Internet Engineering Task Force (IETF) P. van der Stok
Request for Comments: 7732 Consultant
Category: Informational R. Cragie
ISSN: 2070-1721 ARM Ltd.
February 2016
Internet Engineering Task Force (IETF) P. van der Stok
Request for Comments: 7732 Consultant
Category: Informational R. Cragie
ISSN: 2070-1721 ARM Ltd.
February 2016
Forwarder Policy for Multicast with Admin-Local Scope in the Multicast Protocol for Low-Power and Lossy Networks (MPL)
低功耗有损网络（MPL）多播协议中具有管理本地作用域的多播转发器策略
Abstract
摘要
The purpose of this document is to specify an automated policy for the routing of Multicast Protocol for Low-Power and Lossy Networks (MPL) multicast messages with Admin-Local scope in a border router.
本文档的目的是为边界路由器中具有管理本地范围的低功耗和有损网络（MPL）多播消息的多播协议路由指定自动策略。
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/rfc7732.
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/rfc7732.
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 ....................................................2
1.1. Requirements Language ......................................4
1.2. Terminology and Acronyms ...................................4
2. Network Identifier ..............................................4
2.1. IEEE 802.15.4 ..............................................5
2.2. IEEE 802.11 ................................................5
2.3. ITU-T G.9959 ...............................................5
2.4. BLUETOOTH(R) Low Energy ....................................5
3. MPL4 Router .....................................................5
3.1. MPL Interface Parameters ...................................6
3.2. Determination of MPL4 Zone .................................6
4. Admin-Local Policy ..............................................7
4.1. Legal Multicast Messages ...................................7
4.2. Forwarding Legal Packets ...................................8
4.2.1. MPL Message .........................................8
4.2.2. Multicast Messages without MPL Option ...............9
4.3. Encryption Rules ...........................................9
5. MPL Domains and Zones ...........................................9
6. Default Parameter Values .......................................10
7. Security Considerations ........................................11
8. References .....................................................12
8.1. Normative References ......................................12
8.2. Informative References ....................................14
Acknowledgements ..................................................15
Authors' Addresses ................................................15
1. Introduction ....................................................2
1.1. Requirements Language ......................................4
1.2. Terminology and Acronyms ...................................4
2. Network Identifier ..............................................4
2.1. IEEE 802.15.4 ..............................................5
2.2. IEEE 802.11 ................................................5
2.3. ITU-T G.9959 ...............................................5
2.4. BLUETOOTH(R) Low Energy ....................................5
3. MPL4 Router .....................................................5
3.1. MPL Interface Parameters ...................................6
3.2. Determination of MPL4 Zone .................................6
4. Admin-Local Policy ..............................................7
4.1. Legal Multicast Messages ...................................7
4.2. Forwarding Legal Packets ...................................8
4.2.1. MPL Message .........................................8
4.2.2. Multicast Messages without MPL Option ...............9
4.3. Encryption Rules ...........................................9
5. MPL Domains and Zones ...........................................9
6. Default Parameter Values .......................................10
7. Security Considerations ........................................11
8. References .....................................................12
8.1. Normative References ......................................12
8.2. Informative References ....................................14
Acknowledgements ..................................................15
Authors' Addresses ................................................15
Multicast scopes are defined in [RFC4291]. [RFC7346] extends the scope definition with this text:
[RFC4291]中定义了多播作用域。[RFC7346]使用以下文本扩展范围定义：
"Interface-Local, Link-Local, and Realm-Local scope boundaries are automatically derived from physical connectivity or other non-multicast-related configurations. Global scope has no boundary. The boundaries of all other non-reserved scopes of Admin-Local or larger are administratively configured."
接口本地、链路本地和领域本地作用域边界是从物理连接或其他非多播相关配置自动派生的。全局作用域没有边界。管理本地或更大的所有其他非保留作用域的边界是通过管理配置的
The Admin-Local scope must therefore be administratively configured. In this document, "administratively configured" does not imply actions by a human beyond installing the protocol specified herein. "Administratively configured" means an automatic derivation as described in this document.
因此，必须对管理本地作用域进行管理配置。在本文档中，“管理配置”并不意味着除安装本文指定的协议之外的人员操作。“管理配置”指本文件中所述的自动派生。
This document describes an automated policy for the Multicast Protocol for Low-Power and Lossy Networks (MPL) [RFC7731] forwarding of multicast messages with Admin-Local scope within a border router that lies between a network running MPL and some other network. This policy is in line with the autonomous networking ideas presented in [RFC7576].
本文档描述了低功耗和有损网络（MPL）[RFC7731]多播协议的自动策略，该协议在运行MPL的网络和一些其他网络之间的边界路由器内转发具有管理本地范围的多播消息。该政策符合[RFC7576]中提出的自主联网思想。
The Realm-Local multicast address is currently used by MPL to propagate the multicast message to all receivers and forwarders within a mesh network. The multicast propagation is limited to a mesh network with a common Layer 2. For example, a Low-Power Wireless Personal Area Network (LoWPAN) is defined by an IEEE 802.15.4 Layer 2 mesh network, composed of all connected nodes sharing the same Personal Area Network (PAN) ID [RFC4944].
域本地多播地址当前由MPL用于将多播消息传播到网状网络中的所有接收器和转发器。组播传播仅限于具有公共层2的网状网络。例如，低功率无线个人区域网络（LoWPAN）由IEEE 802.15.4第2层网状网络定义，该网络由共享相同个人区域网络（PAN）ID的所有连接节点组成[RFC4944]。
The network concept differs between mesh network technologies. This document maps a general network identifier to the specific network identifier of existing mesh technologies.
网状网络技术之间的网络概念不同。本文档将通用网络标识符映射到现有mesh技术的特定网络标识符。
In current and projected deployments, there is a requirement to propagate a multicast message beyond the boundaries of the mesh network in which it originated, independent of the mesh technology.
