated risks based on the specifics of the environments where the reference is used (e.g., likely or unlikely presence of NAT in the path). In particular, this applies to situations where the CDNI solution needs to construct and convey uniform resource identifiers for directing/redirecting a content request, as well as to situations where the CDNI solution needs to pass on a third-party reference (e.g., identify the IP address of a User Agent) in order to allow another entity to make a more informed decision (e.g., make a more informed request routing decision by attempting to derive location information from the third-party reference).
当使用第三方引用时，CDNI解决方案应考虑与使用各种格式的第三方引用相关的潜在问题。（例如，NAT或IPv4/IPv6转换可能破坏基于IP地址的第三方引用，例如包含IPv4或IPv6地址文本的URI，拆分DNS情况可能破坏基于DNS FQDNs的第三方引用）并根据使用参考的环境的具体情况（例如，路径中可能存在或不可能存在NAT），尽可能避免、最小化或减轻相关风险。具体而言，这适用于CDNI解决方案需要构造和传递统一的资源标识符以指导/重定向内容请求的情况，以及CDNI解决方案需要传递第三方引用（例如，识别用户代理的IP地址）的情况以允许另一实体做出更明智的决策（例如，通过尝试从第三方参考中获取位置信息来做出更明智的请求路由决策）。
GEN-13 {HIGH} The CDNI solution shall support HTTP Adaptive Streaming content.
GEN-13{HIGH}CDNI解决方案应支持HTTP自适应流媒体内容。
The primary purpose of the CDNI Control interface (CI) is to initiate the interconnection across CDNs, bootstrap the other CDNI interfaces and trigger actions into the Downstream CDN by the Upstream CDN (such as delete object from caches or trigger pre-positioned content acquisition). The working group attempts to align requirements with the appropriate interface; however, solutions to these requirements may apply to a different interface or another interface in addition to the interface with which it is associated.
CDNI控制接口（CI）的主要目的是启动CDN之间的互连，引导其他CDNI接口，并通过上游CDN将操作触发到下游CDN中（例如从缓存中删除对象或触发预先定位的内容获取）。工作组试图使需求与适当的接口保持一致；但是，这些需求的解决方案可能适用于不同的接口或与其相关联的接口之外的其他接口。
CI-1 {HIGH} The CDNI Control interface shall allow the Upstream CDN to request that the Downstream CDN, including cascaded Downstream CDNs, delete an object or set of objects and/or its
CI-1{HIGH}CDNI控制接口应允许上游CDN请求下游CDN（包括级联下游CDN）删除一个或一组对象和/或其
CDNI Metadata from the CDN Surrogates and any storage. Only the object(s) and CDNI Metadata that pertain to the requesting Upstream CDN are allowed to be purged.
来自CDN代理和任何存储的CDNI元数据。仅允许清除与请求上游CDN相关的对象和CDNI元数据。
CI-2 {MED} The CDNI Control interface should allow for multiple content items identified by a Content Collection ID to be purged using a single Content Purge action.
CI-2{MED}CDNI控制接口应允许使用单个内容清除操作清除由内容集合ID标识的多个内容项。
CI-3 {MED} The CDNI Control interface should allow the Upstream CDN to request that the Downstream CDN, including cascaded Downstream CDNs, mark an object or set of objects and/or its CDNI Metadata as "stale" and revalidate them before they are delivered again.
CI-3{MED}CDNI控制接口应允许上游CDN请求下游CDN，包括级联下游CDN，将一个或一组对象和/或其CDNI元数据标记为“过时”，并在再次交付之前重新验证它们。
CI-4 {HIGH} The CDNI Control interface shall allow the Downstream CDN to report on the completion of these actions (by itself, and including cascaded Downstream CDNs), in a manner appropriate for the action (e.g., synchronously or asynchronously). The confirmation receipt should include a success or failure indication. The failure indication and the reason are included if the Downstream CDN cannot delete the content in its storage.
CI-4{HIGH}CDNI控制接口应允许下游CDN以适合该动作的方式（例如同步或异步）报告这些动作的完成情况（自身，包括级联下游CDN）。确认收据应包括成功或失败指示。如果下游CDN无法删除其存储器中的内容，则包括故障指示和原因。
CI-5 {MED} The CDNI Control interface should support initiation and control by the Upstream CDN of pre-positioned CDNI Metadata acquisition by the Downstream CDN.
CI-5{MED}CDNI控制接口应支持上游CDN发起和控制下游CDN预先定位的CDNI元数据获取。
CI-6 {MED} The CDNI Control interface should support initiation and control by the Upstream CDN of pre-positioned content acquisition by the Downstream CDN.
CI-6{MED}CDNI控制接口应支持上游CDN发起和控制下游CDN预先定位的内容获取。
CI-7 {LOW} The CDNI Control interface may allow a CDN to establish, update and terminate a CDN interconnection with another CDN whereby one CDN can act as a Downstream CDN for the other CDN (that acts as an Upstream CDN).
CI-7{LOW}CDNI控制接口可允许CDN建立、更新和终止与另一CDN的CDN互连，其中一个CDN可充当另一个CDN（充当上游CDN）的下游CDN。
CI-8 {LOW} The CDNI Control interface may allow control of the CDNI interfaces between any two CDNs independently for each direction (e.g., for the direction where CDN1 is the Upstream CDN and CDN2 is the Downstream CDN, and for the direction where CDN2 is the Upstream CDN and CDN1 is the Downstream CDN).
CI-8{LOW}CDNI控制接口可允许针对每个方向独立控制任意两个CDN之间的CDNI接口（例如，针对CDN1为上游CDN和CDN2为下游CDN的方向，以及针对CDN2为上游CDN和CDN1为下游CDN的方向）。
CI-9 {LOW} The CDNI Control interface may allow bootstrapping of the CDNI Request Routing interface. For example, this can potentially include:
CI-9{LOW}CDNI控制接口可能允许CDNI请求路由接口的引导。例如，这可能包括：
* negotiation of the request routing method (e.g., DNS versus HTTP, if more than one method is specified).
* 请求路由方法的协商（例如，如果指定了多个方法，则DNS与HTTP）。
* discovery of the CDNI Request Routing interface endpoints.
* 发现CDNI请求路由接口终结点。
* information necessary to establish secure communication between the CDNI Request Routing interface endpoints.
