Internet Engineering Task Force (IETF) Y. Weingarten, Ed.
Request for Comments: 6378 Nokia Siemens Networks
Category: Standards Track S. Bryant
ISSN: 2070-1721 E. Osborne
Cisco
N. Sprecher
Nokia Siemens Networks
A. Fulignoli, Ed.
Ericsson
October 2011
Internet Engineering Task Force (IETF) Y. Weingarten, Ed.
Request for Comments: 6378 Nokia Siemens Networks
Category: Standards Track S. Bryant
ISSN: 2070-1721 E. Osborne
Cisco
N. Sprecher
Nokia Siemens Networks
A. Fulignoli, Ed.
Ericsson
October 2011
MPLS Transport Profile (MPLS-TP) Linear Protection
MPLS传输配置文件（MPLS-TP）线性保护
Abstract
摘要
This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunications Union Telecommunications Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge (PWE3) architectures to support the capabilities and functionalities of a packet transport network as defined by the ITU-T.
本文件是联合互联网工程任务组（IETF）/国际电信联盟电信标准化部门（ITU-T）努力的成果，旨在将MPLS传输配置文件纳入IETF MPLS和伪线仿真边到边（PWE3）中支持ITU-T定义的分组传输网络的能力和功能的体系结构。
This document addresses the functionality described in the MPLS-TP Survivability Framework document (RFC 6372) and defines a protocol that may be used to fulfill the function of the Protection State Coordination for linear protection, as described in that document.
本文件阐述了MPLS-TP生存能力框架文件（RFC 6372）中描述的功能，并定义了一个协议，该协议可用于实现线性保护的保护状态协调功能，如该文件所述。
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 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。有关互联网标准的更多信息，请参见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/rfc6378.
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/rfc6378.
Copyright Notice
版权公告
Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2011 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。
This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English.
本文件可能包含2008年11月10日之前发布或公开的IETF文件或IETF贡献中的材料。控制某些材料版权的人员可能未授予IETF信托允许在IETF标准流程之外修改此类材料的权利。在未从控制此类材料版权的人员处获得充分许可的情况下，不得在IETF标准流程之外修改本文件，也不得在IETF标准流程之外创建其衍生作品，除了将其格式化以RFC形式发布或将其翻译成英语以外的其他语言。
Table of Contents
目录
1. Introduction ....................................................4
1.1. Protection Architectures ...................................4
1.2. Scope of the Document ......................................5
2. Conventions Used in This Document ...............................6
2.1. Acronyms ...................................................6
2.2. Definitions and Terminology ................................7
3. Protection State Control Logic ..................................7
3.1. Local Request Logic ........................................9
3.2. Remote Requests ...........................................11
3.3. PSC Control Logic .........................................12
3.4. PSC Message Generator .....................................12
3.5. Wait-to-Restore (WTR) Timer ...............................12
3.6. PSC Control States ........................................13
3.6.1. Local and Remote State .............................14
4. Protection State Coordination (PSC) Protocol ...................14
4.1. Transmission and Acceptance of PSC Control Packets ........15
4.2. Protocol Format ...........................................16
4.2.1. PSC Ver Field ......................................16
4.2.2. PSC Request Field ..................................17
4.2.3. Protection Type (PT) Field .........................18
4.2.4. Revertive (R) Field ................................18
4.2.5. Fault Path (FPath) Field ...........................19
4.2.6. Data Path (Path) Field .............................19
4.2.7. Additional TLV Information .........................19
4.3. Principles of Operation ...................................20
4.3.1. Basic Operation ....................................20
4.3.2. Priority of Inputs .................................21
4.3.3. Operation of PSC States ............................22
5. IANA Considerations ............................................33
5.1. Pseudowire Associated Channel Type ........................33
5.2. PSC Request Field .........................................33
5.3. Additional TLVs ...........................................34
6. Security Considerations ........................................34
7. Acknowledgements ...............................................35
8. Contributing Authors ...........................................36
9. References .....................................................37
9.1. Normative References ......................................37
9.2. Informative References ....................................37
Appendix A. PSC State Machine Tables ..............................39
Appendix B. Exercising the Protection Domain ......................44
1. Introduction ....................................................4
1.1. Protection Architectures ...................................4
1.2. Scope of the Document ......................................5
2. Conventions Used in This Document ...............................6
2.1. Acronyms ...................................................6
2.2. Definitions and Terminology ................................7
3. Protection State Control Logic ..................................7
3.1. Local Request Logic ........................................9
3.2. Remote Requests ...........................................11
3.3. PSC Control Logic .........................................12
3.4. PSC Message Generator .....................................12
3.5. Wait-to-Restore (WTR) Timer ...............................12
3.6. PSC Control States ........................................13
3.6.1. Local and Remote State .............................14
4. Protection State Coordination (PSC) Protocol ...................14
4.1. Transmission and Acceptance of PSC Control Packets ........15
4.2. Protocol Format ...........................................16
4.2.1. PSC Ver Field ......................................16
4.2.2. PSC Request Field ..................................17
4.2.3. Protection Type (PT) Field .........................18
4.2.4. Revertive (R) Field ................................18
4.2.5. Fault Path (FPath) Field ...........................19
4.2.6. Data Path (Path) Field .............................19
4.2.7. Additional TLV Information .........................19
4.3. Principles of Operation ...................................20
4.3.1. Basic Operation ....................................20
4.3.2. Priority of Inputs .................................21
4.3.3. Operation of PSC States ............................22
5. IANA Considerations ............................................33
5.1. Pseudowire Associated Channel Type ........................33
5.2. PSC Request Field .........................................33
5.3. Additional TLVs ...........................................34
6. Security Considerations ........................................34
7. Acknowledgements ...............................................35
8. Contributing Authors ...........................................36
9. References .....................................................37
9.1. Normative References ......................................37
9.2. Informative References ....................................37
Appendix A. PSC State Machine Tables ..............................39
Appendix B. Exercising the Protection Domain ......................44
The MPLS Transport Profile (MPLS-TP) [RFC5921] is a framework for the construction and operation of packet-switched transport networks based on the architectures for MPLS ([RFC3031] and [RFC3032]) and for Pseudowires (PWs) ([RFC3985] and [RFC5659]) and the requirements of [RFC5654].
MPLS传输配置文件（MPLS-TP）[RFC5921]是基于MPLS（[RFC3031]和[RFC3032]）和伪线（PWs）（[RFC3985]和[RFC5659]）的体系结构以及[RFC5654]的要求构建和运行分组交换传输网络的框架。
Network survivability is the ability of a network to recover traffic delivery following failure, or degradation, of network resources. The MPLS-TP Survivability Framework [RFC6372] is a framework for survivability in MPLS-TP networks, and describes recovery elements, types, methods, and topological considerations, focusing on mechanisms for recovering MPLS-TP Label Switched Paths (LSPs).
网络生存性是指网络在网络资源发生故障或退化后恢复通信量交付的能力。MPLS-TP生存性框架[RFC6372]是MPLS-TP网络中的生存性框架，描述了恢复元素、类型、方法和拓扑注意事项，重点介绍了恢复MPLS-TP标签交换路径（LSP）的机制。
Linear protection in mesh networks -- networks with arbitrary interconnectivity between nodes -- is described in Section 4.7 of [RFC6372]. Linear protection provides rapid and simple protection switching. In a mesh network, linear protection provides a very suitable protection mechanism because it can operate between any pair of points within the network. It can protect against a defect in an intermediate node, a span, a transport path segment, or an end-to-end transport path.
网状网络中的线性保护——节点之间具有任意互连性的网络——在[RFC6372]的第4.7节中进行了描述。线性保护提供快速简单的保护切换。在网状网络中，线性保护提供了一种非常合适的保护机制，因为它可以在网络中的任何一对点之间运行。它可以防止中间节点、跨距、传输路径段或端到端传输路径中的缺陷。
Protection switching is a fully allocated survivability mechanism. It is fully allocated in the sense that the route and resources of the protection path are reserved for a selected working path or set of working paths. It provides a fast and simple survivability mechanism that allows the network operator to easily grasp the active state of the network and that can operate between any pair of points within the network.
保护交换是一种完全分配的生存性机制。在保护路径的路由和资源为选定的工作路径或工作路径集保留的意义上，它是完全分配的。它提供了一种快速而简单的生存性机制，允许网络运营商轻松掌握网络的活动状态，并且可以在网络中的任何一对点之间进行操作。
As described in the Survivability Framework document [RFC6372], protection switching is applied to a protection domain. For the purposes of this document, we define the protection domain of a point-to-point LSP as consisting of two Label Edge Routers (LERs) and the transport paths that connect them (see Figure 3). For a point-to-multipoint LSP, the protection domain includes the root (or source) LER, the destination (or sink) LERs, and the transport paths that connect them.
如生存能力框架文件[RFC6372]所述，保护切换应用于保护域。在本文档中，我们将点对点LSP的保护域定义为由两个标签边缘路由器（LER）和连接它们的传输路径组成（见图3）。对于点对多点LSP，保护域包括根（或源）LER、目标（或汇）LER以及连接它们的传输路径。
In 1+1 unidirectional architecture as presented in [RFC6372], a protection transport path is dedicated to the working transport path. Normal traffic is bridged (as defined in [RFC4427]) and fed to both the working and the protection paths by a permanent bridge at the source of the protection domain. The sink of the protection domain
在[RFC6372]中介绍的1+1单向体系结构中，保护传输路径专用于工作传输路径。正常流量桥接（如[RFC4427]中所定义），并通过保护域源处的永久桥接器馈送至工作路径和保护路径。保护域的接收器
uses a selector to choose either the working or protection path from which to receive the traffic, based on predetermined criteria, e.g., server defect indication. When used for bidirectional switching the 1+1 protection architecture must also support a Protection State Coordination (PSC) protocol. This protocol is used to help coordinate between both ends of the protection domain in selecting the proper traffic flow.
使用选择器根据预定标准（例如，服务器缺陷指示）选择接收流量的工作路径或保护路径。当用于双向交换时，1+1保护体系结构还必须支持保护状态协调（PSC）协议。该协议用于帮助协调保护域两端选择适当的流量。
In the 1:1 architecture, a protection transport path is dedicated to the working transport path of a single service, and the traffic is only transmitted on either the working or the protection path, by using a selector at the source of the protection domain. A selector at the sink of the protection domain then selects the path that carries the normal traffic. Since the source and sink need to be coordinated to ensure that the selector at both ends select the same path, this architecture must support a PSC protocol.
在1:1体系结构中，保护传输路径专用于单个服务的工作传输路径，并且通过使用保护域源处的选择器，仅在工作或保护路径上传输流量。然后，保护域接收器上的选择器选择承载正常流量的路径。由于需要协调源和接收器以确保两端的选择器选择相同的路径，因此此体系结构必须支持PSC协议。
The 1:n protection architecture extends the 1:1 architecture above by sharing the protection path among n services. Again, the protection path is fully allocated and disjoint from any of the n working transport paths that it is being used to protect. The normal data traffic for each service is transmitted either on the normal working path for that service or, in cases that trigger protection switching (as listed in [RFC6372]), may be sent on the protection path. The switching action is similar to the 1:1 case where a selector is used at the source. In cases where multiple working path services have triggered protection switching, it should be noted that some services, dependent upon their Service Level Agreement (SLA), may not be transmitted as a result of limited resources on the protection path. In this architecture, there may be a need for coordination of the protection switching and for resource allocation negotiation. The procedures for this are for further study and may be addressed in future documents.
1:n保护体系结构通过在n个服务之间共享保护路径扩展了上述1:1体系结构。同样，保护路径是完全分配的，并且与它正被用来保护的n条工作传输路径中的任何一条不相交。每个服务的正常数据流量在该服务的正常工作路径上传输，或者在触发保护切换的情况下（如[RFC6372]中所列），可以在保护路径上发送。切换动作类似于在震源处使用选择器的1:1情况。在多个工作路径服务触发保护切换的情况下，应注意，由于保护路径上的资源有限，某些服务可能无法传输，这取决于它们的服务级别协议（SLA）。在此架构中，可能需要协调保护切换和资源分配协商。这方面的程序有待进一步研究，可能会在未来的文件中讨论。
As was pointed out in the Survivability Framework [RFC6372] and highlighted above, there is a need for coordination between the end points of the protection domain when employing bidirectional protection schemes. This is especially true when there is a need to verify that the traffic continues to be transported on a bidirectional LSP that is co-routed.
正如在生存能力框架[RFC6372]中指出并在上文中强调的那样，在采用双向保护方案时，需要在保护域的端点之间进行协调。当需要验证通信量是否继续在共同路由的双向LSP上传输时，尤其如此。
The scope of this document is to present a protocol for the Protection State Coordination of Linear Protection. The protocol addresses the protection of LSPs in an MPLS-TP network as required by [RFC5654] (in particular, requirements 63-65 and 74-79) and described in [RFC6372]. The basic protocol is designed for use in conjunction
本文件的范围是介绍线性保护的保护状态协调协议。该协议根据[RFC5654]的要求（特别是要求63-65和74-79）和[RFC6372]中的描述，解决MPLS-TP网络中LSP的保护问题。基本协议是为配合使用而设计的
with the 1:1 protection architecture, bidirectional protection, and for 1+1 protection of a bidirectional path (for both unidirectional and bidirectional protection switching). Applicability of the protocol for 1:1 unidirectional protection and for 1:n protection schemes may be documented in a future document and is out of scope for this document. The applicability of this protocol to additional MPLS-TP constructs and topologies may be documented in future documents.
具有1:1保护体系结构、双向保护和双向路径的1+1保护（用于单向和双向保护切换）。本协议对1:1单向保护和1:n保护方案的适用性可在未来文件中记录，不在本文件范围内。本协议对其他MPLS-TP结构和拓扑的适用性可能会在未来的文档中记录。
While the unidirectional 1+1 protection architecture does not require the use of a coordination protocol, the protocol may be used by the ingress node of the path to notify the far-side end point that a switching condition has occurred and verify the consistency of the end-point configuration. This use may be especially useful for point-to-multipoint transport paths, that are unidirectional by definition of [RFC5654]. The use of this protocol for point-to-multipoint paths is out of scope for this document and may be addressed in a future applicability document.
虽然单向1+1保护体系结构不需要使用协调协议，但是路径的入口节点可以使用该协议来通知远端端点发生了切换条件并验证端点配置的一致性。这种使用对于点对多点传输路径特别有用，根据[RFC5654]的定义，这种传输路径是单向的。本协议用于点对多点路径超出了本文件的范围，可能会在未来的适用性文件中讨论。
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 the following acronyms:
本文件使用以下首字母缩略词：
CT Channel Type DNR Do-not-Revert FS Forced Switch G-ACh Generic Associated Channel LER Label Edge Router LO Lockout of protection LSR Label Switching Router MEG Managed Entity Group MEP MEG End Point MPLS-TP Transport Profile for MPLS MS Manual Switch NR No Request OAM Operations, Administration, and Maintenance PSC Protection State Coordination Protocol S-PE Switching Provider Edge SD Signal Degrade SF Signal Fail SFc Clear Signal Fail SLA Service Level Agreement
CT信道类型DNR不恢复FS强制交换机G-ACh通用关联信道LER标签边缘路由器LO保护锁定LSR标签交换路由器MEG受管实体组MEP MEG端点MPLS-TP MPLS MS手动交换机NR无请求OAM操作、管理、，和维护PSC保护状态协调协议S-PE交换提供程序边缘SD信号降级SF信号失败SFc清除信号失败SLA服务级别协议
T-PE Terminating Provider Edge WTR Wait-to-Restore
T-PE端接提供程序边缘WTR等待恢复
The terminology used in this document is based on the terminology defined in [RFC4427] and further adapted for MPLS-TP in [RFC6372]. In addition, we use the term "LER" to refer to an MPLS-TP Network Element, whether it is an LSR, LER, T-PE, or S-PE.
