Internet Engineering Task Force (IETF) B. Cheng
Request for Comments: 8629 MIT Lincoln Laboratory
Category: Standards Track L. Berger, Ed.
ISSN: 2070-1721 LabN Consulting, L.L.C.
July 2019
Internet Engineering Task Force (IETF) B. Cheng
Request for Comments: 8629 MIT Lincoln Laboratory
Category: Standards Track L. Berger, Ed.
ISSN: 2070-1721 LabN Consulting, L.L.C.
July 2019
Dynamic Link Exchange Protocol (DLEP) Multi-Hop Forwarding Extension
动态链路交换协议（DLEP）多跳转发扩展
Abstract
摘要
This document defines an extension to the Dynamic Link Exchange Protocol (DLEP) that enables the reporting and control of multi-hop forwarding by DLEP-capable modems.
本文档定义了动态链路交换协议（DLEP）的扩展，该协议允许通过支持DLEP的调制解调器报告和控制多跳转发。
Status of This Memo
关于下段备忘
This is an Internet Standards Track document.
这是一份互联网标准跟踪文件。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关互联网标准的更多信息，请参见RFC 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8629.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问https://www.rfc-editor.org/info/rfc8629.
Copyright Notice
版权公告
Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.
版权（c）2019 IETF信托基金和被确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(https://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Extension Usage and Identification . . . . . . . . . . . . . 3
3. Extension Data Items . . . . . . . . . . . . . . . . . . . . 3
3.1. Hop Count . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Hop Control . . . . . . . . . . . . . . . . . . . . . . . 5
3.2.1. Reset . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2.2. Terminate . . . . . . . . . . . . . . . . . . . . . . 7
3.2.3. Direct Connection . . . . . . . . . . . . . . . . . . 7
3.2.4. Suppress Forwarding . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5.1. Extension Type Value . . . . . . . . . . . . . . . . . . 8
5.2. Data Item Values . . . . . . . . . . . . . . . . . . . . 9
5.3. Hop Control Actions Registry . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Normative References . . . . . . . . . . . . . . . . . . 10
6.2. Informative References . . . . . . . . . . . . . . . . . 10
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Extension Usage and Identification . . . . . . . . . . . . . 3
3. Extension Data Items . . . . . . . . . . . . . . . . . . . . 3
3.1. Hop Count . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Hop Control . . . . . . . . . . . . . . . . . . . . . . . 5
3.2.1. Reset . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2.2. Terminate . . . . . . . . . . . . . . . . . . . . . . 7
3.2.3. Direct Connection . . . . . . . . . . . . . . . . . . 7
3.2.4. Suppress Forwarding . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5.1. Extension Type Value . . . . . . . . . . . . . . . . . . 8
5.2. Data Item Values . . . . . . . . . . . . . . . . . . . . 9
5.3. Hop Control Actions Registry . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Normative References . . . . . . . . . . . . . . . . . . 10
6.2. Informative References . . . . . . . . . . . . . . . . . 10
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
The Dynamic Link Exchange Protocol (DLEP) is defined in [RFC8175]. It provides the exchange of link-related control information between a modem and a router. DLEP defines a base set of mechanisms as well as support for possible extensions. This document defines one such extension.
[RFC8175]中定义了动态链路交换协议（DLEP）。它提供调制解调器和路由器之间链路相关控制信息的交换。DLEP定义了一组基本机制以及对可能扩展的支持。本文档定义了一个这样的扩展。
Some modem technologies support mobile ad hoc network (MANET) forwarding where connectivity to destinations is provided via forwarding in intermediate modems. This document refers to forwarding by intermediate modems as "multi-hop forwarding". DLEP Destination Messages can be used to report such reachable destinations (see [RFC8175]), but do not provide any information related to the number or capacity of the hops. The extension defined in this document enables modems to inform routers when multi-hop forwarding is being used and allows routers to request that modems change multi-hop forwarding behavior. The extension defined in this document is referred to as "Multi-Hop Forwarding", where each modem that transmits/sends data to reach a particular destination is counted as a hop.