* 在CDNI请求路由接口端点之间建立安全通信所需的信息。
CI-10 {LOW} The CDNI Control interface may allow bootstrapping of the CDNI Metadata interface. This information could, for example, include:
CI-10{LOW}CDNI控制接口可允许CDNI元数据接口的引导。例如，这些信息可以包括：
* discovery of the CDNI Metadata interface endpoints
* 发现CDNI元数据接口端点
* information necessary to establish secure communication between the CDNI Metadata interface endpoints.
* 在CDNI元数据接口端点之间建立安全通信所需的信息。
CI-11 {LOW} The CDNI Control interface may allow bootstrapping of the Content Acquisition interface. This could, for example, include exchange and negotiation of the Content Acquisition methods to be used across the CDNs (e.g., HTTP, HTTPS, FTP, ATIS C2 [ATIS-0800042]).
CI-11{LOW}CDNI控制接口可允许内容获取接口的引导。例如，这可能包括交换和协商CDN中使用的内容获取方法（例如HTTP、HTTPS、FTP、ATIS C2[ATIS-0800042]）。
CI-12 {LOW} The CDNI Control interface may allow bootstrapping of the CDNI Logging interface. This information could, for example, include:
CI-12{LOW}CDNI控制接口可允许CDNI日志接口的引导。例如，这些信息可以包括：
* discovery of the CDNI Logging interface endpoints.
* 发现CDNI日志记录接口终结点。
* information necessary to establish secure communication between the CDNI Logging interface endpoints.
* 在CDNI日志接口端点之间建立安全通信所需的信息。
* negotiation/definition of the log file format and set of fields to be exported through the logging protocol, with some granularity (e.g., on a per-content-type basis).
* 通过日志协议导出的日志文件格式和字段集的协商/定义，具有一定的粒度（例如，基于每种内容类型）。
* negotiation/definition of parameters related to transaction logs export (e.g., export protocol, file compression, export frequency, directory).
* 与事务日志导出相关的参数协商/定义（例如导出协议、文件压缩、导出频率、目录）。
The main function of the CDNI Request Routing Redirection interface (RI) is to allow the Request Routing systems in interconnected CDNs to communicate to facilitate redirection of the request across CDNs.
CDNI请求路由重定向接口（RI）的主要功能是允许互连CDN中的请求路由系统进行通信，以促进跨CDN的请求重定向。
RI-1 {HIGH} The CDNI Request Routing Redirection interface shall support efficient request routing for small objects. This may, for example, call for a mode of operation (e.g., DNS-based request routing) where freshness and accuracy of CDN/ Surrogate selection can be traded off against reduced request routing load (e.g., Via lighter-weight queries and caching of request routing decisions).
RI-1{HIGH}CDNI请求路由重定向接口应支持小型对象的有效请求路由。例如，这可能需要一种操作模式（例如，基于DNS的请求路由），其中CDN/代理选择的新鲜度和准确性可以与减少的请求路由负载（例如，通过较轻的查询和缓存请求路由决定）进行权衡。
RI-2 {HIGH} The CDNI Request Routing Redirection interface shall support efficient request routing for large objects. This may, for example, call for a mode of operation (e.g., HTTP-based request routing) where freshness and accuracy of CDN/ Surrogate selection justifies a per-request decision and a per-request CDNI Request-Routing protocol call.
RI-2{HIGH}CDNI请求路由重定向接口应支持大型对象的高效请求路由。例如，这可能需要一种操作模式（例如，基于HTTP的请求路由），其中CDN/代理选择的新鲜度和准确性证明了每请求决策和每请求CDNI请求路由协议调用的合理性。
RI-3 {HIGH} The CDNI Request Routing Redirection interface shall support recursive CDNI request routing.
RI-3{HIGH}CDNI请求路由重定向接口应支持递归CDNI请求路由。
RI-4 {HIGH} The CDNI Request Routing Redirection interface shall support iterative CDNI request routing.
RI-4{HIGH}CDNI请求路由重定向接口应支持迭代CDNI请求路由。
RI-5 {MED} In case of detection of a request redirection loop, the CDNI Request Routing Redirection interface's loop prevention mechanism should allow redirection of the request on an alternate CDN path (as opposed to the request not being redirected at all).
RI-5{MED}在检测到请求重定向循环的情况下，CDNI请求路由重定向接口的循环防止机制应允许在备用CDN路径上重定向请求（而不是根本不重定向请求）。
RI-6 {MED} The CDNI Request Routing Redirection interface should support a mechanism allowing enforcement of a limit on the number of successive CDN redirections for a given request.
RI-6{MED}CDNI请求路由重定向接口应支持一种机制，允许对给定请求的连续CDN重定向次数实施限制。
RI-7 {LOW} The CDNI Request Routing Redirection interface may support a mechanism allowing an Upstream CDN to avoid redirecting a request to a Downstream CDN if that is likely to result in the total redirection time exceeding some limit.
RI-7{LOW}CDNI请求路由重定向接口可以支持一种机制，允许上游CDN避免将请求重定向到下游CDN，如果这可能导致总重定向时间超过某个限制。
RI-8 {HIGH} The CDNI Request Routing Redirection interface shall allow the Upstream CDN to include, in the query to the Downstream CDN, the necessary information to allow the Downstream CDN to process the redirection query. This could, for example, include:
RI-8{HIGH}CDNI请求路由重定向接口应允许上游CDN在对下游CDN的查询中包括必要的信息，以允许下游CDN处理重定向查询。例如，这可能包括：
* information from which the geographic region pertaining to the IP address of the User Agent that originated the request can be inferred (e.g., User Agent FQDN in case of HTTP-based request routing, DNS Proxy FQDN in case of DNS-based request routing).
* 可以从中推断与发起请求的用户代理的IP地址相关的地理区域的信息（例如，基于HTTP的请求路由的用户代理FQDN，基于DNS的请求路由的DNS代理FQDN）。
* requested resource information (e.g., Resource URI in case of HTTP-based request routing, Resource hostname in case of DNS-based request routing).
* 请求的资源信息（例如，基于HTTP的请求路由的资源URI，基于DNS的请求路由的资源主机名）。
* additional available request information (e.g., request headers in case of HTTP-based request routing).
* 其他可用的请求信息（例如，在基于HTTP的请求路由的情况下，请求头）。
RI-9 {LOW} The CDNI Request Routing Redirection interface may also allow the Upstream CDN to convey information pointing to CDNI Metadata applicable (individually or through inheritance) to the requested content. For illustration, the CDNI Metadata pointed to could potentially include metadata that is applicable to any content, metadata that is applicable to a content collection (to which the requested content belongs) and/or metadata that is applicable individually to the requested content.