本文件中使用的术语基于[RFC4427]中定义的术语，并进一步适用于[RFC6372]中的MPLS-TP。此外，我们使用术语“LER”来指代MPLS-TP网元，无论它是LSR、LER、T-PE还是S-PE。
Protection switching processes the local triggers described in requirements 74-79 of [RFC5654] together with inputs received from the far-end LER. Based on these inputs, the LER will take certain protection switching actions, e.g., switching the selector to transmit on the working or protection path for 1:1 protection or switching the selector to receive the traffic for either 1:1 or 1+1 protection and transmit different protocol messages.
保护切换处理[RFC5654]要求74-79中描述的本地触发器以及从远端LER接收的输入。基于这些输入，LER将采取某些保护切换动作，例如，切换选择器以在工作或保护路径上传输1:1保护，或切换选择器以接收1:1或1+1保护的通信量并传输不同的协议消息。
The following figure shows the logical decomposition of the Protection State Control logic into different logical processing units. These processing units are presented in subsequent subsections of this document. This logical decomposition is only intended for descriptive purposes; any implementation that produces the external behavior described in Section 4 is acceptable.
下图显示了保护状态控制逻辑到不同逻辑处理单元的逻辑分解。这些处理单元将在本文件的后续小节中介绍。这种逻辑分解仅用于描述目的；任何产生第4节中描述的外部行为的实现都是可以接受的。
Server Indication Control-Plane Indication
-----------------+ +-------------
Operator Command | | OAM Indication
----------------+ | | +---------------
| | | |
V V V V
+---------------+ +-------+
| Local Request |<--------| WTR |
| logic |WTR Exps | Timer |
+---------------+ +-------+
| ^
Highest local|request |
V | Start/Stop
+-----------------+ |
Remote PSC | PSC Control |------------+
------------>| logic |
Request +-----------------+
|
| Action +------------+
+---------------->| Message |
| Generator |
+------------+
|
Output PSC | Message
V
Server Indication Control-Plane Indication
-----------------+ +-------------
Operator Command | | OAM Indication
----------------+ | | +---------------
| | | |
V V V V
+---------------+ +-------+
| Local Request |<--------| WTR |
| logic |WTR Exps | Timer |
+---------------+ +-------+
| ^
Highest local|request |
V | Start/Stop
+-----------------+ |
Remote PSC | PSC Control |------------+
------------>| logic |
Request +-----------------+
|
| Action +------------+
+---------------->| Message |
| Generator |
+------------+
|
Output PSC | Message
V
Figure 1: Protection State Control Logic
图1：保护状态控制逻辑
Figure 1 describes the logical architecture of the protection switching control. The Local Request logic unit accepts the triggers from the OAM, server layer, external operator commands, local control plane (when present), and the Wait-to-Restore timer. By considering all of these local request sources, it determines the highest priority local request. This high-priority request is passed to the PSC Control logic, that will cross-check this local request with the information received from the far-end LER. The PSC Control logic uses this input to determine what actions need to be taken, e.g., local actions at the LER, or what message should be sent to the far-end LER, and the current status of the protection domain.
图1描述了保护切换控制的逻辑架构。本地请求逻辑单元接受来自OAM、服务器层、外部操作员命令、本地控制平面（如果存在）和等待恢复计时器的触发器。通过考虑所有这些本地请求源，它确定最高优先级的本地请求。该高优先级请求被传递到PSC控制逻辑，该逻辑将用从远端LER接收的信息交叉检查该本地请求。PSC控制逻辑使用该输入来确定需要采取的行动，例如，LER的本地行动，或应向远端LER发送的消息，以及保护域的当前状态。
The Local Request logic processes input triggers from five sources.
本地请求逻辑处理来自五个源的输入触发器。
o Operator command - the network operator may issue local administrative commands on the LER that trigger protection switching. The commands Forced Switch, Manual Switch, Clear, Lockout of protection (defined in [RFC4427] as Forced switch-over, Manual switch-over, Clear, and Lockout of recovery LSP/span, respectively) MUST be supported. An implementation MAY provide additional commands for operator use; providing that these commands do not introduce incompatible behavior between two arbitrary implementations, they are outside the scope of this document. For example, an implementation could provide a command to manually set off a "WTR Expires" trigger (see below) input without waiting for the duration of the WTR timer; as this merely hastens the transition from one state to another and has no impact on the state machine itself, it would be perfectly valid.
o 操作员命令-网络操作员可在LER上发出本地管理命令，触发保护切换。必须支持强制切换、手动切换、清除、保护锁定（在[RFC4427]中分别定义为强制切换、手动切换、清除和恢复LSP/span锁定）命令。一个实现可以提供额外的命令供操作员使用；如果这些命令不会在两个任意实现之间引入不兼容的行为，则它们不在本文档的范围内。例如，一个实现可以提供一个命令，在不等待WTR定时器的持续时间的情况下手动设置“WTR Expires”触发器（见下文）输入；由于这只会加快从一个状态到另一个状态的转换，并且对状态机本身没有影响，因此它是完全有效的。
o Server-layer alarm indication - the underlying server layer of the network detects failure conditions at the underlying layer and may issue an indication to the MPLS-TP layer. The server layer may employ its own protection switching mechanism; therefore, this input MAY be controlled by a hold-off timer that SHOULD be configurable by the network operator. The hold-off timer is described in greater detail in [RFC6372].
o 服务器层警报指示-网络的底层服务器层检测底层的故障情况，并可能向MPLS-TP层发出指示。服务器层可采用其自身的保护切换机制；因此，该输入可由网络运营商可配置的保持定时器控制。[RFC6372]中更详细地描述了保持计时器。
o Control-Plane Indication - if there is a control plane active in the network (either signaling or routing), it MAY trigger protection switching based on conditions detected by the control plane. If the control plane is based on GMPLS [RFC3945], then the recovery process SHALL comply with the process described in [RFC4872] and [RFC4873].
o 控制平面指示-如果网络中有一个活动的控制平面（信令或路由），它可能会根据控制平面检测到的条件触发保护切换。如果控制平面基于GMPLS[RFC3945]，则恢复过程应符合[RFC4872]和[RFC4873]中所述的过程。
o OAM indication - OAM fault management or performance measurement tools may detect a failure or degrade condition on either the working or protection transport path, and this MUST input an indication to the Local Request logic.
o OAM指示-OAM故障管理或性能测量工具可检测工作或保护传输路径上的故障或降级情况，这必须向本地请求逻辑输入指示。
o WTR Expires - The Wait-to-Restore timer is used in conjunction with recovery from failure conditions on the working path in revertive mode. The timer SHALL signal the PSC control process when it expires, and the end point SHALL revert to the normal transmission of the user data traffic.
o WTR过期-等待恢复计时器与恢复模式下工作路径上的故障条件恢复一起使用。计时器应在其到期时向PSC控制过程发出信号，且终点应恢复到用户数据通信的正常传输。
The input from these sources SHOULD be retained persistently for the duration of the condition that initiated the trigger. The Local Request logic processes these different input sources and, based on
这些来源的输入应在触发触发条件的持续时间内持续保留。本地请求逻辑处理这些不同的输入源，并基于
the priorities between them (see Section 4.3.2), produces a current local request. If more than one local input source generates a trigger, then the Local Request logic selects the higher priority indicator and ignores any lower priority indicator. As a result, there is a single current local request that is passed to the PSC Control logic. The different local requests that may be output from the Local Request logic are as follows:
它们之间的优先级（见第4.3.2节）产生当前本地请求。如果多个本地输入源生成触发器，则本地请求逻辑选择较高优先级指示器，并忽略任何较低优先级指示器。因此，有一个当前本地请求被传递到PSC控制逻辑。可以从本地请求逻辑输出的不同本地请求如下：
o Clear - if the operator cancels an active local administrative command, i.e., LO/FS/MS.
o 清除-如果操作员取消激活的本地管理命令，即LO/FS/MS。
o Lockout of protection (LO) - if the operator requested to prevent switching data traffic to the protection path, for any purpose.
o 保护锁定（LO）-如果操作员出于任何目的要求防止将数据流量切换到保护路径。
o Signal Fail (SF) - if any of the server-layer, control-plane, or OAM indications signaled a failure condition on either the protection path or one of the working paths.
o 信号故障（SF）-如果任何服务器层、控制平面或OAM指示在保护路径或其中一条工作路径上发出故障状态信号。
o Signal Degrade (SD) - if any of the server-layer, control-plane, or OAM indications signaled a degraded transmission condition on either the protection path or one of the working paths. The determination and actions for SD are for further study and may appear in a separate document. All references to SD input are placeholders for this extension.
o 信号降级（SD）-如果任何服务器层、控制平面或OAM指示在保护路径或其中一条工作路径上发出降级传输条件的信号。SD的确定和行动有待进一步研究，可能会出现在单独的文件中。对SD输入的所有引用都是此扩展的占位符。
o Clear Signal Fail (SFc) - if all of the server-layer, control-plane, or OAM indications are no longer indicating a failure condition on a path that was previously indicating a failure condition.
o 清除信号故障（SFc）-如果所有服务器层、控制平面或OAM指示不再指示先前指示故障状况的路径上的故障状况。
o Forced Switch (FS) - if the operator requested that traffic be switched from one of the working paths to the protection path.
o 强制切换（FS）-如果操作员要求将通信量从一条工作路径切换到保护路径。
o Manual Switch (MS) - if the operator requested that traffic be switched from the working path to the protection path. This is only relevant if there is no currently active fault condition or operator command.
o 手动切换（MS）-如果操作员要求将通信量从工作路径切换到保护路径。这仅在当前没有激活的故障条件或操作员命令时才相关。
o WTR Expires (WTRExp) - generated by the WTR timer completing its period.
o WTR Expires（WTRExp）-由完成其周期的WTR计时器生成。
If none of the input sources have generated any triggers, then the Local Request logic should generate a No Request (NR) as the current local request.
如果没有任何输入源生成任何触发器，则本地请求逻辑应生成一个无请求（NR）作为当前本地请求。
In addition to the local requests, generated as a result of the local triggers, indicated in the previous subsection, the PSC Control logic SHALL accept PSC messages from the far-end LER of the transport path. Remote messages indicate the status of the transport path from the viewpoint of the far-end LER. These messages may drive state changes on the local MEP, as defined later in this document. When using 1+1 unidirectional protection, an LER that receives a remote request SHALL NOT perform any protection switching action, i.e., will continue to select traffic from the working path and transport traffic on both paths.
除了上一小节中指出的由本地触发器生成的本地请求外，PSC控制逻辑还应接受来自传输路径远端LER的PSC消息。远程消息从远端LER的角度指示传输路径的状态。这些消息可能会驱动本地MEP上的状态更改，如本文档后面所述。当使用1+1单向保护时，接收远程请求的LER不得执行任何保护切换动作，即，将继续从工作路径选择流量，并在两条路径上传输流量。
The following remote requests may be received by the PSC process:
PSC进程可以接收以下远程请求：
o Remote LO - indicates that the remote end point is in Unavailable state due to a Lockout of protection operator command.
o 远程LO-表示由于保护操作员命令锁定，远程端点处于不可用状态。
o Remote SF - indicates that the remote end point has detected a Signal Fail condition on one of the transport paths in the protection domain. This remote message includes an indication of which transport path is affected by the SF condition. In addition, it should be noted that the SF condition may be either a unidirectional or a bidirectional failure, even if the transport path is bidirectional.
o 远程SF-表示远程端点已在保护域中的一条传输路径上检测到信号故障情况。此远程消息包括受SF条件影响的传输路径的指示。此外，应当注意，即使传输路径是双向的，SF状况也可以是单向故障或双向故障。
o Remote SD - indicates that the remote end point has detected a Signal Degrade condition on one of the transport paths in the protection domain. This remote message includes an indication of which transport path is affected by the SD condition. In addition, it should be noted that the SD condition may be either a unidirectional or a bidirectional failure, even if the transport path is bidirectional.
o 远程SD-表示远程端点已在保护域中的一条传输路径上检测到信号降级情况。此远程消息包括受SD条件影响的传输路径的指示。此外，应当注意，SD条件可以是单向故障或双向故障，即使传输路径是双向的。
o Remote FS - indicates that the remote end point is operating under an operator command to switch the traffic to the protection path.
o 远程FS-表示远程端点在操作员命令下运行，以将通信量切换到保护路径。
o Remote MS - indicates that the remote end point is operating under an operator command to switch the traffic from the working path to the protection path.
o 远程MS-表示远程端点在操作员命令下运行，以将通信量从工作路径切换到保护路径。
o Remote WTR - indicates that the remote end point has determined that the failure condition has recovered and has started its WTR timer in preparation for reverting to the Normal state.
o 远程WTR-表示远程端点已确定故障条件已恢复，并已启动其WTR计时器，以准备恢复到正常状态。
o Remote DNR - indicates that the remote end point has determined that the failure condition has recovered and will continue transporting traffic on the protection path due to operator configuration that prevents automatic reversion to the Normal state.
o 远程DNR-表示远程端点已确定故障状态已恢复，并将继续在保护路径上传输通信量，因为操作员配置阻止自动恢复到正常状态。
o Remote NR - indicates that the remote end point has no abnormal condition to report.
o 远程NR-表示远程端点没有要报告的异常情况。
The PSC Control logic accepts the following input:
PSC控制逻辑接受以下输入：
a. the current local request output from the Local Request logic (see Section 3.1),
a. 本地请求逻辑的当前本地请求输出（见第3.1节），
b. the remote request message from the remote end point of the transport path (see Section 3.2), and
b. 来自传输路径远程端点的远程请求消息（参见第3.2节），以及
c. the current state of the PSC Control logic (maintained internally by the PSC Control logic).
c. PSC控制逻辑的当前状态（由PSC控制逻辑内部维护）。
Based on the priorities between the different inputs, the PSC Control logic determines the new state of the PSC Control logic and what actions need to be taken.
根据不同输入之间的优先级，PSC控制逻辑确定PSC控制逻辑的新状态以及需要采取的措施。
The new state information is retained by the PSC Control logic, while the requested action should be sent to the PSC Message Generator (see Section 3.4) to generate and transmit the proper PSC message to be transmitted to the remote end point of the protection domain.
新的状态信息由PSC控制逻辑保留，而请求的动作应发送至PSC消息生成器（见第3.4节），以生成并传输适当的PSC消息，并传输至保护域的远程端点。
Based on the action output from the PSC Control logic, this unit formats the PSC protocol message that is transmitted to the remote end point of the protection domain. This message may either be the same as the previously transmitted message or change when the PSC control state (see Section 3.6) has changed. The messages are transmitted as described in Section 4.1 of this document.