在当前和计划的部署中，需要将多播消息传播到其起源的mesh网络的边界之外，而不依赖于mesh技术。
Consider the case where propagation over two mesh networks is required. In one example, each mesh network has a border router and the two border routers are connected with an Ethernet link. In another example, each mesh network is connected to its own network interface connected to the same border router. In both cases, an Admin-Local multicast message originating in one network needs to propagate into the other mesh network. The boundary of the Admin-Local scope is administratively configured.
考虑需要在两个网状网络上传播的情况。在一个示例中，每个网状网络都有一个边界路由器，两个边界路由器通过以太网链路连接。在另一个示例中，每个网状网络连接到其自己的网络接口，该网络接口连接到同一边界路由器。在这两种情况下，源于一个网络的管理本地多播消息需要传播到另一个网状网络。管理本地作用域的边界是以管理方式配置的。
This document describes an "MPL4 router" that forwards MPL messages with a multicast address with Admin-Local scope to all interfaces connected to links that connect to other MPL-enabled interfaces. The MPL4 router enables all its interfaces for MPL messages and allocates an additional variable, MPL_BLOCKED, that either permits or forbids the forwarding of MPL messages.
本文档描述了一个“MPL4路由器”，该路由器将具有多播地址的MPL消息转发到所有连接到连接到其他启用MPL的接口的链路的接口。MPL4路由器为MPL消息启用其所有接口，并分配额外的变量MPL_BLOCKED，该变量允许或禁止转发MPL消息。
The MPL4 router uses the following technique to establish over which links MPL4 messages must be forwarded: The MPL4 router listens on its interfaces for the arrival of MPL4 messages. When MPL4 messages arrive over an interface, the MPL4 router records this interface in the set of interfaces over which incoming MPL4 messages are forwarded. The MPL4 router regularly sends MPL4 messages over its interfaces to provoke the return of MPL4 messages to maintain the set of forwarding interfaces.
MPL4路由器使用以下技术建立必须转发MPL4消息的链路：MPL4路由器在其接口上侦听MPL4消息的到达。当MPL4消息通过接口到达时，MPL4路由器将该接口记录在一组接口中，传入的MPL4消息通过这些接口转发。MPL4路由器定期通过其接口发送MPL4消息，以引发MPL4消息的返回，从而维护转发接口集。
It is expected that the private network of an organization, building, or home is connected to the Internet via the edge routers provided by an ISP. The intention is that MPL messages with multicast addresses of Admin-Local scope are freely forwarded within the private network but are never forwarded outside the private network by edge routers.
预期组织、建筑物或家庭的专用网络通过ISP提供的边缘路由器连接到Internet。其目的是，具有Admin Local作用域的多播地址的MPL消息在专用网络内自由转发，但决不会由边缘路由器在专用网络外转发。
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。
This document uses terminology defined in [RFC7731] and [RFC7346]. In addition, the following terms are used in this document:
本文件使用[RFC7731]和[RFC7346]中定义的术语。此外，本文件中使用了以下术语：
o MPL4: MPL with Admin-Local scope 4.
o MPL4：管理本地作用域为4的MPL。
o MPL4 message: an MPL Data Message with a destination multicast address of scope 4.
o MPL4消息：目标多播地址为作用域4的MPL数据消息。
o MPL4 zone: a convex zone of interconnected interfaces over which MPL messages with Admin-Local scope propagate. An MPL4 zone is bounded by a zone as defined in [RFC4007].
o MPL4区域：互连接口的凸区域，具有管理本地作用域的MPL消息在其上传播。MPL4区域以[RFC4007]中定义的区域为边界。
o MPL4 router: automatically determines the MPL4 zone in which MPL messages with Admin-Local scope can be propagated.
o MPL4路由器：自动确定可以在其中传播具有管理本地作用域的MPL消息的MPL4区域。
Links may have the concept of a channel. For example, in wireless networks, such a channel is associated with a communication frequency. Additionally, for some link technologies, several networks can coexist using the same channel. For these link technologies, a network identifier exists. The network identifier is determined by the link technology specification. When no network identifier exists for a given link, the network identifier has the value "any".
链接可能具有频道的概念。例如，在无线网络中，这样的信道与通信频率相关联。此外，对于某些链路技术，多个网络可以使用同一信道共存。对于这些链路技术，存在一个网络标识符。网络标识符由链路技术规范确定。当给定链路不存在网络标识符时，网络标识符的值为“any”。
IPv6 over IEEE 802.15.4 is described in [RFC4944]. A LoWPAN is composed of the nodes connected by an IEEE 802.15.4 mesh sharing the same PAN ID. The PAN ID identifies a network in the IEEE 802.15.4 mesh. Several networks with different PAN IDs can coexist on the same channel [IEEE802.15.4]. The PAN ID of an interface is defined when the interface is enabled. The value of the network identifier of an IEEE 802.15.4 link is the value of the PAN ID.
[RFC4944]中描述了IEEE 802.15.4上的IPv6。LoWPAN由共享相同PAN ID的IEEE 802.15.4网格连接的节点组成。PAN ID标识IEEE 802.15.4网格中的网络。具有不同PAN ID的多个网络可以在同一信道上共存[IEEE802.15.4]。接口的PAN ID在接口启用时定义。IEEE 802.15.4链路的网络标识符的值是PAN ID的值。
IP over IEEE 802.11 is described in [RFC5416]. The Service Set Identifier (SSID) identifies a network in the IEEE 802.11 link. Several networks with different SSIDs can coexist on the same channel [IEEE802.11]. The SSID of an interface is defined when the interface is switched on. The value of the network identifier of an IEEE 802.11 link is the value of the SSID.
