Network Working Group N. Jones
Request for Comments: 3255 Agere Systems
Category: Standards Track C. Murton
Nortel Networks
April 2002
Network Working Group N. Jones
Request for Comments: 3255 Agere Systems
Category: Standards Track C. Murton
Nortel Networks
April 2002
Extending Point-to-Point Protocol (PPP) over Synchronous Optical NETwork/Synchronous Digital Hierarchy (SONET/SDH) with virtual concatenation, high order and low order payloads
在具有虚拟级联、高阶和低阶有效负载的同步光网络/同步数字体系（SONET/SDH）上扩展点对点协议（PPP）
Status of this Memo
本备忘录的状况
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) The Internet Society (2002). All Rights Reserved.
版权所有（C）互联网协会（2002年）。版权所有。
Abstract
摘要
This document describes an extension to the mapping of Point-to-Point Protocol (PPP) into Synchronous Optical NETwork/Synchronous Digital Hierarchy (SONET/SDH) to include the use of SONET/SDH SPE/VC virtual concatenation and the use of both high order and low order payloads.
本文件描述了点对点协议（PPP）到同步光网络/同步数字体系（SONET/SDH）映射的扩展，包括SONET/SDH SPE/VC虚拟级联的使用以及高阶和低阶有效负载的使用。
Table of Contents
目录
1. Introduction................................................1
2. Rate Comparisons............................................2
3. Physical Layer Requirements.................................4
4. Standards Status............................................5
5. Security Considerations.....................................5
6. References..................................................6
7. Acknowledgements............................................6
8. Authors' Addresses..........................................7
9. Full Copyright Statement....................................8
1. Introduction................................................1
2. Rate Comparisons............................................2
3. Physical Layer Requirements.................................4
4. Standards Status............................................5
5. Security Considerations.....................................5
6. References..................................................6
7. Acknowledgements............................................6
8. Authors' Addresses..........................................7
9. Full Copyright Statement....................................8
Current implementations of PPP over SONET/SDH are required to select transport structures from the relatively limited number of contiguously concatenated signals that are available.
当前SONET/SDH上PPP的实现需要从相对有限的可用连续级联信号中选择传输结构。
The only currently supported SONET/SDH SPE/VCs in RFC 2615 [3] are the following:
RFC 2615[3]中目前唯一支持的SONET/SDH SPE/VCs如下：
SONET SDH
----------------------------------------
STS-3c-SPE VC-4
STS-12c-SPE VC-4-4c
STS-48c-SPE VC-4-16c
STS-192c-SPE VC-4-64c
SONET SDH
----------------------------------------
STS-3c-SPE VC-4
STS-12c-SPE VC-4-4c
STS-48c-SPE VC-4-16c
STS-192c-SPE VC-4-64c
Note that VC-4-4c and above are not widely supported in SDH networks at present.
请注意，目前SDH网络中不广泛支持VC-4-4c及以上版本。
The use of virtual concatenation means that the right size SONET/SDH bandwidth can be selected for PPP links.