根据PSC控制逻辑的动作输出，该装置格式化PSC协议消息，该消息传输至保护域的远程端点。该信息可能与先前传输的信息相同，也可能在PSC控制状态（见第3.6节）发生变化时发生变化。按照本文件第4.1节所述传输信息。
The WTR timer is used to delay reversion to Normal state when recovering from a failure condition on the working path and the protection domain is configured for revertive behavior. The length of the timer may be provisioned by the operator. The WTR may be in
当从工作路径上的故障状态恢复时，WTR定时器用于延迟恢复到正常状态，并且保护域配置为恢复行为。定时器的长度可由操作员设定。WTR可能正在运行
one of two states: Running or Stopped. The control of the WTR timer is managed by the PSC Control logic, by use of internal signals to start and stop, i.e., reset, the WTR timer.
两种状态之一：运行或停止。WTR定时器的控制由PSC控制逻辑管理，通过使用内部信号启动和停止，即重置WTR定时器。
If the WTR timer expires prior to being stopped, it SHALL generate a WTR Expires local signal that is processed by the Local Request logic. If the WTR timer is running, sending a Stop command SHALL reset the timer, and put the WTR timer into Stopped state, but SHALL NOT generate a WTR Expires local signal. If the WTR timer is stopped, a Stop command SHALL be ignored.
如果WTR定时器在停止之前过期，则其应生成由本地请求逻辑处理的WTR过期本地信号。如果WTR计时器正在运行，发送停止命令应重置计时器，并将WTR计时器置于停止状态，但不得生成WTR过期本地信号。如果WTR定时器停止，则应忽略停止命令。
The PSC Control logic should maintain information on the current state of the protection domain. Information on the state of the domain is maintained by each LER within the protection domain. The state information would include information of the current state of the protection domain, an indication of the cause for the current state (e.g., unavailable due to local LO command, protecting due to remote FS), and, for each LER, should include an indication if the state is related to a remote or local condition.
PSC控制逻辑应维护有关保护域当前状态的信息。关于域状态的信息由保护域内的每个LER维护。状态信息将包括保护域当前状态的信息、当前状态原因的指示（例如，由于本地LO命令而不可用、由于远程FS而保护），并且对于每个LER，应包括状态是否与远程或本地条件相关的指示。
It should be noted that when referring to the "transport" of the data traffic, in the following descriptions and later in the document that the data will be transmitted on both the working and the protection paths when using 1+1 protection, and on either the working or the protection path exclusively when using 1:1 protection. When using 1+1 protection, the receiving LER should select the proper transmission, according to the state of the protection domain.
应注意的是，当提及数据通信的“传输”时，在以下描述和随后的文档中，当使用1+1保护时，数据将在工作路径和保护路径上传输，当使用1:1保护时，数据将在工作路径或保护路径上传输。当使用1+1保护时，接收LER应根据保护域的状态选择适当的传输。
The protection domain states that are supported by the PSC Control logic are as follows:
PSC控制逻辑支持的保护域状态如下：
o Normal state - Both the protection and working paths are fully allocated and active, data traffic is being transported over (or selected from) the working path, and no trigger events are reported within the domain.
o 正常状态-保护路径和工作路径均已完全分配并处于活动状态，数据流量正在工作路径上传输（或从中选择），并且域内未报告任何触发事件。
o Unavailable state - The protection path is unavailable -- either as a result of an operator Lockout command or a failure condition detected on the protection path.
o 不可用状态—保护路径不可用—这可能是由于操作员锁定命令或在保护路径上检测到故障条件造成的。
o Protecting failure state - The working path has reported a failure/degrade condition and the user traffic is being transported (or selected) on the protection path.
o 保护故障状态-工作路径已报告故障/降级情况，并且用户流量正在保护路径上传输（或选择）。
o Protecting administrative state - The operator has issued a command switching the user traffic to the protection path.
o 保护管理状态-操作员已发出命令，将用户流量切换到保护路径。
o Wait-to-Restore state - The protection domain is recovering from an SF/SD condition on the working path that is being controlled by the Wait-to-Restore (WTR) timer.
o 等待还原状态-保护域正在从由等待还原（WTR）计时器控制的工作路径上的SF/SD状态恢复。
o Do-not-Revert state - The protection domain has recovered from a Protecting state, but the operator has configured the protection domain not to automatically revert to the Normal state upon recovery. The protection domain SHALL remain in this state until the operator issues a command to revert to the Normal state or there is a new trigger to switch to a different state.
o 不还原状态-保护域已从保护状态恢复，但操作员已将保护域配置为在恢复时不会自动还原到正常状态。保护域应保持在该状态，直到操作员发出恢复到正常状态的命令，或出现切换到不同状态的新触发器。
See Section 4.3.3 for details on what actions are taken by the PSC Process logic for each state and the relevant input.
请参见第4.3.3节，了解PSC过程逻辑对每个状态和相关输入采取的措施的详细信息。
An end point may be in a given state as a result of either a local input indicator (e.g., OAM, WTR timer) or as a result of receiving a PSC message from the far-end LER. If the state is entered as a result of a local input indicator, then the state is considered a local state. If the state is entered as a result of a PSC message, in the absence of a local input, then the state is considered a remote state. This differentiation affects how the LER reacts to different inputs, as described in Section 4.3.3. The PSC Control logic should maintain, together with the current protection domain state, an indication of whether this is a local or remote state, for this LER.
作为本地输入指示符（例如，OAM、WTR定时器）或作为从远端LER接收PSC消息的结果，端点可以处于给定状态。如果该状态是根据本地输入指示器输入的，则该状态被视为本地状态。如果该状态是由于PSC消息而输入的，并且没有本地输入，则该状态被视为远程状态。如第4.3.3节所述，这种差异会影响LER对不同输入的反应。PSC控制逻辑应与当前保护域状态一起，为该LER保留一个指示，表明这是本地状态还是远程状态。
In any instance where the LER has both a local and remote indicator that cause the protection domain to enter a particular state, then the state is considered a local state, regardless of the order in which the indicators were processed. If, however, the LER has local and remote indicators that would cause the protection domain to enter different states, e.g., a local SF on working and a remote Lockout of protection message, then the input with the higher priority (see Section 4.3.2) will be the deciding factor and the source of that indicator will determine whether it is local or remote. In the given example, the result would be a Remote Unavailable state transmitting PSC messages that indicate an SF condition on the working path and that the protection path is not being used to transport protected traffic (as described in the next section).
在任何情况下，如果LER同时具有导致保护域进入特定状态的本地和远程指示符，则该状态被视为本地状态，而不管指示符的处理顺序如何。但是，如果LER具有本地和远程指示器，会导致保护域进入不同的状态，例如，本地SF开启工作和远程锁定保护消息，则输入具有较高优先级（见第4.3.2节）将是决定因素，该指示器的来源将决定它是本地的还是远程的。在给定的示例中，结果将是发送PSC消息的远程不可用状态，该消息指示工作路径上的SF状况，并且保护路径未用于传输受保护的通信量（如下一节所述）。
Bidirectional protection switching, as well as unidirectional 1:1 protection, requires coordination between the two end points in determining which of the two possible paths, the working or protection path, is transmitting the data traffic in any given
双向保护切换以及单向1:1保护需要两个端点之间的协调，以确定两个可能路径（工作路径或保护路径）中的哪一个正在以任何给定方式传输数据流量
situation. When protection switching is triggered as described in Section 3, the end points must inform each other of the switchover from one path to the other in a coordinated fashion.
情况如第3节所述触发保护切换时，端点必须以协调方式相互通知从一条路径切换到另一条路径。
There are different possibilities for the type of coordinating protocol. One possibility is a two-phased coordination in which the LER that is initiating the protection switching sends a protocol message indicating the switch but the actual switchover is performed only after receiving an 'Ack' from the far-end LER. The other possibility is a single-phased coordination, in which the initiating LER performs the protection switchover to the alternate path and informs the far-end LER of the switch, and the far-end LER will complete the switchover.
协调协议的类型有不同的可能性。一种可能性是两阶段协调，其中启动保护切换的LER发送指示切换的协议消息，但实际切换仅在从远端LER接收到“Ack”后执行。另一种可能性是单相协调，其中启动LER执行到备用路径的保护切换，并将切换通知远端LER，远端LER将完成切换。
This protocol is a single-phased protocol, as described above. In the following subsections, we describe the protocol messages that are used between the two end points of the protection domain.
如上所述，该协议是一个单阶段协议。在以下小节中，我们将描述保护域的两个端点之间使用的协议消息。
The PSC control packets SHALL be transmitted over the protection path only. This allows the transmission of the messages without affecting the normal data traffic in the most prevalent case, i.e., the Normal state. In addition, limiting the transmission to a single path avoids possible conflicts and race conditions that could develop if the PSC messages were sent on both paths.
PSC控制数据包只能通过保护路径传输。这允许在最普遍的情况下（即，正常状态）在不影响正常数据流量的情况下传输消息。此外，将传输限制在一条路径上可以避免在两条路径上发送PSC消息时可能出现的冲突和竞争条件。
When the protection domain state is changed due to a local input, three PSC messages SHALL be transmitted as quickly as possible, to allow for rapid protection switching. This set of three rapid messages allows for fast protection switching even if one or two of these packets are lost or corrupted. When the protection domain state changes due to a remote message, the LER SHOULD send the three rapid messages. However, when the LER transfers from WTR state to Normal state as a result of a remote NR message, the three rapid messages SHALL be transmitted. After the transmission of the three rapid messages, the LER MUST retransmit the most recently transmitted PSC message on a continual basis.
当保护域状态因本地输入而改变时，应尽快传输三条PSC消息，以实现快速保护切换。这组三条快速消息允许快速保护切换，即使其中一个或两个数据包丢失或损坏。当保护域状态因远程消息而改变时，LER应发送三条快速消息。但是，当远程NR消息导致LER从WTR状态转移到正常状态时，应传输三条快速消息。传输三条快速消息后，LER必须连续重新传输最近传输的PSC消息。
Both the default frequency of the three rapid messages as well as the default frequency of the continual message transmission SHALL be configurable by the operator. The actual frequencies used MAY be configurable, at the time of establishment, for each individual protected LSP. For management purposes, the operator SHOULD be able to retrieve the current default frequency values as well as the actual values for any specific LSP. For protection switching within 50 ms, it is RECOMMENDED that the default interval of the first three rapid PSC messages SHOULD be no longer than 3.3 ms. Using this
操作员应可配置三条快速信息的默认频率以及连续信息传输的默认频率。在建立时，可为每个单独的受保护LSP配置使用的实际频率。出于管理目的，操作员应能够检索任何特定LSP的当前默认频率值以及实际值。对于50 ms内的保护切换，建议前三条快速PSC消息的默认间隔不超过3.3 ms。使用此
frequency would allow the far-end to be guaranteed of receiving the trigger indication within 10 ms and completion of the switching operation within 50 ms. Subsequent messages SHOULD be continuously transmitted with a default interval of 5 seconds. The purpose of the continual messages is to verify that the PSC session is still alive.
频率将允许远端保证在10毫秒内接收到触发指示，并在50毫秒内完成切换操作。后续消息应以5秒的默认间隔连续传输。连续消息的目的是验证PSC会话是否仍处于活动状态。
If no valid PSC message is received, over a period of several continual messages intervals, the last valid received message remains applicable.
如果没有收到有效的PSC消息，则在几个连续的消息间隔期间，最后收到的有效消息仍然适用。
The protocol messages SHALL be sent over the G-ACh as described in [RFC5586]. There is a single channel type for the set of PSC messages. The actual message function SHALL be identified by the Request field of the ACH payload as described below.
协议消息应通过G-ACh发送，如[RFC5586]所述。PSC消息集只有一个通道类型。实际消息功能应由ACH有效载荷的请求字段标识，如下所述。
The channel type for the PSC messages SHALL be PSC-CT=0x0024.
PSC消息的信道类型应为PSC-CT=0x0024。
The following figure shows the format for the complete PSC message.
下图显示了完整PSC消息的格式。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | PSC-CT |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver|Request|PT |R| Reserved1 | FPath | Path |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Length | Reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | PSC-CT |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver|Request|PT |R| Reserved1 | FPath | Path |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Length | Reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Format of PSC Packet with a G-ACh Header
图2：带有G-ACh报头的PSC数据包格式
Where:
哪里：
o Both Reserved1 and Reserved2 fields MUST be set to 0 and ignored upon receipt.
o Reserved1和Reserved2字段都必须设置为0，并在收到时忽略。
o The following subsections describe the remaining fields of the PSC payload.
o 以下小节描述了PSC有效负载的其余字段。
The Ver field identifies the version of the protocol. For this version of the document, the value SHALL be 1.
“版本”字段标识协议的版本。对于本版本的文件，该值应为1。
The PSC protocol SHALL support transmission of the following requests between the two end points of the protection domain:
PSC协议应支持在保护域的两个端点之间传输以下请求：
o (14) Lockout of protection - indicates that the end point has disabled the protection path as a result of an administrative command. Both the FPath and Path fields SHALL be set to 0.
o （14） 保护锁定-表示端点由于管理命令而禁用了保护路径。FPath和Path字段均应设置为0。
o (12) Forced Switch - indicates that the transmitting end point has switched traffic to the protection path as a result of an administrative command. The FPath field SHALL indicate that the working path is being blocked (i.e., FPath set to 1), and the Path field SHALL indicate that user data traffic is being transported on the protection path (i.e., Path set to 1).
o （12） 强制切换-表示传输端点已根据管理命令将通信量切换到保护路径。FPath字段应指示工作路径正在被阻塞（即FPath设置为1），path字段应指示用户数据流量正在保护路径上传输（即路径设置为1）。
o (10) Signal Fail - indicates that the transmitting end point has identified a signal fail condition on either the working or protection path. The FPath field SHALL identify the path that is reporting the failure condition (i.e., if protection path, then FPath is set to 0; if working path, then FPath is set to 1), and the Path field SHALL indicate where the data traffic is being transported (i.e., if protection path is blocked, then Path is set to 0; if working path is blocked, then Path is set to 1).
o （10） 信号失效-表示传输端点已识别工作或保护路径上的信号失效情况。FPath字段应标识报告故障条件的路径（即，如果是保护路径，则FPath设置为0；如果是工作路径，则FPath设置为1），并且路径字段应指示数据流量传输的位置（即，如果保护路径被阻止，则路径设置为0；如果工作路径被阻止，则路径设置为1）。
o (7) Signal Degrade - indicates that the transmitting end point has identified a degradation of the signal, or integrity of the packet transmission on either the working or protection path. This request is presented here only as a placeholder. The specifics for the method of identifying this degradation is out of scope for this document. The details of the actions to be taken for this situation are left for future specification.
o （7） 信号降级-表示传输端点已识别工作或保护路径上的信号降级或数据包传输完整性。此请求在此处仅作为占位符显示。识别这种退化的方法的细节不在本文件的范围内。针对这种情况采取的措施细节留待将来的规范。
o (5) Manual Switch - indicates that the transmitting end point has switched traffic to the protection path as a result of an administrative Manual Switch command. The FPath field SHALL indicate that the working path is being blocked (i.e., FPath set to 1), and the Path field SHALL indicate that user data traffic is being transported on the protection path (i.e., Path set to 1).
o （5） 手动切换-表示传输端点已根据管理手动切换命令将通信量切换到保护路径。FPath字段应指示工作路径正在被阻塞（即FPath设置为1），path字段应指示用户数据流量正在保护路径上传输（即路径设置为1）。
o (4) Wait-to-Restore - indicates that the transmitting end point is recovering from a failure condition of the working path and has started the Wait-to-Restore timer. FPath SHALL be set to 0 and ignored upon receipt. Path SHALL indicate the working path that is currently being protected (i.e., Path set to 1).
o （4） 等待恢复-表示传输端点正在从工作路径的故障状态恢复，并已启动等待恢复计时器。FPath应设置为0，并在收到时忽略。路径应指示当前受保护的工作路径（即路径设置为1）。
o (1) Do-not-Revert - indicates that the transmitting end point has recovered from a failure/blocked condition, but due to the local settings, is requesting that the protection domain continues to transport the data as if it is in a protecting state, rather than revert to the Normal state. FPath SHALL be set to 0 and ignored upon receipt. Path SHALL indicate the working path that is currently being protected (i.e., Path set to 1).
o （1） 不恢复-表示传输端点已从故障/阻塞状态中恢复，但由于本地设置，正在请求保护域继续传输数据，就像数据处于保护状态一样，而不是恢复到正常状态。FPath应设置为0，并在收到时忽略。路径应指示当前受保护的工作路径（即路径设置为1）。
o (0) No Request - indicates that the transmitting end point has nothing to report, FPath and Path fields SHALL be set according to the transmission state of the end point, see Section 4.3.3 for detailed scenarios.
o （0）无请求-表示发送端点无需报告，根据端点的传输状态设置FPath和Path字段，具体场景见4.3.3节。
All other values are for future extensions (to be administered by IANA) and SHALL be ignored upon receipt.
