Internet Engineering Task Force (IETF)                         S. Venaas
Request for Comments: 7887                                     J. Arango
Updates: 5384                                              Cisco Systems
Category: Standards Track                                    I. Kouvelas
ISSN: 2070-1721                                          Arista Networks
                                                               June 2016
        
Internet Engineering Task Force (IETF)                         S. Venaas
Request for Comments: 7887                                     J. Arango
Updates: 5384                                              Cisco Systems
Category: Standards Track                                    I. Kouvelas
ISSN: 2070-1721                                          Arista Networks
                                                               June 2016

Hierarchical Join/Prune Attributes

层次连接/修剪属性

Abstract

摘要

This document defines a hierarchical method of encoding Join/Prune attributes that provides a more efficient encoding when the same attribute values need to be specified for multiple sources in a PIM Join/Prune message. This document updates RFC 5384 by renaming the encoding type registry specified there.

本文档定义了一种对连接/修剪属性进行编码的分层方法，当需要在PIM连接/修剪消息中为多个源指定相同的属性值时，该方法可提供更有效的编码。本文档通过重命名其中指定的编码类型注册表来更新RFC 5384。

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 http://www.rfc-editor.org/info/rfc7887.

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/rfc7887.

Copyright Notice

版权公告

Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.

版权所有（c）2016 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Notation . . . . . . . . . . . . . . . . . . . .   3
   3.  Hierarchical Join/Prune Attribute Definition  . . . . . . . .   3
   4.  PIM Address Encoding Types  . . . . . . . . . . . . . . . . .   6
   5.  Hierarchical Join/Prune Attribute Hello Option  . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8
        
   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Notation . . . . . . . . . . . . . . . . . . . .   3
   3.  Hierarchical Join/Prune Attribute Definition  . . . . . . . .   3
   4.  PIM Address Encoding Types  . . . . . . . . . . . . . . . . .   6
   5.  Hierarchical Join/Prune Attribute Hello Option  . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8
1. Introduction
1. 介绍

PIM Join attributes as defined in [RFC5384] allow for specifying a set of attributes for each of the joined or pruned sources in a PIM Join/Prune message. Attributes must be separately specified for each individual source in the message. However, in some cases, the same attributes and values need to be specified for some, or even all, the sources in the message. The attributes and their values then need to be repeated for each of the sources where they apply.

[RFC5384]中定义的PIM连接属性允许在PIM连接/修剪消息中为每个连接或修剪的源指定一组属性。必须为消息中的每个源单独指定属性。但是，在某些情况下，需要为消息中的某些甚至所有源指定相同的属性和值。然后，需要为应用属性的每个源重复属性及其值。

This document provides a hierarchical way of encoding attributes and their values in a Join/Prune message so that if the same attribute and value is to apply for all the sources, it only needs to be specified once in the message. Similarly, if all the sources in a specific group set share a specific attribute and value, it only needs to be specified once for the entire group set.

本文档提供了一种在联接/删除消息中对属性及其值进行编码的分层方法，因此，如果相同的属性和值要应用于所有源，则只需在消息中指定一次。类似地，如果特定组集中的所有源共享特定属性和值，则只需为整个组集中指定一次。

This document extends [RFC5384] by specifying that the encoding type defined there also applies to Encoded-Unicast and Encoded-Group formats. This document also updates [RFC5384] by renaming the "PIM Encoded-Source Address Encoding Type Field" registry to "PIM Address Encoding Types". The content of the registry remains the same. The encoding type used for Join attributes is, however, still limited to use in Join/Prune messages. Note that Join attributes, as they are referred to in [RFC5384], also apply to pruned sources in a Join/ Prune message. Thus, the more correct name "Join/Prune attributes" will be used throughout the rest of this document.

本文档通过指定此处定义的编码类型也适用于编码单播和编码组格式来扩展[RFC5384]。本文档还通过将“PIM编码源地址编码类型字段”注册表重命名为“PIM地址编码类型”来更新[RFC5384]。注册表的内容保持不变。但是，用于连接属性的编码类型仍然限于在连接/删除消息中使用。请注意，[RFC5384]中提到的连接属性也适用于连接/修剪消息中的修剪源。因此，本文档的其余部分将使用更正确的名称“Join/Prune attributes”。

This document allows Join/Prune attributes to be specified in the Upstream Neighbor Address field, and also in the Multicast Group Address field, of a Join/Prune message. It defines how this is used to specify the same Join/Prune attribute and value for multiple sources. This document also defines a new Hello Option to indicate support for the hierarchical encoding specified.