RI-9{LOW}CDNI请求路由重定向接口还可以允许上游CDN传递指向适用于（单独地或通过继承）请求内容的CDNI元数据的信息。为了便于说明，所指的CDNI元数据可能包括适用于任何内容的元数据、适用于内容集合（请求的内容所属）的元数据和/或单独适用于请求的内容的元数据。
RI-10 {HIGH} The CDNI Request Routing Redirection interface shall allow the Downstream CDN to include the following information in the response to the Upstream CDN:
RI-10{HIGH}CDNI请求路由重定向接口应允许下游CDN在对上游CDN的响应中包括以下信息：
* status code, in particular indicating acceptance or rejection of request (e.g., because the Downstream CDN is unwilling or unable to serve the request). In case of rejection, an error code is also to be provided, which allows the Upstream CDN to react appropriately (e.g., select another Downstream CDN, or serve the request itself).
* 状态代码，特别是表示接受或拒绝请求（例如，因为下游CDN不愿意或无法服务请求）。在拒绝的情况下，还应提供错误代码，以允许上游CDN做出适当反应（例如，选择另一个下游CDN，或服务于请求本身）。
* redirection information (e.g., Resource URI in case of HTTP-based request routing, equivalent of a DNS record in case of DNS-based request routing).
* 重定向信息（例如，在基于HTTP的请求路由的情况下，资源URI，在基于DNS的请求路由的情况下，相当于DNS记录）。
RI-11 {HIGH} The CDNI Request Routing Redirection interface shall allow for per-chunk request routing of HTTP Adaptive Streaming content.
RI-11{HIGH}CDNI请求路由重定向接口应允许HTTP自适应流媒体内容的每区块请求路由。
RI-12 {LOW} The CDNI Request Routing Redirection interface may allow the Upstream CDN to use the information conveyed by the Downstream CDN during the Recursive Request Routing process to rewrite an HTTP Adaptive Streaming manifest file.
RI-12{LOW}CDNI请求路由重定向接口可允许上游CDN在递归请求路由过程中使用下游CDN传送的信息来重写HTTP自适应流清单文件。
RI-13 {LOW} The CDNI Request Routing interface may allow the Upstream CDN to re-compute the message digest or digital signature over the invariant portion of the chunk URIs embedded in the HTTP Adaptive Streaming manifest file.
RI-13{LOW}CDNI请求路由接口可允许上游CDN在嵌入HTTP自适应流清单文件的区块uri的不变部分上重新计算消息摘要或数字签名。
RI-14 {MED} The CDNI Request Routing Redirection interface should correlate the HTTP Adaptive Stream manifest file to the related chunks referenced in the manifest file.
RI-14{MED}CDNI请求路由重定向接口应将HTTP自适应流清单文件与清单文件中引用的相关区块相关联。
RI-15 {MED} The CDNI Request Routing Redirection interface should allow for an efficient method of transferring request routing information for multiple chunks from the Downstream CDN to the Upstream CDN as part of the recursive request routing process.
RI-15{MED}CDNI请求路由重定向接口应允许一种有效的方法，将多个数据块的请求路由信息从下游CDN传输到上游CDN，作为递归请求路由过程的一部分。
The main function of the CDNI Footprint & Capabilities Advertisement interface (FCI) is to allow the Downstream CDN to advertise the information regarding its footprint and capabilities to the Upstream CDN.
CDNI Footprint&Capabilities Advertision interface（FCI）的主要功能是允许下游CDN向上游CDN发布有关其Footprint和Capabilities的信息。
FCI-1 {HIGH} The CDNI Footprint & Capabilities Advertisement interface shall allow the Downstream CDN to communicate to the Upstream CDN coarse information about the Downstream CDN ability and/or willingness to handle requests from the Upstream CDN. For example, this could potentially include a binary signal ("Downstream CDN ready/not-ready to take additional requests from Upstream CDN") to be used in case of excessive load or failure condition in the Downstream CDN.
FCI-1{HIGH}CDNI足迹和能力广告接口应允许下游CDN向上游CDN传达关于下游CDN能力和/或处理上游CDN请求意愿的粗略信息。例如，这可能包括二进制信号（“下游CDN准备好/不准备接受来自上游CDN的额外请求”），以便在下游CDN中出现过度负载或故障情况时使用。
FCI-2 {MED} The CDNI Footprint & Capabilities Advertisement interface should allow the Downstream CDN to communicate to the Upstream CDN aggregate information to facilitate CDN selection during request routing, such as Downstream CDN capabilities, resources and affinities (i.e., preferences or cost). This information could, for example, include:
FCI-2{MED}CDNI Footprint&Capabilities广告接口应允许下游CDN与上游CDN通信聚合信息，以便于在请求路由期间选择CDN，例如下游CDN功能、资源和亲缘关系（即偏好或成本）。例如，这些信息可以包括：
* supported content types and delivery protocols
* 支持的内容类型和交付协议
* footprint (e.g., Layer 3 coverage).
* 足迹（例如，第3层覆盖）。
* a set of metrics/attributes (e.g., streaming bandwidth, storage resources, distribution and delivery priority).
* 一组指标/属性（例如，流带宽、存储资源、分发和交付优先级）。
* a set of affinities (e.g., preferences, indication of distribution/delivery fees).
* 一组亲缘关系（例如，偏好、分销/交付费用指示）。
* information to facilitate request redirection (e.g., Reachability information of Downstream CDN Request Routing system).
* 有助于请求重定向的信息（例如，下游CDN请求路由系统的可达性信息）。
[Note: Some of this information -- such as supported content types and delivery protocols -- may also potentially be taken into account by the Distribution system in the Upstream CDN for pre-positioning of content and/or metadata in the Downstream CDN in case of pre-positioned content acquisition and/or pre-positioned CDNI Metadata acquisition.]
[注：在预先定位的内容获取和/或预先定位的CDNI元数据获取的情况下，上游CDN中的分发系统还可能考虑其中一些信息，例如支持的内容类型和交付协议，以便在下游CDN中预先定位内容和/或元数据。]
FCI-3 {MED} In the case of cascaded redirection, the CDNI Footprint & Capabilities Advertisement interface should allow the Downstream CDN to also include in the information communicated to the Upstream CDN, information on the capabilities, resources and affinities of CDNs to which the Downstream CDN may (in turn) redirect requests received by the Upstream CDN. In that case, the CDNI Request Routing interface shall prevent looping of such information exchange.
