Network Working Group A. Vainshtein
Request for Comments: 5611 ECI Telecom
Category: Standards Track S. Galtzur
Rebellion
August 2009
Network Working Group A. Vainshtein
Request for Comments: 5611 ECI Telecom
Category: Standards Track S. Galtzur
Rebellion
August 2009
Layer Two Tunneling Protocol version 3 - Setup of Time-Division Multiplexing (TDM) Pseudowires
第二层隧道协议版本3-时分复用（TDM）伪线的设置
Abstract
摘要
This document defines extensions to the Layer Two Tunneling Protocol version 3 (L2TPv3) for support of structure-agnostic and structure-aware (Circuit Emulation Service over Packet Switched Network (CESoPSN) style) Time-Division Multiplexing (TDM) pseudowires. Support of structure-aware (Time-Division Multiplexing over IP (TDMoIP) style) pseudowires over L2TPv3 is left for further study.
本文档定义了第二层隧道协议版本3（L2TPv3）的扩展，以支持结构无关和结构感知（分组交换网络上的电路仿真服务（CESoPSN）样式）时分复用（TDM）伪线。L2TPv3上的结构感知（IP时分复用（TDMoIP）类型）伪线的支持有待进一步研究。
Status of This Memo
关于下段备忘
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。
Copyright Notice
版权公告
Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2009 IETF信托基金和确定为文件作者的人员。版权所有。
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本文件受BCP 78和IETF信托在本文件出版之日生效的与IETF文件有关的法律规定的约束(http://trustee.ietf.org/license-info). 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。
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
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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.
不得在IETF标准流程之外创建，除非将其格式化以RFC形式发布，或将其翻译成英语以外的语言。
Table of Contents
目录
1. Introduction ....................................................2
1.1. Conventions Used in This Document ..........................3
2. L2TPv3 Extensions ...............................................3
2.1. TDM PW Attribute-Value Pair (AVP) (ICRQ, OCRQ) .............4
2.2. RTP Attribute-Value Pair (AVP) (ICRQ, OCRQ, ICRP, OCRP) ....6
2.3. Changes in the Control Connection Management AVPs ..........7
2.4. Changes in the Session Management AVPs .....................7
3. Creation of the TDM Pseudowire Session ..........................7
4. IANA Considerations .............................................9
5. Congestion Control ..............................................9
6. Security Considerations ........................................10
7. Acknowledgements ...............................................10
8. References .....................................................10
8.1. Normative References ......................................10
8.2. Informative References ....................................10
1. Introduction ....................................................2
1.1. Conventions Used in This Document ..........................3
2. L2TPv3 Extensions ...............................................3
2.1. TDM PW Attribute-Value Pair (AVP) (ICRQ, OCRQ) .............4
2.2. RTP Attribute-Value Pair (AVP) (ICRQ, OCRQ, ICRP, OCRP) ....6
2.3. Changes in the Control Connection Management AVPs ..........7
2.4. Changes in the Session Management AVPs .....................7
3. Creation of the TDM Pseudowire Session ..........................7
4. IANA Considerations .............................................9
5. Congestion Control ..............................................9
6. Security Considerations ........................................10
7. Acknowledgements ...............................................10
8. References .....................................................10
8.1. Normative References ......................................10
8.2. Informative References ....................................10
This document defines extensions to the Layer Two Tunneling Protocol Version 3 (L2TPv3) for support of structure-agnostic [RFC4553] and structure-aware (CESoPSN style, see [RFC5086]) Time-Division Multiplexing (TDM) pseudowires. Structure-agnostic encapsulation of TDM bit-streams over L2TPv3 is described in [RFC4553], Figure 2b; Circuit Emulation Service over Packet Switched Networks (CESoPSN), structure-aware encapsulation is described in [RFC5086], Figures 1c (TDM data packets) and 4a (CE application signaling packets). However, the order of the CESoPSN Control Word (CW) and RTP header (if it is used) MUST match between the TDM data and CE signaling packets.
