summaryrefslogtreecommitdiff
path: root/doc/rfc/rfc1619.txt
diff options
context:
space:
mode:
Diffstat (limited to 'doc/rfc/rfc1619.txt')
-rw-r--r--doc/rfc/rfc1619.txt334
1 files changed, 334 insertions, 0 deletions
diff --git a/doc/rfc/rfc1619.txt b/doc/rfc/rfc1619.txt
new file mode 100644
index 0000000..47ad29b
--- /dev/null
+++ b/doc/rfc/rfc1619.txt
@@ -0,0 +1,334 @@
+
+
+
+
+
+
+Network Working Group W. Simpson
+Request for Comments: 1619 Daydreamer
+Category: Standards Track May 1994
+
+
+ PPP over SONET/SDH
+
+
+
+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.
+
+
+
+Abstract
+
+ The Point-to-Point Protocol (PPP) [1] provides a standard method for
+ transporting multi-protocol datagrams over point-to-point links.
+ This document describes the use of PPP over Synchronous Optical
+ Network (SONET) and Synchronous Digital Heirarchy (SDH) circuits.
+
+ This document is the product of the Point-to-Point Protocol Working
+ Group of the Internet Engineering Task Force (IETF). Comments should
+ be submitted to the ietf-ppp@merit.edu mailing list.
+
+
+
+Applicability
+
+ This specification is intended for those implementations which desire
+ to use the PPP encapsulation over high speed private point-to-point
+ links, such as intra-campus single-mode fiber which may already be
+ installed and unused. Because the PPP encapsulation has relatively
+ low overhead, it is anticipated that significantly higher throughput
+ can be attained compared to other SONET/SDH payload mappings, at a
+ significantly lower cost for line termination equipment.
+
+
+
+
+
+
+
+
+
+
+Simpson [Page i]
+ RFC 1619 PPP over SONET/SDH May 1994
+
+
+ Table of Contents
+
+
+ 1. Introduction .......................................... 1
+
+ 2. Physical Layer Requirements ........................... 1
+
+ 3. Framing ............................................... 2
+
+ 4. Configuration Details ................................. 3
+
+ SECURITY CONSIDERATIONS ...................................... 3
+
+ REFERENCES ................................................... 3
+
+ ACKNOWLEDGEMENTS ............................................. 3
+
+ CHAIR'S ADDRESS .............................................. 4
+
+ AUTHOR'S ADDRESS ............................................. 4
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Simpson [Page ii]
+ RFC 1619 PPP over SONET/SDH May 1994
+
+
+1. Introduction
+
+ PPP was designed as a standard method of communicating over point-
+ to-point links. Initial deployment has been over short local lines,
+ leased lines, and plain-old-telephone-service (POTS) using modems.
+ As new packet services and higher speed lines are introduced, PPP is
+ easily deployed in these environments as well.
+
+ This specification is primarily concerned with the use of the PPP
+ encapsulation over SONET/SDH links. Since SONET/SDH is by definition
+ a point-to-point circuit, PPP is well suited to use over these links.
+
+ The Synchronous Optical Network (SONET) [3] is an octet-synchronous
+ multiplex scheme that defines a family of standard rates and formats.
+ Despite the name, it is not limited to optical links. Electrical
+ specifications have been defined for single-mode fiber, multi-mode
+ fiber, and CATV 75 ohm coaxial cable. The transmission rates are
+ integral multiples of 51.840 Mbps, which may be used to carry T3/E3
+ bit-synchronous signals. The allowed multiples are currently
+ specified as
+
+ STS-1 51.840 STS-18 933.120
+ STS-3 155.520 STS-24 1,244.160
+ STS-9 466.560 STS-36 1,866.240
+ STS-12 622.080 STS-48 2,488.320
+
+
+ The CCITT Synchronous Digital Heirarchy (SDH) defines a subset of
+ SONET transmission rates beginning at 155.520 Mbps [5].
+
+ SONET SDH equivalent
+ STS-3c STM-1
+ STS-12c STM-4
+ STS-48c STM-16
+
+
+
+
+2. Physical Layer Requirements
+
+ PPP treats SONET/SDH transport as octet oriented synchronous links.
+ SONET/SDH links are full-duplex by definition.
+
+ Interface Format
+
+ PPP presents an octet interface to the physical layer. There is
+ no provision for sub-octets to be supplied or accepted.