[RFC5416]中描述了IEEE 802.11上的IP。服务集标识符（SSID）标识IEEE 802.11链路中的网络。具有不同SSID的多个网络可以在同一信道上共存[IEEE802.11]。接口的SSID是在接口打开时定义的。IEEE 802.11链路的网络标识符的值是SSID的值。
IPv6 over ITU-T G.9959 is specified in [RFC7428]. The HomeID identifies a network of connected nodes [G.9959]. Several HomeIDs can coexist within communication range, but nodes adhering to a network with a given HomeID cannot communicate with nodes adhering to a network with a different HomeID. The value of the network identifier of a G.9959 link is the value of the HomeID.
[RFC7428]中规定了ITU-T G.9959上的IPv6。HomeID标识连接节点的网络[G.9959]。多个HomeID可以在通信范围内共存，但是使用给定HomeID连接到网络的节点无法与使用不同HomeID连接到网络的节点通信。G.9959链路的网络标识符的值是HomeID的值。
IPv6 over Bluetooth low energy (BTLE) is specified in [RFC7668]. The medium is specified in [BTLE]. BTLE does not know the concept of multiple networks in one channel. The value of the network identifier of a BTLE link is "any".
[RFC7668]中规定了蓝牙低能量（BTLE）上的IPv6。介质在[BTLE]中指定。BTLE不知道一个通道中多个网络的概念。BTLE链路的网络标识符的值为“any”。
The concept of an MPL4 router serves to automatically determine the MPL4 zone in which MPL messages with a scope 4 multicast address can propagate. The MPL4 router periodically executes an algorithm that determines the presence of MPL Interfaces on the links connected to its interfaces. When no MPL Interfaces are present on a given link, the corresponding MPL Interface is signaled as not being part of the MPL4 zone.
MPL4路由器的概念用于自动确定MPL4区域，其中具有scope 4多播地址的MPL消息可以在其中传播。MPL4路由器定期执行一种算法，该算法确定连接到其接口的链路上是否存在MPL接口。当给定链路上不存在MPL接口时，相应的MPL接口被发信号称为不属于MPL4区域。
One parameter is associated with every MPL Interface in the MPL4 router, and two parameters are associated with the behavior of the MPL4 router as a whole.
一个参数与MPL4路由器中的每个MPL接口相关联，两个参数与整个MPL4路由器的行为相关联。
o MPL_BLOCKED: Boolean value that indicates whether or not the associated interface belongs to the MPL4 zone.
o MPL_BLOCKED：布尔值，指示关联接口是否属于MPL4区域。
o MPL_CHECK_INT: Integer that indicates the time interval between successive activations of the MPL4 router algorithm, in seconds.
o MPL_CHECK_INT：表示连续激活MPL4路由器算法之间的时间间隔的整数，以秒为单位。
o MPL_TO: Integer that indicates the interval in which MPL messages are expected to be received, in seconds.
o MPL_TO：整数，表示预期接收MPL消息的时间间隔，以秒为单位。
All interfaces of the MPL4 router MUST be associated with the following MPL protocol parameters, as described in [RFC7731]: PROACTIVE_FORWARDING, DATA_MESSAGE_IMIN, DATA_MESSAGE_IMAX, DATA_MESSAGE_K, and DATA_MESSAGE_TIMER_EXPIRATIONS. Upon startup of the MPL4 router, the parameters associated with all interfaces are assigned the following values: PROACTIVE_FORWARDING = TRUE, MPL_BLOCKED = false. All interfaces MUST subscribe to the multicast addresses ALL_MPL_FORWARDERS scope 3 and scope 4.
MPL4路由器的所有接口必须与以下MPL协议参数相关联，如[RFC7731]中所述：主动转发、数据消息IMIN、数据消息IMAX、数据消息K和数据消息计时器过期。启动MPL4路由器时，与所有接口相关的参数被分配以下值：主动转发=真，MPL阻塞=假。所有接口必须订阅多播地址所有MPL转发器范围3和范围4。
The MPL4 router executes the following algorithm for each interface:
MPL4路由器对每个接口执行以下算法：
o With a frequency determined by the value of MPL_CHECK_INT, the MPL4 router sends an MPL4 message on each interface with a header that includes the MPL Option [RFC7731]; the message is sent to multicast address ALL_MPL_FORWARDERS with scope 4.
o 使用由MPL_CHECK_INT的值确定的频率，MPL4路由器在每个接口上发送一条包含MPL选项[RFC7731]的MPL4消息；消息被发送到作用域为4的所有MPL转发器的多播地址。
o When, within an interval determined by the value of MPL_TO no MPL message is received, the value of MPL_BLOCKED is set to TRUE.
o 当在由MPL_值确定的间隔内没有收到MPL消息时，MPL_BLOCKED的值设置为TRUE。
o On reception of an MPL4 message, the value of MPL_BLOCKED of the receiving interface is set to false.
o 在接收MPL4消息时，接收接口的MPL_BLOCKED值设置为false。
This protocol leads to a state where for each interface MPL_BLOCKED is set to false if and only if MPL-enabled interfaces are connected to the link associated with the interface. When an MPL message is submitted to an MPL-enabled interface called "Interface A" in the MPL router, the Trickle algorithm [RFC6206] is activated to send the MPL message. The MPL4 message with multicast address ALL_MPL_FORWARDERS scope 4 is accepted by every interface connected to the link that has subscribed to ALL_MPL_FORWARDERS with scope 4. On acceptance of the MPL4 message by an interface called "Interface B", the MPL4 message
该协议会导致一种状态，即当且仅当启用MPL的接口连接到与该接口相关联的链路时，每个接口的MPL_BLOCKED设置为false。当MPL消息提交到MPL路由器中名为“接口A”的启用MPL的接口时，触发涓流算法[RFC6206]以发送MPL消息。多播地址为ALL_MPL_转发器作用域4的MPL4消息被连接到已订阅所有作用域4的MPL_转发器的链路的每个接口接受。当称为“接口B”的接口接受MPL4消息时，MPL4消息
is returned with Trickle over Interface B. Consequently, the MPL4 message is received by the originating Interface A, after which MPL_BLOCKED is set to false.
