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+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
+
+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.
+
+Copyright Notice
+
+ Copyright (C) The Internet Society (2002). All Rights Reserved.
+
+Abstract
+
+ 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.
+
+Table of Contents
+
+ 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
+
+ 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.
+
+
+
+
+Jones & Murton Standards Track [Page 1]
+
+RFC 3255 Extending PPP over SONET/SDH April 2002
+
+
+ The only currently supported SONET/SDH SPE/VCs in RFC 2615 [3] are
+ the following:
+
+ 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.
+
+ The use of virtual concatenation means that the right size SONET/SDH
+ bandwidth can be selected for PPP links.
+
+ For the convenience of the reader, the equivalent terms are listed
+ below:
+
+ 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].
+
+2. Rate Comparisons
+
+ Currently supported WAN bandwidth links for PPP over SONET/SDH:
+
+
+
+
+
+
+
+Jones & Murton Standards Track [Page 2]
+
+RFC 3255 Extending PPP over SONET/SDH April 2002
+
+
+ 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.
+
+ With virtual concatenation the following additional WAN bandwidth
+ links would be available for PPP over SONET/SDH:
+
+ SONET
+
+ 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
+
+ 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.
+
+ 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.
+
+ The next column contains two values:
+
+ 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.
+
+ Likewise, the final column also contains two values:
+
+ 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.
+
+
+
+
+
+
+Jones & Murton Standards Track [Page 3]
+
+RFC 3255 Extending PPP over SONET/SDH April 2002
+
+
+ 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.
+
+ Table 1. SONET Virtual Concatenation
+
+ 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%)
+
+ 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.
+
+ Table 2. SDH Virtual Concatenation
+
+ 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%)
+
+3. Physical Layer Requirements
+
+ 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.
+
+ 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].
+
+
+
+
+
+
+Jones & Murton Standards Track [Page 4]
+
+RFC 3255 Extending PPP over SONET/SDH April 2002
+
+
+ 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].
+
+4. Standards Status
+
+ 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 G.803 Architecture of transport networks based on the
+ synchronous digital hierarchy (SDH)
+
+ ITU-T G.707 Network Node Interface for the Synchronous Digital
+ Hierarchy (SDH)
+
+ ITU-T G.783 Characteristics of Synchronous Digital Hierarchy (SDH)
+ Equipment Functional Blocks
+
+ ANSI T1.105 Synchronous Optical Network (SONET) - Basic
+ Description including Multiplex Structure, Rates and Formats
+
+ ANSI T1.105.02 Synchronous Optical Network (SONET) - Payload
+ Mappings
+
+ 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
+
+ Work in ITU-T, ANSI T1X1 and ETSI TM1/WP3 has ensured global
+ standards alignment.
+
+ 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.
+
+5. Security Considerations
+
+ 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.
+
+
+
+Jones & Murton Standards Track [Page 5]
+
+RFC 3255 Extending PPP over SONET/SDH April 2002
+
+
+6. References
+
+ [1] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51, RFC
+ 1661, July 1994.
+
+ [2] Simpson, W., "PPP in HDLC-like Framing", STD 51, RFC 1662, July
+ 1994.
+
+ [3] Malis, A. and W. Simpson, "PPP over SONET/SDH RFC 2615, June
+ 1999.
+
+ [4] Bellcore Publication GR-253-Core "Synchronous Optical Network
+ (SONET) Transport Systems: Common Generic Criteria" January
+ 1999
+
+ [5] American National Standards Institute, "Synchronous Optical
+ Network (SONET) - Basic Description including Multiplex
+ Structure, Rates and Formats" ANSI T1.105-1995
+
+ [6] American National Standards Institute, "Synchronous Optical
+ Network (SONET) - Payload Mappings" ANSI T1.105.02-1998
+
+ [7] ITU-T Recommendation G.707 "Network Node Interface for the
+ Synchronous Digital Hierarchy" 1996
+
+7. Acknowledgements
+
+ 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.
+
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+Jones & Murton Standards Track [Page 6]
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+RFC 3255 Extending PPP over SONET/SDH April 2002
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+8. Authors' Addresses
+
+ Nevin Jones
+ Agere Systems
+ Broadband IC Systems Architecture
+ Rm. 7E-321
+ 600 Mountain Avenue
+ Murray Hill, NJ 07974
+
+ EMail: nrjones@agere.com
+
+
+ Chris Murton
+ Nortel Networks Harlow Laboratories
+ London Road, Harlow,
+ Essex, CM17 9NA UK
+
+ EMail: murton@nortelnetworks.com
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+Jones & Murton Standards Track [Page 7]
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+RFC 3255 Extending PPP over SONET/SDH April 2002
+
+
+9. Full Copyright Statement
+
+ Copyright (C) The Internet Society (2002). All Rights Reserved.
+
+ This document and translations of it may be copied and furnished to
+ others, and derivative works that comment on or otherwise explain it
+ or assist in its implementation may be prepared, copied, published
+ and distributed, in whole or in part, without restriction of any
+ kind, provided that the above copyright notice and this paragraph are
+ included on all such copies and derivative works. However, this
+ document itself may not be modified in any way, such as by removing
+ the copyright notice or references to the Internet Society or other
+ Internet organizations, except as needed for the purpose of
+ developing Internet standards in which case the procedures for
+ copyrights defined in the Internet Standards process must be
+ followed, or as required to translate it into languages other than
+ English.
+
+ The limited permissions granted above are perpetual and will not be
+ revoked by the Internet Society or its successors or assigns.
+
+ This document and the information contained herein is provided on an
+ "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+ TASK FORCE DISCLAIMS 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.
+
+Acknowledgement
+
+ Funding for the RFC Editor function is currently provided by the
+ Internet Society.
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+Jones & Murton Standards Track [Page 8]
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