FCI-3{MED}在级联重定向的情况下，CDNI封装外形和功能广告接口应允许下游CDN也在与上游CDN通信的信息中包括关于下游CDN可能（反过来）连接的CDN的功能、资源和亲和力的信息重定向上游CDN接收的请求。在这种情况下，CDNI请求路由接口应防止此类信息交换的循环。
FCI-4 {LOW} The CDNI Footprint & Capabilities Advertisement interface may allow the Downstream CDN to communicate to the Upstream CDN aggregate information on CDNI administrative limits and policy. This information can be taken into account by the Upstream CDN Request Routing system in its CDN Selection decisions. This information could, for example, include:
FCI-4{LOW}CDNI足迹和能力广告接口可允许下游CDN与上游CDN通信有关CDNI管理限制和政策的聚合信息。上游CDN请求路由系统在其CDN选择决策中可以考虑该信息。例如，这些信息可以包括：
* maximum number of requests redirected by the Upstream CDN to be served simultaneously by the Downstream CDN.
* 由上游CDN重定向并由下游CDN同时服务的最大请求数。
* maximum aggregate volume of content (e.g., in Terabytes) to be delivered by the Downstream CDN over a time period.
* 下游CDN在一段时间内交付的最大内容总量（例如，以TB为单位）。
FCI-5 {MED} The CDNI Footprint & Capabilities Advertisement interface should support advertisement of the following types of capabilities:
FCI-5{MED}CDNI封装外形和功能广告界面应支持以下类型功能的广告：
* delivery protocol (e.g., HTTP versus Real Time Messaging Protocol [RTMP]).
* 交付协议（例如，HTTP与实时消息传递协议[RTMP]）。
* acquisition protocol (for acquiring content from an Upstream CDN).
* 获取协议（用于从上游CDN获取内容）。
* redirection mode (e.g., DNS Redirection versus HTTP Redirection).
* 重定向模式（例如，DNS重定向与HTTP重定向）。
* capabilities related to CDNI Logging (e.g., supported logging mechanisms).
* 与CDNI日志记录相关的功能（例如，受支持的日志记录机制）。
* capabilities related to CDNI Metadata (e.g., authorization algorithms or support for proprietary vendor metadata).
* 与CDNI元数据相关的功能（例如，授权算法或对专有供应商元数据的支持）。
FCI-6 {LOW} The CDNI Control interface may allow exchange and negotiation of delivery authorization mechanisms to be supported across the CDNs (e.g., URI-signature-based validation).
FCI-6{LOW}CDNI控制接口可允许交换和协商CDN中支持的交付授权机制（例如，基于URI签名的验证）。
FCI-7 {HIGH} The CDNI Footprint & Capabilities Advertisement interface shall support extensible fields used to convey the CDN capabilities and methods to indicate the footprint in the advertisement from the Downstream CDN to the Upstream CDN.
FCI-7{HIGH}CDNI封装外形和功能广告接口应支持用于传输CDN功能的可扩展字段，以及指示从下游CDN到上游CDN的广告封装外形的方法。
The primary function of the CDNI Metadata interface (MI) is to allow the Distribution system in interconnected CDNs to communicate to ensure Content Distribution Metadata with inter-CDN scope can be exchanged across CDNs. We observe that while the CDNI Metadata Distribution protocol is currently discussed as a single "protocol", further analysis will determine whether the corresponding requirements are to be realized over a single interface and protocol, or over multiple interfaces and protocols. For example, a subset of the CDNI Metadata might be conveyed in-band along with the actual content acquisition across CDNs (e.g. content MD5 in HTTP header) while another subset might require an out-of-band interface and protocol (e.g., geo-blocking information).
CDNI元数据接口（MI）的主要功能是允许互连CDN中的分发系统进行通信，以确保CDN范围内的内容分发元数据可以在CDN之间交换。我们注意到，虽然CDNI元数据分发协议目前被作为单个“协议”进行讨论，但进一步的分析将确定是通过单个接口和协议实现相应的需求，还是通过多个接口和协议实现相应的需求。例如，CDNI元数据的一个子集可能在带内传输，同时跨CDN进行实际内容获取（例如HTTP报头中的内容MD5），而另一个子集可能需要带外接口和协议（例如地理块信息）。
MI-1 {HIGH} The CDNI Metadata interface shall allow the Upstream CDN to provide the Downstream CDN with content distribution metadata of inter-CDN scope.
MI-1{HIGH}CDNI元数据接口应允许上游CDN向下游CDN提供CDN范围内的内容分发元数据。
MI-2 {HIGH} The CDNI Metadata interface shall support exchange of CDNI Metadata for both the dynamic content acquisition model and the pre-positioning content acquisition model.
MI-2{HIGH}CDNI元数据接口应支持动态内容获取模型和预定位内容获取模型的CDNI元数据交换。
MI-3 {HIGH} The CDNI Metadata interface shall support a mode where no, or a subset of, the CDNI Metadata is initially communicated to the Downstream CDN along with information about how/where to acquire the rest of the CDNI Metadata (i.e., Dynamic CDNI Metadata acquisition).
MI-3{HIGH}CDNI元数据接口应支持这样一种模式，即不向下游CDN传送CDNI元数据或其子集，以及关于如何/在何处获取其余CDNI元数据的信息（即，动态CDNI元数据获取）。
MI-4 {MED} The CDNI Metadata interface should support a mode where all the relevant CDNI Metadata is initially communicated to the Downstream CDN (i.e., pre-positioned CDNI Metadata acquisition).
MI-4{MED}CDNI元数据接口应支持一种模式，即所有相关的CDNI元数据最初被传送到下游CDN（即，预先定位的CDNI元数据获取）。
MI-5 {HIGH} Whether in the pre-positioned content acquisition model or in the dynamic content acquisition model, the CDNI Metadata interface shall provide the necessary information to allow the Downstream CDN to acquire the content from an upstream source (e.g., acquisition protocol and Uniform Resource Identifier in Upstream CDN -- or rules to construct this URI).
MI-5{HIGH}无论是在预先定位的内容获取模型中还是在动态内容获取模型中，CDNI元数据接口都应提供必要的信息，以允许下游CDN从上游来源获取内容（例如，上游CDN中的采集协议和统一资源标识符——或构造此URI的规则）。
MI-6 {HIGH} The CDNI Metadata shall allow signaling of one or more upstream sources, where each upstream source can be in the Upstream CDN, in another CDN, the CSP origin server or any arbitrary source designated by the Upstream CDN. Note that some upstream sources (e.g., the content origin server) may or may not be willing to serve the content to the Downstream CDN; if this policy is known to the Upstream CDN, then it may omit those sources when exchanging CDNI Metadata.