与Trickle over Interface B一起返回。因此，发起接口A接收MPL4消息，之后MPL_BLOCKED设置为false。
When a new node is connected to the link, it can immediately send an MPL4 message, or it can wait for the reception of an MPL4 message to announce its intention to be part of the MPL4 zone.
当新节点连接到链路时，它可以立即发送MPL4消息，也可以等待接收到MPL4消息以宣布其成为MPL4区域一部分的意图。
This section begins by specifying what types of multicast messages arriving at an interface are legal. It continues with a description of forwarding legal Admin-Local multicast messages over other MPL Interfaces.
本节首先指定到达接口的多播消息的类型是合法的。它继续描述通过其他MPL接口转发本地多播消息。
The policy for forwarding Admin-Local multicast messages automatically to an MPL Interface is specified as a function of the state of the MPL Interface and the multicast message. The state of the multicast message is determined by the presence of the MPL Option [RFC7731] and the destination multicast address. The state of the MPL Interface is determined by the subscribed multicast addresses, the zone index [RFC4007], and the values of the PROACTIVE_FORWARDING parameter and the MPL_BLOCKED parameter of the MPL Interface.
将管理本地多播消息自动转发到MPL接口的策略指定为MPL接口和多播消息状态的函数。多播消息的状态由MPL选项[RFC7731]的存在和目标多播地址确定。MPL接口的状态由订阅的多播地址、区域索引[RFC4007]以及MPL接口的主动转发参数和MPL阻塞参数的值确定。
When the zone is undefined or not enabled, all interfaces have the same zone index.
当区域未定义或未启用时，所有接口都具有相同的区域索引。
Multicast messages can be created within the node by an application or can arrive at an interface.
多播消息可以由应用程序在节点内创建，也可以到达接口。
A multicast message created at a source (MPL Seed) is legal when it conforms to the properties described in Section 9.1 of [RFC7731].
在源（MPL种子）上创建的多播消息符合[RFC7731]第9.1节中描述的属性时是合法的。
A multicast message received at a given interface is legal when:
在以下情况下，在给定接口接收的多播消息是合法的：
o The message carries an MPL Option (MPL message) and the incoming MPL Interface is subscribed to the destination multicast address.
o 该消息携带一个MPL选项（MPL消息），并且传入的MPL接口被订阅到目标多播地址。
o The message does not carry an MPL Option and the interface has expressed interest in receiving messages with the specified multicast address via Multicast Listener Discovery (MLD) [RFC3810] or IGMP [RFC3376]. The message was forwarded according to Protocol Independent Multicast - Dense Mode (PIM-DM) [RFC3973] or Protocol Independent Multicast - Sparse Mode (PIM-SM) [RFC4601].
o 消息不带有MPL选项，接口表示有兴趣通过多播侦听器发现（MLD）[RFC3810]或IGMP[RFC3376]接收具有指定多播地址的消息。消息根据协议独立多播密集模式（PIM-DM）[RFC3973]或协议独立多播稀疏模式（PIM-SM）[RFC4601]转发。
Illegal multicast messages are discarded.
非法多播消息将被丢弃。
A legal multicast message received at a given interface is assigned the network identifier of the interface of the incoming link. A message that is created within the node is assigned the network identifier "any".
在给定接口处接收的合法多播消息被分配入局链路接口的网络标识符。在节点内创建的消息被分配网络标识符“any”。
Two types of legal multicast messages are considered in Section 4.1: (1) MPL messages and (2) multicast messages that do not carry the MPL Option.
第4.1节考虑了两种类型的合法多播消息：（1）MPL消息和（2）不携带MPL选项的多播消息。
MPL messages are forwarded on MPL Interfaces using the Trickle parameter values assigned to the MPL Interface according to the following rules:
根据以下规则，使用分配给MPL接口的涓流参数值在MPL接口上转发MPL消息：
o Link-Local (scope 2) MPL messages are not forwarded.
o 链路本地（作用域2）MPL消息不转发。
o Realm-Local (scope 3) MPL messages are forwarded on all MPL Interfaces where all of the following are true:
o 域本地（范围3）MPL消息在所有MPL接口上转发，其中以下所有条件均为真：
* The multicast address to which the MPL Interface subscribes is the same as the multicast address of the MPL message.
* MPL接口订阅的多播地址与MPL消息的多播地址相同。
* The zone index of the MPL Interface is the same as the zone index of the MPL Interface on which the MPL message was received.
* MPL接口的区域索引与接收MPL消息的MPL接口的区域索引相同。
* The MPL Interface has PROACTIVE_FORWARDING set to TRUE.
* MPL接口的主动转发设置为TRUE。
* The assigned network identifier of the MPL message is "any", or the assigned network identifier of the MPL message is equal to the network identifier of the MPL Interface.
* MPL消息的分配网络标识符为“任意”，或者MPL消息的分配网络标识符等于MPL接口的网络标识符。
o Admin-Local (scope 4) MPL messages are forwarded on all MPL Interfaces that are subscribed to the same multicast address, have the same zone index, have PROACTIVE_FORWARDING set to TRUE, and have MPL_BLOCKED set to false.
o 管理本地（作用域4）MPL消息在所有MPL接口上转发，这些MPL接口订阅相同的多播地址，具有相同的区域索引，将主动转发设置为TRUE，并将MPL阻止设置为false。
o MPL messages that encapsulate a message with a multicast scope of 5 or higher are decapsulated and forwarded over the interface when the interface is subscribed to the multicast address of the decapsulated message.