所有其他值用于将来的扩展（由IANA管理），收到后应忽略。
The PT field indicates the currently configured protection architecture type, this SHOULD be validated to be consistent for both ends of the protection domain. If an inconsistency is detected, then an alarm SHALL be sent to the management system. The following are the possible values:
PT字段表示当前配置的保护体系结构类型，应验证其在保护域两端的一致性。如果检测到不一致，则应向管理系统发送警报。以下是可能的值：
o 3: bidirectional switching using a permanent bridge
o 3：使用永久电桥的双向切换
o 2: bidirectional switching using a selector bridge
o 2：使用选择器电桥的双向切换
o 1: unidirectional switching using a permanent bridge
o 1：使用永久电桥的单向切换
o 0: for future extensions
o 0:用于将来的扩展
As described in the Introduction (Section 1.1) a 1+1 protection architecture is characterized by the use of a permanent bridge at the source node, whereas the 1:1 and 1:n protection architectures are characterized by the use of a selector bridge at the source node.
如引言（第1.1节）所述，1+1保护体系结构的特点是在源节点使用永久网桥，而1:1和1:n保护体系结构的特点是在源节点使用选择器网桥。
This field indicates that the transmitting end point is configured to work in revertive mode. If there is an inconsistency between the two end points, i.e., one end point is configured for revertive action and the second end point is in non-revertive mode, then the management system SHOULD be notified. The following are the possible values:
此字段表示传输端点配置为在回复模式下工作。如果两个端点之间存在不一致，即一个端点配置为还原操作，而第二个端点处于非还原模式，则应通知管理系统。以下是可能的值：
o 0 - non-revertive mode
o 0-非还原模式
o 1 - revertive mode
o 1-回复模式
The FPath field indicates which path (i.e., working or protection) is identified to be in a fault condition or affected by an administrative command, when a fault or command is indicated by the Request field to be in effect. The following are the possible values:
当请求字段指示故障或命令生效时，FPath字段指示哪个路径（即工作或保护）被识别为处于故障状态或受管理命令影响。以下是可能的值：
o 0: indicates that the anomaly condition is on the protection path
o 0：表示异常情况在保护路径上
o 1: indicates that the anomaly condition is on the working path
o 1：表示异常情况在工作路径上
o 2-255: for future extensions and SHALL be ignored by this version of the protocol.
o 2-255：用于将来的扩展，此版本的协议应忽略。
The Path field indicates which data is being transported on the protection path. Under normal conditions, the protection path (especially, in 1:1 or 1:n architecture) does not need to carry any user data traffic. If there is a failure/degrade condition on one of the working paths, then that working path's data traffic will be transported over the protection path. The following are the possible values:
路径字段指示在保护路径上传输的数据。在正常情况下，保护路径（特别是在1:1或1:n体系结构中）不需要承载任何用户数据流量。如果其中一条工作路径出现故障/降级情况，则该工作路径的数据流量将通过保护路径传输。以下是可能的值：
o 0: indicates that the protection path is not transporting user data traffic (in 1:n architecture) or transporting redundant user data traffic (in 1+1 architecture).
o 0：表示保护路径未传输用户数据流量（在1:n体系结构中）或冗余用户数据流量（在1+1体系结构中）。
o 1: indicates that the protection path is transmitting user traffic replacing the use of the working path.
o 1：表示保护路径正在传输用户流量，而不是使用工作路径。
o 2-255: for future extensions and SHALL be ignored by this version of the protocol.
o 2-255：用于将来的扩展，此版本的协议应忽略。
It may be necessary for future applications of the protocol to include additional information for the proper processing of the requests. For this purpose, we provide for optional additional information to be included in the PSC payload. This information MUST include a header that indicates the total length (in bytes) of the additional information.
协议的未来应用可能需要包括适当处理请求的附加信息。为此，我们提供了PSC有效载荷中包含的可选附加信息。此信息必须包含一个标头，该标头指示附加信息的总长度（以字节为单位）。
This information includes the following fields:
此信息包括以下字段：
o TLV Length: indicates the number of bytes included in the optional TLV information. For the basic PSC protocol operation described in this document, this value MUST be 0.
o TLV长度：表示可选TLV信息中包含的字节数。对于本文档中描述的基本PSC协议操作，该值必须为0。
o Optional TLVs: this includes any additional information formatted as TLV units. There are no TLV units defined for the basic PSC operation.
o 可选TLV：包括格式化为TLV单位的任何附加信息。没有为基本PSC操作定义TLV装置。
In all of the following subsections, assume a protection domain between LER-A and LER-Z, using paths W (working) and P (protection), as shown in Figure 3.
在以下所有小节中，假设LER-a和LER-Z之间有一个保护域，使用路径W（工作）和P（保护），如图3所示。
+-----+ //=======================\\ +-----+
|LER-A|// Working Path \\|LER-Z|
| /| |\ |
| ?< | | >? |
| \|\\ Protection Path //|/ |
+-----+ \\=======================// +-----+
+-----+ //=======================\\ +-----+
|LER-A|// Working Path \\|LER-Z|
| /| |\ |
| ?< | | >? |
| \|\\ Protection Path //|/ |
+-----+ \\=======================// +-----+
|--------Protection Domain--------|
|--------Protection Domain--------|
Figure 3: Protection Domain
图3：保护域
The purpose of the PSC protocol is to allow an end point of the protection domain to notify its peer of the status of the domain that is known at the end point and coordinate the transmission of the data traffic. The current state of the end point is expressed in the values of the Request field (reflecting the local requests at that end point) and the FPath field (reflecting knowledge of a blocked path). The coordination between the end points is expressed by the value of the Path field (indicating where the user data traffic is being transmitted). Except during a protection switch, the value of the Path field should be identical for both end points at any particular time. The values of the Request and FPath fields may not be identical between the two end points. In particular it should be noted that a remote message may not cause the end point to change the Request field that is being transmitted while it does affect the Path field (see details in the following subsections).
PSC协议的目的是允许保护域的端点通知其对等方在端点处已知的域状态，并协调数据通信量的传输。端点的当前状态用请求字段（反映该端点的本地请求）和FPath字段（反映阻塞路径的知识）的值表示。端点之间的协调由路径字段的值表示（指示用户数据通信正在传输的位置）。除在保护切换期间外，在任何特定时间，两个端点的路径字段值应相同。请求和FPath字段的值在两个端点之间可能不相同。特别值得注意的是，远程消息可能不会导致端点更改正在传输的请求字段，但会影响路径字段（请参阅以下小节中的详细信息）。
The protocol is a single-phased protocol. "Single-phased" implies that each end point notifies its peer of a change in the operation (switching to or from the protection path) and makes the switch without waiting for acknowledgement. As a side effect of using a single-phased protocol, there will be a short period during state transitions of one-sided triggers (e.g., operator commands or unidirectional SF) when one LER may be transporting/selecting the data from one transport path while the other end point is transporting/selecting from the other transport path. This should become coordinated once the remote message is received and the far-end LER performs the protection switching operation.
该协议是一个单阶段协议。“单阶段”意味着每个端点通知其对等方操作的变化（切换到保护路径或从保护路径切换），并在不等待确认的情况下进行切换。作为使用单阶段协议的副作用，当一个LER从一个传输路径传输/选择数据，而另一个端点从另一个传输路径传输/选择数据时，在单边触发器（例如，操作员命令或单向SF）的状态转换期间将有一个短时间。一旦接收到远程消息且远端LER执行保护切换操作，这应协调。
The following subsections will identify the messages that will be transmitted by the end point in different scenarios. The messages are described as REQ(FP, P) -- where REQ is the value of the Request field, FP is the value of the FPath field, and P is the value of the Path field. All examples assume a protection domain between LER-A and LER-Z with a single working path and single protection path (as shown in Figure 3). Again, it should be noted that when using 1:1 protection the data traffic will be transmitted exclusively on either the protection or working path; whereas when using 1+1 protection, the traffic will be transmitted on both paths and the receiving LER should select the appropriate signal based on the state. The text will refer to this transmission/selection as "transport" of the data traffic. For 1+1 unidirectional protection, the state of the selector will only be switched in reaction to a local message. When receiving a remote message, a LER that is configured for 1+1 unidirectional protection, will transfer to the new remote state; however, it will continue to select data according to the latest known local state. When the LER transitions into the Normal state, the PSC Control Process SHALL check the persistent state of the local triggers to decide if it should further transition into a new state.
以下小节将确定在不同场景中端点将传输的消息。消息被描述为REQ（FP，P）——其中REQ是请求字段的值，FP是FPath字段的值，P是路径字段的值。所有示例都假定在LER-a和LER-Z之间有一个保护域，具有一条工作路径和一条保护路径（如图3所示）。再次，应注意，当使用1:1保护时，数据流量将在保护或工作路径上独家传输；然而，当使用1+1保护时，业务将在两条路径上传输，并且接收LER应根据状态选择适当的信号。文本将此传输/选择称为数据通信的“传输”。对于1+1单向保护，选择器的状态将仅根据本地消息进行切换。当接收到远程消息时，配置为1+1单向保护的LER将转移到新的远程状态；但是，它将继续根据已知的最新本地状态选择数据。当LER过渡到正常状态时，PSC控制过程应检查本地触发器的持续状态，以决定是否应进一步过渡到新状态。
As noted above (in Section 3.1), the PSC Control Process accepts input from five local input sources. There is a definition of priority between the different inputs that may be triggered locally. The list of local requests in order of priority are (from highest to lowest priority):
如上所述（第3.1节），PSC控制过程接受来自五个本地输入源的输入。在本地可能触发的不同输入之间有一个优先级定义。按优先级顺序排列的本地请求列表为（从最高优先级到最低优先级）：
1. Clear (operator command)
1. 清除（操作员命令）
2. Lockout of protection (operator command)
2. 保护锁定（操作员命令）
3. Forced Switch (operator command)
3. 强制开关（操作员命令）
4. Signal Fail on protection (OAM / control-plane / server indication)
4. 信号失效保护（OAM/控制平面/服务器指示）
5. Signal Fail on working (OAM / control-plane / server indication)
5. 工作时信号故障（OAM/控制平面/服务器指示）
6. Signal Degrade on working (OAM / control-plane / server indication)
6. 工作时信号降级（OAM/控制平面/服务器指示）
7. Clear Signal Fail/Degrade (OAM / control-plane / server indication)
7. 清除信号失败/降级（OAM/控制平面/服务器指示）
8. Manual Switch (operator command)
8. 手动开关（操作员命令）
9. WTR Expires (WTR timer)
9. WTR过期（WTR计时器）
10. No Request (default)
10. 无请求（默认）
As was noted above, the Local Request logic SHALL always select the local input indicator with the highest priority as the current local request, i.e., only the highest priority local input will be used to affect the control logic. All local inputs with lower priority than this current local request will be ignored.
如上所述，本地请求逻辑应始终选择具有最高优先级的本地输入指示器作为当前本地请求，即，只有最高优先级的本地输入将用于影响控制逻辑。所有优先级低于当前本地请求的本地输入都将被忽略。
The remote message from the far-end LER is assigned a priority just below the similar local input. For example, a remote Forced Switch would have a priority just below a local Forced Switch but above a local Signal Fail on protection input. As mentioned in Section 3.6.1, the state transition is determined by the higher priority input between the highest priority local input and the remote message. This also determines the classification of the state as local or remote. The following subsections detail the transition based on the current state and the higher priority of these two inputs.
来自远端LER的远程消息的优先级仅低于类似的本地输入。例如，远程强制开关的优先级略低于本地强制开关，但高于本地信号故障保护输入。如第3.6.1节所述，状态转换由最高优先级本地输入和远程消息之间的高优先级输入确定。这也决定了将状态分类为本地或远程。以下小节详细介绍了基于当前状态和这两个输入的更高优先级的转换。
The following subsections present the operation of the different states defined in Section 3.6. For each state, we define the reaction, i.e., the new state and the message to transmit, to each possible input -- either the highest priority local input or the PSC message from the remote LER. It should be noted that the new state of the protection domain is described from the point of view of the LER that is reporting the state; therefore, the language of "the LER goes into a state" is referring to the LER reporting that the protection domain is now in this new state. If the definition states to "ignore" the message, the intention is that the protection domain SHALL remain in its current state and the LER SHALL continue transmitting (as presented in Section 4.1) the current PSC message.
以下小节介绍了第3.6节中定义的不同状态的操作。对于每个状态，我们定义对每个可能输入的反应，即新状态和要传输的消息——最高优先级的本地输入或来自远程LER的PSC消息。应注意，保护域的新状态是从报告状态的LER的角度描述的；因此，“LER进入状态”的语言是指LER报告保护域现在处于这种新状态。如果定义规定“忽略”消息，则意图是保护域应保持其当前状态，LER应继续传输（如第4.1节所述）当前PSC消息。
When a LER is in a remote state, i.e., state transition in reaction to a PSC message received from the far-end LER, and receives a new PSC message from the far-end LER that indicates a contradictory state, e.g., in remote Unavailable state receiving a remote FS(1,1) message, then the PSC Control logic SHALL reevaluate all inputs (both the local input and the remote message) as if the LER is in the Normal state.
当LER处于远程状态时，即响应于从远端LER接收到的PSC消息的状态转换，并且从远端LER接收到指示矛盾状态的新PSC消息，例如，在远程不可用状态下接收到远程FS（1,1）消息，则PSC控制逻辑应重新评估所有输入（本地输入和远程消息）就好像LER处于正常状态。
When the protection domain has no special condition in effect, the ingress LER SHALL forward the user data along the working path, and, in the case of 1+1 protection, the Permanent Bridge will bridge the data to the protection path as well. The receiving LER SHALL read the data from the working path.
