Network Working Group                                     A. Farrel, Ed.
Request for Comments: 5151                            Old Dog Consulting
Updates: 3209, 3473                                          A. Ayyangar
Category: Standards Track                               Juniper Networks
                                                             JP. Vasseur
                                                     Cisco Systems, Inc.
                                                           February 2008
Network Working Group                                     A. Farrel, Ed.
Request for Comments: 5151                            Old Dog Consulting
Updates: 3209, 3473                                          A. Ayyangar
Category: Standards Track                               Juniper Networks
                                                             JP. Vasseur
                                                     Cisco Systems, Inc.
                                                           February 2008

Inter-Domain MPLS and GMPLS Traffic Engineering -- Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Extensions


Status of This Memo


This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

本文件规定了互联网社区的互联网标准跟踪协议,并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态,请参考当前版本的“互联网官方协议标准”(STD 1)。本备忘录的分发不受限制。



This document describes procedures and protocol extensions for the use of Resource Reservation Protocol-Traffic Engineering (RSVP-TE) signaling in Multiprotocol Label Switching-Traffic Engineering (MPLS-TE) packet networks and Generalized MPLS (GMPLS) packet and non-packet networks to support the establishment and maintenance of Label Switched Paths that cross domain boundaries.


For the purpose of this document, a domain is considered to be any collection of network elements within a common realm of address space or path computation responsibility. Examples of such domains include Autonomous Systems, Interior Gateway Protocol (IGP) routing areas, and GMPLS overlay networks.


Table of Contents


   1. Introduction ....................................................3
      1.1. Conventions Used in This Document ..........................3
      1.2. Terminology ................................................4
   2. Signaling Overview ..............................................4
      2.1. Signaling Options ..........................................5
   3. Procedures on the Domain Border Node ............................6
      3.1. Rules on ERO Processing ....................................8
      3.2. LSP Setup Failure and Crankback ...........................10
      3.3. RRO Processing across Domains .............................11
      3.4. Notify Message Processing .................................11
   4. RSVP-TE Signaling Extensions ...................................12
      4.1. Control of Downstream Choice of Signaling Method ..........12
   5. Protection and Recovery of Inter-Domain TE LSPs ................13
      5.1. Fast Recovery Support Using MPLS-TE Fast Reroute (FRR) ....14
           5.1.1. Failure within a Domain (Link or Node Failure) .....14
           5.1.2. Failure of Link at Domain Border ...................14
           5.1.3. Failure of a Border Node ...........................15
      5.2. Protection and Recovery of GMPLS LSPs .....................15
   6. Reoptimization of Inter-Domain TE LSPs .........................16
   7. Backward Compatibility .........................................17
   8. Security Considerations ........................................18
   9. IANA Considerations ............................................20
      9.1. Attribute Flags for LSP_Attributes Object .................20
      9.2. New Error Codes ...........................................20
   10. Acknowledgments ...............................................21
   11. References ....................................................21
       11.1. Normative References ....................................21
       11.2. Informative References ..................................22
   1. Introduction ....................................................3
      1.1. Conventions Used in This Document ..........................3
      1.2. Terminology ................................................4
   2. Signaling Overview ..............................................4
      2.1. Signaling Options ..........................................5
   3. Procedures on the Domain Border Node ............................6
      3.1. Rules on ERO Processing ....................................8
      3.2. LSP Setup Failure and Crankback ...........................10
      3.3. RRO Processing across Domains .............................11
      3.4. Notify Message Processing .................................11
   4. RSVP-TE Signaling Extensions ...................................12
      4.1. Control of Downstream Choice of Signaling Method ..........12
   5. Protection and Recovery of Inter-Domain TE LSPs ................13
      5.1. Fast Recovery Support Using MPLS-TE Fast Reroute (FRR) ....14
           5.1.1. Failure within a Domain (Link or Node Failure) .....14
           5.1.2. Failure of Link at Domain Border ...................14
           5.1.3. Failure of a Border Node ...........................15
      5.2. Protection and Recovery of GMPLS LSPs .....................15
   6. Reoptimization of Inter-Domain TE LSPs .........................16
   7. Backward Compatibility .........................................17
   8. Security Considerations ........................................18
   9. IANA Considerations ............................................20
      9.1. Attribute Flags for LSP_Attributes Object .................20
      9.2. New Error Codes ...........................................20
   10. Acknowledgments ...............................................21
   11. References ....................................................21
       11.1. Normative References ....................................21
       11.2. Informative References ..................................22
1. Introduction
1. 介绍

The requirements for inter-area and inter-AS (Autonomous System) Multiprotocol Label Switching (MPLS) Traffic Engineering (TE) are stated in [RFC4105] and [RFC4216], respectively. Many of these requirements also apply to Generalized MPLS (GMPLS) networks. The framework for inter-domain MPLS-TE is provided in [RFC4726].


This document presents procedures and extensions to Resource Reservation Protocol-Traffic Engineering (RSVP-TE) signaling for the setup and maintenance of traffic engineered Label Switched Paths (TE LSPs) that span multiple domains in MPLS-TE or GMPLS networks. The signaling procedures described in this document are applicable to MPLS-TE packet LSPs established using RSVP-TE ([RFC3209]) and all LSPs (packet and non-packet) that use RSVP-TE GMPLS extensions as described in [RFC3473].

本文档介绍了资源预留协议流量工程(RSVP-TE)信令的程序和扩展,用于在MPLS-TE或GMPLS网络中建立和维护跨多个域的流量工程标签交换路径(TE LSP)。本文件中描述的信令程序适用于使用RSVP-TE([RFC3209])建立的MPLS-TE分组LSP以及使用RSVP-TE GMPLS扩展的所有LSP(分组和非分组),如[RFC3473]中所述。

Three different signaling methods for inter-domain RSVP-TE signaling are identified in [RFC4726]. Contiguous LSPs are achieved using the procedures of [RFC3209] and [RFC3473] to create a single end-to-end LSP that spans all domains. Nested LSPs are established using the techniques described in [RFC4206] to carry the end-to-end LSP in a separate tunnel across each domain. Stitched LSPs are established using the procedures of [RFC5150] to construct an end-to-end LSP from the concatenation of separate LSPs each spanning a domain.


This document defines the RSVP-TE protocol extensions necessary to control and select which of the three signaling mechanisms is used for any one end-to-end inter-domain TE LSP.

本文件定义了控制和选择三种信令机制中的哪一种用于任何一个端到端域间TE LSP所需的RSVP-TE协议扩展。

For the purpose of this document, a domain is considered to be any collection of network elements within a common realm of address space or path computation responsibility. Examples of such domains include Autonomous Systems, IGP areas, and GMPLS overlay networks ([RFC4208]).


1.1. Conventions Used in This Document
1.1. 本文件中使用的公约

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 RFC 2119 [RFC2119].

本文件中的关键词“必须”、“不得”、“要求”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119[RFC2119]中所述进行解释。

1.2. Terminology
1.2. 术语

AS: Autonomous System.


ASBR: Autonomous System Border Router. A router used to connect together ASs of a different or the same Service Provider via one or more inter-AS links.


Bypass Tunnel: An LSP that is used to protect a set of LSPs passing over a common facility.


ERO: Explicit Route Object.


FA: Forwarding Adjacency.


LSR: Label Switching Router.


MP: Merge Point. The node where bypass tunnels meet the protected LSP.