此文档允许在Join/Prune消息的上游邻居地址字段以及多播组地址字段中指定Join/Prune属性。它定义了如何使用它为多个源指定相同的联接/修剪属性和值。本文档还定义了一个新的Hello选项，以指示对指定层次编码的支持。

2. Requirements Notation
2. 需求符号

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照[RFC2119]中所述进行解释。

3. Hierarchical Join/Prune Attribute Definition
3. 层次连接/删除属性定义

The format of a PIM Join/Prune message is defined in [RFC7761] as follows:

[RFC7761]中定义了PIM加入/删除消息的格式，如下所示： 

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |PIM Ver| Type  |   Reserved    |           Checksum            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Upstream Neighbor Address (Encoded-Unicast format)     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Reserved     | Num groups    |          Holdtime             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Multicast Group Address 1 (Encoded-Group format)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Number of Joined Sources    |   Number of Pruned Sources    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           .                                   |
      |                           .                                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Multicast Group Address m (Encoded-Group format)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Number of Joined Sources    |   Number of Pruned Sources    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        
       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |PIM Ver| Type  |   Reserved    |           Checksum            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Upstream Neighbor Address (Encoded-Unicast format)     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Reserved     | Num groups    |          Holdtime             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Multicast Group Address 1 (Encoded-Group format)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Number of Joined Sources    |   Number of Pruned Sources    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           .                                   |
      |                           .                                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Multicast Group Address m (Encoded-Group format)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Number of Joined Sources    |   Number of Pruned Sources    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Joined Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address 1 (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             .                                 |
      |                             .                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Pruned Source Address n (Encoded-Source format)        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The message contains a single Upstream Neighbor Address and one or more group sets. Each group set contains a Group Address and two source lists: the Joined Sources and the Pruned Sources. The Upstream Neighbor Address, the group addresses, and the source addresses are encoded in Encoded-Unicast format, Encoded-Group format, and Encoded-Source format, respectively. This document extends the use of the source address encoding defined in [RFC5384] to also apply to the Upstream Neighbor Address and the Group Address fields (see Section 4).

该消息包含单个上游邻居地址和一个或多个组集。每个组集包含一个组地址和两个源列表：合并的源和修剪的源。上游邻居地址、组地址和源地址分别以编码单播格式、编码组格式和编码源格式编码。本文件扩展了[RFC5384]中定义的源地址编码的使用，也适用于上游邻居地址和组地址字段（见第4节）。

For a Join/Prune message, a hierarchy of Join/Prune attributes is defined. Attributes at the highest level, which is the least specific, apply to every source in the message. These are encoded in the Upstream Neighbor Address. Attributes at the next, more-specific level apply to every source in a group set. They are encoded in a Group Address. And finally, there are attributes that apply to a single source and are encoded in the source address as defined in [RFC5384].

对于Join/Prune消息，定义了Join/Prune属性的层次结构。最高级别的属性（最不具体）应用于消息中的每个源。这些被编码在上游邻居地址中。下一个更具体级别的属性适用于组集中的每个源。它们被编码在一个组地址中。最后，还有一些属性适用于单个源，并在[RFC5384]中定义的源地址中进行编码。

The complete set of attributes that apply to a given source is obtained by combining the message-wide attributes, the attributes of the group set that the source belongs to, and the source-specific attributes. However, if the same attribute is specified at multiple levels, then the one at the most specific level overrides the other instances of the attribute. Note that the set of attributes and their values is formed before processing the attributes. Hence, a value that is invalid for a given type might override a valid value at a higher level.