o 封装多播作用域为5或更高的消息的MPL消息在接口订阅多播地址时被解除封装并通过接口转发。
Multicast messages without the MPL Option are forwarded on MPL Interfaces according to the following rules:
不带MPL选项的多播消息根据以下规则在MPL接口上转发：
o Link-Local (scope 2), Realm-Local (scope 3), and Admin-Local (scope 4) multicast messages are not forwarded.
o 链路本地（作用域2）、领域本地（作用域3）和管理本地（作用域4）多播消息不会转发。
o Multicast messages with a multicast scope of 5 or higher are encapsulated in an MPL message with destination address ALL_MPL_FORWARDERS with scope 4. The resulting message is then treated as described in Section 4.2.1.
o 多播作用域为5或更高的多播消息封装在目标地址为所有作用域为4的MPL转发器的MPL消息中。然后，按照第4.2.1节所述处理产生的消息。
An incoming message protected at Layer 2 MUST be subsequently re-protected at Layer 2 at all outgoing interfaces. Incoming messages are integrity checked and optionally decrypted at the incoming interface at Layer 2 using the keys and protection algorithm appropriate to the incoming interface's network and are re-protected at the outgoing interface using the keys and protection algorithm appropriate to the outgoing interface's network. It may be necessary to assess the relative levels of protection on the respective interfaces and apply policy rules -- for example, to avoid downgrading security where one network has a lower level of security than another.
在第2层受到保护的传入消息随后必须在所有传出接口的第2层重新受到保护。在第2层的传入接口处，使用适用于传入接口网络的密钥和保护算法对传入消息进行完整性检查和选择性解密，并在传出接口处使用适用于传出接口网络的密钥和保护算法对传入消息进行重新保护。可能需要评估各个接口上的相对保护级别，并应用策略规则——例如，在一个网络的安全级别低于另一个网络的情况下，避免降低安全级别。
An incoming MPL4 message that is not protected at Layer 2 MUST NOT be re-protected at Layer 2 at all outgoing interfaces.
在第2层未受保护的传入MPL4消息不得在所有传出接口的第2层重新保护。
An MPL Domain is a scope zone in which MPL Interfaces subscribe to the same MPL Domain Address [RFC7731]. In accordance with [RFC4007], a zone boundary passes through a node. For example, a small Low-Power and Lossy Network (LLN) node usually has one MPL mesh interface that is subscribed to the ALL_MPL_FORWARDERS multicast address with a scope value of 3 (Realm-Local) [RFC7346]. The node interface belongs to the zone, and the corresponding zone boundary does not pass through this node. In the border router with MPL Interfaces subscribed to the multicast address ALL_MPL_FORWARDERS with scope value 3, the zone usually includes this single interface and excludes all other interfaces. A notable exception is provided by a node where MPL Interfaces of the same technology share the same network identifier. These interfaces belong to the same MPL4 zone when the interfaces share the same zone index.
MPL域是MPL接口订阅相同MPL域地址的作用域[RFC7731]。根据[RFC4007]，区域边界通过节点。例如，小型低功耗有损网络（LLN）节点通常具有一个MPL网状接口，该接口订阅了作用域值为3（Realm Local）[RFC7346]的所有MPL转发器多播地址。节点接口属于分区，相应的分区边界不通过该节点。在多播地址为所有作用域值为3的MPL转发器订阅了MPL接口的边界路由器中，区域通常包括此单一接口，不包括所有其他接口。一个值得注意的例外是节点提供了相同技术的MPL接口共享相同的网络标识符。当这些接口共享相同的区域索引时，这些接口属于相同的MPL4区域。
In an MPL4 router, every MPL Interface subscribes to the Admin-Local ALL_MPL_FORWARDERS multicast address in addition to the Realm-Local ALL_MPL_FORWARDERS address.
在MPL4路由器中，除了域本地所有MPL转发器地址之外，每个MPL接口都订阅管理本地所有MPL转发器多播地址。
Every interface that belongs to an MPL Domain that extends over border routers MUST be subscribed to the Admin-Local ALL_MPL_FORWARDERS address.
属于扩展到边界路由器的MPL域的每个接口必须订阅Admin Local ALL_MPL_FORWARDERS地址。
The MPL4 zone corresponding with the MPL multicast address ALL_MPL_FORWARDERS with scope 4 (Admin-Local) applies to border routers with multiple interfaces, of which at least one interface is MPL enabled and is subscribed to multicast address ALL_MPL_FORWARDERS with scope 4. In a border router, all MPL-enabled interfaces that subscribe to the ALL_MPL_FORWARDERS address with scope 4 and for which MPL_BLOCKED is false belong to the same MPL4 zone when the interfaces share the same zone index.
与MPL多播地址对应的MPL4区域—作用域为4的所有\u MPL\u转发器（管理本地）适用于具有多个接口的边界路由器，其中至少有一个接口已启用MPL，并且订阅了作用域为4的所有\u MPL\u转发器的多播地址。在边界路由器中，当接口共享相同的区域索引时，订阅作用域为4的所有MPL转发器地址且MPL阻塞为false的所有启用MPL的接口都属于相同的MPL4区域。
MPL4 messages remain bounded within a zone as defined in [RFC4007]. Consequently, MPL4 messages cannot be routed between interfaces belonging to different zones. When the concept of zone is unknown or disabled in a router, all interfaces belong to the same zone. For example, consider a router with five interfaces, where Interfaces A and B belong to zone 1 and Interfaces C, D, and E belong to zone 2. MPL4 messages can be routed freely between Interfaces A and B, and freely between Interfaces C, D, and E. However, an MPL4 message MUST NOT be routed from Interface A to Interface D.
MPL4消息保持在[RFC4007]中定义的区域内。因此，MPL4消息不能在属于不同区域的接口之间路由。当路由器中区域的概念未知或禁用时，所有接口都属于同一区域。例如，考虑一个具有五个接口的路由器，其中接口A和B属于区域1，接口C、D和E属于区域2。MPL4消息可以在接口A和B之间自由路由，也可以在接口C、D和E之间自由路由。但是，MPL4消息不能从接口A路由到接口D。
Three parameters are created by this document. Their values are related to the Trickle timer intervals.