本文档定义了第二层隧道协议版本3（L2TPv3）的扩展，以支持结构无关[RFC4553]和结构感知（CESoPSN样式，请参见[RFC5086]）时分复用（TDM）伪线。[RFC4553]中描述了L2TPv3上TDM比特流的结构无关封装，图2b；[RFC5086]、图1c（TDM数据包）和4a（CE应用信令包）中描述了分组交换网络上的电路仿真服务（CESoPSN）、结构感知封装。然而，在TDM数据和CE信令分组之间，CESoPSN控制字（CW）和RTP报头（如果使用）的顺序必须匹配。
Setup of structure-aware TDM pseudowires using the encapsulations described in [RFC5087] has been left for further study.
使用[RFC5087]中描述的封装设置结构感知TDM伪线有待进一步研究。
Setup and maintenance of TDM pseudowires (PWs) in MPLS networks using LDP is described in [RFC5287].
[RFC5287]中描述了使用LDP在MPLS网络中设置和维护TDM伪线（PWs）。
In this document, we refer to the "control plane" as meaning the packets that contain control information (via Attribute-Value Pairs (AVPs)) and the mechanism that handles these packets. We also refer to the "data plane" as meaning the packets that contain transported user data.
在本文中，我们将“控制平面”称为包含控制信息的数据包（通过属性值对（AVP））以及处理这些数据包的机制。我们还将“数据平面”称为包含传输的用户数据的数据包。
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。
The L2TPv3 Control Connection is responsible for 3 main operations:
L2TPv3控制连接负责3个主要操作：
1. Establishment and validation of a pseudowire (PW) session.
1. 伪线（PW）会话的建立和验证。
2. Ending (tearing down) of a pseudowire session.
2. 结束（拆除）伪线会话。
3. Transferring of End Point status.
3. 传输端点状态。
Tearing down of the session for a TDM pseudowire is performed following the L2TPv3 tear-down operations as described in Section 3.4.3 of [RFC3931].
按照[RFC3931]第3.4.3节所述的L2TPv3拆除操作，拆除TDM伪线的会话。
[RFC5086] and [RFC4553] describe how to transfer the Attachment Circuit (AC) status via the data plane. Therefore, the Set-Link-Info (SLI) message described in [RFC3931] SHOULD NOT be used for conveying this status for the PWs in question.
[RFC5086]和[RFC4553]描述了如何通过数据平面传输连接电路（AC）状态。因此，[RFC3931]中所述的Set Link Info（SLI）消息不应用于传达相关PWs的该状态。
[RFC3931] specifies that the Circuit Status Attribute-Value Pair (AVP) MUST be present in the ICRQ/ICRP (Incoming-Call-Request / Incoming-Call-Reply) messages. It also specifies that the N bit in this AVP should be set during the PW setup, even if the specific AC does not provide any way to convey the "new AC" indication. Accordingly, the Circuit Status AVP for the PWs in question, when used in the ICRQ/ICRP messages, MUST always have both N and A bits set.
[RFC3931]指定ICRQ/ICRP（来电请求/来电回复）消息中必须存在电路状态属性值对（AVP）。它还规定在PW设置期间应设置此AVP中的N位，即使特定AC没有提供任何方式来传达“新AC”指示。因此，当在ICRQ/ICRP消息中使用相关PW的电路状态AVP时，必须始终设置N位和A位。
The next sections describe the extensions to L2TPv3 for establishment and validation of TDM pseudowire sessions.
下一节将描述L2TPv3的扩展，用于建立和验证TDM伪线会话。
There are two new AVPs for the Session Management messages. One AVP describes the TDM pseudowire attributes. The second AVP describes the RTP attributes for this TDM pseudowire.
会话管理消息有两个新的AVP。一个AVP描述TDM伪线属性。第二个AVP描述此TDM伪线的RTP属性。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|M|H| rsvd | Length | Vendor Id (IETF) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attribute Type (99) | Reserved |SP |CAS|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bit Rate | Payload Bytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|M|H| rsvd | Length | Vendor Id (IETF) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attribute Type (99) | Reserved |SP |CAS|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bit Rate | Payload Bytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This AVP MAY be hidden (the H bit MAY be 0 or 1). The M bit for this AVP SHOULD be set to 0. The Length (before hiding) of this AVP is 12.