一些调制解调器技术支持移动自组织网络（MANET）转发，其中通过中间调制解调器中的转发提供到目的地的连接。本文档将中间调制解调器的转发称为“多跳转发”。DLEP目的地消息可用于报告此类可到达目的地（请参见[RFC8175]），但不提供与跃点数量或容量相关的任何信息。本文档中定义的扩展允许调制解调器在使用多跳转发时通知路由器，并允许路由器请求调制解调器更改多跳转发行为。本文档中定义的扩展称为“多跳转发”，其中传输/发送数据以到达特定目的地的每个调制解调器都算作一个跳。
It is important to note that the use of the Hop Control mechanism defined in this document can result in connectivity changes and even loss of the ability to reach one or more destinations. The defined
需要注意的是，使用本文档中定义的跃点控制机制可能会导致连接更改，甚至失去到达一个或多个目的地的能力。定义的
mechanism will report such connectivity changes, but the details of what a router does or how it reacts to such are out scope of this document.
该机制将报告此类连接更改，但路由器做什么或如何对此类更改作出反应的详细信息超出了本文档的范围。
This document defines a new DLEP Extension Type Value in Section 2, which indicates the use of the extension, and three new DLEP Data Items in Section 3.
本文档在第2节中定义了一个新的DLEP扩展类型值，该值指示扩展的使用，并在第3节中定义了三个新的DLEP数据项。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“建议”、“不建议”、“可”和“可选”在所有大写字母出现时（如图所示）应按照BCP 14[RFC2119][RFC8174]所述进行解释。
The use of the Multi-Hop Forwarding Extension SHOULD be configurable. Per [RFC8175], to indicate that the extension is to be used, an implementation includes the Multi-Hop Forwarding Extension Type Value in the Extensions Supported Data Item. The Extensions Supported Data Item is sent and processed according to [RFC8175].
多跳转发扩展的使用应该是可配置的。根据[RFC8175]，为了指示要使用扩展，实现在支持扩展的数据项中包括多跳转发扩展类型值。支持扩展的数据项根据[RFC8175]发送和处理。
The Multi-Hop Forwarding Extension Type Value is 1 (see Section 5).
多跳转发扩展类型值为1（参见第5节）。
Three data items are defined by this extension. The Hop Count Data Item is used by a modem to provide the number of modem hops traversed to reach a particular destination. The Hop Control Data Item is used by a router to request that a modem alter connectivity to a particular destination. The Suppress Forwarding Data Item is used by a router to request that a modem disable multi-hop forwarding on either a device or destination basis.
此扩展定义了三个数据项。跳数数据项由调制解调器用来提供到达特定目的地所经过的调制解调器跳数。路由器使用跃点控制数据项请求调制解调器改变与特定目的地的连接。路由器使用抑制转发数据项请求调制解调器禁用设备或目的地的多跳转发。
The Hop Count Data Item is used by a modem to indicate the number of modems that transmit/send data to reach a particular destination, i.e., hops, between the modem and a specific destination. In other words, each hop represents a transmission, and the number of hops is equal to the number of transmissions required to go from a router's connected modem to the destination's connected modem. The minimum number of hops is 1, which represents transmission to destinations that are directly reachable via the router's locally connected modem.
跳数数据项由调制解调器使用，以指示传输/发送数据以到达特定目的地的调制解调器数量，即调制解调器与特定目的地之间的跳数。换句话说，每个跃点代表一次传输，跃点的数量等于从路由器连接的调制解调器到目的地连接的调制解调器所需的传输数量。最小跳数为1，表示可通过路由器的本地连接调制解调器直接到达目的地的传输。
The data item also contains an indication of when a destination that currently has a hop count of greater than one (1) could be made directly reachable by a modem, e.g., by reaiming an antenna.
该数据项还包含一个指示，指示当前跳数大于一（1）的目的地何时可由调制解调器（例如，通过重新对准天线）直接到达。
The Hop Count Data Item SHOULD be carried in the Destination Up, Destination Update, Destination Announce Response, and Link Characteristics Response Messages when the Hop Count to a destination is greater than one (1).
当到达目的地的跃点计数大于一（1）时，跃点计数数据项应包含在目的地Up、目的地更新、目的地公告响应和链路特性响应消息中。
A router receiving a Hop Count Data Item can use this information in its forwarding and routing decisions, but specific use is out of scope of this document. When using this extension, the absence of the Hop Count Data Item MUST be interpreted by the router as a Hop Count value of one (1).