此文档创建了三个参数。它们的值与涓流计时器间隔有关。
o MPL_TO = DATA_MESSAGE_IMAX times 2, which leaves enough time to receive the second response message.
o MPL_TO=数据_消息_IMAX乘以2，留出足够的时间来接收第二条响应消息。
o MPL_CHECK_INT = 5 minutes, which means that a reaction to a network malfunction happens within 5 minutes.
o MPL_CHECK_INT=5分钟，这意味着对网络故障的反应在5分钟内发生。
o MPL_BLOCKED = TRUE, which means that the interface has not received MPL-enabled messages to include the interface in the MPL4 zone.
o MPL_BLOCKED=TRUE，这意味着接口尚未收到启用MPL的消息以将接口包括在MPL4区域中。
The security considerations of [RFC7731] also apply to MPL4 routers.
[RFC7731]的安全注意事项也适用于MPL4路由器。
The sending of MPL4 messages by a malicious node can have unwanted consequences, as explained by the following example. It is not unusual for a wired (e.g., Ethernet) link to be used between two floors or sections of an LLN, as radio propagation through reinforced concrete is generally poor. The MPL4 zone can thus envelop multiple routers, meshes, and links. It is possible that a malicious node could connect to a wired link on which no MPL-enabled nodes are foreseen. In this example configuration, the malicious node can send MPL4 messages to the MPL4 router interfaces. When nothing is done, the MPL4 routers will consequently distribute MPL4 messages from one mesh over the wired link to the next mesh, although the wired link was not expected to transport MPL4 messages.
恶意节点发送MPL4消息可能会产生不必要的后果，如下例所述。在LLN的两个楼层或部分之间使用有线（如以太网）链路并不罕见，因为通过钢筋混凝土的无线电传播通常很差。因此，MPL4区域可以封装多个路由器、网格和链路。恶意节点可能连接到有线链路，在该链路上无法预见启用MPL的节点。在此示例配置中，恶意节点可以向MPL4路由器接口发送MPL4消息。如果什么也不做，MPL4路由器将通过有线链路将MPL4消息从一个网格分发到下一个网格，尽管有线链路不希望传输MPL4消息。
To understand the consequences of this unwanted behavior, the following cases should be distinguished:
为了理解这种不必要行为的后果，应区分以下情况：
o The source mesh uses Layer 2 encryption.
o 源网格使用第2层加密。
o The MPL4 router can be managed.
o 可以管理MPL4路由器。
The four possible combinations are discussed below:
下面讨论四种可能的组合：
Layer 2 unsecured, router unmanaged: In this case, MPL4 messages are freely distributed over meshes and links that are interconnected by MPL4 routers within a zone. The MPL-enabled (malicious) nodes can read all MPL4 messages and distribute MPL4 messages over a network limited by a zone. This situation can be acceptable for an isolated network within a clearly defined space, where the connection of nodes can be tightly controlled. A completely wired LLN, e.g., such as is seen in BACnet (a protocol for building automation and control networks) [BACnet] is an example of an unencrypted LLN that would be considered physically secure.
第2层不安全，路由器不受管理：在这种情况下，MPL4消息自由分布在网格和链路上，这些网格和链路由区域内的MPL4路由器互连。启用MPL的（恶意）节点可以读取所有MPL4消息，并通过受区域限制的网络分发MPL4消息。这种情况对于在明确定义的空间内的隔离网络是可以接受的，其中节点的连接可以被严格控制。如BACnet（楼宇自动化和控制网络协议）[BACnet]中所示的完全有线LLN是被视为物理安全的未加密LLN的一个示例。
Layer 2 secured, router unmanaged: In this case, MPL4 messages are freely distributed over meshes and links that are interconnected by MPL4 routers within a zone. Following the rules of Section 4.3, the MPL4-enabled (malicious) nodes cannot read the MPL4 messages, and MPL4 messages sent by the malicious node are not accepted by other nodes. This situation is acceptable for a home network or managed network extending over precisely one zone, occupying a clearly defined physical space, where ease of installation is important. In such a network, the presence of the malicious node is not different from any other malicious node that
第2层安全，路由器非托管：在这种情况下，MPL4消息自由分布在网格和链路上，这些网格和链路由区域内的MPL4路由器互连。按照第4.3节的规则，启用MPL4的（恶意）节点无法读取MPL4消息，并且恶意节点发送的MPL4消息不被其他节点接受。这种情况对于家庭网络或管理网络来说是可以接受的，家庭网络或管理网络精确地扩展到一个区域，占据一个明确定义的物理空间，在这里易于安装是很重要的。在这样一个网络中，恶意节点的存在与其他恶意节点没有区别
tries to send messages over Layer 2 protected links. Because the network occupies exactly one zone, the MPL4 message distribution cannot be extended outside the network.
尝试通过第2层受保护的链接发送消息。由于网络只占用一个区域，因此不能将MPL4消息分发扩展到网络之外。
Layer 2 unsecured, router managed: In this case, the distribution of MPL4 messages over MPL4 router interfaces can be limited to those interfaces for which a manager has enabled MPL, as well as a set of multicast addresses. The malicious node cannot extend the distribution of MPL4 messages over unwanted interfaces. It is important that the handling of the interfaces by the manager is protected. However, MPL4 messages sent over the mesh can be interpreted by malicious nodes, and malicious messages can be injected into the set of meshes and links that are connected by the MPL4 routers for which the manager enabled the interfaces. This situation can be practical for interconnected links and meshes that are connected to a LAN over a limited period -- for example, during installation of the interconnected meshes and links.