NHOP bypass tunnel: Next-Hop Bypass Tunnel. A backup tunnel, which bypasses a single link of the protected LSP.


NNHOP bypass tunnel: Next-Next-Hop Bypass Tunnel. A backup tunnel, which bypasses a single node of the protected LSP.


PLR: Point of Local Repair. The ingress of a bypass tunnel.


RRO: Record Route Object.


TE link: Traffic Engineering link.


2. Signaling Overview
2. 信令概述

The RSVP-TE signaling of a TE LSP within a single domain is described in [RFC3209] and [RFC3473]. Inter-domain TE LSPs can be supported by one of three options as described in [RFC4726] and set out in the next section:

[RFC3209]和[RFC3473]中描述了单个域内TE LSP的RSVP-TE信令。域间TE LSP可由[RFC4726]中描述的三个选项之一支持,并在下一节中阐述:

- contiguous LSPs - nested LSPs - stitched LSPs.

- 连续LSP-嵌套LSP-缝合LSP。

In fact, as pointed out in [RFC4726], any combination of these three options may be used in the course of an end-to-end inter-domain LSP. That is, the options should be considered as per-domain transit options so that an end-to-end inter-domain LSP that starts in domain A, transits domains B, C, and D, and ends in domain E might use an


LSP that runs contiguously from the ingress in domain A, through domain B to the border with domain C. Domain C might be transited using the nested LSP option to reach the border with domain D, and domain D might be transited using the stitched LSP option to reach the border with domain E, from where a normal LSP runs to the egress.


This document describes the RSVP-TE signaling extensions required to select and control which of the three signaling mechanisms is used.


The specific protocol extensions required to signal each LSP type are described in other documents and are out of scope for this document. Similarly, the routing extensions and path computation techniques necessary for the establishment of inter-domain LSPs are out of scope. An implementation of a transit LSR is unaware of the options for inter-domain TE LSPs since it sees only TE LSPs. An implementation of a domain border LSR has to decide what mechanisms of inter-domain TE LSP support to include, but must in any case support contiguous inter-domain TE LSPs since this is the default mode of operation for RSVP-TE. Failure to support either or both of nested LSPs or stitched LSPs, restricts the operators options, but does not prevent the establishment of inter-domain TE LSPs.

其他文档中描述了向每种LSP类型发送信号所需的特定协议扩展,这些扩展超出了本文档的范围。类似地,建立域间lsp所需的路由扩展和路径计算技术也超出了范围。传输LSR的实现不知道域间TE LSP的选项,因为它只看到TE LSP。域边界LSR的实现必须决定要包括哪些域间TE LSP支持机制,但在任何情况下都必须支持连续的域间TE LSP,因为这是RSVP-TE的默认操作模式。无法支持嵌套LSP或缝合LSP中的一个或两个,将限制操作员选项,但不会阻止建立域间TE LSP。

2.1. Signaling Options
2.1. 信号选项

There are three ways in which an RSVP-TE LSP could be signaled across multiple domains:

RSVP-TE LSP可通过三种方式跨多个域发送信号:

Contiguous A contiguous TE LSP is a single TE LSP that is set up across multiple domains using RSVP-TE signaling procedures described in [RFC3209] and [RFC3473]. No additional TE LSPs are required to create a contiguous TE LSP, and the same RSVP-TE information for the TE LSP is maintained along the entire LSP path. In particular, the TE LSP has the same RSVP-TE session and LSP ID at every LSR along its path.

连续TE LSP是使用[RFC3209]和[RFC3473]中描述的RSVP-TE信令过程跨多个域设置的单个TE LSP。创建连续的TE LSP不需要额外的TE LSP,并且沿着整个LSP路径维护TE LSP的相同RSVP-TE信息。特别地,TE LSP在其路径上的每个LSR处具有相同的RSVP-TE会话和LSP ID。

Nested One or more TE LSPs may be nested within another TE LSP as described in [RFC4206]. This technique can be used to nest one or more inter-domain TE LSPs into an intra-domain hierarchical LSP (H-LSP). The label stacking construct is used to achieve nesting in packet networks. In the rest of this document, the term H-LSP is used to refer to an LSP that allows other LSPs to be nested within it. An H-LSP may be advertised as a TE link within the same instance of the routing protocol as was used to advertise the TE links from which it was created, in which case it is a Forwarding Adjacency (FA) [RFC4206].

嵌套的一个或多个TE LSP可以嵌套在另一个TE LSP中,如[RFC4206]中所述。该技术可用于将一个或多个域间TE-LSP嵌套到域内分层LSP(H-LSP)中。标签堆叠结构用于在分组网络中实现嵌套。在本文档的其余部分中,术语H-LSP用于指允许在其中嵌套其他LSP的LSP。H-LSP可以作为路由协议的同一实例内的TE链路进行广告,该实例用于广告从中创建H-LSP的TE链路,在这种情况下,H-LSP是转发邻接(FA)[RFC4206]。

Stitched The concept of LSP stitching as well as the required signaling procedures are described in [RFC5150]. This technique can be used to stitch together shorter LSPs (LSP segments) to create a single, longer LSP. The LSP segments of an inter-domain LSP may be intra-domain LSPs or inter-domain LSPs.


The process of stitching in the data plane results in a single, end-to-end contiguous LSP. But in the control plane, each segment is signaled as a separate LSP (with distinct RSVP sessions) and the end-to-end LSP is signaled as yet another LSP with its own RSVP session. Thus, the control plane operation for LSP stitching is very similar to that for nesting.


An end-to-end inter-domain TE LSP may be achieved using one or more of the signaling techniques described. The choice is a matter of policy for the node requesting LSP setup (the ingress) and policy for each successive domain border node. On receipt of an LSP setup request (RSVP-TE Path message) for an inter-domain TE LSP, the decision of whether to signal the LSP contiguously or whether to nest or stitch it to another TE LSP depends on the parameters signaled from the ingress node and on the configuration of the local node.

可以使用所描述的一种或多种信令技术来实现端到端域间TE LSP。选择是请求LSP设置(入口)的节点的策略问题,以及每个后续域边界节点的策略问题。在接收到域间TE LSP的LSP设置请求(RSVP-TE Path消息)时,是否连续地向LSP发送信号或是否将其嵌套或缝合到另一个TE LSP的决定取决于从入口节点发送信号的参数和本地节点的配置。

The stitching segment LSP or H-LSP used to cross a domain may be pre-established or signaled dynamically based on the demand caused by the arrival of the inter-domain TE LSP setup request.

用于跨域的缝合段LSP或H-LSP可以基于域间TE LSP设置请求的到达引起的需求而预先建立或动态地发信号。

3. Procedures on the Domain Border Node
3. 域边界节点上的过程

Whether an inter-domain TE LSP is contiguous, nested, or stitched is limited by the signaling methods supported by or configured on the intermediate nodes. It is usually the domain border nodes where this restriction applies since other transit nodes are oblivious to the mechanism in use. The ingress of the LSP may further restrict the choice by setting parameters in the Path message when it is signaled.