应用于给定源的完整属性集是通过组合消息范围的属性、源所属组集的属性以及源特定属性而获得的。但是，如果在多个级别指定同一属性，则最特定级别的属性将覆盖该属性的其他实例。请注意，属性集及其值是在处理属性之前形成的。因此，对于给定类型无效的值可能会覆盖更高级别的有效值。

As an example, say that for a given source, we have attributes T_1 with value V_1, T_2 with value V_2, and T_3 with value V_3. Also assume that in the Group Address of the source's group set, we have attributes T_1 with value V_6 and T_4 with value V_4. And assume that we in the Upstream Neighbor Address have encoded the attributes T_1 with value V_7, T_4 with value V_8, and T_5 with value V_5. The attributes applied to the given source will be T_1 with value V_1, T_2 with value V_2, T_3 with value V_3, T_4 with value V_4, and T_5 with value V_5. Here we have T_1 with different values at each level, so we use the value specified at the source level. Also, we have T_4 with different values at the group and message levels, so we use the value at the group level. Here it could be that V_1 is not a valid value for T_1, but it still overrides the values at the higher levels as we do not process the attributes until after forming the set.

例如，假设对于给定的源，我们有值为V_1的属性T_1，值为V_2的属性T_2，值为V_3的属性T_3。还假设在源组集合的组地址中，有值为V_6的属性T_1和值为V_4的属性T_4。并假设我们在上游邻居地址中已将属性T_1编码为值V_7，T_4编码为值V_8，T_5编码为值V_5。应用于给定源的属性将是值为V_1的T_1、值为V_2的T_2、值为V_3的T_3、值为V_4的T_4和值为V_5的T_5。这里我们有T_1，每个级别有不同的值，所以我们使用在源级别指定的值。此外，我们在组和消息级别使用了具有不同值的T_4，因此我们在组级别使用该值。这里可能是V_1不是T_1的有效值，但它仍然覆盖更高级别的值，因为我们在形成集合之前不会处理属性。

Note that Join/Prune attributes are still applied to sources as specified in [RFC5384]. This document does not change the meaning of any attributes; it is simply a more compact way of encoding an

请注意，如[RFC5384]中所述，联接/修剪属性仍应用于源。本文件不改变任何属性的含义；这只是一种更简洁的编码方法

attribute when the same attribute and value applies to multiple sources, e.g., with the example above, we would have the exact same meaning if we instead had encoded all the attributes T1, ..., T5 with the respective values V1, ..., V5 in the source address.

属性当相同的属性和值应用于多个源时，例如，在上面的示例中，如果我们使用源地址中的相应值V1、…、V5对所有属性T1、…、T5进行编码，则我们将具有完全相同的含义。

4. PIM Address Encoding Types
4. PIM地址编码类型

Addresses in PIM messages are specified together with an address family and an encoding type. This applies to Encoded-Unicast, Encoded-Group, and Encoded-Source addresses. The encoding types allow the address to be encoded according to different schemes. An encoding type indicates how an address is encoded irrespective of address type, Encoded-Unicast, Encoded-Group, or Encoded-Source. It is possible that there will be future encoding types that do not apply to all address types though. This means that as currently defined, 0 is native encoding [RFC7761], and 1 is Join/Prune attributes encoding [RFC5384]. Note that as specified in [RFC5384], a type 1 Encoded Address MUST contain at least one Join/Prune attribute.

PIM消息中的地址与地址族和编码类型一起指定。这适用于编码单播、编码组和编码源地址。编码类型允许根据不同的方案对地址进行编码。编码类型表示地址的编码方式，与地址类型、编码单播、编码组或编码源无关。不过，将来可能会有不适用于所有地址类型的编码类型。这意味着，按照当前定义，0是本机编码[RFC7761]，1是连接/删除属性编码[RFC5384]。请注意，如[RFC5384]中所述，类型1编码地址必须至少包含一个Join/Prune属性。

5. Hierarchical Join/Prune Attribute Hello Option
5. 分层连接/删除属性Hello选项

A PIM router indicates that it supports the mechanism specified in this document by including the Hierarchical Join/Prune Attribute Hello Option in its PIM Hello message. When this new Hello Option is included, it MUST also include the Join Attribute Hello Option as specified in [RFC5384]. The format of the Hierarchical Join/Prune Attribute Hello Option is defined to be:

PIM路由器通过在其PIM Hello消息中包含分层连接/修剪属性Hello选项，表示它支持本文档中指定的机制。包括此新的Hello选项时，还必须包括[RFC5384]中指定的连接属性Hello选项。分层连接/修剪属性Hello选项的格式定义为： 

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        OptionType = 36        |       OptionLength = 0        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        
       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        OptionType = 36        |       OptionLength = 0        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

OptionType = 36, OptionLength = 0. Note that there is no option value included.