第2层不安全，路由器管理：在这种情况下，MPL4路由器接口上的MPL4消息分发可以限制为管理器已启用MPL的接口以及一组多播地址。恶意节点无法在不需要的接口上扩展MPL4消息的分发。保护管理器对接口的处理非常重要。然而，恶意节点可以解释通过网格发送的MPL4消息，并且恶意消息可以被注入到由MPL4路由器连接的网格和链路集中，管理器为其启用了接口。这种情况对于在有限的时间内连接到LAN的互连链路和网格是可行的，例如，在安装互连的网格和链路期间。
Layer 2 secured, router managed: In this case, the distribution of MPL4 messages over MPL4 router interfaces can be limited to those interfaces for which a manager has enabled MPL, as well as a set of multicast addresses. Following the rules of Section 4.3, the malicious node cannot extend the distribution of MPL4 messages over unwanted interfaces, and MPL4 messages sent by the malicious node are not accepted by other nodes. It is important that the handling of the interfaces by the manager is protected. The MPL-enabled (malicious) nodes cannot read the MPL4 messages, and MPL4 messages sent by the malicious node are not accepted by other nodes. Depending on the number of managed interfaces, the network can progressively pass from autoconfigured to fully administratively controlled.
第2层安全、路由器管理：在这种情况下，MPL4路由器接口上的MPL4消息分发可以限制为管理器已启用MPL的接口以及一组多播地址。按照第4.3节的规则，恶意节点无法将MPL4消息的分发扩展到不需要的接口上，并且恶意节点发送的MPL4消息不被其他节点接受。保护管理器对接口的处理非常重要。启用MPL的（恶意）节点无法读取MPL4消息，并且恶意节点发送的MPL4消息不被其他节点接受。根据受管接口的数量，网络可以从自动配置逐步过渡到完全管理控制。
[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>.
[RFC3810] Vida, R., Ed., and L. Costa, Ed., "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, DOI 10.17487/RFC3810, June 2004, <http://www.rfc-editor.org/info/rfc3810>.
[RFC3810]Vida，R.，Ed.，和L.Costa，Ed.，“IPv6的多播侦听器发现版本2（MLDv2）”，RFC 3810，DOI 10.17487/RFC3810，2004年6月<http://www.rfc-editor.org/info/rfc3810>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, DOI 10.17487/RFC4291, February 2006, <http://www.rfc-editor.org/info/rfc4291>.
[RFC4291]Hinden，R.和S.Deering，“IP版本6寻址体系结构”，RFC 4291，DOI 10.17487/RFC42912006年2月<http://www.rfc-editor.org/info/rfc4291>.
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, "Transmission of IPv6 Packets over IEEE 802.15.4 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, <http://www.rfc-editor.org/info/rfc4944>.
[RFC4944]黑山，G.，Kushalnagar，N.，Hui，J.，和D.Culler，“通过IEEE 802.15.4网络传输IPv6数据包”，RFC 4944，DOI 10.17487/RFC4944，2007年9月<http://www.rfc-editor.org/info/rfc4944>.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. Thyagarajan, "Internet Group Management Protocol, Version 3", RFC 3376, DOI 10.17487/RFC3376, October 2002, <http://www.rfc-editor.org/info/rfc3376>.
[RFC3376]Cain，B.，Deering，S.，Kouvelas，I.，Fenner，B.，和A.Thyagarajan，“互联网组管理协议，版本3”，RFC 3376，DOI 10.17487/RFC3376，2002年10月<http://www.rfc-editor.org/info/rfc3376>.
[RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and B. Zill, "IPv6 Scoped Address Architecture", RFC 4007, DOI 10.17487/RFC4007, March 2005, <http://www.rfc-editor.org/info/rfc4007>.
[RFC4007]Deering，S.，Haberman，B.，Jinmei，T.，Nordmark，E.，和B.Zill，“IPv6作用域地址体系结构”，RFC 4007，DOI 10.17487/RFC4007，2005年3月<http://www.rfc-editor.org/info/rfc4007>.
[RFC5416] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, Ed., "Control and Provisioning of Wireless Access Points (CAPWAP) Protocol Binding for IEEE 802.11", RFC 5416, DOI 10.17487/RFC5416, March 2009, <http://www.rfc-editor.org/info/rfc5416>.
[RFC5416]Calhoun，P.，Ed.，Montemurro，M.，Ed.，和D.Stanley，Ed.，“IEEE 802.11无线接入点（CAPWAP）协议绑定的控制和供应”，RFC 5416，DOI 10.17487/RFC5416，2009年3月<http://www.rfc-editor.org/info/rfc5416>.
[RFC6206] Levis, P., Clausen, T., Hui, J., Gnawali, O., and J. Ko, "The Trickle Algorithm", RFC 6206, DOI 10.17487/RFC6206, March 2011, <http://www.rfc-editor.org/info/rfc6206>.
[RFC6206]Levis，P.，Clausen，T.，Hui，J.，Gnawali，O.，和J.Ko，“涓流算法”，RFC 6206，DOI 10.17487/RFC6206，2011年3月<http://www.rfc-editor.org/info/rfc6206>.
[RFC7346] Droms, R., "IPv6 Multicast Address Scopes", RFC 7346, DOI 10.17487/RFC7346, August 2014, <http://www.rfc-editor.org/info/rfc7346>.
[RFC7346]Droms，R.，“IPv6多播地址范围”，RFC 7346，DOI 10.17487/RFC7346，2014年8月<http://www.rfc-editor.org/info/rfc7346>.
[RFC7731] Hui, J. and R. Kelsey, "Multicast Protocol for Low-Power and Lossy Networks (MPL)", RFC 7731, DOI 10.17487/RFC7731, February 2016, <http://www.rfc-editor.org/info/rfc7731>.
[RFC7731]Hui，J.和R.Kelsey，“低功耗和有损网络的多播协议（MPL）”，RFC 7731，DOI 10.17487/RFC7731，2016年2月<http://www.rfc-editor.org/info/rfc7731>.