该AVP可能被隐藏（H位可能为0或1）。此AVP的M位应设置为0。此AVP的长度（隐藏前）为12。
The Bit Rate field contains the value that represents the bit rate of the local AC in the units of 64 Kbit/s, encoded as an unsigned 16-bit integer. Its usage for all types of TDM PWs employs the following semantics:
比特率字段包含表示本地AC比特率的值，单位为64 Kbit/s，编码为无符号16位整数。它对所有类型的TDM PWs的使用采用以下语义：
1) For structure-agnostic emulation, this parameter MUST be set to one of the following values (see [RFC4553]):
1) 对于结构无关仿真，此参数必须设置为以下值之一（请参见[RFC4553]）：
a) Structure-agnostic E1 emulation - 32
a) 结构不可知E1仿真-32
b) Structure-agnostic T1 emulation:
b) 结构不可知T1仿真：
i) MUST be set to 24 for the basic mode
i) 对于基本模式，必须设置为24
ii) MUST be set to 25 for the "Octet-aligned T1" mode
ii）对于“八位组对齐T1”模式，必须设置为25
c) Structure-agnostic E3 emulation - 535
c) 结构不可知E3仿真-535
d) Structure-agnostic T3 emulation - 699
d) 结构不可知T3仿真-699
2) For CESoPSN PWs, this parameter MUST be set to the number of DS0 channels in the corresponding attachment circuit.
2) 对于CESoPSN PWs，此参数必须设置为相应附件电路中的DS0通道数。
Note: For structure-agnostic T1 emulation, the values 24 and 25 do not reflect the exact bit rate and are used for convenience only.
注意：对于结构无关T1仿真，值24和25不反映准确的比特率，仅用于方便。
Note: The semantics of the Bit Rate field defined above are consistent with those of the CEP/TDM Bit-Rate interface parameter as defined in [RFC5287].
注：上面定义的比特率字段的语义与[RFC5287]中定义的CEP/TDM比特率接口参数的语义一致。
The Payload Bytes field contains the value representing the number of TDM payload bytes in the PW packet and is used with the following semantics:
有效负载字节字段包含表示PW数据包中TDM有效负载字节数的值，并与以下语义一起使用：
1) For structure-agnostic emulation, any value of the Payload Bytes can be specified.
1) 对于结构无关仿真，可以指定有效负载字节的任何值。
2) For CESoPSN PWs:
2) 对于CESoPSN PWs：
a) The specified value MUST be an integer multiple of the number of DS0 channels in the corresponding attachment circuit.
a) 指定值必须是相应附件电路中DS0通道数的整数倍。
b) In addition to that, for trunk-specific NxDS0 with Channel-Associated Signaling (CAS), the number of the trunk frames per multiframe fragment (value resulting from the Payload Bytes divided by the number of DS0 channels) MUST be an integer divisor of the number of frames per corresponding trunk multiframe.
b) 除此之外，对于具有信道相关信令（CAS）的中继特定NxDS0，每个多帧片段的中继帧数（有效负载字节除以DS0信道数所得的值）必须是每个对应中继多帧的帧数的整数除数。
The Reserved bits MUST be set to 0 on transmission and MUST be ignored on reception.
传输时必须将保留位设置为0，接收时必须忽略保留位。
The SP bits define support for the CESoPSN-application signaling packets (see [RFC5086]) and MUST be used as follows:
SP位定义了对CESoPSN应用信令包的支持（请参阅[RFC5086]），必须按如下方式使用：
1) Set to '01' for the CESoPSN PWs carrying TDM data packets and expecting CE application signaling packets in a separate PW.
1) 对于承载TDM数据包且在单独PW中期望CE应用信令包的CESoPSN PW，设置为“01”。
2) Set to '10' for a PW carrying CE application signaling packets with the data packets in a separate PW.
2) 将携带CE应用信令包的PW设置为“10”，数据包在单独的PW中。
3) Set to '11' for a CESoPSN PW carrying both TDM data and signaling packets.
3) 对于同时承载TDM数据和信令分组的CESoPSN PW，设置为“11”。
4) Set to '00' for Structure-Agnostic Time-Division Multiplexing over Packet (SAToP) PWs and for CESoPSN PWs not using separate signaling packets.