OptionType=36，OptionLength=0。请注意，没有包含任何选项值。

A PIM router MUST NOT send a Join/Prune message with Join/Prune attributes encoded in the Upstream Neighbor Address or any of the group addresses out of any interface on which there is a PIM neighbor that has not included this option in its Hellos. Even a router that is not the upstream neighbor must be able to parse the message in order to perform Join suppression and Prune override.

PIM路由器不得从任何接口发送包含上游邻居地址或任何组地址中编码的Join/Prune属性的Join/Prune消息，该接口上的PIM邻居未在其Hellos中包含此选项。即使不是上游邻居的路由器也必须能够解析消息，以便执行连接抑制和修剪覆盖。

6. Security Considerations
6. 安全考虑

This document specifies a more compact encoding of Join/Prune attributes. Use of the encoding has no impact on security aside from using the encoding in [RFC5384]. For instance, an attack with a forged message with certain attribute values is equally difficult independent of which encoding is used. If an attribute that applies to the entire message is wrong, then that may cause an issue for all the sources in the message. But without this encoding, one would instead include that attribute for every single source, and that would also cause an issue for all the sources in the message.

本文档指定了一种更紧凑的联接/修剪属性编码。除了使用[RFC5384]中的编码外，编码的使用对安全性没有影响。例如，使用具有特定属性值的伪造消息进行攻击同样困难，这与使用哪种编码无关。如果应用于整个消息的属性错误，则可能会导致消息中所有源出现问题。但是如果没有这种编码，则会为每个源包含该属性，这也会导致消息中所有源都出现问题。

7. IANA Considerations
7. IANA考虑

IANA has renamed the "PIM Encoded-Source Address Encoding Type Field" registry to "PIM Address Encoding Types".

IANA已将“PIM编码源地址编码类型字段”注册表重命名为“PIM地址编码类型”。

The Hierarchical Join/Prune Attribute (36) has been added to the "PIM-Hello Options" registry.

层次连接/修剪属性（36）已添加到“PIM Hello Options”注册表中。

8. Normative References
8. 规范性引用文件

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://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<http://www.rfc-editor.org/info/rfc2119>.

[RFC5384] Boers, A., Wijnands, I., and E. Rosen, "The Protocol Independent Multicast (PIM) Join Attribute Format", RFC 5384, DOI 10.17487/RFC5384, November 2008, <http://www.rfc-editor.org/info/rfc5384>.

[RFC5384]Boers，A.，Wijnands，I.，和E.Rosen，“协议独立多播（PIM）连接属性格式”，RFC 5384，DOI 10.17487/RFC5384，2008年11月<http://www.rfc-editor.org/info/rfc5384>.

[RFC7761] Fenner, B., Handley, M., Holbrook, H., Kouvelas, I., Parekh, R., Zhang, Z., and L. Zheng, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", STD 83, RFC 7761, DOI 10.17487/RFC7761, March 2016, <http://www.rfc-editor.org/info/rfc7761>.

[RFC7761]Fenner，B.，Handley，M.，Holbrook，H.，Kouvelas，I.，Parekh，R.，Zhang，Z.，和L.Zheng，“协议独立多播-稀疏模式（PIM-SM）：协议规范（修订版）”，STD 83，RFC 7761，DOI 10.17487/RFC7761，2016年3月<http://www.rfc-editor.org/info/rfc7761>.

Authors' Addresses

作者地址

Stig Venaas Cisco Systems Tasman Drive San Jose, CA 95134 United States

美国加利福尼亚州圣何塞市塔斯曼大道Stig Venaas思科系统公司，邮编95134 

   Email: stig@cisco.com
        
   Email: stig@cisco.com

Jesus Arango Cisco Systems Tasman Drive San Jose, CA 95134 United States

美国加利福尼亚州圣何塞市塔斯曼大道Jesus Arango Cisco Systems，邮编95134 

   Email: jearango@cisco.com
        
   Email: jearango@cisco.com

Isidor Kouvelas Arista Networks 5453 Great America Parkway Santa Clara, CA 95054 United States

Isidor Kouvelas Arista Networks 5453美国加利福尼亚州圣克拉拉大美洲公园路95054 

   Email: kouvelas@arista.com
        
   Email: kouvelas@arista.com