Network Working Group                                           B. Black
Request for Comments: 3988                               Layer8 Networks
Category: Experimental                                       K. Kompella
                                                        Juniper Networks
                                                            January 2005
        
Network Working Group                                           B. Black
Request for Comments: 3988                               Layer8 Networks
Category: Experimental                                       K. Kompella
                                                        Juniper Networks
                                                            January 2005
        

Maximum Transmission Unit Signalling Extensions for the Label Distribution Protocol

标签分发协议的最大传输单元信令扩展

Status of This Memo

关于下段备忘

This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.

这份备忘录为互联网社区定义了一个实验性协议。它没有规定任何类型的互联网标准。要求进行讨论并提出改进建议。本备忘录的分发不受限制。

Copyright Notice

版权公告

Copyright (C) The Internet Society (2005).

版权所有(C)互联网协会(2005年)。

Abstract

摘要

Proper functioning of RFC 1191 path Maximum Transmission Unit (MTU) discovery requires that IP routers have knowledge of the MTU for each link to which they are connected. As currently specified, the Label Distribution Protocol (LDP) does not have the ability to signal the MTU for a Label Switched Path (LSP) to the ingress Label Switching Router (LSR). In the absence of this functionality, the MTU for each LSP must be statically configured by network operators or by equivalent off-line mechanisms.

RFC1191路径最大传输单元(MTU)发现的正常运行要求IP路由器了解其所连接的每条链路的MTU。按照目前的规定,标签分发协议(LDP)不具备向入口标签交换路由器(LSR)发送标签交换路径(LSP)的MTU信号的能力。在缺少此功能的情况下,每个LSP的MTU必须由网络运营商或等效离线机制静态配置。

This document specifies experimental extensions to LDP in support of LSP MTU discovery.

本文档指定了LDP的实验扩展,以支持LSP MTU发现。

1. Introduction
1. 介绍

As currently specified in [2], the LDP protocol for MPLS does not support signalling of the MTU for LSPs to ingress LSRs. This functionality is essential to the proper functioning of RFC 1191 path MTU detection [3]. Without knowledge of the MTU for an LSP, edge LSRs may transmit packets along that LSP which are, according to [4], too big. These packets may be silently discarded by LSRs along the LSP, effectively preventing communication between certain end hosts.

如[2]中当前所述,MPLS的LDP协议不支持LSP的MTU向入口LSR发送信令。该功能对于RFC 1191路径MTU检测的正常运行至关重要[3]。在不知道LSP的MTU的情况下,边缘lsr可以沿着该LSP发送根据[4]过大的分组。这些数据包可能被LSR沿着LSP悄悄地丢弃,从而有效地阻止某些终端主机之间的通信。

The solution proposed in this document enables automatic determination of the MTU for an LSP by adding a Type-Length-Value triplet (TLV) to carry MTU information for a Forwarding Equivalence Class (FEC) between adjacent LSRs in LDP Label Mapping messages. This information is sufficient for a set of LSRs along the path followed by an LSP to discover either the exact MTU for that LSP, or an approximation that is no worse than could be generated with local information on the ingress LSR.

本文提出的解决方案通过添加类型长度值三元组(TLV)来携带LDP标签映射消息中相邻LSR之间的转发等价类(FEC)的MTU信息,从而能够自动确定LSP的MTU。该信息足以使LSP跟随的路径上的一组LSR发现该LSP的确切MTU,或者发现比使用入口LSR上的本地信息生成的近似值更差的近似值。

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 BCP 14, RFC 2119 [1].

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BCP 14、RFC 2119[1]中的描述进行解释。

2. MTU Signalling
2. MTU信令

The signalling procedure described in this document employs the addition of a single TLV to LDP Label Mapping messages and a simple algorithm for LSP MTU calculation.

本文件中描述的信令过程采用添加单个TLV到LDP标签映射消息和用于LSP MTU计算的简单算法。

2.1. Definitions
2.1. 定义

Link MTU: The MTU of a given link. This size includes the IP header and data (or other payload) and the label stack but does not include any lower-layer headers. A link may be an interface (such as Ethernet or Packet-over-SONET), a tunnel (such as GRE or IPsec), or an LSP.

链路MTU:给定链路的MTU。此大小包括IP标头和数据(或其他有效负载)以及标签堆栈,但不包括任何较低层标头。链路可以是接口(如以太网或SONET上的数据包)、隧道(如GRE或IPsec)或LSP。

Peer LSRs: For LSR A and FEC F, this is the set of LSRs that sent a Label Mapping for FEC F to A.