虚拟连接的使用意味着可以为PPP链路选择适当大小的SONET/SDH带宽。
For the convenience of the reader, the equivalent terms are listed below:
为方便读者，以下列出了等效术语：
SONET SDH
---------------------------------------------
SPE VC
VT (1.5/2/6) Low order VC (VC-11/12/2)
STS SPE Higher Order VC (VC-3/4/4-Nc)
STS-1 frame STM-0 frame (rarely used)
STS-1 SPE VC-3
STS-1-nv VC-3-nv (virtual concatenation)
STS-1 payload C-3
STS-3c frame STM-1 frame, AU-4
STS-3c SPE VC-4
STS-3c-nv VC-4-nv (virtual concatenation)
STS-3c payload C-4
STS-12c/48c/192c frame STM-4/16/64 frame, AU-4-4c/16c/64c
STS-12c/48c/192c-SPE VC-4-4c/16c/64c
STS-12c/48c/192c payload C-4-4c/16c/64c
SONET SDH
---------------------------------------------
SPE VC
VT (1.5/2/6) Low order VC (VC-11/12/2)
STS SPE Higher Order VC (VC-3/4/4-Nc)
STS-1 frame STM-0 frame (rarely used)
STS-1 SPE VC-3
STS-1-nv VC-3-nv (virtual concatenation)
STS-1 payload C-3
STS-3c frame STM-1 frame, AU-4
STS-3c SPE VC-4
STS-3c-nv VC-4-nv (virtual concatenation)
STS-3c payload C-4
STS-12c/48c/192c frame STM-4/16/64 frame, AU-4-4c/16c/64c
STS-12c/48c/192c-SPE VC-4-4c/16c/64c
STS-12c/48c/192c payload C-4-4c/16c/64c
This table is an extended version of the equivalent table in RFC 2615 [3]. Additional information on the above terms can be found in Bellcore GR-253-CORE [4], ANSI T1.105 [5], ANSI T1.105.02 [6] and ITU-T G.707 [7].
此表是RFC 2615[3]中等效表的扩展版本。有关上述术语的更多信息，请参见Bellcore GR-253-CORE[4]、ANSI T1.105[5]、ANSI T1.105.02[6]和ITU-T G.707[7]。
Currently supported WAN bandwidth links for PPP over SONET/SDH:
SONET/SDH上PPP当前支持的WAN带宽链路：
ANSI ETSI
-----------------------------------------------------
STS-3c (150Mbit/s) STM-1 (150Mbit/s)
STS-12c (620Mbit/s) STM-4 AU-4-4c (620Mbit/s)
STS-48c (2.4Gbit/s) STM-16 AU-4-16c (2.4Gbit/s)
STS-192c (9.6Gbit/s) STM-64 AU-4-64c (9.6Gbit/s)
ANSI ETSI
-----------------------------------------------------
STS-3c (150Mbit/s) STM-1 (150Mbit/s)
STS-12c (620Mbit/s) STM-4 AU-4-4c (620Mbit/s)
STS-48c (2.4Gbit/s) STM-16 AU-4-16c (2.4Gbit/s)
STS-192c (9.6Gbit/s) STM-64 AU-4-64c (9.6Gbit/s)
Note that AU-4-4c and AU-4-16c are not generally available in SDH networks at present.
请注意，目前SDH网络中通常不提供AU-4-4c和AU-4-16c。
With virtual concatenation the following additional WAN bandwidth links would be available for PPP over SONET/SDH:
通过虚拟连接，以下额外的WAN带宽链路将可用于SONET/SDH上的PPP：
SONET
索内特
VT-1.5-nv (n=1-64) 1.6Mbit/s-102Mbit/s
STS-1-nv (n=1-64) 49Mbit/s-3.1Gbit/s
STS-3c-nv (n=1-64) 150Mbit/s-10Gbit/s
VT-1.5-nv (n=1-64) 1.6Mbit/s-102Mbit/s
STS-1-nv (n=1-64) 49Mbit/s-3.1Gbit/s
STS-3c-nv (n=1-64) 150Mbit/s-10Gbit/s
SDH
SDH
VC-12-nv (n=1-64) 2.2Mbit/s-139Mbit/s
VC-3-nv (n=1-64) 49Mbit/s-3.1Gbit/s
VC-4-nv (n=1-64) 150Mbit/s-10Gbit/s
VC-12-nv (n=1-64) 2.2Mbit/s-139Mbit/s
VC-3-nv (n=1-64) 49Mbit/s-3.1Gbit/s
VC-4-nv (n=1-64) 150Mbit/s-10Gbit/s
Higher levels of virtual concatenation are possible, but not necessarily useful. Lower levels of virtual concatenation are defined in the telecommunications standards for use if needed.
更高级别的虚拟连接是可能的，但不一定有用。电信标准中定义了较低级别的虚拟连接，以便在需要时使用。
Table 1 and Table 2, respectively depict the SONET/SDH transport structures that are currently available to carry various popular bit rates. Each table contains three columns. The first column shows the bit rates of the service to be transported.