当保护域没有有效的特殊条件时，入口LER应沿工作路径转发用户数据，在1+1保护的情况下，永久网桥也将数据桥接到保护路径。接收LER应从工作路径读取数据。
When the LER transitions into the Normal state, the PSC Control Process SHALL check the persistent state of the local triggers to decide if it should further transition into a new state. If the result of this check is a transition into a new state, the LER SHALL transmit the corresponding message described in this section and SHALL use the data path corresponding to the new state. When the protection domain remains in Normal state, the end point SHALL transmit an NR(0,0) message, indicating -- Nothing to report and data traffic is being transported on the working path.
当LER过渡到正常状态时，PSC控制过程应检查本地触发器的持续状态，以决定是否应进一步过渡到新状态。如果该检查的结果是转换到新状态，LER应发送本节中描述的相应消息，并应使用与新状态对应的数据路径。当保护域保持正常状态时，端点应发送一条NR（0,0）消息，指示——无需报告，数据流量正在工作路径上传输。
When the protection domain is in Normal state, the following transitions are relevant in reaction to a local input to the LER:
当保护域处于正常状态时，以下转换与LER的本地输入有关：
o A local Lockout of protection input SHALL cause the LER to go into local Unavailable state and begin transmission of an LO(0,0) message.
o 保护输入的本地锁定应使LER进入本地不可用状态，并开始传输LO（0,0）信息。
o A local Forced Switch input SHALL cause the LER to go into local Protecting administrative state and begin transmission of an FS(1,1) message.
o 本地强制开关输入应使LER进入本地保护管理状态，并开始传输FS（1,1）消息。
o A local Signal Fail indication on the protection path SHALL cause the LER to go into local Unavailable state and begin transmission of an SF(0,0) message.
o 保护路径上的本地信号故障指示应使LER进入本地不可用状态，并开始传输SF（0,0）消息。
o A local Signal Fail indication on the working path SHALL cause the LER to go into local Protecting failure state and begin transmission of an SF(1,1) message.
o 工作路径上的本地信号故障指示应使LER进入本地保护故障状态，并开始传输SF（1,1）消息。
o A local Manual Switch input SHALL cause the LER to go into local Protecting administrative state and begin transmission of an MS(1,1) message.
o 本地手动开关输入应使LER进入本地保护管理状态，并开始传输MS（1,1）信息。
o All other local inputs SHALL be ignored.
o 应忽略所有其他本地输入。
In Normal state, remote messages would cause the following reaction from the LER:
在正常状态下，远程消息会引起LER的以下反应：
o A remote Lockout of protection message SHALL cause the LER to go into remote Unavailable state, while continuing to transmit the NR(0,0) message.
o 远程锁定保护信息应使LER进入远程不可用状态，同时继续传输NR（0,0）信息。
o A remote Forced Switch message SHALL cause the LER to go into remote Protecting administrative state and begin transmitting an NR(0,1) message.
o 远程强制切换消息应使LER进入远程保护管理状态，并开始传输NR（0,1）消息。
o A remote Signal Fail message that indicates that the failure is on the protection path SHALL cause the LER (LER-A) to go into remote Unavailable state, while continuing to transmit the NR(0,0) message.
o 指示故障在保护路径上的远程信号故障消息应导致LER（LER-A）进入远程不可用状态，同时继续传输NR（0,0）消息。
o A remote Signal Fail message that indicates that the failure is on the working path SHALL cause the LER to go into remote Protecting failure state, and transmit an NR(0,1) message.
o 指示故障在工作路径上的远程信号故障消息应导致LER进入远程保护故障状态，并传输NR（0,1）消息。
o A remote Manual Switch message SHALL cause the LER to go into remote Protecting administrative state, and transmit an NR(0,1) message.
o 远程手动开关信息应使LER进入远程保护管理状态，并传输NR（0,1）信息。
o All other remote messages SHALL be ignored.
o 应忽略所有其他远程消息。
When the protection path is unavailable -- either as a result of a Lockout operator command, or as a result of a SF detected on the protection path -- then the protection domain is in the Unavailable state. In this state, the data traffic SHALL be transported on the working path and is not protected. When the domain is in Unavailable state, the PSC messages may not get through: therefore, the protection is more dependent on the local inputs than the remote messages (that may not be received).
当保护路径不可用时（由于锁定操作员命令，或由于在保护路径上检测到SF），则保护域处于不可用状态。在此状态下，数据流量应在工作路径上传输，且不受保护。当域处于不可用状态时，PSC消息可能无法通过：因此，保护比远程消息（可能无法接收）更依赖于本地输入。
The protection domain will exit the Unavailable state and revert to the Normal state when either the operator clears the Lockout command or the protection path recovers from the signal fail or degraded situation. Both ends will continue to send the PSC messages over the protection path, as a result of this recovery.
当操作员清除锁定命令或保护路径从信号故障或降级情况恢复时，保护域将退出不可用状态并恢复到正常状态。恢复后，两端将继续通过保护路径发送PSC消息。
When the LER (assume LER-A) is in Unavailable state, the following transitions are relevant in reaction to a local input:
当LER（假设LER-A）处于不可用状态时，以下转换与本地输入相关：
o A local Clear input SHALL be ignored if the LER is in remote Unavailable state. If in local Unavailable state due to a Lockout command, then the input SHALL cause the LER to go to Normal state.
o 如果LER处于远程不可用状态，则应忽略本地清除输入。如果由于锁定命令而处于本地不可用状态，则输入应使LER进入正常状态。
o A local Lockout of protection input SHALL cause the LER to remain in local Unavailable state and transmit an LO(0,0) message to the far-end LER (LER-Z).
o 保护输入的本地锁定应使LER保持在本地不可用状态，并向远端LER（LER-Z）发送LO（0,0）消息。
o A local Clear SF of the protection path in local Unavailable state that is due to an SF on the protection path SHALL cause the LER to go to Normal state. If the LER is in remote Unavailable state but has an active local SF condition, then the local Clear SF SHALL clear the SF local condition and the LER SHALL remain in remote Unavailable state and begin transmitting NR(0,0) messages. In all other cases, the local Clear SF SHALL be ignored.
o 由于保护路径上的SF而导致的本地不可用状态下保护路径的本地清除SF应导致LER进入正常状态。如果LER处于远程不可用状态，但具有激活的本地SF条件，则本地清除SF应清除SF本地条件，LER应保持远程不可用状态，并开始传输NR（0,0）消息。在所有其他情况下，应忽略本地清除SF。
o A local Forced Switch SHALL be ignored by the PSC Control logic when in Unavailable state as a result of a (local or remote) Lockout of protection. If in Unavailable state due to an SF on protection, then the FS SHALL cause the LER to go into local Protecting administrative state and begin transmitting an FS(1,1) message. It should be noted that due to the unavailability of the protection path (i.e., due to the SF condition) that this FS may not be received by the far-end until the SF condition is cleared.
o 当由于（本地或远程）保护锁定而处于不可用状态时，PSC控制逻辑应忽略本地强制开关。如果由于SF on保护而处于不可用状态，则FS应使LER进入本地保护管理状态，并开始传输FS（1,1）消息。应注意，由于保护路径不可用（即，由于SF条件），在清除SF条件之前，远端可能无法接收到该FS。
o A local Signal Fail on the protection path input when in local Unavailable state (by implication, this is due to a local SF on protection) SHALL cause the LER to remain in local Unavailable state and transmit an SF(0,0) message.
o 当处于本地不可用状态时，保护路径输入上的本地信号故障（暗示这是由于本地SF开启保护）应导致LER保持在本地不可用状态，并传输SF（0,0）消息。
o A local Signal Fail on the working path input when in remote Unavailable state SHALL cause the LER to remain in remote Unavailable state and transmit an SF(1,0) message.
o 当处于远程不可用状态时，工作路径输入上的本地信号故障应导致LER保持在远程不可用状态，并传输SF（1,0）消息。
o All other local inputs SHALL be ignored.
o 应忽略所有其他本地输入。
If remote messages are being received over the protection path, then they would have the following effect:
如果通过保护路径接收远程消息，则它们将具有以下效果：
o A remote Lockout of protection message SHALL cause the LER to remain in Unavailable state (note that if the LER was previously in local Unavailable state due to a Signal Fail on the protection path, then it will now be in remote Unavailable state) and continue transmission of the current message (either NR(0,0) or LO(0,0) or SF(0,0)).
o 保护消息的远程锁定应使LER保持不可用状态（注意，如果LER先前由于保护路径上的信号故障而处于本地不可用状态，则现在将处于远程不可用状态），并继续传输当前消息（NR（0,0）或LO（0,0）或SF（0,0））。
o A remote Forced Switch message SHALL be ignored by the PSC Control logic when in Unavailable state as a result of a (local or remote) Lockout of protection. If in Unavailable state due to a local or remote SF on protection, then the FS SHALL cause the LER to go into remote Protecting administrative state; if in Unavailable state due to local SF, begin transmitting an SF(0,1) message.
o 当由于（本地或远程）保护锁定而处于不可用状态时，PSC控制逻辑应忽略远程强制开关信息。如果由于本地或远程SF on保护而处于不可用状态，则FS应使LER进入远程保护管理状态；如果由于本地SF而处于不可用状态，则开始传输SF（0,1）消息。
o A remote Signal Fail message that indicates that the failure is on the protection path SHALL cause the LER to remain in Unavailable state and continue transmission of the current message (either NR(0,0) or SF(0,0) or LO(0,0)).
o 指示故障在保护路径上的远程信号故障消息应使LER保持不可用状态，并继续传输当前消息（NR（0,0）或SF（0,0）或LO（0,0））。
o A remote No Request, when the LER is in remote Unavailable state and there is no active local Signal Fail SHALL cause the LER to go into Normal state and continue transmission of the current message. If there is a local Signal Fail on the protection path, the LER SHALL remain in local Unavailable state and transmit an SF(0,0) message. If there is a local Signal Fail on the working path, the LER SHALL go into local Protecting Failure state and transmit an SF(1,1) message. When in local Unavailable state, the remote message SHALL be ignored.
o 当LER处于远程不可用状态且没有激活的本地信号故障时，远程无请求将导致LER进入正常状态并继续传输当前消息。如果保护路径上存在本地信号故障，LER应保持本地不可用状态，并发送SF（0,0）消息。如果工作路径上存在本地信号故障，LER应进入本地保护故障状态，并发送SF（1,1）消息。当处于本地不可用状态时，应忽略远程消息。
o All other remote messages SHALL be ignored.
o 应忽略所有其他远程消息。
In the Protecting administrative state, the user data traffic SHALL be transported on the protection path, while the working path is blocked due to an operator command, i.e., Forced Switch or Manual Switch. The difference between a local FS and local MS affects what local indicators may be received -- the Local Request logic will block any local SF when under the influence of a local FS, whereas the SF would override a local MS. In general, an MS will be canceled in case of either a local or remote SF or LO condition.
在保护管理状态下，用户数据流量应在保护路径上传输，而工作路径因操作员命令（即强制切换或手动切换）而受阻。本地FS和本地MS之间的差异影响可能接收到的本地指示符——当受到本地FS的影响时，本地请求逻辑将阻止任何本地SF，而SF将覆盖本地MS。通常，在本地或远程SF或LO情况下，MS将被取消。
The following describe the reaction to local input:
以下描述了对本地输入的反应：
o A local Clear SHALL be ignored if in remote Protecting administrative state. If in local Protecting administrative state, then this input SHALL cause the LER to go into Normal state.
o 如果处于远程保护管理状态，则应忽略本地清除。如果处于本地保护管理状态，则该输入应使LER进入正常状态。
o A local Lockout of protection input SHALL cause the LER to go into local Unavailable state and begin transmission of an LO(0,0) message.
o 保护输入的本地锁定应使LER进入本地不可用状态，并开始传输LO（0,0）信息。
o A local Forced Switch input SHALL cause the LER to remain in local Protecting administrative state and transmit an FS(1,1) message.
o 本地强制开关输入应使LER保持本地保护管理状态，并传输FS（1,1）消息。
o A local Signal Fail indication on the protection path SHALL cause the LER to go into local Unavailable state and begin transmission of an SF(0,0) message, if the current state is due to a (local or remote) Manual Switch operator command. If the LER is in (local or remote) Protecting administrative state due to an FS situation, then the SF on protection SHALL be ignored.
o 如果当前状态是由（本地或远程）手动开关操作员命令引起的，则保护路径上的本地信号故障指示应使LER进入本地不可用状态并开始传输SF（0,0）消息。如果由于FS情况，LER处于（本地或远程）保护管理状态，则应忽略SF on保护。
o A local Signal Fail indication on the working path SHALL cause the LER to go into local Protecting failure state and begin transmitting an SF(1,1) message, if the current state is due to a (local or remote) Manual Switch operator command. If the LER is in remote Protecting administrative state due to a remote Forced Switch command, then this local indication SHALL cause the LER to remain in remote Protecting administrative state and transmit an SF(1,1) message. If the LER is in local Protecting administrative state due to a local Forced Switch command, then this indication SHALL be ignored (i.e., the indication should have been blocked by the Local Request logic).
o 如果当前状态是由（本地或远程）手动开关操作员命令引起的，则工作路径上的本地信号故障指示应使LER进入本地保护故障状态并开始传输SF（1,1）消息。如果由于远程强制开关命令，LER处于远程保护管理状态，则该本地指示应使LER保持远程保护管理状态，并传输SF（1,1）消息。如果由于本地强制开关命令，LER处于本地保护管理状态，则应忽略该指示（即，该指示应已被本地请求逻辑阻止）。
o A local Clear SF SHALL clear any local SF condition that may exist. If in remote Protecting administrative state, the LER SHALL stop transmitting the SF(x,1) message and begin transmitting an NR(0,1) message.
o 局部清除SF应清除可能存在的任何局部SF条件。如果处于远程保护管理状态，LER应停止发送SF（x，1）消息，并开始发送NR（0，1）消息。
o A local Manual Switch input SHALL be ignored if in remote Protecting administrative state due to a remote Forced Switch command. If the current state is due to a (local or remote) Manual Switch operator command, it SHALL cause the LER to remain in local Protecting administrative state and transmit an MS(1,1) message.
o 如果由于远程强制开关命令而处于远程保护管理状态，则应忽略本地手动开关输入。如果当前状态是由（本地或远程）手动开关操作员命令引起的，则应使LER保持在本地保护管理状态，并发送MS（1,1）消息。
o All other local inputs SHALL be ignored.
o 应忽略所有其他本地输入。
While in Protecting administrative state the LER may receive and react as follows to remote PSC messages:
在保护管理状态下，LER可接收远程PSC消息并作出如下反应：
o A remote Lockout of protection message SHALL cause the LER to go into remote Unavailable state and begin transmitting an NR(0,0) message. It should be noted that this automatically cancels the current Forced Switch or Manual Switch command and data traffic is reverted to the working path.
o 远程锁定保护信息应使LER进入远程不可用状态，并开始传输NR（0,0）信息。应注意的是，这会自动取消当前强制切换或手动切换命令，并且数据流量会恢复到工作路径。
o A remote Forced Switch message SHALL be ignored by the PSC Process logic if there is an active local Forced Switch operator command. If the Protecting administrative state is due to a remote Forced Switch message, then the LER SHALL remain in remote Protecting administrative state and continue transmitting the last message. If the Protecting administrative state is due to either a local or
o 如果存在激活的本地强制开关操作员命令，则PSC过程逻辑应忽略远程强制开关消息。如果保护管理状态是由远程强制切换消息引起的，则LER应保持远程保护管理状态，并继续传输最后一条消息。如果保护管理状态是由于本地或本地
remote Manual Switch, then the LER SHALL remain in remote Protecting administrative state (updating the state information with the proper relevant information) and begin transmitting an NR(0,1) message.