域间TE LSP是连续的、嵌套的还是缝合的受中间节点支持的或在中间节点上配置的信令方法的限制。这一限制通常适用于域边界节点,因为其他传输节点不知道所使用的机制。LSP的进入可以通过在发送信号时在路径消息中设置参数来进一步限制选择。

When a domain border node receives the RSVP Path message for an inter-domain TE LSP setup, it MUST carry out the following procedures before it can forward the Path message to the next node along the path:

当域边界节点接收到域间TE LSP设置的RSVP Path消息时,它必须执行以下步骤,然后才能将Path消息沿路径转发到下一个节点:

1. Apply policies for the domain and the domain border node. These policies may restrict the establishment of inter-domain TE LSPs. In case of a policy failure, the node SHOULD fail the setup and send a PathErr message with error code "Policy control failure"/ "Inter-domain policy failure".

1. 为域和域边界节点应用策略。这些策略可能会限制域间TE LSP的建立。在策略失败的情况下,节点应使设置失败,并发送错误代码为“策略控制失败”/“域间策略失败”的PathErr消息。

2. Determine the signaling method to be used to cross the domain. If the ingress node of the inter-domain TE LSP has specified restrictions on the methods to be used, these MUST be adhered to. Within the freedom allowed by the ingress node, the domain border node MAY choose any method according to local configuration and policies. If no resultant signaling method is available or allowed, the domain border node MUST send a PathErr message with an error code as described in Section 4.1.

2. 确定用于跨域的信令方法。如果域间TE LSP的入口节点对要使用的方法有特定的限制,则必须遵守这些限制。在入口节点允许的自由范围内,域边界节点可以根据本地配置和策略选择任何方法。如果没有可用或允许的结果信令方法,则域边界节点必须发送带有错误代码的PathErr消息,如第4.1节所述。

Thus, for example, an ingress may request a contiguous LSP because it wishes to exert maximal control over the LSP's path and to control when reoptimization takes place. But the operator of a transit domain may decide (for example) that only LSP stitching is allowed for exactly the reason that it gives the operator the chance to reoptimize their own domain under their own control. In this case, the policy applied at the entry to the transit domain will result in the return of a PathErr message and the ingress has a choice to:


- find another path avoiding the transit domain, - relax his requirements, or - fail to provide the service.

- 找到另一条避开中转域的路径,-放宽他的要求,或者-无法提供服务。

3. Carry out ERO procedures as described in Section 3 in addition to the procedures in [RFC3209] and [RFC3473].

3. 除[RFC3209]和[RFC3473]中的程序外,执行第3节中所述的ERO程序。

4. Perform any path computations as required to determine the path across the domain and potentially to select the exit point from the domain.

4. 根据需要执行任何路径计算,以确定跨域的路径,并可能从域中选择退出点。

The path computation procedure is outside the scope of this document. A path computation option is specified in [RFC5152], and another option is to use a Path Computation Element (PCE) [RFC4655].


4a. In the case of nesting or stitching, either find an existing intra-domain TE LSP to carry the inter-domain TE LSP or signal a new one, depending on local policy.

4a。在嵌套或缝合的情况下,根据本地策略,查找现有的域内TE LSP以承载域间TE LSP或发送新的TE LSP。

In the event of a path computation failure, a PathErr message SHOULD be sent with error code "Routing Problem" using an error value selected according to the reason for computation failure. A domain border node MAY opt to silently discard the Path message in this case as described in Section 8.


In the event of the receipt of a PathErr message reporting signaling failure from within the domain or reported from a downstream domain, the domain border node MAY apply crankback procedures as described in Section 3.2. If crankback is not applied, or is exhausted, the border node MUST continue with PathErr processing as described in [RFC3209] and [RFC3473].


In the event of successful processing of a Path or Resv message, the domain border node MUST carry out RRO procedures as described in Section 3.3.


3.1. Rules on ERO Processing
3.1. 能源监管局的处理规则

The ERO that a domain border node receives in the Path message was supplied by the ingress node of the TE LSP and may have been updated by other nodes (for example, other domain border nodes) as the Path message was propagated. The content of the ERO depends on several factors including:

域边界节点在路径消息中接收的ERO由TE LSP的入口节点提供,并且在传播路径消息时可能已由其他节点(例如,其他域边界节点)更新。能源监管局的内容取决于几个因素,包括:

- the path computation techniques used, - the degree of TE visibility available to the nodes performing path computation, and - the policy at the nodes creating/modifying the ERO.

- 使用的路径计算技术,-执行路径计算的节点可用的TE可见性程度,以及-创建/修改ERO的节点的策略。

In general, H-LSPs and LSP segments are used between domain border nodes, but there is no restriction on the use of such LSPs to span multiple hops entirely within a domain. Therefore, the discussion that follows may be equally applied to any node within a domain although the term "domain border node" continues to be used for clarity.


When a Path message reaches the domain border node, the following rules apply for ERO processing and for further signaling.


1. If there are any policies related to ERO processing for the LSP, they MUST be applied and corresponding actions MUST be taken. For example, there might be a policy to reject EROs that identify nodes within the domain. In case of inter-domain LSP setup failures due to policy failures related to ERO processing, the node SHOULD issue a PathErr with error code "Policy control failure"/"Inter-domain explicit route rejected", but MAY be configured to silently discard the Path message or to return a different error code for security reasons.

1. 如果存在与LSP的ERO处理相关的任何政策,则必须应用这些政策并采取相应的措施。例如,可能存在拒绝标识域内节点的ERO的策略。如果由于与ERO处理相关的策略失败而导致域间LSP设置失败,则节点应发出错误代码为“策略控制失败”/“域间显式路由被拒绝”的PathErr,但可以配置为以静默方式放弃路径消息或出于安全原因返回不同的错误代码。

2. Section 8.2 of [RFC4206] describes how a node at the edge of a region processes the ERO in the incoming Path message and uses this ERO, to either find an existing H-LSP or signal a new H-LSP using the ERO hops. This process includes adjusting the ERO before sending the Path message to the next hop. These procedures MUST be followed for nesting or stitching of inter-domain TE LSPs.

2. [RFC4206]第8.2节描述了区域边缘的节点如何处理传入路径消息中的ERO,并使用该ERO查找现有的H-LSP或使用ERO跳向新的H-LSP发送信号。此过程包括在将Path消息发送到下一跳之前调整ERO。域间TE LSP的嵌套或缝合必须遵循这些程序。

3. If an ERO subobject identifies a TE link formed by the advertisement of an H-LSP or LSP segment (whether numbered or unnumbered), contiguous signaling MUST NOT be used. The node MUST use either nesting or stitching according to the capabilities of the LSP that forms the TE link, the parameters signaled in the Path message, and local policy. If there is a conflict between the capabilities of the LSP that forms the TE link indicated in the ERO and the parameters on the Path message, the domain border node SHOULD send a PathErr with error code "Routing Problem"/"ERO conflicts with inter-domain signaling method", but MAY be configured to silently discard the Path message or to return a different error code for security reasons.

3. 如果ERO子对象识别由H-LSP或LSP段(无论是否编号)的播发形成的TE链路,则不得使用连续信令。节点必须根据形成TE链路的LSP的能力、路径消息中发送的参数和本地策略使用嵌套或缝合。如果形成ERO中指示的TE链路的LSP的能力与Path消息上的参数之间存在冲突,则域边界节点应发送错误代码为“路由问题”/“ERO与域间信令方法冲突”的PathErr,但出于安全原因,可能会配置为以静默方式放弃路径消息或返回不同的错误代码。

4. An ERO in a Path message received by a domain border node may have a loose hop as the next hop. This may be an IP address or an AS number. In such cases, the ERO MUST be expanded to determine the path to the next hop using some form of path computation that may, itself, generate loose hops.