4) 对于结构无关的分组时分多路复用（SAToP）PWs和不使用单独信令分组的CESoPSN PWs，设置为“00”。
The CAS bits define the trunk type for trunk-specific CESoPSN services with CAS. These bits MUST be set to:
CAS位定义具有CAS的中继特定CESoPSN服务的中继类型。这些位必须设置为：
1) For trunk-specific CESoPSN with CAS:
1) 对于具有CAS的中继特定CESoPSN：
a) '01' in the case of an E1 trunk
a) 对于E1中继，“01”
b) '10' in the case of a T1/ESF trunk
b) 对于T1/ESF中继，“10”
c) '11' in the case of a T1/SF trunk
c) 对于T1/SF中继，“11”
2) '00' for all the other TDM pseudowire types
2) 所有其他TDM伪线类型的“00”
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|M|H| rsvd | Length | Vendor Id (IETF) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attribute Type (100) |D| PT |C| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Timestamp Clock Frequency |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|M|H| rsvd | Length | Vendor Id (IETF) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attribute Type (100) |D| PT |C| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Timestamp Clock Frequency |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Presence of this AVP indicates that the RTP header is used in the TDM pseudowire encapsulation. Use or non-use of the RTP header MUST match for the two directions of a TDM PW. This AVP MAY be hidden (the H bit MAY be 0 or 1). The M bit for this AVP SHOULD be set to 0. The Length (before hiding) of this AVP is 16.
此AVP的存在表明RTP报头用于TDM伪线封装。RTP头的使用或不使用必须与TDM PW的两个方向相匹配。该AVP可能被隐藏（H位可能为0或1）。此AVP的M位应设置为0。此AVP的长度（隐藏前）为16。
The D bit indicates the timestamping mode (absolute or differential) in the RTP header. These modes are described in, e.g., Section 4.3.2 of [RFC4553]. If the D bit is set to 1, then the differential timestamping mode is used; otherwise, the absolute timestamping mode is used. Timestamping modes can be used independently for the two directions of a TDM PW.
D位表示RTP报头中的时间戳模式（绝对或差分）。这些模式如[RFC4553]第4.3.2节所述。如果D位设置为1，则使用差分时间戳模式；否则，将使用绝对时间戳模式。时间戳模式可独立用于TDM PW的两个方向。
The C bit indicates the ordering of the RTP header and the Control Word as following:
C位表示RTP头和控制字的顺序，如下所示：
o If the C bit is set to 1, the RTP header appears after the Control Word in the data channel of the TDM pseudowire. This mode is described in [RFC4553] and [RFC5086] as SAToP/CESoPSN encapsulation over IPv4/IPv6 PSN with L2TPv3 demultiplexing, respectively.
o 如果C位设置为1，则RTP报头出现在TDM伪线数据通道中的控制字之后。[RFC4553]和[RFC5086]中分别将该模式描述为IPv4/IPv6 PSN上的SAToP/CESoPSN封装和L2TPv3解复用。
o If the C bit is set to 0, the RTP header appears before the Control Word. This mode is described as the old mode of the SAToP/CESoPSN encapsulation over L2TPv3 in Appendix A of [RFC4553] and Appendix C of [RFC5086], respectively.
o 如果C位设置为0，则RTP头显示在控制字之前。该模式分别在[RFC4553]的附录A和[RFC5086]的附录C中描述为L2TPv3上的SAToP/CESoPSN封装的旧模式。
PT is the payload type expected in the RTP header. A value of 0 indicates that the receiver shall not check payload type to detect malformed packets.
PT是RTP标头中预期的有效负载类型。值为0表示接收器不应检查有效负载类型以检测格式错误的数据包。
Timestamp Clock Frequency is the clock frequency used for timestamping in units of 8 KHz.
时间戳时钟频率是用于时间戳的时钟频率，单位为8 KHz。
SSRC indicates the expected value of the synchronization source (SSRC) ID in the RTP header. A 0 in this field means that the SSRC ID will not be used for detecting misconnections. Since L2TP provides an alternative security mechanism using cookies, if the cookie length is larger than 0, the SSRC SHOULD be 0.