远程手动开关，则LER应保持远程保护管理状态（使用适当的相关信息更新状态信息），并开始传输NR（0,1）消息。
o A remote Signal Fail message indicating a failure on the protection path SHALL cause the LER to go into remote Unavailable state and begin transmitting an NR(0,0) message, if the Protecting administrative state is due to a Manual Switch command. It should be noted that this automatically cancels the current Manual Switch command and data traffic is reverted to the working path.
o 如果保护管理状态是由手动开关命令引起的，则指示保护路径故障的远程信号故障消息应导致LER进入远程不可用状态并开始传输NR（0,0）消息。应注意的是，这会自动取消当前的手动切换命令，并且数据流量会恢复到工作路径。
o A remote Signal Fail message indicating a failure on the working path SHALL be ignored if there is an active local Forced Switch command. If the Protecting state is due to a local or remote Manual Switch, then the LER SHALL go to remote Protecting failure state and begin transmitting an NR(0,1) message.
o 如果存在激活的本地强制开关命令，则指示工作路径故障的远程信号故障信息应被忽略。如果保护状态是由本地或远程手动开关引起的，则LER应进入远程保护故障状态，并开始传输NR（0,1）消息。
o A remote Manual Switch message SHALL be ignored by the PSC Control logic if in Protecting administrative state due to a local or remote Forced Switch. If in Protecting administrative state due to a remote Manual Switch, then the LER SHALL remain in remote Protecting administrative state and continue transmitting the current message. If in local Protecting administrative state due to an active Manual Switch, then the LER SHALL remain in local Protecting administrative state and continue transmission of the MS(1,1) message.
o 如果由于本地或远程强制开关而处于保护管理状态，则PSC控制逻辑应忽略远程手动开关信息。如果由于远程手动开关而处于保护管理状态，则LER应保持在远程保护管理状态，并继续传输当前消息。如果由于激活的手动开关而处于本地保护管理状态，则LER应保持本地保护管理状态，并继续传输MS（1,1）消息。
o A remote DNR(0,1) message SHALL be ignored if in local Protecting administrative state. If in remote Protecting administrative state, then the LER SHALL go to Do-not-Revert state and continue transmitting the current message.
o 如果处于本地保护管理状态，则应忽略远程DNR（0,1）消息。如果处于远程保护管理状态，则LER应进入不恢复状态并继续传输当前消息。
o A remote NR(0,0) message SHALL be ignored if in local Protecting administrative state. If in remote Protecting administrative state and there is no active local Signal Fail indication, then the LER SHALL go to Normal state and begin transmitting an NR(0,0) message. If there is a local Signal Fail on the working path, the LER SHALL go to local Protecting failure state and begin transmitting an SF(1,1) message.
o 如果处于本地保护管理状态，则应忽略远程NR（0,0）消息。如果处于远程保护管理状态且没有激活的本地信号故障指示，则LER应进入正常状态并开始发送NR（0,0）消息。如果工作路径上存在本地信号故障，LER应进入本地保护故障状态，并开始传输SF（1,1）消息。
o All other remote messages SHALL be ignored.
o 应忽略所有其他远程消息。
When the protection mechanism has been triggered and the protection domain has performed a protection switch, the domain is in the Protecting failure state. In this state, the normal data traffic
当保护机制已触发且保护域已执行保护切换时，该域处于保护故障状态。在此状态下，正常数据流量
SHALL be transported on the protection path. When an LER is in this state, it implies that there either was a local SF condition or it received a remote SF PSC message. The SF condition or message indicated that the failure is on the working path.
应在保护路径上运输。当LER处于该状态时，表示存在本地SF情况或收到远程SF PSC消息。SF条件或消息表明故障在工作路径上。
This state may be overridden by the Unavailable state triggers, i.e., Lockout of protection or SF on the protection path, or by issuing an FS operator command. This state will be cleared when the SF condition is cleared. In order to prevent flapping due to an intermittent fault, the LER SHOULD employ a Wait-to-Restore timer to delay return to Normal state until the network has stabilized (see Section 3.5).
该状态可由不可用状态触发器覆盖，即保护锁定或保护路径上的SF，或通过发出FS操作员命令来覆盖。当SF条件被清除时，该状态将被清除。为了防止间歇性故障引起的拍打，LER应使用等待恢复定时器延迟恢复到正常状态，直到网络稳定（见第3.5节）。
The following describe the reaction to local input:
以下描述了对本地输入的反应：
o A local Clear SF SHALL be ignored if in remote Protecting failure state. If in local Protecting failure state and the LER is configured for revertive behavior, then this input SHALL cause the LER to go into Wait-to-Restore state, start the WTR timer, and begin transmitting a WTR(0,1) message. If in local Protecting failure state and the LER is configured for non-revertive behavior, then this input SHALL cause the LER to go into Do-not-Revert state and begin transmitting a DNR(0,1) message.
o 如果处于远程保护故障状态，则应忽略本地清除SF。如果处于本地保护故障状态且LER配置为恢复行为，则该输入应使LER进入等待恢复状态，启动WTR定时器，并开始传输WTR（0,1）消息。如果处于本地保护故障状态，且LER配置为非恢复行为，则该输入应使LER进入不恢复状态，并开始传输DNR（0,1）消息。
o A local Lockout of protection input SHALL cause the LER to go into Unavailable state and begin transmission of an LO(0,0) message.
o 保护输入的本地锁定应使LER进入不可用状态，并开始传输LO（0,0）信息。
o A local Forced Switch input SHALL cause the LER to go into Protecting administrative state and begin transmission of an FS(1,1) message.
o 本地强制开关输入应使LER进入保护管理状态，并开始传输FS（1,1）消息。
o A local Signal Fail indication on the protection path SHALL cause the LER to go into Unavailable state and begin transmission of an SF(0,0) message.
o 保护路径上的本地信号故障指示应使LER进入不可用状态，并开始传输SF（0,0）消息。
o A local Signal Fail indication on the working path SHALL cause the LER to remain in local Protecting failure state and transmit an SF(1,1) message.
o 工作路径上的本地信号故障指示应使LER保持在本地保护故障状态，并传输SF（1,1）消息。
o All other local inputs SHALL be ignored.
o 应忽略所有其他本地输入。
While in Protecting failure state, the LER may receive and react as follows to remote PSC messages:
处于保护故障状态时，LER可接收远程PSC消息并作出如下反应：
o A remote Lockout of protection message SHALL cause the LER to go into remote Unavailable state, and if in local Protecting failure state, then the LER SHALL transmit an SF(1,0) message; otherwise,
o 远程锁定保护信息应使LER进入远程不可用状态，如果处于本地保护故障状态，则LER应发送SF（1,0）信息；否则
it SHALL transmit an NR(0,0) message. It should be noted that this may cause loss of user data since the working path is still in a failure condition.
应发送NR（0,0）信息。应注意，这可能会导致用户数据丢失，因为工作路径仍处于故障状态。
o A remote Forced Switch message SHALL cause the LER go into remote Protecting administrative state, and if in local Protecting failure state, the LER SHALL transmit the SF(1,1) message; otherwise, it SHALL transmit NR(0,1).
o 远程强制切换消息应使LER进入远程保护管理状态，如果处于本地保护故障状态，LER应发送SF（1,1）消息；否则，应传输NR（0,1）。
o A remote Signal Fail message indicating a failure on the protection path SHALL cause the LER to go into remote Unavailable state, and if in local Protecting failure state, then the LER SHALL transmit an SF(1,0) message; otherwise, it SHALL transmit an NR(0,0) message. It should be noted that this may cause loss of user data since the working path is still in a failure condition.
o 指示保护路径故障的远程信号故障消息应使LER进入远程不可用状态，如果处于本地保护故障状态，则LER应发送SF（1,0）消息；否则，应发送NR（0,0）消息。应注意，这可能会导致用户数据丢失，因为工作路径仍处于故障状态。
o If in remote Protecting failure state, a remote Wait-to-Restore message SHALL cause the LER to go into remote Wait-to-Restore state and continue transmission of the current message.
o 如果处于远程保护故障状态，远程等待恢复消息将导致LER进入远程等待恢复状态并继续传输当前消息。
o If in remote Protecting failure state, a remote Do-not-Revert message SHALL cause the LER to go into remote Do-not-Revert state and continue transmission of the current message.
o 如果处于远程保护故障状态，远程不恢复消息应使LER进入远程不恢复状态，并继续传输当前消息。
o If in remote Protecting failure state, a remote NR(0,0) SHALL cause the LER to go to Normal state.
o 如果处于远程保护故障状态，远程NR（0,0）应使LER进入正常状态。
o All other remote messages SHALL be ignored.
o 应忽略所有其他远程消息。
When recovering from a failure condition on the working path, the Wait-to-Restore state is used by the PSC protocol to delay reverting to the Normal state, for the period of the WTR timer to allow the recovering failure to stabilize. While in the Wait-to-Restore state, the data traffic SHALL continue to be transported on the protection path. The natural transition from the Wait-to-Restore state to Normal state will occur when the WTR timer expires.
当从工作路径上的故障条件中恢复时，PSC协议使用等待恢复状态延迟恢复到正常状态，在WTR定时器期间，以允许恢复故障稳定。在等待恢复状态下，数据流量应继续在保护路径上传输。WTR计时器过期时，将发生从等待恢复状态到正常状态的自然转换。
When in Wait-to-Restore state, the following describe the reaction to local inputs:
当处于等待恢复状态时，以下描述了对本地输入的反应：
o A local Lockout of protection command SHALL send the Stop command to the WTR timer, go into local Unavailable state, and begin transmitting an LO(0,0) message.
o 本地锁定保护命令应向WTR定时器发送停止命令，进入本地不可用状态，并开始发送LO（0,0）消息。
o A local Forced Switch command SHALL send the Stop command to the WTR timer, go into local Protecting administrative state, and begin transmission of an FS(1,1) message.
o A local Forced Switch command SHALL send the Stop command to the WTR timer, go into local Protecting administrative state, and begin transmission of an FS(1,1) message.translate error, please retry
o A local Signal Fail indication on the protection path SHALL send the Stop command to the WTR timer, go into local Unavailable state, and begin transmission of an SF(0,0) message.
o 保护路径上的本地信号故障指示应向WTR定时器发送停止命令，进入本地不可用状态，并开始传输SF（0,0）消息。
o A local Signal Fail indication on the working path SHALL send the Stop command to the WTR timer, go into local Protecting failure state, and begin transmission of an SF(1,1) message.
o 工作路径上的本地信号故障指示应向WTR定时器发送停止命令，进入本地保护故障状态，并开始传输SF（1,1）消息。
o A local Manual Switch input SHALL send the Stop command to the WTR timer, go into local Protecting administrative state, and begin transmission of an MS(1,1) message.
o 本地手动开关输入应向WTR定时器发送停止命令，进入本地保护管理状态，并开始传输MS（1,1）消息。
o A local WTR Expires input SHALL cause the LER to remain in Wait-to-Restore state, and begin transmitting an NR(0,1) message.
o 本地WTR Expires输入应使LER保持等待恢复状态，并开始传输NR（0,1）消息。
o All other local inputs SHALL be ignored.
o 应忽略所有其他本地输入。
When in Wait-to-Restore state, the following describe the reaction to remote messages:
当处于等待还原状态时，以下描述对远程消息的反应：
o A remote Lockout of protection message SHALL send the Stop command to the WTR timer, go into remote Unavailable state, and begin transmitting an NR(0,0) message.
o 远程锁定保护消息应向WTR定时器发送停止命令，进入远程不可用状态，并开始发送NR（0,0）消息。
o A remote Forced Switch message SHALL send the Stop command to the WTR timer, go into remote Protecting administrative state, and begin transmission of an NR(0,1) message.
o 远程强制开关信息应向WTR定时器发送停止命令，进入远程保护管理状态，并开始传输NR（0,1）信息。
o A remote Signal Fail message for the protection path SHALL send the Stop command to the WTR timer, go into remote Unavailable state, and begin transmission of an NR(0,0) message.
o 保护路径的远程信号故障消息应向WTR定时器发送停止命令，进入远程不可用状态，并开始传输NR（0,0）消息。
o A remote Signal Fail message for the working path SHALL send the Stop command to the WTR timer, go into remote Protecting failure state, and begin transmission of an NR(0,1) message.
o 工作路径的远程信号故障消息应向WTR定时器发送停止命令，进入远程保护故障状态，并开始传输NR（0,1）消息。
o A remote Manual Switch message SHALL send the Stop command to the WTR timer, go into remote Protecting administrative state, and begin transmission of an NR(0,1) message.
o 远程手动开关信息应向WTR定时器发送停止命令，进入远程保护管理状态，并开始传输NR（0,1）信息。
o If the WTR timer is running, then a remote NR message SHALL be ignored. If the WTR timer is stopped, then a remote NR message SHALL cause the LER to go into Normal state.
o 如果WTR定时器正在运行，则应忽略远程NR消息。如果WTR定时器停止，则远程NR消息将导致LER进入正常状态。
o All other remote messages SHALL be ignored.
o 应忽略所有其他远程消息。
Do-not-Revert state is a continuation of the Protecting failure state when the protection domain is configured for non-revertive behavior. While in Do-not-Revert state, data traffic SHALL continue to be transported on the protection path until the administrator sends a command to revert to Normal state. It should be noted that there is a fundamental difference between this state and Normal -- whereas Forced Switch in Normal state actually causes a switch in the transport path used, in Do-not-Revert state, the Forced Switch just switches the state (to Protecting administrative state) but the traffic would continue to be transported on the protection path! To revert back to Normal state, the administrator SHALL issue a Lockout of protection command followed by a Clear command.