4. 域边界节点接收的路径消息中的ERO可能有一个松散的跃点作为下一个跃点。这可能是IP地址或AS号码。在这种情况下,必须使用某种形式的路径计算来扩展ERO,以确定到下一跳的路径,该路径计算本身可能会生成松散的跳。

5. In the absence of any ERO subobjects beyond the local domain border node, the LSP egress (the destination encoded in the RSVP Session object) MUST be considered as the next loose hop and rule 4 applied.

5. 在本地域边界节点之外没有任何ERO子对象的情况下,必须将LSP出口(在RSVP会话对象中编码的目的地)视为下一个松散跃点,并应用规则4。

6. In the event of any other failures processing the ERO, a PathErr message SHOULD be sent as described in [RFC3209] or [RFC3473], but a domain border router MAY be configured to silently discard the Path message or to return a different error code for security reasons.

6. 在处理ERO的任何其他故障的情况下,应按照[RFC3209]或[RFC3473]中所述发送PathErr消息,但出于安全原因,可将域边界路由器配置为以静默方式丢弃路径消息或返回不同的错误代码。

3.2. LSP Setup Failure and Crankback
3.2. LSP设置失败和回退

When an error occurs during LSP setup, a PathErr message is sent back towards the LSP ingress node to report the problem. If the LSP traverses multiple domains, this PathErr will be seen successively by each domain border node.


Domain border nodes MAY apply local policies to restrict the propagation of information about the contents of the domain. For example, a domain border node MAY replace the information in a PathErr message that indicates a specific failure at a specific node with information that reports a more general error with the entire domain. These procedures are similar to those described for the borders of overlay networks in [RFC4208].




- A domain border node MUST NOT suppress the propagation of a PathErr message except to attempt rerouting as described below.

- 域边界节点不得禁止PathErr消息的传播,除非尝试如下所述的重新路由。

- Nodes other than domain border nodes SHOULD NOT modify the contents of a PathErr message.

- 域边界节点以外的节点不应修改PathErr消息的内容。

- Domain border nodes SHOULD NOT modify the contents of a PathErr message unless domain confidentiality is a specific requirement.

- 域边界节点不应修改PathErr消息的内容,除非特定要求域机密性。

Domain border nodes provide an opportunity for crankback rerouting [RFC4920]. On receipt of a PathErr message generated because of an LSP setup failure, a domain border node MAY hold the PathErr and make further attempts to establish the LSP if allowed by local policy and by the parameters signaled on the Path message for the LSP. Such attempts might involve the computation of alternate routes through the domain, or the selection of different downstream domains. If a subsequent attempt is successful, the domain border router MUST discard the held PathErr message, but if all subsequent attempts are unsuccessful, the domain border router MUST send the PathErr upstream toward the ingress node. In this latter case, the domain border router MAY change the information in the PathErr message to provide further crankback details and information aggregation as described in [RFC4920].


Crankback rerouting MAY also be used to handle the failure of LSPs after they have been established [RFC4920].


3.3. RRO Processing across Domains
3.3. 跨域的错误处理

[RFC3209] defines the RRO as an optional object used for loop detection and for providing information about the hops traversed by LSPs.


As described for overlay networks in [RFC4208], a domain border node MAY filter or modify the information provided in an RRO for confidentiality reasons according to local policy. For example, a series of identifiers of hops within a domain MAY be replaced with the domain identifier (such as the AS number) or be removed entirely leaving just the domain border nodes.


Note that a domain border router MUST NOT mask its own presence, and MUST include itself in the RRO.


Such filtering of RRO information does not hamper the working of the signaling protocol, but the subsequent information loss may render management diagnostic procedures inoperable or at least make them more complicated, requiring the coordination of administrators of multiple domains.


Similarly, protocol procedures that depend on the presence of RRO information may become inefficient. For example, the Fast Reroute procedures defined in [RFC4090] use information in the RRO to determine the labels to use and the downstream MP.


3.4. Notify Message Processing
3.4. 通知消息处理

Notify messages are introduced in [RFC3473]. They may be sent direct rather than hop-by-hop, and so may speed the propagation of error information. If a domain border router is interested in seeing such messages (for example, to enable it to provide protection switching), it is RECOMMENDED that the domain border router update the Notify Request objects in the Path and Resv messages to show its own address following the procedures of [RFC3473].

[RFC3473]中介绍了通知消息。它们可以直接发送,而不是逐跳发送,因此可以加快错误信息的传播。如果域边界路由器有兴趣查看此类消息(例如,为了使其能够提供保护交换),建议域边界路由器按照[RFC3473]的过程更新路径和Resv消息中的Notify Request对象,以显示其自己的地址。

Note that the replacement of a Notify Recipient in the Notify Request object means that some Notify messages (for example, those intended for delivery to the ingress LSR) may need to be examined, processed, and forwarded at domain borders. This is an obvious trade-off issue as the ability to handle notifiable events locally (i.e., within the domain) may or may not outweigh the cost of processing and forwarding Notify messages beyond the domain. Observe that the cost increases linearly with the number of domains in use.

请注意,替换Notify请求对象中的Notify Recipient意味着可能需要在域边界处检查、处理和转发某些Notify消息(例如,打算传递到入口LSR的消息)。这是一个明显的权衡问题,因为本地(即域内)处理应通知事件的能力可能会或可能不会超过域外处理和转发通知消息的成本。请注意,成本随使用的域数线性增加。

Also note that, as described in Section 8, a domain administrator may wish to filter or modify Notify messages that are generated within a domain in order to preserve security or confidentiality of network information. This is most easily achieved if the Notify messages are sent via the domain borders.


4. RSVP-TE Signaling Extensions
4. RSVP-TE信令扩展

The following RSVP-TE signaling extensions are defined to enable inter-domain LSP setup.


4.1. Control of Choice of Signaling Method
4.1. 控制信号方式的选择

In many network environments, there may be a network-wide policy that determines which one of the three inter-domain LSP techniques is used. In these cases, no protocol extensions are required.


However, in environments that support more than one technique, an ingress node may wish to constrain the choice made by domain border nodes for each inter-domain TE LSP that it originates.

然而,在支持多种技术的环境中,入口节点可能希望约束域边界节点对其发起的每个域间TE LSP所做的选择。

[RFC4420] defines the LSP_Attributes object that can be used to signal required attributes of an LSP. The Attributes Flags TLV includes Boolean flags that define individual attributes.


This document defines a new bit in the TLV that can be set by the ingress node of an inter-domain TE LSP to restrict the intermediate nodes to using contiguous signaling:

本文档定义了TLV中的一个新位,该位可由域间TE LSP的入口节点设置,以限制中间节点使用连续信令:

Contiguous LSP bit (bit number assignment in Section 9.1)


This flag is set by the ingress node that originates a Path message to set up an inter-domain TE LSP if it requires that the contiguous LSP technique is used. This flag bit is only to be used in the Attributes Flags TLV.

如果需要使用连续LSP技术,则该标志由发起路径消息以建立域间TE LSP的入口节点设置。此标志位仅用于属性标志TLV。

When a domain border LSR receives a Path message containing this bit set (one), the node MUST NOT perform stitching or nesting in support of the inter-domain TE LSP being set up. When this bit is clear (zero), a domain border LSR MAY perform stitching or nesting according to local policy.