SSRC表示RTP标头中同步源（SSRC）ID的预期值。此字段中的0表示SSRC ID将不用于检测错误连接。由于L2TP提供了一种使用cookie的替代安全机制，因此如果cookie长度大于0，则SSRC应为0。
Control Connections that support TDM PWs MUST add the appropriate PW Type value(s) to the list in the Pseudowire Capabilities List AVP. The valid values are listed in the next section.
支持TDM PWs的控制连接必须将适当的PW类型值添加到伪线能力列表AVP中的列表中。有效值将在下一节中列出。
PW Type AVP should be set to one of the following values:
PW型AVP应设置为以下值之一：
1. Structure-agnostic emulation [RFC4553] of:
1. 结构不可知模拟[RFC4553]：
a. E1 circuits - 0x0011
a. E1电路-0x0011
b. T1 (DS1) circuits - 0x0012
b. T1（DS1）电路-0x0012
c. E3 circuits - 0x0013
c. E3电路-0x0013
d. T3 (DS3) circuits - 0x0014
d. T3（DS3）电路-0x0014
2. Structure-aware emulation [RFC5086] of:
2. 结构感知仿真[RFC5086]：
a. CESoPSN basic mode - 0x0015
a. CESoPSN基本模式-0x0015
b. Trunk-specific CESoPSN service with CAS - 0x0017
b. 具有CAS的中继特定CESoPSN服务-0x0017
TDM pseudowires use their own Control Word. Therefore, the L2- Specific Sublayer AVP MUST either be omitted or set to 0.
TDM伪线使用它们自己的控制字。因此，L2特定子层AVP必须忽略或设置为0。
TDM pseudowires use their own sequencing. Therefore, the Data Sequencing AVP MUST either be omitted or set to 0.
TDM伪线使用它们自己的序列。因此，必须忽略数据排序AVP或将其设置为0。
Note: The Control Word (CW) used in the SAToP and CESoPSN encapsulations over L2TPv3 effectively represents a dedicated L2- Specific Sublayer.
注：L2TPv3上的SAToP和CESoPSN封装中使用的控制字（CW）有效地表示专用的L2特定子层。
When an L2TP Control Connection Endpoint (LCCE) wants to open a Session for a TDM PW, it MUST include the TDM PW AVP (in any case) and the RTP AVP (if and only if the RTP header is used) in the ICRQ or OCRQ (Outgoing-Call-Request) message. The LCCE peer must validate
当L2TP控制连接端点（LCCE）想要为TDM PW打开会话时，它必须在ICRQ或OCRQ（传出呼叫请求）消息中包含TDM PW AVP（在任何情况下）和RTP AVP（当且仅当使用RTP头时）。LCCE对等方必须进行验证
the TDM PW AVP and make sure it can meet the requirements derived from the RTP AVP (if it exists). If the peer agrees with the TDM AVP, it will send an appropriate ICRP or OCRP (Outgoing-Call-Reply) message with the matching RTP AVP (if needed). The initiator needs to validate that it can supply the requirements derived from the received RTP AVP.
TDM PW AVP，并确保其能够满足RTP AVP（如果存在）的要求。如果对等方同意TDM AVP，它将发送适当的ICRP或OCRP（呼出呼叫应答）消息和匹配的RTP AVP（如果需要）。发起者需要验证它是否能够提供从接收到的RTP AVP派生的需求。
The two peers MUST agree on the values in the TDM PW AVP:
两位同行必须就TDM PW AVP中的值达成一致：
1. Bit Rate values MUST be equal on both sides. If they are different, the connection will be rejected with Result Code 30 and Error Code 1.
1. 两侧的比特率值必须相等。如果它们不同，将拒绝连接，结果代码为30，错误代码为1。
2. In the case of trunk-specific CESoPSN with CAS, the trunk type (as encoded in the CAS bits of the TDM AVP) MUST be the same for the two sides. Otherwise, the connection will be rejected with Result Code 30 and Error Code 2.
2. 对于具有CAS的中继特定CESoPSN，双方的中继类型（在TDM AVP的CAS位中编码）必须相同。否则，连接将被拒绝，结果代码为30，错误代码为2。
3. If one side does not support the Payload Bytes value proposed by the other one, the connection will be rejected with Result Code 30 and Error Code 3.