对等LSR:对于LSR A和FEC F,这是将FEC F的标签映射发送到A的LSR集。

Downstream LSRs: For LSR A and FEC F, this is the subset of A's peer LSRs for FEC F to which A will forward packets for the FEC. Typically, this subset is determined via the routing table.

下游LSR:对于LSR A和FEC F,这是A的FEC F对等LSR的子集,A将向其转发FEC的数据包。通常,该子集通过路由表确定。

Hop MTU: The MTU of an LSP hop between an upstream LSR, A, and a downstream LSR, B. This size includes the IP header and data (or other payload) and the part of the label stack that is considered payload as far as this LSP goes. It does not include any lower-level headers. (Note: If there are multiple links between A and B, the Hop MTU is the minimum of the Hop MTU of those links used for forwarding.)

跃点MTU:上游LSR A和下游LSR B之间LSP跃点的MTU。该大小包括IP头和数据(或其他有效载荷)以及标签堆栈中被视为有效载荷的部分,只要该LSP到达。它不包括任何较低级别的标题。(注意:如果A和B之间存在多个链路,则跃点MTU是用于转发的这些链路的跃点MTU的最小值。)

LSP MTU: The MTU of an LSP from a given LSR to the egress(es), over each valid (forwarding) path. This size includes the IP header and data (or other payload) and any part of the label stack that was received by the ingress LSR before it placed the packet into the LSP

LSP MTU:LSP在每个有效(转发)路径上从给定LSR到出口的MTU。该大小包括IP报头和数据(或其他有效负载)以及入口LSR在将数据包放入LSP之前接收到的标签堆栈的任何部分

(this part of the label stack is considered part of the payload for this LSP). The size does not include any lower-level headers.

(标签堆栈的这一部分被视为此LSP有效负载的一部分)。该大小不包括任何较低级别的标题。

2.2. Example
2.2. 实例

Consider LSRs A - F, interconnected as follows:

考虑LSR A—F,互连如下:

                     M       P
                   _____ C =====
                  /      |      \
         A ~~~~~ B ===== D ----- E ----- F
             L       N       Q       R
        
                     M       P
                   _____ C =====
                  /      |      \
         A ~~~~~ B ===== D ----- E ----- F
             L       N       Q       R
        

Say that the link MTU for link L is 9216; for links M, Q, and R, 4470; and for N and P, is 1500.

假设链路L的链路MTU为9216;对于链路M、Q和R,4470;对于N和P,是1500。

Consider an FEC X for which F is the egress, and say that all LSRs advertise X to their neighbors.

考虑一个FEC X,其中F是出口,并且说所有LSR向其邻居宣传X。

Note that although LDP may be running on the C - D link, it is not used for forwarding (e.g., because it has a high metric). In particular, D is an LDP neighbor of C, but D is not one of C's downstream LSRs for FEC X.

请注意,尽管LDP可能在C-D链路上运行,但它不用于转发(例如,因为它具有较高的度量)。特别地,D是C的LDP邻居,但D不是FEC X的C的下游lsr之一。

E's peers for FEC X are C, D, and F. Say that E chooses F as its downstream LSR for X. E's Hop MTU for link R is 4466. If F advertised an implicit null label to E, then E MAY set the Hop MTU for R to 4470.

E的FEC X的对等点是C、D和F。假设E选择F作为X的下游LSR。E的Hop MTU用于链路R是4466。如果F向E通告隐式空标签,则E可将R的跃点MTU设置为4470。

C's peers for FEC X are B, D, and E. Say that C chooses E as its downstream LSR for X. Similarly, A chooses B, B chooses C and D (equal cost multi-path), D chooses E, and E chooses F (respectively) as downstream LSRs.

对于FEC X,C的对等点是B、D和E。假设C选择E作为其X的下游LSR。类似地,A选择B、B选择C和D(等成本多径),D选择E,E选择F(分别)作为下游LSR。

C's Hop MTU to E for FEC X is 1496. B's Hop MTU to C is 4466 and to D is 1496. A's LSP MTU for FEC X is 1496. If A has another LSP for FEC Y to F (learned via targeted LDP) that rides over the LSP for FEC X, the MTU for that LSP would be 1492.