表1和表2分别描述了目前可用于承载各种流行比特率的SONET/SDH传输结构。每个表包含三列。第一列显示要传输的服务的比特率。
The next column contains two values:
下一列包含两个值：
a) the logical signals that are currently available to provide such transport and, b) in parenthesis, the percent efficiency of the given transport signal without the use of virtual concatenation.
a) 当前可用于提供此类传输的逻辑信号，以及（b）括号中未使用虚拟串联的给定传输信号的效率百分比。
Likewise, the final column also contains two values:
同样，最后一列也包含两个值：
a) the logical signals that are currently available to provide such transport and, b) in parenthesis, the percent efficiency of the given transport signal with the use of virtual concatenation.
a) 当前可用于提供此类传输的逻辑信号，以及（b）括号中使用虚拟级联的给定传输信号的效率百分比。
Note, that Table 1, contains SONET transport signals with the following effective payload capacity: VT-1.5 SPE = 1.600 Mbit/s, STS-1 SPE = 49.536 Mbit/s, STS-3c SPE = 149.760 Mbit/s, STS-12c SPE = 599.040 Mbit/s, STS-48c SPE = 2,396.160 Mbit/s, and STS-192c SPE = 9,584.640 Mbit/s.
注意，表1包含具有以下有效负载容量的SONET传输信号：VT-1.5 SPE=1.600 Mbit/s，STS-1 SPE=49.536 Mbit/s，STS-3c SPE=149.760 Mbit/s，STS-12c SPE=599.040 Mbit/s，STS-48c SPE=2396.160 Mbit/s，以及STS-192c SPE=9584.640 Mbit/s。
Table 1. SONET Virtual Concatenation
表1。SONET虚级联
Bit rate Without With
--------------------------------------------
Bit rate Without With
--------------------------------------------
10Mbit/s STS-1 (20%) VT-1.5-7v (89%)
100Mbit/s STS-3c (67%) STS-1-2v (100%)
200Mbit/s STS-12c(33%) STS-1-4v (100%)
1Gbit/s STS-48c(42%) STS-3c-7v (95%)
10Mbit/s STS-1 (20%) VT-1.5-7v (89%)
100Mbit/s STS-3c (67%) STS-1-2v (100%)
200Mbit/s STS-12c(33%) STS-1-4v (100%)
1Gbit/s STS-48c(42%) STS-3c-7v (95%)
Similarly, Table 2, contains SDH transport signals with the following effective payload capacity: VC-12 = 2.176 Mbit/s, VC-3 = 48.960 Mbit/s, VC-4 = 149.760 Mbit/s, VC-4-4c = 599.040 Mbit/s, VC-4-16c = 2,396.160 Mbit/s, and VC-4-64c = 9,584.640 Mbit/s.
类似地，表2包含具有以下有效负载容量的SDH传输信号：VC-12=2.176 Mbit/s，VC-3=48.960 Mbit/s，VC-4=149.760 Mbit/s，VC-4-4c=599.040 Mbit/s，VC-4-16c=2396.160 Mbit/s，VC-4-64c=9584.640 Mbit/s。
Table 2. SDH Virtual Concatenation
表2。SDH虚拟级联
Bit rate Without With
-------------------------------------------
Bit rate Without With
-------------------------------------------
10Mbit/s VC-3 (20%) VC-12-5v (92%)
100Mbit/s VC-4 (67%) VC-3-2v (100%)
200Mbit/s VC-4-4c(33%) VC-3-4v (100%)
1Gbit/s VC-4-16c(42%) VC-4-7v (95%)
10Mbit/s VC-3 (20%) VC-12-5v (92%)
100Mbit/s VC-4 (67%) VC-3-2v (100%)
200Mbit/s VC-4-4c(33%) VC-3-4v (100%)
1Gbit/s VC-4-16c(42%) VC-4-7v (95%)
There are two minor modifications to the physical layer requirements as defined in RFC 2615 when virtually concatenated SPEs/VCs are used to provide transport for PPP over SONET/SDH.