当域边界LSR接收到包含此位集(一)的路径消息时,节点不得执行缝合或嵌套以支持正在设置的域间TE LSP。当该位清除(零)时,域边界LSR可以根据本地策略执行缝合或嵌套。

This bit MUST NOT be modified by any transit node.


An intermediate node that supports the LSP_Attributes object and the Attributes Flags TLV, and also recognizes the "Contiguous LSP" bit, but cannot support contiguous TE LSPs, MUST send a Path Error message with an error code "Routing Problem"/"Contiguous LSP type not supported" if it receives a Path message with this bit set.

支持LSP_Attributes对象和属性标志TLV,并且还识别“连续LSP”位但不支持连续TE LSP的中间节点,如果接收到设置了此位的路径消息,则必须发送带有错误代码“路由问题”/“不支持连续LSP类型”的路径错误消息。

If an intermediate node receiving a Path message with the "Contiguous LSP" bit set in the Flags field of the LSP_Attributes, recognizes the object, the TLV, and the bit and also supports the desired contiguous LSP behavior, then it MUST signal a contiguous LSP. If the node is a domain border node, or if the node expands a loose hop in the ERO, it MUST include an RRO Attributes subobject in the RRO of the corresponding Resv message (if such an object is present) with the "Contiguous LSP" bit set to report its behavior.

如果中间节点接收路径消息时在LSP_属性的标志字段中设置了“连续LSP”位,识别对象、TLV和该位,并且还支持所需的连续LSP行为,则它必须向连续LSP发送信号。如果该节点是域边界节点,或者如果该节点在ERO中扩展一个松散跃点,则它必须在相应Resv消息(如果存在此类对象)的RRO中包含一个RRO Attributes子对象,并设置“连续LSP”位以报告其行为。

Domain border LSRs MUST support and act on the setting of the "Contiguous LSP" flag.


However, if the intermediate node supports the LSP_Attributes object but does not recognize the Attributes Flags TLV, or supports the TLV but does not recognize this "Contiguous LSP" bit, then it MUST forward the object unmodified.

但是,如果中间节点支持LSP_Attributes对象但不识别Attributes Flags TLV,或者支持TLV但不识别此“连续LSP”位,则它必须转发未修改的对象。

The choice of action by an ingress node that receives a PathErr when requesting the use of a contiguous LSP is out of the scope of this document, but may include the computation of an alternate path.


5. Protection and Recovery of Inter-Domain TE LSPs
5. 域间TE-lsp的保护和恢复

The procedures described in Sections 3 and 4 MUST be applied to all inter-domain TE LSPs, including bypass tunnels, detour LSPs [RFC4090], and segment recovery LSPs [RFC4873]. This means that these LSPs will also be subjected to ERO processing, policies, path computation, etc.

第3节和第4节中描述的程序必须适用于所有域间TE LSP,包括旁通隧道、绕行LSP[RFC4090]和段恢复LSP[RFC4873]。这意味着这些LSP也将受到ERO处理、策略、路径计算等的影响。

Note also that the paths for these backup LSPs need to be either pre-configured, computed, and signaled with the protected LSP or computed on-demand at the PLR. Just as with any inter-domain TE LSP, the ERO may comprise strict or loose hops and will depend on the TE visibility of the computation point into the subsequent domain.

还请注意,这些备份LSP的路径需要预先配置、计算并用受保护LSP发送信号,或者在PLR处按需计算。与任何域间TE LSP一样,ERO可以包括严格的跳数或松散的跳数,并且将取决于计算点在后续域中的TE可见性。

If loose hops are present in the path of the backup LSP, ERO expansion will be required at some point along the path: probably at a domain border node. In order that the backup path remains disjoint from the protected LSP(s) the node performing the ERO expansion must


be provided with the path of the protected LSPs between the PLR and the MP. This information can be gathered from the RROs of the protected LSPs and is signaled in the DETOUR object for Fast Reroute [RFC4090] and uses route exclusion [RFC4874] for other protection schemes.


5.1. Fast Recovery Support Using MPLS-TE Fast Reroute (FRR)
5.1. 使用MPLS-TE快速重路由(FRR)的快速恢复支持

[RFC4090] describes two methods for local protection for a packet TE LSP in case of link, Shared Risk Link Group (SRLG), or node failure. This section describes how these mechanisms work with the proposed signaling solutions for inter-domain TE LSP setup.

[RFC4090]描述了在链路、共享风险链路组(SRLG)或节点故障情况下对数据包TE LSP进行本地保护的两种方法。本节描述了这些机制如何与域间TE LSP设置的拟议信令解决方案协同工作。

5.1.1. Failure within a Domain (Link or Node Failure)
5.1.1. 域内故障(链路或节点故障)

The mode of operation of MPLS-TE Fast Reroute to protect a contiguous, stitched, or nested TE LSP within a domain is identical to the existing procedures described in [RFC4090]. Note that, in the case of nesting or stitching, the end-to-end LSP is automatically protected by the protection operation performed on the H-LSP or stitching segment LSP.

MPLS-TE快速重路由保护域内连续、缝合或嵌套TE LSP的操作模式与[RFC4090]中描述的现有程序相同。注意,在嵌套或缝合的情况下,通过对H-LSP或缝合段LSP执行的保护操作自动保护端到端LSP。

No protocol extensions are required.


5.1.2. Failure of a Link at a Domain Border
5.1.2. 域边界处的链接失败

This case arises where two domains are connected by a TE link. In this case, each domain has its own domain border node, and these two nodes are connected by the TE link. An example of this case is where the ASBRs of two ASs are connected by a TE link.


A contiguous LSP can be backed up using any PLR and MP, but if the LSP uses stitching or nesting in either of the connected domains, the PLR and MP MUST be domain border nodes for those domains. It will be usual to attempt to use the local (connected by the failed link) domain border nodes as the PLR and MP.


To protect an inter-domain link with MPLS-TE Fast Reroute, a set of backup tunnels must be configured or dynamically computed between the PLR and MP such that they are diversely routed from the protected inter-domain link and the protected inter-domain LSPs.


Each protected inter-domain LSP using the protected inter-domain TE link must be assigned to an NHOP bypass tunnel that is diverse from the protected LSP. Such an NHOP bypass tunnel can be selected by analyzing the RROs in the Resv messages of the available bypass


tunnels and the protected TE LSP. It may be helpful to this process if the extensions defined in [RFC4561] are used to clearly distinguish nodes and links in the RROs.

隧道和受保护的TE LSP。如果使用[RFC4561]中定义的扩展来明确区分RRO中的节点和链接,则可能有助于此过程。

5.1.3. Failure of a Border Node
5.1.3. 边界节点故障

Two border node failure cases exist. If the domain border falls on a link as described in the previous section, the border node at either end of the link may fail. Alternatively, if the border falls on a border node (as is the case with IGP areas), that single border node may fail.


It can be seen that if stitching or nesting is used, the failed node will be the start or end (or both) of a stitching segment LSP or H-LSP, in which case protection must be provided to the far end of the stitching segment or H-LSP. Thus, where one of these two techniques is in use, the PLR will be the upstream domain entry point in the case of the failure of the domain exit point, and the MP will be the downstream domain exit point in the case of the failure of the domain entry point. Where the domain border falls at a single domain border node, both cases will apply.


If the contiguous LSP mechanism is in use, normal selection of the PLR and MP can be applied, and any node within the domains may be used to fill these roles.