对于FEC X,从C跳到E的MTU为1496。B的跃点MTU到C是4466,到D是1496。A的FEC X的LSP MTU为1496。如果A具有另一个用于FEC Y到F的LSP(通过目标LDP学习),该LSP越过用于FEC X的LSP,则该LSP的MTU将为1492。

If B had a targeted LDP session to E (e.g., over an RSVP-TE tunnel T) and B received a Mapping for FEC X over the targeted LDP session, then E would also be B's peer, and E may be chosen as a downstream LSR for B. In that case, B's LSP MTU for FEC X would then be the smaller of {(T's MTU - 4), E's LSP MTU for X}.

如果B对E有一个目标LDP会话(例如,通过RSVP-TE隧道T),并且B在目标LDP会话上收到了FEC X的映射,那么E也将是B的对等方,并且E可以被选为B的下游LSR。在这种情况下,B对FEC X的LSP MTU将是{(T的MTU-4),E对X的LSP MTU中的较小者。

This memo describes how A determines its LSP MTU for FECs X and Y.

本备忘录描述了A如何为FECs X和Y确定其LSP MTU。

2.3. Signalling Procedure
2.3. 信号程序

The procedure for signalling the MTU is performed hop-by-hop by each LSR L along an LSP for a given FEC, F. The steps are as follows:

发送MTU信号的过程由每个LSR L沿着给定FEC,F的LSP逐跳执行。步骤如下:

1. First, L computes its LSP MTU for FEC F:

1. 首先,L为FEC F计算其LSP MTU:

A. If L is the egress for F, L sets the LSP MTU for F to 65535.

A.如果L是F的出口,则L将F的LSP MTU设置为65535。

B. [OPTIONAL] If L's only downstream LSR is the egress for F (i.e., L is a penultimate hop for F) and L receives an implicit null label as its Mapping for F, then L can set the Hop MTU for its downstream link to the link MTU instead of (link MTU - 4 octets). L's LSP MTU for F is the Hop MTU.

B.[可选]如果L的唯一下游LSR是F的出口(即,L是F的倒数第二个跃点),并且L接收到一个隐式空标签作为F的映射,则L可以将其下游链路的跃点MTU设置为链路MTU,而不是(链路MTU-4个八位字节)。L代表F的LSP MTU是跃点MTU。

C. Otherwise (L is not the egress LSR), L computes the LSP MTU for F as follows:

C.否则(L不是出口LSR),L计算F的LSP MTU,如下所示:

a) L determines its downstream LSRs for FEC F.

a) L确定FEC F的下游LSR。

b) For each downstream LSR Z, L computes the minimum of the Hop MTU to Z and the LSP MTU in the MTU TLV that Z advertised to L. If Z did not include the MTU TLV in its Label Mapping, then Z's LSP MTU is set to 65535.

b) 对于每个下游LSR Z,L计算Z播发给L的MTU TLV中跳MTU到Z和LSP MTU的最小值。如果Z在其标签映射中不包括MTU TLV,则Z的LSP MTU设置为65535。

c) L sets its LSP MTU to the minimum of the MTUs it computed for its downstream LSRs.

c) L将其LSP MTU设置为其为下游LSR计算的MTU的最小值。

2. For each LDP neighbor (direct or targeted) of L to which L decides to send a Mapping for FEC F, L attaches an MTU TLV with the LSP MTU that it computed for this FEC. L MAY (because of policy or for other reasons) advertise a smaller MTU than it has computed, but L MUST NOT advertise a larger MTU.

2. 对于L的每个LDP邻居(直接或目标),L决定向其发送FEC F的映射,L附加一个MTU TLV和它为此FEC计算的LSP MTU。我可以(由于政策或其他原因)公布一个比它计算的更小的MTU,但我不能公布一个更大的MTU。

3. When a new MTU is received for FEC F from a downstream LSR or the set of downstream LSRs for F changes, L returns to step 1. If the newly computed LSP MTU is unchanged, L SHOULD NOT advertise new information to its neighbors. Otherwise, L readvertises its Mappings for F to all its peers with an updated MTU TLV.

3. 当从下游LSR接收到用于FEC F的新MTU或用于F的下游LSR集合改变时,L返回到步骤1。如果新计算的LSP MTU不变,则L不应向其邻居公布新信息。否则,L将使用更新的MTU TLV将F的映射读取到其所有对等方。

This behavior is standard for attributes such as path vector and hop count, and the same rules apply, as specified in [2].

此行为是路径向量和跃点计数等属性的标准行为,适用于[2]中指定的相同规则。

If the LSP MTU decreases, L SHOULD readvertise the new MTU immediately; if the LSP MTU increases, L MAY hold down the readvertisement.