当使用虚拟连接的SPE/VCs通过SONET/SDH为PPP提供传输时，RFC 2615中定义的物理层要求有两个小修改。
First, the path signal label (C2 byte) value for SONET/SDH STS-1/VC-3 and above SPE/VCs is required to be the same for all constituent channels. This is in contrast to the use of a single C2 byte for PPP transport over contiguously concatenated SONET/SDH SPE/VCs. The values used for the C2 bytes should be in accordance with RFC 2615. For SONET VT-1.5/2/6 and SDH VC-11/12/2 the path signal label (V5 byte bits 5-7) is required to be the same for all constituent channels per ITU-T G.707 [7] and ANSI T1.105.02 [6].
首先，对于所有组成信道，SONET/SDH STS-1/VC-3及以上SPE/VCs的路径信号标签（C2字节）值必须相同。这与在连续连接的SONET/SDH SPE/VCs上使用单个C2字节进行PPP传输形成对比。C2字节使用的值应符合RFC 2615的要求。对于SONET VT-1.5/2/6和SDH VC-11/12/2，根据ITU-T G.707[7]和ANSI T1.105.02[6]，所有组成信道的路径信号标签（V5字节位5-7）必须相同。
Second, for SONET/SDH STS-1/VC-3 and above SPE/VCs the multi-frame indicator (H4) byte will be unused for transport links utilizing contiguously concatenated SONET/SDH SPE/VCs. When the concatenation scheme is virtual as opposed to contiguous, the H4 byte must be populated as per ITU-T G.707 or T1.105.02. Similarly, for virtual concatenation based on SONET VT-1.5/2/6 and SDH VC-11/12/2 channels bit 2 of the path overhead K4 byte will be set to the value indicated per ITU-T G.707 [7] and ANSI T1.105.02 [6].
其次，对于SONET/SDH STS-1/VC-3及以上SPE/VCs，多帧指示符（H4）字节将不用于使用连续级联SONET/SDH SPE/VCs的传输链路。当串联方案是虚拟的而不是连续的时，必须按照ITU-T G.707或T1.105.02填充H4字节。同样，对于基于SONET VT-1.5/2/6和SDH VC-11/12/2通道的虚拟级联，路径开销K4字节的第2位将设置为根据ITU-T G.707[7]和ANSI T1.105.02[6]指示的值。
ITU-T (SG13/SG15), ANSI T1X1 and ETSI TM1/WP3 have developed a global standard for SONET/SDH High Order and Low Order payload Virtual Concatenation. This standard is defined in the following documents:
ITU-T（SG13/SG15）、ANSI T1X1和ETSI TM1/WP3为SONET/SDH高阶和低阶有效负载虚拟级联制定了全球标准。本标准在以下文件中定义：
ITU-T G.803 Architecture of transport networks based on the synchronous digital hierarchy (SDH)
ITU-T G.803基于同步数字体系（SDH）的传输网络体系结构
ITU-T G.707 Network Node Interface for the Synchronous Digital Hierarchy (SDH)
ITU-T G.707同步数字体系（SDH）的网络节点接口
ITU-T G.783 Characteristics of Synchronous Digital Hierarchy (SDH) Equipment Functional Blocks
ITU-T G.783同步数字体系（SDH）设备功能块的特性
ANSI T1.105 Synchronous Optical Network (SONET) - Basic Description including Multiplex Structure, Rates and Formats
ANSI T1.105同步光网络（SONET）.包括复用结构、速率和格式的基本说明
ANSI T1.105.02 Synchronous Optical Network (SONET) - Payload Mappings
ANSI T1.105.02同步光网络（SONET）-有效负载映射
ETSI EN 300 417-9-1 Transmission and Multiplexing (TM) Generic requirements of transport functionality of equipment Part 9: Synchronous Digital Hierarchy (SDH) concatenated path layer functions. Subpart 1: Requirements
ETSI EN 300 417-9-1传输和多路复用（TM）设备传输功能的一般要求第9部分：同步数字体系（SDH）级联路径层功能。第1子部分：要求
Work in ITU-T, ANSI T1X1 and ETSI TM1/WP3 has ensured global standards alignment.