3. 如果一方不支持另一方提出的有效负载字节值，连接将被拒绝，结果代码为30，错误代码为3。
4. If one side cannot send the RTP header as requested by the other side, the connection will be rejected with Result Code 30 and Error Code 4.
4. 如果一方不能按照另一方的请求发送RTP报头，连接将被拒绝，结果代码为30，错误代码为4。
5. If one side can send the RTP header but not with the requested timestamp clock frequency, the connection will be rejected with Result Code 30 and Error Code 5.
5. 如果一方可以发送RTP报头，但不能以请求的时间戳时钟频率发送，则连接将被拒绝，结果代码为30，错误代码为5。
If CE signaling for a CESoPSN basic PW is transported in a separate PW instance, then the two PW instances:
如果CESoPSN基本PW的CE信令在单独的PW实例中传输，则两个PW实例：
1. MUST use the same PW type.
1. 必须使用相同的PW类型。
2. MUST use the same values in all the fields of the TDM AVP excluding the SP field, which must be set to '01' for the TDM data PW and to '10' for the PW carrying CE application signaling.
2. 必须在TDM AVP的所有字段（SP字段除外）中使用相同的值，对于TDM数据PW，SP字段必须设置为“01”，对于承载CE应用信令的PW，必须设置为“10”。
3. MUST both either use or not use the RTP header (and, accordingly, include or not include the RTP AVP).
3. 必须使用或不使用RTP报头（相应地，包括或不包括RTP AVP）。
IANA assigned the following values according to this document:
IANA根据本文件分配了以下值：
New L2TPv3 Pseudowire Types:
新L2TPv3伪导线类型：
0x0011 - Structure-agnostic E1 circuit 0x0012 - Structure-agnostic T1 (DS1) circuit 0x0013 - Structure-agnostic E3 circuit 0x0014 - Structure-agnostic T3 (DS3) circuit 0x0015 - CESoPSN basic mode 0x0017 - CESoPSN TDM with CAS
0x0011-结构不可知E1电路0x0012-结构不可知T1（DS1）电路0x0013-结构不可知E3电路0x0014-结构不可知T3（DS3）电路0x0015-CESoPSN基本模式0x0017-带CAS的CESoPSN TDM
Note that the values listed match the values defined in [RFC4446] for the MPLS Pseudowire Types.
请注意，列出的值与[RFC4446]中为MPLS伪线类型定义的值相匹配。
New Attribute-Value Pair IDs:
新属性值对ID：
99 - TDM Pseudowire AVP 100 - RTP AVP
99-TDM伪线AVP 100-RTP AVP
New Result Codes for the CDN message:
CDN消息的新结果代码：
30 - Result Code to indicate connection was refused because of TDM PW parameters. The Error Code indicates the problem.
30-由于TDM PW参数，指示连接被拒绝的结果代码。错误代码指示问题。
New TDM PW specific Error Codes, to be used with 30 Result Code for the CDN message:
新的TDM PW特定错误代码，与CDN消息的30个结果代码一起使用：
This is a new registry for IANA to maintain within the Result Code AVP (Attribute Type 1) Values. Additional values may be assigned by Expert Review [RFC5226].
这是IANA在结果代码AVP（属性类型1）值内维护的新注册表。专家评审[RFC5226]可指定其他值。
0 - Reserved. 1 - Bit Rate values disagree. 2 - Different trunk types in the case of trunk-specific CESoPSN with CAS. 3 - Requested payload size too big or too small. 4 - RTP header cannot be generated. 5 - Requested timestamp clock frequency cannot be generated.
0-保留。1-比特率值不一致。2-对于带有CAS的中继特定CESoPSN，不同的中继类型。3-请求的有效负载大小太大或太小。4-无法生成RTP标头。5-无法生成请求的时间戳时钟频率。
The congestion considerations from [RFC4553] and [RFC5086] apply respectively to the structure-agnostic and CESoPSN modes of this specification.