如果LSP MTU减少,L应立即读取新MTU;如果LSP MTU增加,L可能会抑制读取。

2.4. MTU TLV
2.4. MTU TLV

The MTU TLV encodes information on the maximum transmission unit for an LSP, from the advertising LSR to the egress(es) over all valid paths.

MTU TLV对LSP的最大传输单元上的信息进行编码,在所有有效路径上从广告LSR到出口。

The encoding for the MTU TLV is as follows:

MTU TLV的编码如下所示:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |1|1|      MTU TLV (0x0601)     |            Length             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              MTU              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        
       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |1|1|      MTU TLV (0x0601)     |            Length             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              MTU              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        

MTU

MTU

This is a 16-bit unsigned integer that represents the MTU in octets for an LSP or a segment of an LSP.

这是一个16位无符号整数,表示LSP或LSP段的MTU(以八位字节为单位)。

Note that the U and F bits are set. An LSR that doesn't recognize the MTU TLV MUST ignore it when it processes the Label Mapping message and forward the TLV to its peers. This may result in the incorrect computation of the LSP MTU; however, silently forwarding the MTU TLV preserves the maximal amount of information about the LSP MTU.

请注意,U和F位已设置。不识别MTU TLV的LSR在处理标签映射消息并将TLV转发给对等方时必须忽略它。这可能导致LSP MTU的计算不正确;然而,静默地转发MTU TLV保留关于LSP MTU的最大信息量。

3. Example of Operation
3. 操作示例

Consider the network example in Section 2.2. For each LSR, Table 1 describes the links to its downstream LSRs, the Hop MTU for the peer, the LSP MTU received from the peer, and the LSR's computed LSP MTU.

考虑第2.2节中的网络示例。对于每个LSR,表1描述了到其下游LSR的链路、对等方的跃点MTU、从对等方接收的LSP MTU以及LSR的计算LSP MTU。

Now consider the same network with the following changes: There is an LSP T from B to E, and a targeted LDP session from B to E. B's peer LSRs are A, C, D, and E; B's downstream LSRs are D and E; to reach E, B chooses to go over T. The LSP MTU for LSP T is 1496. This information is depicted in Table 2.

现在考虑与以下变化相同的网络:从B到E有一个LSP T,并且从B到E. B的对等LSRs的有针对性的LDP会话是A、C、D和E;B的下游LSR为D和E;为了达到E,B选择越过T。LSP T的LSP MTU为1496。该信息如表2所示。

         LSR  |  Link  |  Hop MTU  |  Recvd MTU  |  LSP MTU
         --------------------------------------------------
          F   |    -   |    65535  |      -      |    65535
         --------------------------------------------------
          E   |    R   |     4466  |  F:  65535  |     4466
         --------------------------------------------------
          D   |    Q   |     4466  |  E:   4466  |     4466
         --------------------------------------------------
          C   |    P   |     1496  |  E:   4466  |     1496
         --------------------------------------------------
          B   |    M   |     4466  |  C:   1496  |
              |    N   |     1496  |  D:   4466  |     1496
         --------------------------------------------------
          A   |    L   |     9212  |  B:   1496  |     1496
         --------------------------------------------------
                              Table 1
        
         LSR  |  Link  |  Hop MTU  |  Recvd MTU  |  LSP MTU
         --------------------------------------------------
          F   |    -   |    65535  |      -      |    65535
         --------------------------------------------------
          E   |    R   |     4466  |  F:  65535  |     4466
         --------------------------------------------------
          D   |    Q   |     4466  |  E:   4466  |     4466
         --------------------------------------------------
          C   |    P   |     1496  |  E:   4466  |     1496
         --------------------------------------------------
          B   |    M   |     4466  |  C:   1496  |
              |    N   |     1496  |  D:   4466  |     1496
         --------------------------------------------------
          A   |    L   |     9212  |  B:   1496  |     1496
         --------------------------------------------------
                              Table 1
        
         LSR  |  Link  |  Hop MTU  |  Recvd MTU  |  LSP MTU
         --------------------------------------------------
          F   |    -   |    65535  |      -      |    65535
         --------------------------------------------------
          E   |    R   |     4466  |  F:  65535  |     4466
         --------------------------------------------------
          D   |    Q   |     4466  |  E:   4466  |     4466
         --------------------------------------------------
          C   |    P   |     1496  |  E:   4466  |     1496
         --------------------------------------------------
          B   |    T   |     1492  |  E:   4466  |
              |    N   |     1496  |  D:   4466  |     1492
         --------------------------------------------------
          A   |    L   |     9212  |  B:   1492  |     1492
         --------------------------------------------------
                              Table 2
        