[IEEE802.15.4] IEEE, "IEEE Standard for Local and metropolitan area networks--Part 15.4: Low-Rate Wireless Personal Area Networks (LR-WPANs)", IEEE 802.15.4, DOI 10.1109/ieeestd.2011.6012487, <http://ieeexplore.ieee.org/servlet/ opac?punumber=6012485>.
[IEEE802.15.4]IEEE，“局域网和城域网的IEEE标准——第15.4部分：低速无线个人区域网（LR WPAN）”，IEEE 802.15.4，DOI 10.1109/ieeestd.2011.6012487<http://ieeexplore.ieee.org/servlet/ opac？punumber=6012485>。
[IEEE802.11] IEEE, "IEEE Standard for Information technology-- Telecommunications and information exchange between systems Local and metropolitan area networks--Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications", IEEE 802.11-2012, DOI 10.1109/ieeestd.2012.6178212, <http://ieeexplore.ieee.org/servlet/ opac?punumber=6178209>.
[IEEE802.11]IEEE，“IEEE信息技术标准——系统局域网和城域网之间的电信和信息交换——具体要求第11部分：无线局域网介质访问控制（MAC）和物理层（PHY）规范”，IEEE 802.11-2012，DOI 10.1109/ieeestd.2012.6178212， <http://ieeexplore.ieee.org/servlet/ opac？punumber=6178209>。
[G.9959] International Telecommunication Union, "Short range narrow-band digital radiocommunication transceivers - PHY, MAC, SAR and LLC layer specifications", ITU-T Recommendation G.9959, January 2015, <http://www.itu.int/rec/T-REC-G.9959>.
[G.9959]国际电信联盟，“短程窄带数字无线电通信收发器-物理层、MAC层、SAR层和LLC层规范”，ITU-T建议G.9959，2015年1月<http://www.itu.int/rec/T-REC-G.9959>.
[BTLE] Bluetooth Special Interest Group, "Bluetooth Core Specification Version 4.1", December 2013, <https://www.bluetooth.org/en-us/specification/ adopted-specifications>.
[BTLE]蓝牙特别兴趣小组，“蓝牙核心规范版本4.1”，2013年12月<https://www.bluetooth.org/en-us/specification/ 采用规范>。
[RFC3973] Adams, A., Nicholas, J., and W. Siadak, "Protocol Independent Multicast - Dense Mode (PIM-DM): Protocol Specification (Revised)", RFC 3973, DOI 10.17487/RFC3973, January 2005, <http://www.rfc-editor.org/info/rfc3973>.
[RFC3973]Adams，A.，Nicholas，J.，和W.Siadak，“协议独立多播-密集模式（PIM-DM）：协议规范（修订版）”，RFC 3973，DOI 10.17487/RFC3973，2005年1月<http://www.rfc-editor.org/info/rfc3973>.
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", RFC 4601, DOI 10.17487/RFC4601, August 2006, <http://www.rfc-editor.org/info/rfc4601>.
[RFC4601]Fenner，B.，Handley，M.，Holbrook，H.，和I.Kouvelas，“协议独立多播-稀疏模式（PIM-SM）：协议规范（修订版）”，RFC 4601，DOI 10.17487/RFC4601，2006年8月<http://www.rfc-editor.org/info/rfc4601>.
[RFC7576] Jiang, S., Carpenter, B., and M. Behringer, "General Gap Analysis for Autonomic Networking", RFC 7576, DOI 10.17487/RFC7576, June 2015, <http://www.rfc-editor.org/info/rfc7576>.
[RFC7576]Jiang，S.，Carpenter，B.，和M.Behringer，“自主网络的一般差距分析”，RFC 7576，DOI 10.17487/RFC7576，2015年6月<http://www.rfc-editor.org/info/rfc7576>.
[RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets over ITU-T G.9959 Networks", RFC 7428, DOI 10.17487/RFC7428, February 2015, <http://www.rfc-editor.org/info/rfc7428>.
[RFC7428]Brandt，A.和J.Buron，“通过ITU-T G.9959网络传输IPv6数据包”，RFC 7428，DOI 10.17487/RFC7428，2015年2月<http://www.rfc-editor.org/info/rfc7428>.
[RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015, <http://www.rfc-editor.org/info/rfc7668>.
[RFC7668]Nieminen，J.，Savolainen，T.，Isomaki，M.，Patil，B.，Shelby，Z.，和C.Gomez，“蓝牙（R）低能量IPv6”，RFC 7668，DOI 10.17487/RFC7668，2015年10月<http://www.rfc-editor.org/info/rfc7668>.
[BACnet] "BACnet Webpage", <http://www.bacnet.org>.
[BACnet]“BACnet网页”<http://www.bacnet.org>.
Acknowledgements
致谢
This document reflects discussions and remarks from several individuals, including (in alphabetical order) Scott Bradner, Esko Dijk, Adrian Farrel, Matthew Gillmore, Joel Halpern, Steve Hanna, Michael Richardson, and Pascal Thubert.
本文件反映了几个人的讨论和评论，包括（按字母顺序排列）斯科特·布拉德纳、埃斯科·迪克、阿德里安·法雷尔、马修·吉尔摩、乔尔·哈尔佩恩、史蒂夫·汉纳、迈克尔·理查森和帕斯卡·苏伯特。
Authors' Addresses
作者地址
Peter van der Stok Consultant
彼得·范德斯托克顾问
Email: consultancy@vanderstok.org
Email: consultancy@vanderstok.org
Robert Cragie ARM Ltd. 110 Fulbourn Road Cambridge CB1 9NJ United Kingdom
Robert Cragie ARM Ltd.英国剑桥CB1 9NJ富尔伯恩路110号
Email: robert.cragie@arm.com
Email: robert.cragie@arm.com