接收跃点计数数据项的路由器可以在其转发和路由决策中使用此信息，但具体使用超出本文档的范围。使用此扩展时，路由器必须将缺少跃点计数数据项解释为跃点计数值为一（1）。
The format of the Hop Count Data Item is:
跃点计数数据项的格式为：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P| Reserved | Hop Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P| Reserved | Hop Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 21
数据项类型：21
Length: 2
长度：2
P:
P:
The P-bit indicates that a destination is potentially directly reachable. When the P-bit is set, the router MAY request a direct link to the associated destination using the Hop Control Data Item described below. This field MUST be ignored when the value contained in the Hop Count field is one (1).
P位表示可能直接到达目的地。当P位被设置时，路由器可以使用下面描述的跳控制数据项请求到相关目的地的直接链路。当跃点计数字段中包含的值为一（1）时，必须忽略此字段。
Reserved:
保留：
The Reserved field MUST be set to zero by the sender (a modem) and ignored by the receiver (a router).
发送方（调制解调器）必须将保留字段设置为零，接收方（路由器）必须忽略该字段。
Hop Count:
跃点计数：
The Hop Count is an unsigned 8-bit integer indicating the number of modem hops required (i.e., number of times a packet will be transmitted) to reach the destination indicated in the message. The special value of 255 (0xFF) is used to indicate that the
跳数是一个无符号8位整数，表示到达消息中指示的目的地所需的调制解调器跳数（即，数据包将被传输的次数）。特殊值255（0xFF）用于指示
number of hops is an unknown number greater than one (1). This field MUST contain a value of at least one (1) if the associated destination is reachable.
跃点数是大于一（1）的未知数。如果关联的目标是可访问的，则此字段必须包含至少一（1）个值。
A value of zero (0) is used to indicate that the processing of a Hop Control action (see Section 3.2) has resulted in the destination no longer being reachable. A zero value MUST NOT be used in any message other than a Link Characteristics Response Message.
零（0）值用于表示跃点控制操作（参见第3.2节）的处理导致无法再到达目的地。除链路特性响应消息外，任何消息中不得使用零值。
The Hop Control Data Item is used by a router to request a change in connectivity to a particular destination or to perform multi-hop processing on a device-wide basis. A router can request that a multi-hop-reachable destination be changed to a single-hop destination. A router can also indicate that the modem terminates a previous direct connectivity request to a particular destination.
路由器使用跳控制数据项来请求改变到特定目的地的连接，或在设备范围内执行多跳处理。路由器可以请求将多跳可到达目的地更改为单跳目的地。路由器还可以指示调制解调器终止先前对特定目的地的直接连接请求。
The Hop Control Data Item MAY be carried in a Session Update Message sent by a router when the control applies to the whole device, or a Link Characteristics Request Message when the control applies to a particular destination.
当控制应用于整个设备时，跳控制数据项可以在路由器发送的会话更新消息中携带，或者当控制应用于特定目的地时在链路特性请求消息中携带。
A modem that receives the Hop Control Data Item in a Link Characteristics Request Message SHOULD take whatever actions are needed to make the change indicated by the data item for the associated destination Media Access Control (MAC) address. Once the change is made, fails, or is rejected, the modem MUST respond with a Link Characteristics Response Message containing an updated Hop Count Data Item. Note that other destinations can be impacted as a result of the change, and such changes are reported in Destination Down and Destination Update Messages. The modem MUST notify the router of each destination that is not identified in the Link Characteristics Response Message and is no longer reachable via a Destination Down Message. The modem MUST also notify the router of each impacted destination that is not identified in the Link Characteristics Response Message via a Destination Update Message.
在链路特性请求消息中接收跃点控制数据项的调制解调器应采取所需的任何措施，以对相关目标媒体访问控制（MAC）地址进行数据项指示的更改。一旦更改完成、失败或被拒绝，调制解调器必须以包含更新的跃点计数数据项的链路特性响应消息进行响应。请注意，更改可能会影响其他目的地，此类更改会在目的地关闭和目的地更新消息中报告。调制解调器必须向路由器通知链路特性响应消息中未标识且无法通过目的地关闭消息到达的每个目的地。调制解调器还必须通过目的地更新消息将链路特性响应消息中未识别的每个受影响目的地通知路由器。
Failures may occur for multiple reasons, for example, the transmission characteristics of the link don't support the one-hop connection at the time of the request. Requests can be rejected by local policy.