MI-6{HIGH}CDNI元数据应允许一个或多个上游源的信令，其中每个上游源可以位于上游CDN、另一个CDN、CSP源服务器或上游CDN指定的任何任意源中。注意，一些上游源（例如，内容源服务器）可能愿意也可能不愿意将内容服务于下游CDN；如果上游CDN知道此策略，则在交换CDNI元数据时可能会忽略这些源。
MI-7 {HIGH} The CDNI Metadata interface (possibly in conjunction with the CDNI Control interface) shall allow the Upstream CDN to request addition and modification of CDNI Metadata into the Downstream CDN.
MI-7{HIGH}CDNI元数据接口（可能与CDNI控制接口结合使用）应允许上游CDN请求向下游CDN添加和修改CDNI元数据。
MI-8 {HIGH} The CDNI Metadata interface (possibly in conjunction with the CDNI Control interface) shall allow removal of obsolete CDNI Metadata from the Downstream CDN (this could, for example, be achieved via an explicit removal request from the Upstream CDN or via expiration of a Time-To-Live (TTL) associated with the CDNI Metadata).
MI-8{HIGH}CDNI元数据接口（可能与CDNI控制接口一起）应允许从下游CDN中删除过时的CDNI元数据（例如，可以通过上游CDN的明确删除请求或与CDNI元数据相关的生存时间（TTL）到期来实现）。
MI-9 {HIGH} The CDNI Metadata interface shall allow association of CDNI Metadata at the granularity of individual object. This is necessary to achieve fine-grain CDNI Metadata distribution at the level of an individual object when necessary.
MI-9{HIGH}CDNI元数据接口应允许在单个对象的粒度上关联CDNI元数据。必要时，这对于在单个对象级别实现细粒度CDNI元数据分发是必要的。
MI-10 {HIGH} The CDNI Metadata interface shall allow association of CDNI Metadata at the granularity of an object set. This is necessary to achieve scalable distribution of metadata when a large number of objects share the same distribution policy.
MI-10{HIGH}CDNI元数据接口应允许在对象集的粒度上关联CDNI元数据。当大量对象共享相同的分发策略时，这对于实现元数据的可伸缩分发是必要的。
MI-11 {HIGH} The CDNI Metadata interface shall support multiple levels of inheritance with precedence to more specific metadata. For example, the CDNI Metadata Distribution protocol may support metadata that is applicable to any content, metadata that is applicable to a content collection
MI-11{HIGH}CDNI元数据接口应支持多级继承，优先于更具体的元数据。例如，CDNI元数据分发协议可以支持适用于任何内容的元数据、适用于内容集合的元数据
and metadata that is applicable to an individual content where content level metadata overrides content collection metadata that overrides metadata for any content.
以及适用于单个内容的元数据，其中内容级元数据覆盖覆盖任何内容的元数据的内容集合元数据。
MI-12 {HIGH} The CDNI Metadata interface shall ensure that conflicting metadata with overlapping scope are prevented or deterministically handled.
MI-12{HIGH}CDNI元数据接口应确保防止或决定性地处理范围重叠的冲突元数据。
MI-13 {HIGH} The CDNI Metadata interface shall allow signaling of content distribution control policies. For example, this could potentially include:
MI-13{HIGH}CDNI元数据接口应允许发送内容分发控制策略的信号。例如，这可能包括：
* geo-blocking information (i.e., information defining geographical areas where the content is to be made available or blocked).
* 地理阻止信息（即定义内容可用或阻止的地理区域的信息）。
* availability windows (i.e., information defining time windows during which the content is to be made available or blocked; expiration time may also be included to remove content).
* 可用性窗口（即，定义内容可用或阻止的时间窗口的信息；还可以包括过期时间以删除内容）。
* delegation whitelist/blacklist (i.e., information defining through which Downstream CDNs the content may/may not be delivered)
* 委托白名单/黑名单（即定义内容可以/不可以通过哪些下游CDN交付的信息）
MI-14 {HIGH} The CDNI Metadata interface shall be able to exchange a set of metadata elements with specified semantics (e.g., start of time window, end of time window).
MI-14{HIGH}CDNI元数据接口应能够交换一组具有指定语义的元数据元素（例如，时间窗口开始、时间窗口结束）。
MI-15 {HIGH} The CDNI Metadata interface shall allow exchange of opaque metadata element, whose semantic is not defined in CDNI but established by private CDN agreement.
MI-15{HIGH}CDNI元数据接口应允许交换不透明元数据元素，其语义未在CDNI中定义，但由私有CDN协议建立。
MI-16 {HIGH} The CDNI Metadata interface shall allow signaling of authorization checks and validation that are to be performed by the Surrogate before delivery. For example, this could potentially include the need to validate information (e.g., Expiry time, Client IP address) required for access authorization.
MI-16{HIGH}CDNI元数据接口应允许在交付前由代理执行授权检查和验证的信号。例如，这可能包括需要验证访问授权所需的信息（例如，到期时间、客户端IP地址）。
MI-17 {MED} The CDNI Metadata interface should allow signaling of CDNI-relevant Surrogate cache behavior parameters. For example, this could potentially include:
MI-17{MED}CDNI元数据接口应允许发送CDNI相关代理缓存行为参数的信号。例如，这可能包括：
* control of whether the query string of HTTP URI is to be ignored by Surrogate cache.
* 控制代理缓存是否忽略HTTP URI的查询字符串。
* enforcement of caching directives by Downstream CDN that are different than the ones signaled in the HTTP headers (e.g., "Expires" field).
* 下游CDN强制执行缓存指令，这些指令不同于HTTP头中发出的指令（例如，“Expires”字段）。
* rate-pacing by Downstream CDN for content delivery (e.g., Progressive Download).
* 通过下游CDN为内容交付（例如，渐进式下载）进行速率调整。
MI-18 {HIGH} The CDNI Metadata interface shall provide indication of related content (e.g., HTTP Adaptive Bit Rate chunks) by the Content Collection ID (CCID) metadata. This could be used by the Downstream CDN for operations on the group of content. For example, this could potentially include:
MI-18{HIGH}CDNI元数据接口应通过内容收集ID（CCID）元数据提供相关内容（例如HTTP自适应比特率块）的指示。这可由下游CDN用于内容组上的操作。例如，这可能包括：
* content acquisition for the entire set of files when one piece of content is requested.