当保护域配置为非还原行为时，不还原状态是保护故障状态的延续。当处于“不恢复”状态时，数据流量应继续在保护路径上传输，直到管理员发出恢复到正常状态的命令。应该注意的是，此状态和正常状态之间有一个根本区别——正常状态下的强制切换实际上会导致所用传输路径中的交换机，而在不还原状态下，强制切换只是切换状态（到保护管理状态）但流量将继续在保护路径上传输！要恢复到正常状态，管理员应发出锁定保护命令，然后发出清除命令。
When in Do-not-Revert state, the following describe the reaction to local input:
当处于“不还原”状态时，以下描述对本地输入的反应：
o A local Lockout of protection command SHALL cause the LER to go into local Unavailable state and begin transmitting an LO(0,0) message.
o 保护命令的本地锁定应使LER进入本地不可用状态，并开始传输LO（0,0）消息。
o A local Forced Switch command SHALL cause the LER to go into local Protecting administrative state and begin transmission of an FS(1,1) message.
o 本地强制切换命令应使LER进入本地保护管理状态，并开始传输FS（1,1）消息。
o A local Signal Fail indication on the protection path SHALL cause the LER to go into local Unavailable state and begin transmission of an SF(0,0) message.
o 保护路径上的本地信号故障指示应使LER进入本地不可用状态，并开始传输SF（0,0）消息。
o A local Signal Fail indication on the working path SHALL cause the LER to go into local Protecting failure state and begin transmission of an SF(1,1) message.
o 工作路径上的本地信号故障指示应使LER进入本地保护故障状态，并开始传输SF（1,1）消息。
o A local Manual Switch input SHALL cause the LER to go into local Protecting administrative state and begin transmission of an MS(1,1) message.
o 本地手动开关输入应使LER进入本地保护管理状态，并开始传输MS（1,1）信息。
o All other local inputs SHALL be ignored.
o 应忽略所有其他本地输入。
When in Do-not-Revert state, the following describe the reaction to remote messages:
当处于“不还原”状态时，以下内容描述了对远程消息的反应：
o A remote Lockout of protection message SHALL cause the LER to go into remote Unavailable state and begin transmitting an NR(0,0) message.
o 远程锁定保护信息应使LER进入远程不可用状态，并开始传输NR（0,0）信息。
o A remote Forced Switch message SHALL cause the LER to go into remote Protecting administrative state and begin transmission of an NR(0,1) message.
o 远程强制切换消息应使LER进入远程保护管理状态，并开始传输NR（0,1）消息。
o A remote Signal Fail message for the protection path SHALL cause the LER to go into remote Unavailable state and begin transmission of an NR(0,0) message.
o 保护路径的远程信号故障消息应使LER进入远程不可用状态，并开始传输NR（0,0）消息。
o A remote Signal Fail message for the working path SHALL cause the LER to go into remote Protecting failure state and begin transmission of an NR(0,1) message.
o 工作路径的远程信号故障消息应使LER进入远程保护故障状态，并开始传输NR（0,1）消息。
o A remote Manual Switch message SHALL cause the LER to go into remote Protecting administrative state and begin transmission of an NR(0,1) message.
o 远程手动开关信息应使LER进入远程保护管理状态，并开始传输NR（0,1）信息。
o All other remote messages SHALL be ignored.
o 应忽略所有其他远程消息。
In the "Pseudowire Name Spaces (PWE3)" registry, IANA maintains the "Pseudowire Associated Channel Types" registry.
在“伪线名称空间（PWE3）”注册表中，IANA维护“伪线关联通道类型”注册表。
IANA has assigned a new code point from this registry. The code point has been assigned from the code point space that requires "IETF Review" as follows:
IANA已从此注册表分配了一个新的代码点。代码点已从需要“IETF审查”的代码点空间分配，如下所示：
Registry:
注册处：
Value Description TLV Follows Reference
------ ----------------------- ----------- ---------------
0x0024 Protection State no [this document]
Coordination Protocol -
Channel Type (PSC-CT)
Value Description TLV Follows Reference
------ ----------------------- ----------- ---------------
0x0024 Protection State no [this document]
Coordination Protocol -
Channel Type (PSC-CT)
IANA has created and maintains a new sub-registry within the "Multiprotocol Label Switching (MPLS) Operations, Administration, and Management (OAM) Parameters" registry called the "MPLS PSC Request Registry". All code points within this registry shall be allocated according to the "Standards Action" procedure as specified in [RFC5226].
IANA在“多协议标签交换（MPLS）操作、管理和管理（OAM）参数”注册表中创建并维护了一个新的子注册表，称为“MPLS PSC请求注册表”。应根据[RFC5226]中规定的“标准行动”程序分配该注册表中的所有代码点。
The PSC Request Field is 4 bits, and the values have been allocated as follows:
PSC请求字段为4位，值分配如下：
Value Description Reference
----- --------------------- ---------------
0 No Request [this document]
1 Do-not-Revert [this document]
2 - 3 Unassigned
4 Wait-to-Restore [this document]
5 Manual Switch [this document]
6 Unassigned
7 Signal Degrade [this document]
8 - 9 Unassigned
10 Signal Fail [this document]
11 Unassigned
12 Forced Switch [this document]
13 Unassigned
14 Lockout of protection [this document]
15 Unassigned
Value Description Reference
----- --------------------- ---------------
0 No Request [this document]
1 Do-not-Revert [this document]
2 - 3 Unassigned
4 Wait-to-Restore [this document]
5 Manual Switch [this document]
6 Unassigned
7 Signal Degrade [this document]
8 - 9 Unassigned
10 Signal Fail [this document]
11 Unassigned
12 Forced Switch [this document]
13 Unassigned
14 Lockout of protection [this document]
15 Unassigned
The IANA has created and maintains a new sub-registry within the "Multiprotocol Label Switching (MPLS) Operations, Administration, and Management (OAM) Parameters" registry called the "MPLS PSC TLV Registry". All code points within this registry shall be allocated according to the "IETF Review" procedure as specified in [RFC5226].
IANA在“多协议标签交换（MPLS）操作、管理和管理（OAM）参数”注册表中创建并维护了一个新的子注册表，称为“MPLS PSC TLV注册表”。应根据[RFC5226]中规定的“IETF审查”程序分配该注册表中的所有代码点。
MPLS-TP is a subset of MPLS and so builds upon many of the aspects of the security model of MPLS. MPLS networks make the assumption that it is very hard to inject traffic into a network and equally hard to cause traffic to be directed outside the network. The control-plane protocols utilize hop-by-hop security and assume a "chain-of-trust" model such that end-to-end control-plane security is not used. For more information on the generic aspects of MPLS security, see [RFC5920].
MPLS-TP是MPLS的一个子集，因此建立在MPLS安全模型的许多方面之上。MPLS网络假设很难将流量注入网络，也很难将流量定向到网络外部。控制平面协议利用逐跳安全性，并假设“信任链”模型，因此不使用端到端控制平面安全性。有关MPLS安全性的一般方面的更多信息，请参阅[RFC5920]。
This document describes a protocol carried in the G-ACh [RFC5586], and so is dependent on the security of the G-ACh, itself. The G-ACh is a generalization of the Associated Channel defined in [RFC4385]. Thus, this document relies heavily on the security mechanisms provided for the Associated Channel and described in those two documents.
本文档描述了G-ACh[RFC5586]中携带的协议，因此依赖于G-ACh本身的安全性。G-ACh是[RFC4385]中定义的相关信道的推广。因此，本文档在很大程度上依赖于为相关通道提供的、并在这两个文档中描述的安全机制。
A specific concern for the G-ACh is that is can be used to provide a covert channel. This problem is wider than the scope of this document and does not need to be addressed here, but it should be noted that the channel provides end-to-end connectivity and SHOULD
G-ACh的一个特别关注点是，它可以用来提供隐蔽通道。此问题超出了本文档的范围，此处不需要解决，但应注意，通道提供端到端连接，因此应
NOT be policed by transit nodes. Thus, there is no simple way of preventing any traffic being carried between in the G-ACh consenting nodes.
不受传输节点的监控。因此，没有简单的方法来防止在G-ACh同意节点之间承载任何业务。
A good discussion of the data-plane security of an associated channel may be found in [RFC5085]. That document also describes some mitigation techniques.
有关相关信道的数据平面安全性的详细讨论，请参见[RFC5085]。该文件还描述了一些缓解技术。
It should be noted that the G-ACh is essentially connection oriented so injection or modification of control messages specified in this document require the subversion of a transit node. Such subversion is generally considered hard in MPLS networks and impossible to protect against at the protocol level. Management level techniques are more appropriate.
应该注意的是，G-ACh基本上是面向连接的，因此本文档中指定的控制消息的注入或修改需要对传输节点进行颠覆。在MPLS网络中，这种颠覆通常被认为是很难实现的，并且不可能在协议级别进行保护。管理层技术更合适。
However, a new concern for this document is the accidental corruption of messages (through faulty implementations or random corruption). The main concern is around the Request, FPath, and Path fields as a change to these fields would change the behavior of the peer end point. Although this document does not define a way to avoid a change in network behavior upon receipt of a message indicating a change in protection status, the transition between states will converge on a known and stable behavior in the face of messages that do not match reality.
然而，本文档的一个新问题是消息的意外损坏（通过错误的实现或随机损坏）。主要关注的是Request、FPath和Path字段，因为对这些字段的更改将改变对等端点的行为。尽管本文件未定义在收到指示保护状态变化的消息时避免网络行为变化的方法，但在不符合实际情况的消息面前，状态之间的转换将收敛于已知和稳定的行为。
The authors would like to thank all members of the teams (the Joint Working Team, the MPLS Interoperability Design Team in the IETF, and the T-MPLS Ad Hoc Group in ITU-T) involved in the definition and specification of the MPLS Transport Profile.
作者要感谢参与MPLS传输配置文件定义和规范的所有团队成员（联合工作团队、IETF中的MPLS互操作性设计团队和ITU-T中的T-MPLS特设小组）。
Hao Long Huawei Technologies Co., Ltd. F3 Building, Huawei Industrial Park Bantian, Shenzhen, China
中国深圳市半天华为工业园豪龙华为技术有限公司F3楼
EMail: longhao@huawei.com
EMail: longhao@huawei.com
Davide Chiara Ericsson Via Calda 5, 16152 Genova Italy
Davide Chiara Ericsson Via Calda 516152意大利热那亚
EMail: davide.chiara@ericsson.com
EMail: davide.chiara@ericsson.com
Dan Frost Cisco Systems
丹弗罗斯特思科系统公司
EMail: danfrost@cisco.com
EMail: danfrost@cisco.com
Francesco Fondelli Ericsson via Moruzzi 1 56100, Pisa Italy
弗朗西斯科·丰德利·爱立信via Moruzzi 156100，意大利比萨
EMail: francesco.fondelli@ericsson.com
EMail: francesco.fondelli@ericsson.com
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson, "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN", RFC 4385, February 2006.
[RFC4385]Bryant，S.，Swallow，G.，Martini，L.，和D.McPherson，“用于MPLS PSN的伪线仿真边到边（PWE3）控制字”，RFC 43852006年2月。
[RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic Associated Channel", RFC 5586, June 2009.
[RFC5586]Bocci，M.，Vigoureux，M.，和S.Bryant，“MPLS通用关联信道”，RFC 55862009年6月。
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654, September 2009.
[RFC5654]Niven Jenkins，B.，Brungard，D.，Betts，M.，Sprecher，N.，和S.Ueno，“MPLS传输配置文件的要求”，RFC 56542009年9月。
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001.
[RFC3031]Rosen，E.，Viswanathan，A.，和R.Callon，“多协议标签交换体系结构”，RFC 30312001年1月。
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, January 2001.
[RFC3032]Rosen，E.，Tappan，D.，Fedorkow，G.，Rekhter，Y.，Farinaci，D.，Li，T.，和A.Conta，“MPLS标签堆栈编码”，RFC 3032，2001年1月。
[RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", RFC 3945, October 2004.
[RFC3945]Mannie，E.“通用多协议标签交换（GMPLS）体系结构”，RFC 39452004年10月。
[RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture", RFC 3985, March 2005.
[RFC3985]Bryant，S.和P.Pate，“伪线仿真边到边（PWE3）架构”，RFC 39852005年3月。
[RFC4427] Mannie, E. and D. Papadimitriou, "Recovery (Protection and Restoration) Terminology for Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4427, March 2006.
[RFC4427]Mannie，E.和D.Papadimitriou，“通用多协议标签交换（GMPLS）的恢复（保护和恢复）术语”，RFC 4427，2006年3月。
[RFC4872] Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE Extensions in Support of End-to-End Generalized Multi-Protocol Label Switching (GMPLS) Recovery", RFC 4872, May 2007.
[RFC4872]Lang，J.，Rekhter，Y.，和D.Papadimitriou，“支持端到端通用多协议标签交换（GMPLS）恢复的RSVP-TE扩展”，RFC 4872，2007年5月。
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel, "GMPLS Segment Recovery", RFC 4873, May 2007.
[RFC4873]Berger，L.，Bryskin，I.，Papadimitriou，D.，和A.Farrel，“GMPLS段恢复”，RFC 4873，2007年5月。
[RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires", RFC 5085, December 2007.
[RFC5085]Nadeau，T.和C.Pignataro，“伪线虚拟电路连接验证（VCCV）：伪线的控制通道”，RFC 5085，2007年12月。
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008.
[RFC5226]Narten，T.和H.Alvestrand，“在RFCs中编写IANA注意事项部分的指南”，BCP 26，RFC 5226，2008年5月。
[RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi-Segment Pseudowire Emulation Edge-to-Edge", RFC 5659, October 2009.
[RFC5659]Bocci，M.和S.Bryant，“多段伪线边到边仿真的体系结构”，RFC 5659，2009年10月。
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS Networks", RFC 5920, July 2010.
[RFC5920]方，L，“MPLS和GMPLS网络的安全框架”，RFC 5920，2010年7月。
[RFC5921] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A Framework for MPLS in Transport Networks", RFC 5921, July 2010.
[RFC5921]Bocci，M.，Bryant，S.，Frost，D.，Levrau，L.，和L.Berger，“传输网络中MPLS的框架”，RFC 59212010年7月。
[RFC6372] Sprecher, N., Ed. and A. Farrel, Ed., "MPLS Transport Profile (MPLS-TP) Survivability Framework", RFC 6372, September 2011.
[RFC6372]Sprecher，N.，Ed.和A.Farrel，Ed.，“MPLS传输配置文件（MPLS-TP）生存能力框架”，RFC 6372，2011年9月。
The PSC state machine is described in Section 4.3.3. This appendix provides the same information but in tabular format. In the event of a mismatch between these tables and the text in Section 4.3.3, the text is authoritative. Note that this appendix is intended to be a functional description, not an implementation specification.
第4.3.3节描述了PSC状态机。本附录以表格形式提供了相同的信息。如果这些表格与第4.3.3节中的文本不匹配，则文本具有权威性。请注意，本附录旨在作为功能说明，而不是实施规范。
For the sake of clarity of the table, the six states listed in the text are split into 13 states. The logic of the split is to differentiate between the different cases given in the conditional statements in the descriptions of each state in the text. In addition, the remote and local states were split for the Unavailable, Protecting failure, and Protecting administrative states.
为清楚起见，将案文所列六个国家分为13个国家。拆分的逻辑是区分文本中每个状态描述的条件语句中给出的不同情况。此外，远程和本地状态因不可用、保护故障和保护管理状态而被拆分。
There is only one table for the PSC state machine, but it is broken into two parts for space reasons. The first part lists the 13 possible states, the eight possible local inputs (that is, inputs that are generated by the node in question), and the action taken when a given input is received when the node is in a particular state. The second part of the table lists the 13 possible states and the eight remote inputs (inputs that come from a node other than the one executing the state machine).
PSC状态机只有一个表，但由于空间原因，它被分成两部分。第一部分列出了13种可能的状态、8种可能的本地输入（即相关节点生成的输入）以及当节点处于特定状态时接收到给定输入时所采取的操作。表的第二部分列出了13种可能的状态和8个远程输入（来自执行状态机的节点以外的节点的输入）。
There are 13 rows in the table, headers notwithstanding. These rows are the 13 possible extended states in the state machine.
表中有13行，尽管有标题。这些行是状态机中13种可能的扩展状态。
The text in the first column is the current state. Those states that have both source and cause are formatted as State:Cause:Source. For example, the string UA:LO:L indicates that the current state is 'Unavailable', that the cause of the current state is a Lockout of protection that was a local input. In contrast, the state N simply is Normal; there is no need to track the cause for entry into Normal state.