As before, selection of a suitable backup tunnel (in this case, an NNHOP backup) must consider the paths of the backed-up LSPs and the available NNHOP tunnels by examination of their RROs.


Note that where the PLR is not immediately upstream of the failed node, error propagation time may be delayed unless some mechanism such as [BFD-MPLS] is implemented or unless direct reporting, such as through the GMPLS Notify message [RFC3473], is employed.


5.2. Protection and Recovery of GMPLS LSPs
5.2. GMPLS LSP的保护和恢复

[RFC4873] describes GMPLS-based segment recovery. This allows protection against a span failure, a node failure, or failure over any particular portion of a network used by an LSP.


The domain border failure cases described in Section 5.1 may also occur in GMPLS networks (including packet networks) and can be protected against using segment protection without any additional protocol extensions.


Note that if loose hops are used in the construction of the working and protection paths signaled for segment protection, then care is required to keep these paths disjoint. If the paths are signaled incrementally, then route exclusion [RFC4874] may be used to ensure that the paths are disjoint. Otherwise, a coordinated path computation technique such as that offered by cooperating Path Computation Elements [RFC4655] can provide suitable paths.


6. Reoptimization of Inter-Domain TE LSPs
6. 域间TE-lsp的再优化

Reoptimization of a TE LSP is the process of moving the LSP from the current path to a more preferred path. This involves the determination of the preferred path and make-before-break signaling procedures [RFC3209] to minimize traffic disruption.

TE LSP的再优化是将LSP从当前路径移动到更优选路径的过程。这涉及确定首选路径和先通后断信令程序[RFC3209],以最大限度地减少交通中断。

Reoptimization of an inter-domain TE LSP may require a new path in more than one domain.

域间TE LSP的重新优化可能需要在多个域中使用新路径。

The nature of the inter-domain LSP setup mechanism defines how reoptimization can be applied. If the LSP is contiguous, then the signaling of the make-before-break process MUST be initiated by the ingress node as defined in [RFC3209]. But if the reoptimization is limited to a change in path within one domain (that is, if there is no change to the domain border nodes) and nesting or stitching is in use, the H-LSP or stitching segment may be independently reoptimized within the domain without impacting the end-to-end LSP.


In all cases, however, the ingress LSR may wish to exert control and coordination over the reoptimization process. For example, a transit domain may be aware of the potential for reoptimization, but not bother because it is not worried by the level of service being provided across the domain. But the cumulative effect on the end-to-end LSP may cause the head-end to worry and trigger an end-to-end reoptimization request (of course, the transit domain may choose to ignore the request).


Another benefit of end-to-end reoptimization over per-domain reoptimization for non-contiguous inter-domain LSPs is that per-domain reoptimization is restricted to preserve the domain entry and exit points (since to do otherwise would break the LSP!). But end-to-end reoptimization is more flexible and can select new domain border LSRs.


There may be different cost-benefit analysis considerations between end-to-end reoptimization and per-domain reoptimization. The greater the number of hops involved in the reoptimization, the higher the risk of traffic disruption. The shorter the segment reoptimized, the lower the chance of making a substantial improvement on the quality of the end-to-end LSP. Administrative policies should be applied in this area with care.


[RFC4736] describes mechanisms that allow:


- The ingress node to request each node with a loose next hop to re-evaluate the current path in order to search for a more optimal path.

- 入口节点请求具有松散下一跳的每个节点重新评估当前路径,以便搜索更优化的路径。

- A node with a loose next hop to inform the ingress node that a better path exists.

- 具有松散下一跳的节点,用于通知入口节点存在更好的路径。

These mechanisms SHOULD be used for reoptimization of a contiguous inter-domain TE LSP.

这些机制应用于重新优化连续域间TE LSP。

Note that end-to-end reoptimization may involve a non-local modification that might select new entry / exit points. In this case, we can observe that local reoptimization is more easily and flexibly achieved using nesting or stitching. Further, the "locality principle" (i.e., the idea of keeping information only where it is needed) is best achieved using stitching or nesting. That said, a contiguous LSP can easily be modified to take advantage of local reoptimizations (as defined in [RFC4736]) even if this would require the dissemination of information and the invocation of signaling outside the local domain.


7. Backward Compatibility
7. 向后兼容性

The procedures in this document are backward compatible with existing deployments.


- Ingress LSRs are not required to support the extensions in this document to provision intra-domain LSPs. The default behavior by transit LSRs that receive a Path message that does not have the "Contiguous LSP" bit set in the Attributes Flags TLV of the LSP_Attributes object or does not even have the object present is to allow all modes of inter-domain TE LSP, so back-level ingress LSRs are able to initiate inter-domain LSPs.

- 入口LSR不需要支持本文档中的扩展来提供域内LSP。接收路径消息的传输LSR的默认行为是,在LSP_Attributes对象的属性标志TLV中没有设置“连续LSP”位,或者甚至没有对象存在,允许域间TE LSP的所有模式,因此后级入口LSR能够启动域间LSP。

- Transit, non-border LSRs are not required to perform any special processing and will pass the LSP_Attributes object onwards unmodified according to the rules of [RFC2205]. Thus, back-level transit LSRs are fully supported.

- 传输、非边界LSR无需执行任何特殊处理,并将根据[RFC2205]的规则向前传递LSP_属性对象,而不进行修改。因此,完全支持后级运输LSR。

- Domain border LSRs will need to be upgraded before inter-domain TE LSPs are allowed. This is because of the need to establish policy, administrative, and security controls before permitting inter-domain LSPs to be signaled across a domain border. Thus, legacy domain border LSRs do not need to be considered.

- 在允许域间TE LSP之前,需要升级域边界LSR。这是因为在允许跨域边界发送域间LSP信号之前,需要建立策略、管理和安全控制。因此,不需要考虑遗留域边界LSR。

The RRO additions in this document are fully backward compatible.


8. Security Considerations
8. 安全考虑

RSVP does not currently provide for automated key management. [RFC4107] states a requirement for mandatory automated key management under certain situations. There is work starting in the IETF to define improved authentication including automated key management for RSVP. Implementations and deployments of RSVP should pay attention to any capabilities and requirements that are outputs from this ongoing work.


A separate document is being prepared to examine the security aspects of RSVP-TE signaling with special reference to multi-domain scenarios [MPLS-SEC]. [RFC4726] provides an overview of the requirements for security in an MPLS-TE or GMPLS multi-domain environment.


Before electing to utilize inter-domain signaling for MPLS-TE, the administrators of neighboring domains MUST satisfy themselves as to the existence of a suitable trust relationship between the domains. In the absence of such a relationship, the administrators SHOULD decide not to deploy inter-domain signaling, and SHOULD disable RSVP-TE on any inter-domain interfaces.


When signaling an inter-domain RSVP-TE LSP, an operator MAY make use of the security features already defined for RSVP-TE [RFC3209]. This may require some coordination between the domains to share the keys (see [RFC2747] and [RFC3097]), and care is required to ensure that the keys are changed sufficiently frequently. Note that this may involve additional synchronization, should the domain border nodes be protected with FRR, since the MP and PLR should also share the key.