故障可能由于多种原因发生，例如，链路的传输特性在请求时不支持单跳连接。本地策略可以拒绝请求。
A modem that receives the Hop Control Data Item in a Session Update Message SHOULD take whatever actions are needed to make the change indicated by the data item for all known destinations. Once the change is made, fails, or is rejected, the modem MUST respond with a
在会话更新消息中接收跃点控制数据项的调制解调器应采取所需的任何操作，以对所有已知目的地进行数据项指示的更改。一旦更改完成、失败或被拒绝，调制解调器必须以
Session Update Response Message with an appropriate Status Code. The destination-specific impact of processing a Hop Control Data Item in a Session Update Message is provided via Destination Down and Destination Update Messages. The modem MUST notify the router of each destination that is no longer reachable via a Destination Down Message. The modem MUST notify the router of any changes in Hop Counts via Destination Update Messages.
具有适当状态代码的会话更新响应消息。处理会话更新消息中的跃点控制数据项的特定于目的地的影响通过目的地关闭和目的地更新消息提供。调制解调器必须通过目的地关闭消息通知路由器无法再到达的每个目的地。调制解调器必须通过目标更新消息通知路由器跳数的任何变化。
The format of the Hop Control Data Item is:
跃点控制数据项的格式为：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Control Actions |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Control Actions |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 22
数据项类型：22
Length: 2
长度：2
Hop Control Actions:
跃点控制操作：
The Hop Control Actions field is an unsigned 16-bit value with the following meaning:
跃点控制操作字段是一个无符号的16位值，具有以下含义：
+-------+---------------------+
| Value | Action |
+-------+---------------------+
| 0 | Reset |
| 1 | Terminate |
| 2 | Direct Connection |
| 3 | Suppress Forwarding |
+-------+---------------------+
+-------+---------------------+
| Value | Action |
+-------+---------------------+
| 0 | Reset |
| 1 | Terminate |
| 2 | Direct Connection |
| 3 | Suppress Forwarding |
+-------+---------------------+
Table 1: Hop Control Actions Values
表1：跃点控制动作值
The Reset Action requests that the default behavior be restored. When received in a Session Update Message, a modem MUST clear all control actions that have previously been processed on a device-wide basis and revert to its configured behavior. When received in a Link Characteristics Request Message, a modem MUST clear all control actions that have previously been processed for the destination indicated in the message.
重置操作请求恢复默认行为。当在会话更新消息中收到时，调制解调器必须清除以前在设备范围内处理过的所有控制操作，并恢复到其配置的行为。当在链路特性请求消息中收到时，调制解调器必须清除先前为消息中所示目的地处理的所有控制动作。
The Terminate Action is only valid on a per-destination basis and MUST NOT be sent in a Session Update Message. It indicates that a direct connection is no longer needed with the destination identified in the message. This request has no impact on multi-hop destinations and may fail even in a single-hop case, i.e., it can result in the Hop Count to the destination not being impacted by the processing of the request.
终止操作仅在每个目标上有效，不能在会话更新消息中发送。它表示不再需要与消息中标识的目的地直接连接。此请求对多跳目的地没有影响，甚至在单跳情况下也可能失败，即，它可能导致到目的地的跳数不受请求处理的影响。
The Direct Connection Action is only valid on a per-destination basis and MUST NOT be sent in a Session Update Message. It indicates that the modem SHOULD attempt to establish a direct connection with the destination identified in the message. This action SHOULD only be sent for destinations for which the Hop Count is both greater than 1 and has the P-Bit set in the previously received Hop Count Data Item. Results of the request for the destination identified in the message are provided as described above.
直接连接操作仅在每个目标上有效，不能在会话更新消息中发送。它表示调制解调器应尝试与消息中标识的目的地建立直接连接。此操作应仅针对跃点计数大于1且在先前接收的跃点计数数据项中设置了P位的目的地发送。如上所述，提供对消息中标识的目的地的请求的结果。
The Suppress Forwarding Action is used by a router to indicate to its peer that multi-hop forwarding performed by the modem is to be suppressed. A router can request that multi-hop forwarding be suppressed on a device-wide or destination-specific basis.
路由器使用抑制转发动作向其对等方指示要抑制调制解调器执行的多跳转发。路由器可以请求在设备范围内或特定于目的地的基础上抑制多跳转发。
A modem that receives the Suppress Forwarding Data Item in a Session Update Message MUST suppress multi-hop forwarding on a device-wide basis. This means that data traffic originating from the modem's peer router SHALL only be sent by the modem to destinations that are one modem hop away, and that any data traffic received by the modem from another modem that is not destined to the peer router SHALL be dropped. The impact on destination hop counts are provided to the router by the modem as described above.