         LSR  |  Link  |  Hop MTU  |  Recvd MTU  |  LSP MTU
         --------------------------------------------------
          F   |    -   |    65535  |      -      |    65535
         --------------------------------------------------
          E   |    R   |     4466  |  F:  65535  |     4466
         --------------------------------------------------
          D   |    Q   |     4466  |  E:   4466  |     4466
         --------------------------------------------------
          C   |    P   |     1496  |  E:   4466  |     1496
         --------------------------------------------------
          B   |    T   |     1492  |  E:   4466  |
              |    N   |     1496  |  D:   4466  |     1492
         --------------------------------------------------
          A   |    L   |     9212  |  B:   1492  |     1492
         --------------------------------------------------
                              Table 2
        
4. Using the LSP MTU
4. 使用LSP MTU

An ingress LSR that forwards an IP packet into an LSP whose MTU it knows MUST either fragment the IP packet to the LSP's MTU (if the Don't Fragment bit is clear) or drop the packet and respond with an ICMP Destination Unreachable message to the source of the packet, with the Code indicating "fragmentation needed and DF set", and the Next-Hop MTU set to the LSP MTU. In other words, the LSR behaves as RFC 1191 says, except that it treats the LSP as the next hop "network".

将IP数据包转发到LSP的入口LSR,它知道LSP的MTU必须将IP数据包分段到LSP的MTU(如果不分段位是清除的),或者丢弃数据包,并用ICMP目的地不可到达消息响应到数据包的源,代码指示“需要分段并设置DF”,下一跳MTU设置为LSP MTU。换句话说,LSR的行为与RFC1191所说的一样,只是它将LSP视为下一跳“网络”。

If the payload for the LSP is not an IP packet, the LSR MUST forward the packet if it fits (size <= LSP MTU) and SHOULD drop it if it doesn't.

如果LSP的有效负载不是IP数据包,则LSR必须转发适合(大小<=LSP MTU)的数据包,如果不适合,则应丢弃该数据包。

5. Protocol Interaction
5. 协议交互
5.1. Interaction with LSRs that Do Not Support MTU Signalling
5.1. 与不支持MTU信令的LSR的交互

Changes in MTU for sections of an LSP may cause intermediate LSRs to generate unsolicited label Mapping messages to advertise the new MTU. LSRs that do not support MTU signalling will, due to message and TLV processing mechanisms specified in RFC3036 [2], accept the messages carrying the MTU TLV but will ignore the TLV and forward the TLV to the upstream nodes (see Section 2.4).

LSP部分MTU的更改可能导致中间LSR生成未经请求的标签映射消息,以公布新MTU。由于RFC3036[2]中规定的消息和TLV处理机制,不支持MTU信令的LSR将接受承载MTU TLV的消息,但将忽略TLV并将TLV转发给上游节点(参见第2.4节)。

5.2. Interaction with CR-LDP and RSVP-TE
5.2. 与CR-LDP和RSVP-TE的相互作用

The MTU TLV can be used to discover the Path MTU of both LDP LSPs and CR-LDP LSPs. This proposal is not impacted in the presence of LSPs created with CR-LDP, as specified in [5].

MTU TLV可用于发现LDP LSP和CR-LDP LSP的路径MTU。如[5]所述,在存在使用CR-LDP创建的LSP的情况下,本提案不受影响。

Note that LDP/CR-LDP LSPs may tunnel through other LSPs signalled using LDP, CR-LDP, or RSVP-TE [6]; the mechanism suggested here applies in all of these cases, essentially by treating the tunnel LSPs as links.

注意,LDP/CR-LDP LSP可以隧道通过使用LDP、CR-LDP或RSVP-TE发信号的其他LSP[6];这里建议的机制适用于所有这些情况,主要是将隧道LSP视为链路。

6. References
6. 工具书类
6.1. Normative References
6.1. 规范性引用文件

[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[1] Bradner,S.,“RFC中用于表示需求水平的关键词”,BCP 14,RFC 2119,1997年3月。

[2] Andersson, L., Doolan, P., Feldman, N., Fredette, A., and B. Thomas, "LDP Specification", RFC 3036, January 2001.

[2] Andersson,L.,Doolan,P.,Feldman,N.,Fredette,A.,和B.Thomas,“LDP规范”,RFC 3036,2001年1月。

[3] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191, November 1990.