当向域间RSVP-TE LSP发送信号时,运营商可以利用已经为RSVP-TE定义的安全特性[RFC3209]。这可能需要在域之间进行一些协调以共享密钥(请参见[RFC2747]和[RFC3097]),并且需要注意确保密钥的更改足够频繁。注意,如果域边界节点受到FRR保护,这可能涉及额外的同步,因为MP和PLR也应该共享密钥。

For an inter-domain TE LSP, especially when it traverses different administrative or trust domains, the following mechanisms SHOULD be provided to an operator (also see [RFC4216]):

对于域间TE LSP,尤其是当它穿越不同的管理域或信任域时,应向操作员提供以下机制(另请参见[RFC4216]):

1) A way to enforce policies and filters at the domain borders to process the incoming inter-domain TE LSP setup requests (Path messages) based on certain agreed trust and service levels/contracts between domains. Various LSP attributes such as bandwidth, priority, etc. could be part of such a contract.

1) 一种在域边界强制执行策略和筛选器的方法,以根据域之间的某些约定信任和服务级别/契约处理传入的域间TE LSP设置请求(路径消息)。各种LSP属性(如带宽、优先级等)可以是此类合同的一部分。

2) A way for the operator to rate-limit LSP setup requests or error notifications from a particular domain.

2) 操作员对特定域的LSP设置请求或错误通知进行分级限制的一种方法。

3) A mechanism to allow policy-based outbound RSVP message processing at the domain border node, which may involve filtering or modification of certain addresses in RSVP objects and messages.

3) 允许在域边界节点上处理基于策略的出站RSVP消息的机制,这可能涉及过滤或修改RSVP对象和消息中的某些地址。

Additionally, an operator may wish to reduce the signaling interactions between domains to improve security. For example, the operator might not trust the neighboring domain to supply correct or trustable restart information [RFC5063] and might ensure that the availability of restart function is not configured in the Hello message exchange across the domain border. Thus, suitable configuration MUST be provided in an RSVP-TE implementation to enable the operator to control optional protocol features that may be considered a security risk.


Some examples of the policies described above are as follows:


A) An operator may choose to implement some kind of ERO filtering policy on the domain border node to disallow or ignore hops within the domain from being identified in the ERO of an incoming Path message. That is, the policy is that a node outside the domain cannot specify the path of the LSP inside the domain. The domain border LSR can make implement this policy in one of two ways:

A) 运营商可以选择在域边界节点上实施某种ERO过滤策略,以禁止或忽略域内的跃点在传入路径消息的ERO中被识别。也就是说,策略是域外的节点不能指定域内LSP的路径。域边界LSR可以通过以下两种方式之一实施此策略:

- It can reject the Path message.

- 它可以拒绝路径消息。

- It can ignore the hops in the ERO that lie within the domain.

- 它可以忽略域内ERO中的跳数。

B) In order to preserve confidentiality of network topology, an operator may choose to disallow recording of hops within the domain in the RRO or may choose to filter out certain recorded RRO addresses at the domain border node.

B) 为了保护网络拓扑的机密性,运营商可以选择不允许在RRO中记录域内的跃点,或者选择在域边界节点过滤掉某些记录的RRO地址。

C) An operator may require the border node to modify the addresses of certain messages like PathErr or Notify originated from hops within the domain.

C) 操作员可能会要求边界节点修改某些消息的地址,如来自域内跃点的PathErr或Notify。

D) In the event of a path computation failure, an operator may require the border node to silently discard the Path message instead of returning a PathErr. This is because a Path message could be interpreted as a network probe, and a PathErr provides information about the network capabilities and policies.

D) 如果路径计算失败,操作员可能会要求边界节点以静默方式放弃路径消息,而不是返回路径错误。这是因为路径消息可以解释为网络探测,而PathErr提供有关网络功能和策略的信息。

Note that the detailed specification of such policies and their implementation are outside the scope of this document.


Operations, Administration, and Management (OAM) mechanisms including [BFD-MPLS] and [RFC4379] are commonly used to verify the connectivity of end-to-end LSPs and to trace their paths. Where the LSPs are inter-domain LSPs, such OAM techniques MAY require that OAM messages are intercepted or modified at domain borders, or are passed transparently across domains. Further discussion of this topic can be found in [INTERAS-PING] and [MPLS-SEC].


9. IANA Considerations
9. IANA考虑

IANA has made the codepoint allocations described in the following sections.


9.1. Attribute Flags for LSP_Attributes Object
9.1. LSP_属性对象的属性标志

A new bit has been allocated from the "Attributes Flags" sub-registry of the "RSVP TE Parameters" registry.

已从“RSVP TE Parameters”注册表的“Attributes Flags”子注册表中分配了一个新位。

  Bit | Name                 | Attribute  | Path       | RRO | Reference
  No  |                      | Flags Path | Flags Resv |     |
  4     Contiguous LSP         Yes          No           Yes   [RFC5150]
  Bit | Name                 | Attribute  | Path       | RRO | Reference
  No  |                      | Flags Path | Flags Resv |     |
  4     Contiguous LSP         Yes          No           Yes   [RFC5150]
9.2. New Error Codes
9.2. 新错误代码

New RSVP error codes/values have been allocated from the "Error Codes and Globally-Defined Error Value Sub-Codes" sub-registry of the "RSVP Parameters" registry.


For the existing error code "Policy control failure" (value 2), two new error values have been registered as follows:


103 = Inter-domain policy failure 104 = Inter-domain explicit route rejected


For the existing error code "Routing Problem" (value 24), two new error values have been registered as follows:


28 = Contiguous LSP type not supported 29 = ERO conflicts with inter-domain signaling method


10. Acknowledgements
10. 致谢

The authors would like to acknowledge the input and helpful comments from Kireeti Kompella on various aspects discussed in the document. Deborah Brungard and Dimitri Papdimitriou provided thorough reviews.

作者希望感谢Kireeti Kompella就文件中讨论的各个方面提出的意见和有益的评论。黛博拉·布伦加德(Deborah Brungard)和迪米特里·帕普迪米特里欧(Dimitri Papdimitriou)提供了详尽的评论。

Thanks to Sam Hartman for detailed discussions of the security considerations.

感谢Sam Hartman对安全考虑的详细讨论。

11. References
11. 工具书类
11.1. Normative References
11.1. 规范性引用文件

[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。

[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997.

[RFC2205]Braden,R.,Ed.,Zhang,L.,Berson,S.,Herzog,S.,和S.Jamin,“资源预留协议(RSVP)——版本1功能规范”,RFC 22052997年9月。

[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001.

[RFC3209]Awduche,D.,Berger,L.,Gan,D.,Li,T.,Srinivasan,V.,和G.Swallow,“RSVP-TE:LSP隧道RSVP的扩展”,RFC 3209,2001年12月。

[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

[RFC3473]Berger,L.,Ed.“通用多协议标签交换(GMPLS)信令资源预留协议流量工程(RSVP-TE)扩展”,RFC 3473,2003年1月。

[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.

[RFC4206]Kompella,K.和Y.Rekhter,“具有通用多协议标签交换(GMPLS)流量工程(TE)的标签交换路径(LSP)层次结构”,RFC 4206,2005年10月。

[RFC4420] Farrel, A., Ed., Papadimitriou, D., Vasseur, J.-P., and A. Ayyangar, "Encoding of Attributes for Multiprotocol Label Switching (MPLS) Label Switched Path (LSP) Establishment Using Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)", RFC 4420, February 2006.