在会话更新消息中接收抑制转发数据项的调制解调器必须在设备范围内抑制多跳转发。这意味着来自调制解调器对等路由器的数据通信量只能由调制解调器发送到一个调制解调器跳距的目的地，并且调制解调器从另一个调制解调器接收到的任何数据通信量，如果没有发送到对等路由器，则应丢弃。如上所述，调制解调器向路由器提供对目的地跳数的影响。
A modem that receives the Suppress Forwarding Data Item in a Link Characteristics Request Message MUST suppress multi-hop forwarding for only the destination indicated in the message. This means that data traffic originating from the modem's peer router SHALL be sent by the modem to the destination indicated in the Link Characteristics Request Message only when it is one modem hop away. Notably, data traffic received by the modem from another modem can be forwarded by the modem per its normal processing. Results are provided as described above.
在链路特性请求消息中接收抑制转发数据项的调制解调器必须仅对消息中指示的目的地抑制多跳转发。这意味着来自调制解调器对等路由器的数据通信量只有在距离调制解调器一个跃点时，才能由调制解调器发送到链路特性请求消息中指示的目的地。值得注意的是，调制解调器从另一个调制解调器接收的数据通信量可以由调制解调器按照其正常处理进行转发。结果如上所述。
The extension defined in this document enables the reporting and control of forwarding information by DLEP-capable modems. The extension does not inherently introduce any additional vulnerabilities above those documented in [RFC8175]. The approach taken to security in that document applies equally when running the extension defined in this document.
本文档中定义的扩展支持通过支持DLEP的调制解调器报告和控制转发信息。扩展本身不会引入任何超过[RFC8175]中记录的漏洞的额外漏洞。在运行本文档中定义的扩展时，该文档中的安全方法同样适用。
The extension does define one mechanism that is worth particular note. It includes a Hop Control mechanism (see Section 3.2) that is similar to the Link Characteristics Request Message defined in [RFC8175] in that it can impact the set of destinations reported as reachable. With the Link Characteristics Request Message, this risk is implicit. With the Hop Control mechanism defined in this document, it is more likely. From a security perspective, implementations should be aware of this increased risk and may choose to implement additional configuration control mechanisms to ensure that the Hop Control mechanism is only used under conditions intended by the network operator.
扩展确实定义了一种值得特别注意的机制。它包括一个跃点控制机制（见第3.2节），该机制类似于[RFC8175]中定义的链路特性请求消息，因为它可以影响报告为可到达的目的地集。对于链路特性请求消息，这种风险是隐含的。通过本文档中定义的跃点控制机制，更有可能实现。从安全角度来看，实现应意识到这种增加的风险，并可选择实现额外的配置控制机制，以确保跳控制机制仅在网络运营商预期的条件下使用。
Implementations of the extension defined in this document MUST support configuration of TLS usage, as described in [RFC8175], in order to protect configurations where injection attacks are possible, i.e., when the link between a modem and router is not otherwise protected.
本文档中定义的扩展的实现必须支持配置TLS使用，如[RFC8175]中所述，以保护可能发生注入攻击的配置，即当调制解调器和路由器之间的链路没有其他保护时。
Note that this extension does allow a compromised or impersonating modem to suppress transmission by the router or a switch that interconnects the modem and router. Similar attacks are generally possible for DLEP, for example, an impersonating modem may cause a session reset or cause a compromised modem to simply drop all traffic destined to, or sent by, a router. [RFC8175] defines the use of TLS to protect against the impersonating attacker.
请注意，此扩展允许受损或模拟调制解调器抑制路由器或互连调制解调器和路由器的交换机的传输。对于DLEP，类似的攻击通常是可能的，例如，模拟调制解调器可能会导致会话重置或导致受损的调制解调器简单地丢弃所有发送到路由器或由路由器发送的通信量。[RFC8175]定义了使用TLS来防止模拟攻击者的攻击。
As described below, IANA has assigned 3 values to registries defined by [RFC8175] and created a new registry.
如下所述，IANA为[RFC8175]定义的注册表分配了3个值，并创建了一个新的注册表。
IANA has registered the following new value in the Specification Required range of the "Extension Type Values" registry within the "Dynamic Link Exchange Protocol (DLEP) Parameters" registry.