第一列中的文本是当前状态。同时具有源和原因的那些状态的格式为State:cause:source。例如，字符串UA:LO:L表示当前状态为“不可用”，当前状态的原因是本地输入的保护锁定。相反，状态N仅仅是正常的；无需跟踪进入正常状态的原因。
The 13 extended states, as they appear in the table, are as follows:
表中显示的13个扩展状态如下：
N Normal state
UA:LO:L Unavailable state due to local Lockout
UA:P:L Unavailable state due to local SF on protection path
UA:LO:R Unavailable state due to remote Lockout of protection message
UA:P:R Unavailable state due to remote SF message on protection path
PF:W:L Protecting failure state due to local SF on working path
PF:W:R Protecting failure state due to remote SF message on working
path
PA:F:L Protecting administrative state due to local FS operator
command
PA:M:L Protecting administrative state due to local MS operator
command
PA:F:R Protecting administrative state due to remote FS message
PA:M:R Protecting administrative state due to remote MS message
WTR Wait-to-Restore state
DNR Do-not-Revert state
N Normal state
UA:LO:L Unavailable state due to local Lockout
UA:P:L Unavailable state due to local SF on protection path
UA:LO:R Unavailable state due to remote Lockout of protection message
UA:P:R Unavailable state due to remote SF message on protection path
PF:W:L Protecting failure state due to local SF on working path
PF:W:R Protecting failure state due to remote SF message on working
path
PA:F:L Protecting administrative state due to local FS operator
command
PA:M:L Protecting administrative state due to local MS operator
command
PA:F:R Protecting administrative state due to remote FS message
PA:M:R Protecting administrative state due to remote MS message
WTR Wait-to-Restore state
DNR Do-not-Revert state
Each state corresponds to the transmission of a particular set of Request, FPath and Path bits. The table below lists the message that is generally sent in each particular state. If the message to be sent in a particular state deviates from the table below, it is noted in the footnotes to the state-machine table.
每个状态对应于一组特定请求、FPath和Path位的传输。下表列出了通常在每个特定状态下发送的消息。如果要在特定状态下发送的消息与下表不同，则会在状态机表的脚注中注明。
State REQ(FP,P)
------- ---------
N NR(0,0)
UA:LO:L LO(0,0)
UA:P:L SF(0,0)
UA:LO:R NR(0,0)
UA:P:R NR(0,0)
PF:W:L SF(1,1)
PF:W:R NR(0,1)
PA:F:L FS(1,1)
PA:M:L MS(1,1)
PA:F:R NR(0,1)
PA:M:R NR(0,1)
WTR WTR(0,1)
DNR DNR(0,1)
State REQ(FP,P)
------- ---------
N NR(0,0)
UA:LO:L LO(0,0)
UA:P:L SF(0,0)
UA:LO:R NR(0,0)
UA:P:R NR(0,0)
PF:W:L SF(1,1)
PF:W:R NR(0,1)
PA:F:L FS(1,1)
PA:M:L MS(1,1)
PA:F:R NR(0,1)
PA:M:R NR(0,1)
WTR WTR(0,1)
DNR DNR(0,1)
The top row in each table is the list of possible inputs. The local inputs are as follows:
每个表的顶行是可能输入的列表。本地输入如下所示：
NR No Request OC Operator Clear LO Lockout of protection SF-P Signal Fail on protection path SF-W Signal Fail on working path FS Forced Switch SFc Clear Signal Fail MS Manual Switch WTRExp WTR Expired
NR无请求OC操作员清除LO保护锁定SF-P信号保护路径故障SF-W信号工作路径故障FS强制开关SFc清除信号故障MS手动开关WTRExp WTR过期
and the remote inputs are as follows:
远程输入如下所示：
LO remote LO message SF-P remote SF message indicating protection path SF-W remote SF message indicating working path FS remote FS message MS remote MS message WTR remote WTR message DNR remote DNR message NR remote NR message
LO remote LO message SF-P remote SF message指示保护路径SF-W remote SF message指示工作路径FS remote FS message MS remote MS message WTR remote WTR message DNR remote DNR message NR remote NR message
Section 4.3.3 refers to some states as 'remote' and some as 'local'. By definition, all states listed in the table of local sources are local states, and all states listed in the table of remote sources are remote states. For example, Section 4.3.3.1 says "A local Lockout of protection input SHALL cause the LER to go into local Unavailable state". As the trigger for this state change is a local one, 'local Unavailable state' is, by definition, displayed in the table of local sources. Similarly, Section 4.3.3.1 also states that
第4.3.3节将某些状态称为“远程”，而将某些状态称为“本地”。根据定义，本地源表中列出的所有状态都是本地状态，远程源表中列出的所有状态都是远程状态。例如，第4.3.3.1节规定“保护输入的本地锁定应导致LER进入本地不可用状态”。由于此状态更改的触发器是本地触发器，“本地不可用状态”根据定义显示在本地源表中。同样，第4.3.3.1节也规定
"A remote Lockout of protection message SHALL cause the LER to go into remote Unavailable state" means that the state represented in the Unavailable rows in the table of remote sources is by definition a remote Unavailable state.
“远程锁定保护消息将导致LER进入远程不可用状态”意味着远程源表中不可用行中表示的状态定义为远程不可用状态。
Each cell in the table below contains either a state, a footnote, or the letter 'i'. 'i' stands for Ignore, and is an indication to continue with the current behavior. See Section 4.3.3. The footnotes are listed below the table.
下表中的每个单元格都包含状态、脚注或字母“i”i’代表忽略，表示继续当前行为。见第4.3.3节。下表列出了脚注。
Part 1: Local input state machine
第1部分：本地输入状态机
| OC | LO | SF-P | FS | SF-W | SFc | MS | WTRExp
--------+-----+-------+------+------+------+------+------+-------
N | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| i
UA:LO:L | N | i | i | i | i | i | i | i
UA:P:L | i |UA:LO:L| i |PA:F:L| i | [5] | i | i
UA:LO:R | i |UA:LO:L| [1] | i | [2] | [6] | i | i
UA:P:R | i |UA:LO:L|UA:P:L|PA:F:L| [3] | [6] | i | i
PF:W:L | i |UA:LO:L|UA:P:L|PA:F:L| i | [7] | i | i
PF:W:R | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i | i | i
PA:F:L | N |UA:LO:L| i | i | i | i | i | i
PA:M:L | N |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i | i | i
PA:F:R | i |UA:LO:L| i |PA:F:L| [4] | [8] | i | i
PA:M:R | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| i
WTR | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| [9]
DNR | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| i
| OC | LO | SF-P | FS | SF-W | SFc | MS | WTRExp
--------+-----+-------+------+------+------+------+------+-------
N | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| i
UA:LO:L | N | i | i | i | i | i | i | i
UA:P:L | i |UA:LO:L| i |PA:F:L| i | [5] | i | i
UA:LO:R | i |UA:LO:L| [1] | i | [2] | [6] | i | i
UA:P:R | i |UA:LO:L|UA:P:L|PA:F:L| [3] | [6] | i | i
PF:W:L | i |UA:LO:L|UA:P:L|PA:F:L| i | [7] | i | i
PF:W:R | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i | i | i
PA:F:L | N |UA:LO:L| i | i | i | i | i | i
PA:M:L | N |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i | i | i
PA:F:R | i |UA:LO:L| i |PA:F:L| [4] | [8] | i | i
PA:M:R | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| i
WTR | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| [9]
DNR | i |UA:LO:L|UA:P:L|PA:F:L|PF:W:L| i |PA:M:L| i
Part 2: Remote messages state machine
第2部分：远程消息状态机
| LO | SF-P | FS | SF-W | MS | WTR | DNR | NR
--------+-------+------+------+------+------+------+------+------
N |UA:LO:R|UA:P:R|PA:F:R|PF:W:R|PA:M:R| i | i | i
UA:LO:L | i | i | i | i | i | i | i | i
UA:P:L | [10] | i | [19] | i | i | i | i | i
UA:LO:R | i | i | i | i | i | i | i | [16]
UA:P:R |UA:LO:R| i |PA:F:R| i | i | i | i | [16]
PF:W:L | [11] | [12] |PA:F:R| i | i | i | i | i
PF:W:R |UA:LO:R|UA:P:R|PA:F:R| i | i | [14] | [15] | N
PA:F:L |UA:LO:R| i | i | i | i | i | i | i
PA:M:L |UA:LO:R|UA:P:R|PA:F:R| [13] | i | i | i | i
PA:F:R |UA:LO:R| i | i | i | i | i | DNR | [17]
PA:M:R |UA:LO:R|UA:P:R|PA:F:R| [13] | i | i | DNR | N
WTR |UA:LO:R|UA:P:R|PA:F:R|PF:W:R|PA:M:R| i | i | [18]
DNR |UA:LO:R|UA:P:R|PA:F:R|PF:W:R|PA:M:R| i | i | i
| LO | SF-P | FS | SF-W | MS | WTR | DNR | NR
--------+-------+------+------+------+------+------+------+------
N |UA:LO:R|UA:P:R|PA:F:R|PF:W:R|PA:M:R| i | i | i
UA:LO:L | i | i | i | i | i | i | i | i
UA:P:L | [10] | i | [19] | i | i | i | i | i
UA:LO:R | i | i | i | i | i | i | i | [16]
UA:P:R |UA:LO:R| i |PA:F:R| i | i | i | i | [16]
PF:W:L | [11] | [12] |PA:F:R| i | i | i | i | i
PF:W:R |UA:LO:R|UA:P:R|PA:F:R| i | i | [14] | [15] | N
PA:F:L |UA:LO:R| i | i | i | i | i | i | i
PA:M:L |UA:LO:R|UA:P:R|PA:F:R| [13] | i | i | i | i
PA:F:R |UA:LO:R| i | i | i | i | i | DNR | [17]
PA:M:R |UA:LO:R|UA:P:R|PA:F:R| [13] | i | i | DNR | N
WTR |UA:LO:R|UA:P:R|PA:F:R|PF:W:R|PA:M:R| i | i | [18]
DNR |UA:LO:R|UA:P:R|PA:F:R|PF:W:R|PA:M:R| i | i | i
The following are the footnotes for the table:
下表为脚注：
[1] Remain in the current state (UA:LO:R) and transmit SF(0,0).
[1] 保持当前状态（UA:LO:R）并传输SF（0,0）。
[2] Remain in the current state (UA:LO:R) and transmit SF(1,0).
[2] 保持当前状态（UA:LO:R）并传输SF（1,0）。
[3] Remain in the current state (UA:P:R) and transmit SF(1,0).
[3] 保持当前状态（UA:P:R）并传输SF（1,0）。
[4] Remain in the current state (PA:F:R) and transmit SF(1,1).
[4] 保持当前状态（PA:F:R）并传输SF（1,1）。
[5] If the SF being cleared is SF-P, transition to N. If it's SF-W, ignore the clear.
[5] 如果要清除的SF为SF-P，则转换为N。如果为SF-W，则忽略清除。
[6] Remain in current state (UA:x:R), if the SFc corresponds to a previous SF, then begin transmitting NR(0,0).
[6] 保持当前状态（UA:x:R），如果SFc对应于前一个SF，则开始传输NR（0,0）。
[7] If domain configured for revertive behavior transition to WTR, else transition to DNR.
[7] 如果域配置为还原行为转换为WTR，则转换为DNR。
[8] Remain in PA:F:R and transmit NR(0,1).
[8] 保持在PA:F:R，并传输NR（0,1）。
[9] Remain in WTR, send NR(0,1).
[9] 保持在WTR中，发送NR（0,1）。
[10] Transition to UA:LO:R continue sending SF(0,0).
[10] 转换到UA:LO:R继续发送SF（0,0）。
[11] Transition to UA:LO:R and send SF(1,0).
[11] 转换到UA:LO:R并发送SF（1,0）。
[12] Transition to UA and send SF(1,0).
[12] 转换到UA并发送SF（1,0）。
[13] Transition to PF:W:R and send NR(0,1).
[13] 转换到PF:W:R并发送NR（0,1）。
[14] Transition to WTR state and continue to send the current message.
[14] 转换到WTR状态并继续发送当前消息。
[15] Transition to DNR state and continue to send the current message.
[15] 转换到DNR状态并继续发送当前消息。
[16] If the local input is SF-P, then transition to UA:P:L. If the local input is SF-W, then transition to PF:W:L. Else, transition to N state and continue to send the current message.
[16] 如果本地输入为SF-P，则转换为UA:P:L。如果本地输入为SF-W，则转换为PF:W:L。否则，转换为N状态并继续发送当前消息。
[17] If the local input is SF-W, then transition to PF:W:L. Else, transition to N state and continue to send the current message.
[17] 如果本地输入为SF-W，则转换为PF:W:L。否则，转换为N状态并继续发送当前消息。
[18] If the receiving LER's WTR timer is running, maintain current state and message. If the WTR timer is stopped, transition to N.
[18] 如果接收LER的WTR计时器正在运行，请保持当前状态和消息。如果WTR计时器停止，则转换到N。
[19] Transition to PA:F:R and send SF (0,1).
[19] 转换到PA:F:R并发送SF（0,1）。
There is a requirement in [RFC5654] (number 84) that discusses a requirement to verify that the protection path is viable. While the PSC protocol does not define a specific operation for this functionality, it is possible to perform this operation by combining operations of the PSC and other OAM functionalities. One such possible combination would be to issue a Lockout of protection operation and then use the OAM function for diagnostic testing of the protection path. Similarly, to test the paths when the working path is not active would involve performing a Forced Switch to protection and then perform the diagnostic function on either the working or protection path.
[RFC5654]（编号84）中有一项要求，其中讨论了验证保护路径是否可行的要求。虽然PSC协议没有为该功能定义特定操作，但是可以通过组合PSC和其他OAM功能的操作来执行该操作。一种可能的组合是发出保护操作锁定，然后使用OAM功能对保护路径进行诊断测试。类似地，在工作路径未激活时测试路径将涉及强制切换到保护，然后在工作路径或保护路径上执行诊断功能。
Authors' Addresses
作者地址
Yaacov Weingarten (editor) Nokia Siemens Networks 3 Hanagar St. Neve Ne'eman B Hod Hasharon 45241 Israel
Yaacov Weingarten（编辑）诺基亚西门子网络3号哈纳加圣内韦内曼B Hod Hasharon以色列45241
EMail: yaacov.weingarten@nsn.com
EMail: yaacov.weingarten@nsn.com
Stewart Bryant Cisco United Kingdom
斯图尔特·布莱恩特（英国）
EMail: stbryant@cisco.com
EMail: stbryant@cisco.com
Eric Osborne Cisco United States
埃里克·奥斯本美国思科公司
EMail: eosborne@cisco.com
EMail: eosborne@cisco.com
Nurit Sprecher Nokia Siemens Networks 3 Hanagar St. Neve Ne'eman B Hod Hasharon 45241 Israel
Nurit Sprecher诺基亚西门子网络3以色列内韦内曼哈沙隆市哈纳加街45241号
EMail: nurit.sprecher@nsn.com
EMail: nurit.sprecher@nsn.com
Annamaria Fulignoli (editor) Ericsson Via Moruzzi Pisa 56100 Italy
安娜玛丽亚·富利诺利（编辑）爱立信Via Moruzzi Pisa 56100意大利
EMail: annamaria.fulignoli@ericsson.com
EMail: annamaria.fulignoli@ericsson.com