* 当请求一段内容时，获取整个文件集的内容。
* local file management and storage bundles all the files for the content.
* 本地文件管理和存储捆绑了内容的所有文件。
* purging the entire set of files associated with the content.
* 清除与内容关联的整个文件集。
* logging of the delivery of the content for the session when at least one file in the set was delivered.
* 当集合中至少有一个文件已传递时，记录会话内容的传递。
MI-19 {MED} The CDNI Metadata interface should support an optional mechanism allowing the Upstream CDN to indicate to the Downstream CDN which CDNI Log fields are to be provided for all content items, for specific sets of content items, or for specific content items delivered using HTTP. A CDNI implementation that does not support this optional CDNI Metadata Distribution interface mechanism shall ignore this log format indication and generate CDNI Logging format for HTTP Adaptive Streaming using the default set of CDNI Logging fields. (Note: This function may be part of the CDNI Metadata interface or the CDNI Control interface.)
MI-19{MED}CDNI元数据接口应支持一种可选机制，允许上游CDN向下游CDN指示为所有内容项、特定内容项集或使用HTTP交付的特定内容项提供哪些CDNI日志字段。不支持此可选CDNI元数据分发接口机制的CDNI实现应忽略此日志格式指示，并使用默认的CDNI日志字段集为HTTP自适应流生成CDNI日志格式。（注意：此功能可能是CDNI元数据接口或CDNI控制接口的一部分。）
MI-20 {MED} The CDNI Metadata interface should allow the Upstream CDN to signal to the Downstream CDN the Content Collection ID value for all, for specific sets of, or for specific content items delivered using HTTP. Whenever the Downstream CDN is instructed by the Upstream CDN to report the Content Collection ID field in the log records, the Downstream CDN is to use the value provided through the CDNI Metadata interface for the corresponding content. Note the Session ID field along with Content Collection ID may be used for HTTP Adaptive Streaming content.
MI-20{MED}CDNI元数据接口应允许上游CDN向下游CDN发送所有、特定集合或使用HTTP交付的特定内容项的内容集合ID值的信号。每当上游CDN指示下游CDN报告日志记录中的内容收集ID字段时，下游CDN将使用通过CDNI元数据接口为相应内容提供的值。注意：会话ID字段和内容集合ID可用于HTTP自适应流式传输内容。
MI-21 {MED} The CDNI Metadata interface should allow the Upstream CDN to signal to the Downstream CDN the Authorization Group ID value for all the related HTTP Adaptive Streaming content (i.e., manifest file and chunks). The authorization result of a content (e.g., manifest file) is transferred over to related content (e.g., chunks).
MI-21{MED}CDNI元数据接口应允许上游CDN向下游CDN发送所有相关HTTP自适应流内容（即清单文件和区块）的授权组ID值的信号。内容（如清单文件）的授权结果被传输到相关内容（如区块）。
MI-22 {HIGH} The CDNI Metadata interface shall support extensible format for CDNI Metadata delivery from the Upstream CDN to the Downstream CDN.
MI-22{HIGH}CDNI元数据接口应支持从上游CDN向下游CDN交付CDNI元数据的可扩展格式。
This section identifies the requirements related to the CDNI Logging interface (LI). We observe that while the CDNI Logging interface is currently discussed as a single "protocol", further analysis will determine whether the corresponding requirements are to be realized over a single interface and protocol or over multiple interfaces and protocols.
本节确定了与CDNI日志记录接口（LI）相关的要求。我们注意到，虽然CDNI日志记录接口目前作为单个“协议”进行讨论，但进一步的分析将确定是通过单个接口和协议还是通过多个接口和协议实现相应的需求。
LI-1 {HIGH} The CDNI Logging interface and architecture shall ensure reliable transfer of CDNI logging information across CDNs.
LI-1{HIGH}CDNI记录接口和体系结构应确保CDNI记录信息在CDN之间的可靠传输。
LI-2 {HIGH} The CDNI Logging interface shall provide logging of deliveries and incomplete deliveries to User Agents performed by the Downstream CDN as a result of request redirection by the Upstream CDN.
LI-2{HIGH}由于上游CDN的请求重定向，CDNI日志接口应向下游CDN执行的用户代理提供交付和不完整交付的日志记录。
LI-3 {MED} In the case of cascaded CDNs, the CDNI Logging interface should allow the Downstream CDN to report to the Upstream CDN logging for deliveries and incomplete deliveries performed by the Downstream CDN itself as well as logging for deliveries and incomplete deliveries performed by cascaded CDNs on behalf of the Downstream CDN.
LI-3{MED}在级联CDN的情况下，CDNI日志接口应允许下游CDN向上游CDN报告由下游CDN自身执行的交付和不完整交付的日志记录，以及由级联CDN代表下游CDN执行的交付和不完整交付的日志记录。
LI-4 {HIGH} The CDNI Logging interface shall support batch/offline exchange of logging records.
LI-4{HIGH}CDNI日志记录接口应支持日志记录的批量/离线交换。
LI-5 {MED} The CDNI Logging interface should also support an additional mechanism taking into account the timing constraints for some types of logging records (e.g., near-real time for monitoring and analytics applications).
LI-5{MED}CDNI日志接口还应支持一个额外的机制，考虑到某些类型日志记录的时间限制（例如，用于监控和分析应用的近实时）。
LI-6 {HIGH} The CDNI Logging interface shall define a log file format and a set of fields to be exported for various CDNI Logging events.
LI-6{HIGH}CDNI日志记录接口应定义日志文件格式和一组字段，以便为各种CDNI日志记录事件导出。
LI-7 {HIGH} The CDNI Logging interface shall define a transport mechanism to exchange CDNI Logging files.
LI-7{HIGH}CDNI日志接口应定义一种传输机制，以交换CDNI日志文件。
LI-8 {MED} The CDNI Logging interface should allow a CDN to query another CDN for relevant current logging records (e.g., for on-demand access to real-time logging information).
LI-8{MED}CDNI日志接口应允许CDN查询另一个CDN的相关当前日志记录（例如，按需访问实时日志信息）。
LI-9 {LOW} The CDNI Logging interface may support aggregate/ summarized logs (e.g., total bytes delivered for a content regardless of individual User Agents to which it was delivered).
LI-9{LOW}CDNI日志接口可能支持聚合/汇总日志（例如，无论内容交付到哪个用户代理，内容交付的总字节数）。
LI-10 {LOW} The CDNI Logging interface may support logging of performance data for deliveries to User Agents performed by the Downstream CDN as a result of request redirection by the Upstream CDN. Performance data may include various traffic statistics (the specific parameters are to be determined). The CDNI Logging interface may support the Upstream CDN to indicate the nature and contents of the performance data to be reported by the Downstream CDN.