IANA已在“动态链接交换协议（DLEP）参数”注册表中的“扩展类型值”注册表的规范要求范围内注册了以下新值。
+------+----------------------+
| Code | Description |
+------+----------------------+
| 1 | Multi-Hop Forwarding |
+------+----------------------+
+------+----------------------+
| Code | Description |
+------+----------------------+
| 1 | Multi-Hop Forwarding |
+------+----------------------+
Table 2: Requested Extension Type Value
表2：请求的扩展类型值
IANA has registered the following 2 values in the Specification Required range of the "Data Item Type Values" registry within the "Dynamic Link Exchange Protocol (DLEP) Parameters" registry.
IANA已在“动态链接交换协议（DLEP）参数”注册表中的“数据项类型值”注册表的规范要求范围内注册了以下2个值。
+-----------+-------------+
| Type Code | Description |
+-----------+-------------+
| 21 | Hop Count |
| 22 | Hop Control |
+-----------+-------------+
+-----------+-------------+
| Type Code | Description |
+-----------+-------------+
| 21 | Hop Count |
| 22 | Hop Control |
+-----------+-------------+
Table 3: Requested Data Item Values
表3：请求的数据项值
IANA has created the "Hop Control Actions Values" registry within the "Dynamic Link Exchange Protocol (DLEP) Parameters" registry. The following table provides initial registry values and the registration procedures [RFC8126] that apply:
IANA已在“动态链路交换协议（DLEP）参数”注册表中创建了“跃点控制操作值”注册表。下表提供了初始注册表值和适用的注册过程[RFC8126]：
+-------------+------------------------+
| Value | Action/Policy |
+-------------+------------------------+
| 0 | Reset |
| 1 | Terminate |
| 2 | Direct Connection |
| 3 | Suppress Forwarding |
| 4-65519 | Specification Required |
| 65520-65534 | Private Use |
| 65535 | Reserved |
+-------------+------------------------+
+-------------+------------------------+
| Value | Action/Policy |
+-------------+------------------------+
| 0 | Reset |
| 1 | Terminate |
| 2 | Direct Connection |
| 3 | Suppress Forwarding |
| 4-65519 | Specification Required |
| 65520-65534 | Private Use |
| 65535 | Reserved |
+-------------+------------------------+
Table 4: Hop Control Actions Values
表4：跃点控制动作值
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，DOI 10.17487/RFC2119，1997年3月<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8174]Leiba，B.，“RFC 2119关键词中大写与小写的歧义”，BCP 14，RFC 8174，DOI 10.17487/RFC8174，2017年5月<https://www.rfc-editor.org/info/rfc8174>.
[RFC8175] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B. Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175, DOI 10.17487/RFC8175, June 2017, <https://www.rfc-editor.org/info/rfc8175>.
[RFC8175]Ratliff，S.，Jury，S.，Satterwhite，D.，Taylor，R.，和B.Berry，“动态链路交换协议（DLEP）”，RFC 8175，DOI 10.17487/RFC81752017年6月<https://www.rfc-editor.org/info/rfc8175>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, <https://www.rfc-editor.org/info/rfc8126>.
[RFC8126]Cotton，M.，Leiba，B.，和T.Narten，“在RFC中编写IANA考虑事项部分的指南”，BCP 26，RFC 8126，DOI 10.17487/RFC8126，2017年6月<https://www.rfc-editor.org/info/rfc8126>.
Acknowledgments
致谢
Helpful comments were received from members of the MANET working group, including Henning Rogge, Victoria Pritchard, and David Wiggins.
MANET工作组成员，包括亨宁·罗格、维多利亚·普里查德和大卫·维金斯，提出了有益的意见。
Authors' Addresses
作者地址
Bow-Nan Cheng MIT Lincoln Laboratory Massachusetts Institute of Technology 244 Wood Street Lexington, MA 02421-6426
麻省理工学院林肯实验室马萨诸塞州莱克星顿伍德街244号，马萨诸塞州02421-6426
Email: bcheng@ll.mit.edu
Email: bcheng@ll.mit.edu
Lou Berger (editor) LabN Consulting, L.L.C.
Lou Berger（编辑）LabN咨询公司，L.L.C。
Email: lberger@labn.net
Email: lberger@labn.net