在ITU-T、ANSI T1X1和ETSI TM1/WP3中的工作确保了全球标准的一致性。
With the completion of a standard for SONET/SDH SPE/VC virtual concatenation it is appropriate to document the use of this standard for PPP transport over SONET/SDH, which is the intent of this document.
随着SONET/SDH SPE/VC虚拟级联标准的完成，记录本标准在SONET/SDH上PPP传输的使用是合适的，这是本文件的目的。
The security discussion in RFC 2615 also applies to this document. No new security features have been explicitly introduced or removed compared to RFC 2615.
RFC 2615中的安全讨论也适用于本文件。与RFC 2615相比，没有明确引入或删除新的安全功能。
[1] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51, RFC 1661, July 1994.
[1] 辛普森，W.，“点对点协议（PPP）”，STD 51，RFC 1661994年7月。
[2] Simpson, W., "PPP in HDLC-like Framing", STD 51, RFC 1662, July 1994.
[2] 辛普森，W.“HDLC类框架中的PPP”，STD 51，RFC 16621994年7月。
[3] Malis, A. and W. Simpson, "PPP over SONET/SDH RFC 2615, June 1999.
[3] Malis，A.和W.Simpson，“SONET/SDH RFC 2615上的PPP，1999年6月。
[4] Bellcore Publication GR-253-Core "Synchronous Optical Network (SONET) Transport Systems: Common Generic Criteria" January 1999
[4] Bellcore出版物GR-253-Core“同步光网络（SONET）传输系统：通用通用标准”，1999年1月
[5] American National Standards Institute, "Synchronous Optical Network (SONET) - Basic Description including Multiplex Structure, Rates and Formats" ANSI T1.105-1995
[5] 美国国家标准协会，“同步光网络（SONET）-基本说明，包括多路复用结构、速率和格式”，ANSI T1.105-1995
[6] American National Standards Institute, "Synchronous Optical Network (SONET) - Payload Mappings" ANSI T1.105.02-1998
[6] 美国国家标准协会，“同步光网络（SONET）-有效载荷映射”，ANSI T1.105.02-1998
[7] ITU-T Recommendation G.707 "Network Node Interface for the Synchronous Digital Hierarchy" 1996
[7] ITU-T建议G.707“同步数字体系的网络节点接口”1996
We would like to acknowledge Huub van Helvoort, Maarten Vissers (Lucent Technologies), Paul Langner (Lucent Microelectronics), Trevor Wilson (Nortel Networks), Mark Carson (Nortel Networks) and James McKee (Nortel Networks) for their contribution to the development of virtual concatenation of SONET/SDH payloads.
我们要感谢Huub van Helvoort、Maarten Vissers（朗讯科技公司）、Paul Langner（朗讯微电子公司）、Trevor Wilson（北电网络公司）、Mark Carson（北电网络公司）和James McKee（北电网络公司）为SONET/SDH有效载荷虚拟连接的发展所做的贡献。
Nevin Jones Agere Systems Broadband IC Systems Architecture Rm. 7E-321 600 Mountain Avenue Murray Hill, NJ 07974
Nevin Jones Agere Systems宽带IC系统架构Rm。新泽西州默里山山地大道600号7E-321 07974
EMail: nrjones@agere.com
EMail: nrjones@agere.com
Chris Murton Nortel Networks Harlow Laboratories London Road, Harlow, Essex, CM17 9NA UK
Chris Murton Nortel Networks哈洛实验室伦敦路，哈洛，埃塞克斯，CM17 9NA英国
EMail: murton@nortelnetworks.com
EMail: murton@nortelnetworks.com
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