LI-10{LOW}CDNI日志记录接口可以支持记录性能数据，以便作为上游CDN的请求重定向的结果，由下游CDN执行向用户代理的交付。性能数据可能包括各种交通统计数据（具体参数待定）。CDNI日志接口可支持上游CDN，以指示下游CDN报告的性能数据的性质和内容。
LI-11 {MED} The CDNI Logging interface should support logging of consumed resources (e.g., storage, bandwidth) to the Upstream CDN for deliveries where content is stored by the Downstream CDN for delivery to User Agents. The information logged may include the type of storage (e.g., Origin, Intermediate, Edge, Cache) as well as the amount of storage (e.g., total GB, GB used, per time period, per content domain) all of which may impact the cost of the services.
LI-11{MED}CDNI日志记录接口应支持将消耗的资源（例如，存储、带宽）记录到上游CDN以进行交付，其中内容由下游CDN存储以交付给用户代理。记录的信息可能包括存储类型（例如，源、中间、边缘、缓存）以及存储量（例如，总GB、使用GB、每个时间段、每个内容域），所有这些都可能影响服务的成本。
LI-12 {MED} In the case of cascaded CDNs, the CDNI Logging interface should support the Downstream CDN to report consumed resources (e.g. storage, bandwidth) to the Upstream CDN where content is stored by the Downstream CDN itself as well as logging for storage resources when content storage is performed by cascaded CDNs on behalf of the Downstream CDN.
LI-12{MED}在级联CDN的情况下，CDNI日志接口应支持下游CDN报告消耗的资源（例如存储、带宽）到上游CDN，其中内容由下游CDN本身存储，以及在内容存储由级联CDN代表下游CDN执行时记录存储资源。
LI-13 {HIGH} The CDNI Logging interface shall support logging of deleted objects from the Downstream CDN to the Upstream CDN as a result of explicit delete requests on via the CDNI Control interface from the Upstream CDN.
LI-13{HIGH}CDNI日志记录接口应支持通过上游CDN的CDNI控制接口，通过上显式删除请求，将下游CDN中删除的对象记录到上游CDN中。
LI-14 {HIGH} The CDNI Logging interface shall support the exchange of extensible log file formats to support proprietary information fields. These information fields shall be agreed upon ahead of time between the corresponding CDNs.
LI-14{HIGH}CDNI日志接口应支持交换可扩展日志文件格式，以支持专有信息字段。这些信息字段应在相应CDN之间提前商定。
LI-15 {HIGH} The CDNI Logging interface shall allow a CDN to notify another CDN about which CDNI Logging information is available for transfer and/or no longer available (e.g., it exceeded some logging retention period or some logging retention volume).
LI-15{HIGH}CDNI日志记录接口应允许CDN通知另一CDN哪些CDNI日志记录信息可用于传输和/或不再可用（例如，它超过了某些日志记录保留期或某些日志记录保留量）。
LI-16 {MED} The CDNI Logging interface should support the ability for the Downstream CDN to include the Content Collection ID and Session ID fields in CDNI log entries generated for HTTP Adaptive Streaming content.
LI-16{MED}CDNI日志接口应支持下游CDN在为HTTP自适应流内容生成的CDNI日志条目中包含内容集合ID和会话ID字段的能力。
LI-17 {MED} The CDNI Logging interface should provide privacy protection by not disclosing information that can be used to identify the user (e.g., method that anonymizes the IP address carried in the logging field). The use of the privacy protection mechanism is optional.
LI-17{MED}CDNI日志记录界面应提供隐私保护，不披露可用于识别用户的信息（例如，匿名记录字段中携带的IP地址的方法）。隐私保护机制的使用是可选的。
This section identifies the requirements related to the CDNI security. Some of these are expected to affect multiple or all protocols.
本节确定了与CDNI安全相关的要求。其中一些可能会影响多个或所有协议。
SEC-1 {HIGH} All the CDNI interface shall support secure operation over unsecured IP connectivity (e.g., the Internet). This includes authentication, confidentiality, integrity protection as well as protection against spoofing and replay.
SEC-1{高}所有CDNI接口应支持通过不安全的IP连接（如互联网）进行安全操作。这包括身份验证、机密性、完整性保护以及防止欺骗和重播。
SEC-2 {HIGH} The CDNI solution shall provide sufficient protection against denial-of-service attacks. This includes protection against spoofed delivery requests sent by User Agents directly to a Downstream CDN attempting to appear as if they had been redirected by a given Upstream CDN when they have not.
SEC-2{HIGH}CDNI解决方案应提供足够的保护，防止拒绝服务攻击。这包括防止用户代理直接发送到下游CDN的欺骗传递请求，这些请求试图显示为它们已被给定的上游CDN重定向，而实际上它们并未被重定向。
SEC-3 {MED} The CDNI solution should be able to ensure that for any given request redirected to a Downstream CDN, the Downstream CDN can determine the Upstream CDN that redirected the request directly to the Downstream CDN (leading to that request being served by that CDN, or being further redirected).
SEC-3{MED}CDNI解决方案应该能够确保对于重定向到下游CDN的任何给定请求，下游CDN可以确定将请求直接重定向到下游CDN的上游CDN（导致该请求由该CDN服务，或进一步重定向）。
SEC-4 {MED} The CDNI solution should be able to ensure that for any given transaction log generated by the Downstream CDN and communicated to an Upstream CDN, the Upstream CDN can confirm the transmitted log record corresponds to a request redirection by the Upstream CDN.
SEC-4{MED}CDNI解决方案应能够确保对于由下游CDN生成并传送到上游CDN的任何给定事务日志，上游CDN可以确认传输的日志记录对应于上游CDN的请求重定向。
SEC-5 {LOW} The CDNI solution may provide a mechanism allowing an Upstream CDN that has credentials to acquire content from the CSP origin server (or another CDN), to allow establishment of credentials authorizing the Downstream CDN to acquire the content from the CSP origin server (or the other CDN) (e.g., in case the content cannot be acquired from the Upstream CDN).
SEC-5{LOW}CDNI解决方案可以提供一种机制，允许具有凭据的上游CDN从CSP源服务器（或另一CDN）获取内容，以允许建立凭据，授权下游CDN从CSP源服务器（或另一CDN）获取内容（例如，如果无法从上游CDN获取内容）。
This document discusses CDNI security requirements in Section 9.