[3] Mogul,J.和S.Deering,“MTU发现路径”,RFC191990年11月。

[4] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, January 2001.

[4] 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。

[6] 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.

[6] 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。

6.2. Informative References
6.2. 资料性引用

[5] Jamoussi, B., Andersson, L., Callon, R., Dantu, R., Wu, L., Doolan, P., Worster, T., Feldman, N., Fredette, A., Girish, M., Gray, E., Heinanen, J., Kilty, T., and A. Malis, "Constraint-Based LSP Setup using LDP", RFC 3212, January 2002.

[5] Jamoussi,B.,Andersson,L.,Callon,R.,Dantu,R.,Wu,L.,Doolan,P.,Worster,T.,Feldman,N.,Fredette,A.,Girish,M.,Gray,E.,Heinanen,J.,Kilty,T.,和A.Malis,“使用LDP的基于约束的LSP设置”,RFC 3212,2002年1月。

7. Security Considerations
7. 安全考虑

This mechanism does not introduce any new weaknesses in LDP. It is possible to spoof TCP packets belonging to an LDP session to manipulate the LSP MTU, but LDP has mechanisms to thwart these types of attacks. See Section 5 of [2] for more information on security aspects of LDP.

这种机制不会给自民党带来任何新的弱点。可以欺骗属于LDP会话的TCP数据包来操纵LSP MTU,但LDP具有阻止此类攻击的机制。有关LDP安全方面的更多信息,请参见[2]第5节。

8. IANA Considerations
8. IANA考虑
   IANA has allocated 0x0601 as a new LDP TLV Type, defined in Section
   2.4.  See: http://www.iana.org/assignments/ldp-namespaces
        
   IANA has allocated 0x0601 as a new LDP TLV Type, defined in Section
   2.4.  See: http://www.iana.org/assignments/ldp-namespaces
        
9. Acknowledgements
9. 致谢

We would like to thank Andre Fredette for a number of detailed comments on earlier versions of the signalling mechanism. Eric Gray, Giles Heron, and Mark Duffy have contributed numerous useful suggestions.

我们要感谢Andre Fredette对信号机制早期版本的一些详细评论。Eric Gray、Giles Heron和Mark Duffy提出了许多有用的建议。

Authors' Addresses

作者地址

Benjamin Black Layer8 Networks

Benjamin Black Layer8网络

   EMail: ben@layer8.net
        
   EMail: ben@layer8.net
        

Kireeti Kompella Juniper Networks 1194 N. Mathilda Ave Sunnyvale, CA 94089 US

Kireeti Kompella Juniper Networks 1194 N.Mathilda Ave Sunnyvale,加利福尼亚州,美国94089

   EMail: kireeti@juniper.net
        
   EMail: kireeti@juniper.net
        

Full Copyright Statement

完整版权声明

Copyright (C) The Internet Society (2005).

版权所有(C)互联网协会(2005年)。

This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights.

本文件受BCP 78中包含的权利、许可和限制的约束,除其中规定外,作者保留其所有权利。

This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

本文件及其包含的信息是按“原样”提供的,贡献者、他/她所代表或赞助的组织(如有)、互联网协会和互联网工程任务组不承担任何明示或暗示的担保,包括但不限于任何保证,即使用本文中的信息不会侵犯任何权利,或对适销性或特定用途适用性的任何默示保证。

Intellectual Property

知识产权

The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the IETF's procedures with respect to rights in IETF Documents can be found in BCP 78 and BCP 79.

IETF对可能声称与本文件所述技术的实施或使用有关的任何知识产权或其他权利的有效性或范围,或此类权利下的任何许可可能或可能不可用的程度,不采取任何立场;它也不表示它已作出任何独立努力来确定任何此类权利。有关IETF文件中权利的IETF程序信息,请参见BCP 78和BCP 79。

Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr.

向IETF秘书处披露的知识产权副本和任何许可证保证,或本规范实施者或用户试图获得使用此类专有权利的一般许可证或许可的结果,可从IETF在线知识产权存储库获取,网址为http://www.ietf.org/ipr.

The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org.

IETF邀请任何相关方提请其注意任何版权、专利或专利申请,或其他可能涵盖实施本标准所需技术的专有权利。请将信息发送至IETF的IETF-ipr@ietf.org.

Acknowledgement

确认

Funding for the RFC Editor function is currently provided by the Internet Society.

RFC编辑功能的资金目前由互联网协会提供。