PPP Extensions Working Group N. Jones, INTERNET DRAFT Agere Systems, Category: Standards Track C. Murton, Expires: December 2001 Nortel Networks June 2001 Extending PPP over SONET/SDH with virtual concatenation, high order and low order payloads Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. Internet Drafts are working documents of the Internet Engineering Task Force (IETF), its Areas, and its Working Groups. Note that other groups may also distribute working documents as Internet Drafts. Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a "working draft" or "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this draft is unlimited. Jones Expires December 2001 1 Internet Draft POS with VC, HO & LO June 2001 Abstract The RFC 1661 Point-to-Point Protocol (PPP) [1] provides a standard method for transporting multi-protocol datagrams over point-to-point links. The RFC 1662 PPP in HDLC-like Framing [2] and RFC 2615 PPP over SONET/SDH (POS) [3] documents describe the use of PPP over Synchronous Optical Network (SONET) and Synchronous Digital Hierarchy (SDH) circuits. This document describes an extension to the mapping of PPP into SONET/SDH defined in RFC 2615 PPP over SONET/SDH (POS) [3], to include use of SONET/SDH SPE/VC virtual concatenation and use of both high order and low order payloads. This document is the product of the Point-to-Point Protocol Extensions Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the ietf-ppp@merit.edu mailing list. Table of Contents 1. Introduction................................................3 2. Rate Comparisons............................................4 3. Physical Layer Requirements.................................5 4. Standards Status............................................6 5. Security Considerations.....................................6 6. References..................................................7 7. Acknowledgments.............................................7 10. Author's Addresses..........................................7 11. Copyright Notice............................................8 Jones Expires December 2001 2 Internet Draft POS with VC, HO & LO June 2001 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 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]. Jones Expires December 2001 3 Internet Draft POS with VC, HO & LO June 2001 2. Rate Comparisons Currently supported WAN bandwidth links for PPP over SONET/SDH: 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 STS-1-nv (n=1-64) 49Mbit/s-3.1Gbit/s STS-3c-nv (n=1-64) 150Mbit/s-10Gbit/s SDH 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 Expires December 2001 4 Internet Draft POS with VC, HO & LO June 2001 Note, that Table 1, contains SONET transport signals with the following effective payload capacity: 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 -------------------------------------------- 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-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 ------------------------------------------- 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 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. Second, the multi-frame indicator (H4) byte will be unused for transport links utilizing contiguously concatenated SONET/SDH SPE/VCs. When the concatenation scheme is Ÿvirtual÷ as opposed to Ÿcontiguous÷ the H4 byte must be populated as per ITU-T G.707 or T1.105.02. Jones Expires December 2001 5 Internet Draft POS with VC, HO & LO June 2001 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 Expires December 2001 6 Internet Draft POS with VC, HO & LO June 2001 6. References [1] Simpson, W., Editor, "The Point-to-Point Protocol (PPP)", RFC 1661, Daydreamer, July 1994. [2] Simpson, W., Editor, "PPP in HDLC-like Framing, "RFC 1662, Daydreamer, July 1994. [3] Malis, A. & Simpson, W., "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. Acknowledgments 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. 8. Author's Addresses Nevin Jones Agere Systems Broadband IC Systems Architecture Rm. 7E-321 600 Mountain Avenue Murray Hill, NJ 07974 Email: nrjones@lucent.com Chris Murton Nortel Networks Harlow Laboratories London Road, Harlow, Essex, CM17 9NA UK Email: murton@nortelnetworks.com Jones Expires December 2001 7 Internet Draft POS with VC, HO & LO June 2001 9. Copyright Notice Copyright (C) The Internet Society 2001. 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 organisations, 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. Jones Expires December 2001 8