本文件在第9节中讨论了CDNI安全要求。
This document reflects contributions from the following individuals:
本文件反映了以下个人的贡献：
Francois Le Faucheur Cisco Systems EMail: flefauch@cisco.com
Francois Le Faucheur Cisco Systems电子邮件：flefauch@cisco.com
Mahesh Viveganandhan Cisco Systems EMail: mvittal@cisco.com
Mahesh Viveganandhan Cisco Systems电子邮件：mvittal@cisco.com
Grant Watson Alcatel-Lucent (Velocix) EMail: gwatson@velocix.com
Grant Watson Alcatel-Lucent（Velocix）电子邮件：gwatson@velocix.com
This document leverages the earlier work of the IETF CDI working group in particular, as documented in [REQ-ROUTE], [DIST-REQS], and [AAA-REQS].
本文件特别利用了IETF CDI工作组的早期工作，如[REQ-ROUTE]、[DIST-REQS]和[AAA-REQS]中所述。
The authors would like to thank Gilles Bertrand, Christophe Caillet, Bruce Davie, Phil Eardley, Ben Niven-Jenkins, Agustin Schapira, Emile Stephan, Eric Burger, Susan He, Kevin Ma, Daryl Malas, Iuniana Oprescu, and Spencer Dawkins for their input. Serge Manning along with Robert Streijl, Vishwa Prasad, Percy Tarapore, Mike Geller, and Ramki Krishnan contributed to this document by addressing the requirements of the ATIS Cloud Services Forum.
作者要感谢Gilles Bertrand、Christophe Caillet、Bruce Davie、Phil Eardley、Ben Niven Jenkins、Agustin Schapira、Emile Stephan、Eric Burger、Susan He、Kevin Ma、Daryl Malas、Iuniana Oprescu和Spencer Dawkins的投入。Serge Manning以及Robert Streijl、Vishwa Prasad、Percy Tarapore、Mike Geller和Ramki Krishnan通过满足ATIS云服务论坛的要求，对本文件做出了贡献。
Ray Brandenburg, Matt Caufield, and Gilles Bertrand provided valuable inputs for HTTP Adaptive Streaming, CDNI Metadata interface, and CDNI Logging interface, respectively.
Ray Brandenburg、Matt Caufield和Gilles Bertrand分别为HTTP自适应流、CDNI元数据接口和CDNI日志接口提供了有价值的输入。
Stephen Farrell, Adrian Farrel, Benoit Claise, Sean Turner, Christer Holmberg, and Carlos Pignataro provided review comments that helped improve the document.
Stephen Farrell、Adrian Farrel、Benoit Claise、Sean Turner、Christer Holmberg和Carlos Pignataro提供了有助于改进文档的审查意见。
[RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content Distribution Network Interconnection (CDNI) Problem Statement", RFC 6707, September 2012.
[RFC6707]Niven Jenkins，B.，Le Faucheur，F.，和N.Bitar，“内容分发网络互连（CDNI）问题声明”，RFC 67072012年9月。
[RFC7336] Peterson, L., Davie, B., and R. Brandenburg, Ed., "Framework for Content Distribution Network Interconnection (CDNI)", RFC 7336, August 2014.
[RFC7336]Peterson，L.，Davie，B.，和R.Brandenburg，编辑，“内容分发网络互连框架（CDNI）”，RFC 7336，2014年8月。
[AAA-REQS] Gilletti, D., Nair, R., Scharber, J., and J. Guha, "Content Internetworking (CDI) Authentication, Authorization, and Accounting Requirements", Work in Progress, June 2001.
[AAA-REQS]Gilletti，D.，Nair，R.，Scharber，J.，和J.Guha，“内容互联网（CDI）认证、授权和会计要求”，正在进行的工作，2001年6月。
[ATIS-0800042] ATIS, "ATIS IPTV Content on Demand Service", ATIS-0800042 v002, September 2011, <https://www.atis.org/docstore/ product.aspx?id=25670>.
[ATIS-0800042]ATIS，“ATIS IPTV内容点播服务”，ATIS-0800042 v002，2011年9月<https://www.atis.org/docstore/ product.aspx？id=25670>。
[DIST-REQS] Amini, L., "Distribution Requirements for Content Internetworking", Work in Progress, November 2001.
[DIST-REQS]Amini，L.，“内容互联的分发要求”，正在进行的工作，2001年11月。
[REQ-ROUTE] Cain, B., "Request Routing Requirements for Content Internetworking", Work in Progress, November 2001.
[REQ-ROUTE]Cain，B.，“内容互联的请求路由要求”，正在进行的工作，2001年11月。
[RFC6770] Bertrand, G., Stephan, E., Burbridge, T., Eardley, P., Ma, K., and G. Watson, "Use Cases for Content Delivery Network Interconnection", RFC 6770, November 2012.
[RFC6770]Bertrand，G.，Stephan，E.，Burbridge，T.，Eardley，P.，Ma，K.，和G.Watson，“内容交付网络互连的用例”，RFC 67702012年11月。
[RFC7230] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing", RFC 7230, June 2014.
[RFC7230]Fielding，R.和J.Reschke，“超文本传输协议（HTTP/1.1）：消息语法和路由”，RFC 7230，2014年6月。
[RTMP] Parmar, H., Ed. and M. Thornburgh, Ed., "Adobe's Real Time Messaging Protocol", December 2012, <http://www.adobe.com/content/dam/Adobe/en/devnet/rtmp/ pdf/rtmp_specification_1.0.pdf>.
[RTMP]Parmar，H.，Ed.和M.Thornburgh，Ed.，“Adobe的实时消息协议”，2012年12月<http://www.adobe.com/content/dam/Adobe/en/devnet/rtmp/ pdf/rtmp_规范_1.0.pdf>。
Authors' Addresses
作者地址
Kent Leung (editor) Cisco Systems 170 West Tasman Drive San Jose, CA 95134 USA
梁健（编辑）思科系统170西塔斯曼大道圣何塞，加利福尼亚州95134
Phone: +1 408 526 5030
EMail: kleung@cisco.com
Phone: +1 408 526 5030
EMail: kleung@cisco.com
Yiu Lee (editor) Comcast One Comcast Center Philadelphia, PA 19103 USA
姚莉（编辑）美国宾夕法尼亚州费城康卡斯特中心康卡斯特一号康卡斯特19103
EMail: yiu_lee@cable.comcast.com
EMail: yiu_lee@cable.comcast.com