[RFC4420]Farrel,A.,Ed.,Papadimitriou,D.,Vasseur,J.-P.,和A.Ayyangar,“使用资源预留协议流量工程(RSVP-TE)建立多协议标签交换(MPLS)标签交换路径(LSP)的属性编码”,RFC 4420,2006年2月。

[RFC5150] Ayyangar, A., Kompella, K., and JP. Vasseur, "Label Switched Path Stitching with Generalized Multiprotocol Label Switching Traffic Engineering (GMPLS TE)", RFC 5150, February 2008.

[RFC5150]Ayyangar,A.,Kompella,K.,和JP。Vasseur,“使用通用多协议标签交换流量工程(GMPLS TE)的标签交换路径缝合”,RFC 51502008年2月。

11.2. Informative References
11.2. 资料性引用

[RFC2747] Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic Authentication", RFC 2747, January 2000.

[RFC2747]Baker,F.,Lindell,B.和M.Talwar,“RSVP加密认证”,RFC 2747,2000年1月。

[RFC3097] Braden, R. and L. Zhang, "RSVP Cryptographic Authentication -- Updated Message Type Value", RFC 3097, April 2001.

[RFC3097]Braden,R.和L.Zhang,“RSVP加密身份验证——更新的消息类型值”,RFC 3097,2001年4月。

[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May 2005.

[RFC4090]Pan,P.,Ed.,Swallow,G.,Ed.,和A.Atlas,Ed.,“LSP隧道RSVP-TE快速重路由扩展”,RFC 40902005年5月。

[RFC4105] Le Roux, J.-L., Ed., Vasseur, J.-P., Ed., and J. Boyle, Ed., "Requirements for Inter-Area MPLS Traffic Engineering", RFC 4105, June 2005.

[RFC4105]Le Roux,J.-L.,Ed.,Vasseur,J.-P.,Ed.,和J.Boyle,Ed.,“区域间MPLS流量工程的要求”,RFC 4105,2005年6月。

[RFC4107] Bellovin, S. and R. Housley, "Guidelines for Cryptographic Key Management", BCP 107, RFC 4107, June 2005.

[RFC4107]Bellovin,S.和R.Housley,“加密密钥管理指南”,BCP 107,RFC 4107,2005年6月。

[RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter, "Generalized Multiprotocol Label Switching (GMPLS) User-Network Interface (UNI): Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Support for the Overlay Model", RFC 4208, October 2005.

[RFC4208]Swallow,G.,Drake,J.,Ishimatsu,H.,和Y.Rekhter,“通用多协议标签交换(GMPLS)用户网络接口(UNI):覆盖模型的资源预留协议流量工程(RSVP-TE)支持”,RFC 4208,2005年10月。

[RFC4216] Zhang, R., Ed., and J.-P. Vasseur, Ed., "MPLS Inter-Autonomous System (AS) Traffic Engineering (TE) Requirements", RFC 4216, November 2005.

[RFC4216]Zhang,R.,Ed.,和J.-P.Vasseur,Ed.,“MPLS自治系统间(AS)流量工程(TE)要求”,RFC 42162005年11月。

[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006.

[RFC4379]Kompella,K.和G.Swallow,“检测多协议标签交换(MPLS)数据平面故障”,RFC 4379,2006年2月。

[RFC4561] Vasseur, J.-P., Ed., Ali, Z., and S. Sivabalan, "Definition of a Record Route Object (RRO) Node-Id Sub-Object", RFC 4561, June 2006.

[RFC4561]Vasseur,J.-P.,Ed.,Ali,Z.,和S.Sivabalan,“记录路由对象(RRO)节点Id子对象的定义”,RFC 4561,2006年6月。

[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006.

[RFC4655]Farrel,A.,Vasseur,J.-P.,和J.Ash,“基于路径计算元素(PCE)的体系结构”,RFC 46552006年8月。

[RFC4726] Farrel, A., Vasseur, J.-P., and A. Ayyangar, "A Framework for Inter-Domain Multiprotocol Label Switching Traffic Engineering", RFC 4726, November 2006.

[RFC4726]Farrel,A.,Vasseur,J.-P.,和A.Ayyangar,“域间多协议标签交换流量工程框架”,RFC 4726,2006年11月。

[RFC4736] Vasseur, JP., Ed., Ikejiri, Y., and R. Zhang, "Reoptimization of Multiprotocol Label Switching (MPLS) Traffic Engineering (TE) Loosely Routed Label Switched Path (LSP)", RFC 4736, November 2006.

[RFC4736]Vasseur,JP.,Ed.,Ikejiri,Y.,和R.Zhang,“多协议标签交换(MPLS)流量工程(TE)松路由标签交换路径(LSP)的再优化”,RFC 47362006年11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。

[RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes - Extension to Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)", RFC 4874, April 2007.

[RFC4874]Lee,CY.,Farrel,A.和S.De Cnodder,“排除路由-资源预留协议流量工程(RSVP-TE)的扩展”,RFC 48742007年4月。

[RFC4920] Farrel, A., Ed., Satyanarayana, A., Iwata, A., Fujita, N., and G. Ash, "Crankback Signaling Extensions for MPLS and GMPLS RSVP-TE", RFC 4920, July 2007.

[RFC4920]Farrel,A.,Ed.,Satyanarayana,A.,Iwata,A.,Fujita,N.,和G.Ash,“MPLS和GMPLS RSVP-TE的回退信令扩展”,RFC 4920,2007年7月。

[BFD-MPLS] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD For MPLS LSPs", Work in Progress, February 2005.

[BFD-MPLS]Aggarwal,R.,Kompella,K.,Nadeau,T.,和G.Swallow,“MPLS LSP的BFD”,正在进行的工作,2005年2月。

[INTERAS-PING] Nadeau, T. and G. Swallow, "Detecting MPLS Data Plane Failures in Inter-AS and inter-provider Scenarios", Work in Progress, October 2006.


[RFC5152] Vasseur, JP., Ed., Ayyangar, A., Ed., and R. Zhang, "A Per-Domain Path Computation Method for Establishing Inter-Domain Traffic Engineering (TE) Label Switched Paths (LSPs)", RFC 5152, February 2008.

[RFC5152]Vasseur,JP.,Ed.,Ayyangar,A.,Ed.,和R.Zhang,“用于建立域间流量工程(TE)标签交换路径(LSP)的每域路径计算方法”,RFC 5152,2008年2月。

[MPLS-SEC] Fang, L., Ed., Behringer, M., Callon, R., Le Roux, J. L., Zhang, R., Knight, P., Stein, Y., Bitar, N., and R. Graveman., "Security Framework for MPLS and GMPLS Networks", Work in Progress, July 2007.


[RFC5063] Satyanarayana, A., Ed., and R. Rahman, Ed., "Extensions to GMPLS Resource Reservation Protocol (RSVP) Graceful Restart", RFC 5063, October 2007.

[RFC5063]Satyanarayana,A.,Ed.,和R.Rahman,Ed.,“GMPLS资源预留协议(RSVP)优雅重启的扩展”,RFC 5063,2007年10月。

Authors' Addresses


Adrian Farrel Old Dog Consulting



Arthi Ayyangar Juniper Networks 1194 N. Mathilda Avenue Sunnyvale, CA 94089 USA



Jean Philippe Vasseur Cisco Systems, Inc. 300 Beaver Brook Road Boxborough , MA - 01719 USA

Jean-Philippe Vasseur Cisco Systems,Inc.美国马萨诸塞州Boxborough市比弗布鲁克路300号-01719


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