[RFC4553]和[RFC5086]中的拥塞注意事项分别适用于本规范的结构无关和CESoPSN模式。
This document specifies only the L2TPv3-based control plane for setup of TDM PWs. Within this scope, there are no additional security considerations in addition to those discussed in [RFC3931].
本文件仅规定了用于设置TDM PWs的基于L2TPv3的控制平面。在此范围内，除[RFC3931]中讨论的安全注意事项外，没有其他安全注意事项。
Common data plane security considerations for the TDM PWs have been discussed in some detail in both [RFC4553] and [RFC5086]. On top of these, the L2TPv3-based data plane provides additional security mechanisms based on the usage of cookies.
[RFC4553]和[RFC5086]中详细讨论了TDM PWs的常见数据平面安全注意事项。除此之外，基于L2TPv3的数据平面还基于cookie的使用提供了额外的安全机制。
The authors want to thank Carlos Pignataro, Ignacio Goyret, and Yaakov Stein for careful review and useful suggestions.
作者要感谢卡洛斯·皮格纳塔罗、伊格纳西奥·戈雷特和雅科夫·斯坦的仔细审查和有用的建议。
[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。
[RFC3931] Lau, J., Ed., Townsley, M., Ed., and I. Goyret, Ed., "Layer Two Tunneling Protocol - Version 3 (L2TPv3)", RFC 3931, March 2005.
[RFC3931]Lau，J.，Ed.，Townsley，M.，Ed.，和I.Goyret，Ed.，“第二层隧道协议-版本3（L2TPv3）”，RFC 39312005年3月。
[RFC4553] Vainshtein, A., Ed., and YJ. Stein, Ed., "Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP)", RFC 4553, June 2006.
[RFC4553]Vainstein，A.，Ed.，和YJ。Stein，Ed.“数据包上的结构不可知时分复用（TDM）（SAToP）”，RFC4553，2006年6月。
[RFC5086] Vainshtein, A., Ed., Sasson, I., Metz, E., Frost, T., and P. Pate, "Structure-Aware Time Division Multiplexed (TDM) Circuit Emulation Service over Packet Switched Network (CESoPSN)", RFC 5086, December 2007.
[RFC5086]Vainstein，A.，Ed.，Sasson，I.，Metz，E.，Frost，T.，和P.Pate，“分组交换网络上的结构感知时分多路复用（TDM）电路仿真服务（CESoPSN）”，RFC 5086，2007年12月。
[RFC4446] Martini, L., "IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3)", BCP 116, RFC 4446, April 2006.
[RFC4446]Martini，L.，“伪线边到边仿真（PWE3）的IANA分配”，BCP 116，RFC 4446，2006年4月。
[RFC5087] Y(J). Stein, Shashoua, R., Insler, R., and M. Anavi, "Time Division Multiplexing over IP (TDMoIP)", RFC 5087, December 2007.
[RFC5087]Y（J）。Stein，Shashoua，R.，Insler，R.，和M.Anavi，“IP时分多路复用（TDMoIP）”，RFC 5087，2007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。
[RFC5287] Vainshtein, A. and Y(J). Stein, "Control Protocol Extensions for the Setup of Time-Division Multiplexing (TDM) Pseudowires in MPLS Networks", RFC 5287, August 2008.
[RFC5287]Vainstein，A.和Y（J）。Stein，“MPLS网络中时分复用（TDM）伪线设置的控制协议扩展”，RFC 5287，2008年8月。
Authors' Addresses
作者地址
Alexander Vainshtein, ECI Telecom, 30 ha-Sivim St. PO Box 500, Petah-Tiqva 49517, Israel EMail: Alexander.Vainshtein@ecitele.com
Alexander Vainstein，ECI Telecom，30公顷，西维姆街，邮政信箱500，Petah Tiqva 49517，以色列电子邮件：Alexander。Vainshtein@ecitele.com
Sharon Galtzur Rebellion Inc. 29 The Chilterns, Gloucester Green, Oxford, OX1 2DF, UK EMail: sharon.galtzur@rebellion.co.uk
Sharon Galtzur Rebession Inc.29 Chilterns，牛津格洛斯特格林，OX1 2DF，英国电子邮件：Sharon。galtzur@rebellion.co.uk