+
+
+
+
+Simpson [Page 1]
+ RFC 1619 PPP over SONET/SDH May 1994
+
+
+ The octet stream is mapped into the SONET/SDH Synchronous Payload
+ Envelope (SPE), with the octet boundaries aligned with the SPE
+ octet boundaries.
+
+ No scrambling is needed during insertion into the SPE.
+
+ The Path Signal Label (C2) is intended to indicate the contents of
+ the SPE. The experimental value of 207 (cf hex) is used to
+ indicate PPP.
+
+ The Multiframe Indicator (H4) is currently unused, and MUST be
+ zero.
+
+ Transmission Rate
+
+ The basic rate for PPP over SONET/SDH is that of STS-3c/STM-1 at
+ 155.520 Mbps. The available information bandwidth is 149.760
+ Mbps, which is the STS-3c/STM-1 SPE with section, line and path
+ overhead removed. This is the same super-rate mapping that is
+ used for ATM and FDDI [4].
+
+ Lower signal rates MUST use the Virtual Tributary (VT) mechanism
+ of SONET/SDH. This maps existing signals up to T3/E3 rates
+ asynchronously into the SPE, or uses available clocks for bit-
+ synchronous and byte-synchronous mapping.
+
+ Higher signal rates SHOULD conform to the SDH STM series, rather
+ than the SONET STS series, as equipment becomes available. The
+ STM series progresses in powers of 4 (instead of 3), and employs
+ fewer steps, which is likely to simplify multiplexing and
+ integration.
+
+ Control Signals
+
+ PPP does not require the use of control signals. When available,
+ using such signals can allow greater functionality and
+ performance. Implications are discussed in [2].
+
+
+
+3. Framing
+
+ The framing for octet-synchronous links is described in "PPP in HDLC
+ Framing" [2].
+
+ The PPP frames are located by row within the SPE payload. Because
+ frames are variable in length, the frames are allowed to cross SPE
+ boundaries.
+
+
+
+Simpson [Page 2]
+ RFC 1619 PPP over SONET/SDH May 1994
+
+
+4. Configuration Details
+
+ The standard LCP sync configuration defaults apply to SONET/SDH
+ links.
+
+ The following Configuration Options are recommended:
+
+ Magic Number
+ No Address and Control Field Compression
+ No Protocol Field Compression
+ 32-bit FCS
+
+
+
+
+Security Considerations
+
+ Security issues are not discussed in this memo.
+
+
+
+References
+
+ [1] Simpson, W., Editor, "The Point-to-Point Protocol (PPP)", RFC
+ 1548, Daydreamer, December 1993.
+
+ [2] Simpson, W., Editor, "PPP in HDLC Framing", RFC 1549,
+ Daydreamer, December 1993.
+
+ [3] "American National Standard for Telecommunications - Digital
+ Hierarchy - Optical Interface Rates and Formats Specification",
+ ANSI T1.105-1991.
+
+ [4] "American National Standard for Telecommunications -
+ Synchronous Optical Network (SONET) Payload Mappings", ANSI
+ T1.105.02-1993 draft.
+
+ [5] CCITT Recommendation G.707, "Synchronous Digital Hierarchy Bit
+ Rates", June 1992.
+
+
+
+
+
+
+
+
+
+
+
+
+Simpson [Page 3]
+ RFC 1619 PPP over SONET/SDH May 1994
+
+
+Acknowledgments
+
+ PPP over SONET was first proposed by Craig Partridge (BBN). Some
+ information was obtained from the good folks at Bellcore.
+
+ Technical assistance and information was also provided by Victor
+ Demjanenko (SUNY Buffalo).
+
+ Special thanks to Morning Star Technologies for providing computing
+ resources and network access support for writing this specification.
+
+
+
+Chair's Address
+
+ The working group can be contacted via the current chair:
+
+ Fred Baker
+ Advanced Computer Communications
+ 315 Bollay Drive
+ Santa Barbara, California 93117
+
+ EMail: fbaker@acc.com
+
+
+
+Author's Address
+
+ Questions about this memo can also be directed to:
+
+ William Allen Simpson
+ Daydreamer
+ Computer Systems Consulting Services
+ 1384 Fontaine
+ Madison Heights, Michigan 48071
+
+ EMail: Bill.Simpson@um.cc.umich.edu
+ bsimpson@MorningStar.com
+
+
+
+
+
+
+
+
+
+
+
+
+
+Simpson [Page 4]
+
+