1、ANSI INCITS 237-1995 (R2001)(formerly ANSI X3.237-1995 (R2001)for Information Technology Fibre Distributed Data Interface (FDDI) Token Ring Low-Cost Fibre Physical LayerMedium Dependent (LCF-PMD)ANSI X3.237-l 995 for information Technology - Fibre Distributed Data Interface (FDDI) - Token Ring Low-C
2、ost Fibre Physical Layer Medium Dependent (LCF-PMD) Secretariat Information Technology Industry Council (ITI) Approved September 25, 1995 American National Standards Institute, Inc. Abstract This standard is intended for use in a high-performance multi-station network. This protocol is designed to b
3、e effective at 100 megabits per second using a token ring architecture and fibre optics as the transmission medium over optical link distances of up to five hundred meters. AmericanNationalStandardApproval of an American National Standard requires review by ANSI that therequirements for due process,
4、 consensus, and other criteria for approval havebeen met by the standards developer.Consensus is established when, in the judgment of the ANSI Board of StandardsReview, substantial agreement has been reached by directly and materiallyaffected interests. Substantial agreement means much more than a s
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6、as approved the standardsor not, from manufacturing, marketing, purchasing, or using products, processes,or procedures not conforming to the standards.The American National Standards Institute does not develop standards and will inno circumstances give an interpretation of any American National Stan
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8、andard.CAUTION NOTICE: This American National Standard may be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute require that action be taken periodically to reaffirm, revise, or withdrawthis standard. Purchasers of American National Standards may receive cur
9、rentinformation on all standards by calling or writing the American National StandardsInstitute.CAUTION: The developers of this standard have requested that holders of patents that may be required for theimplementation of the standard disclose such patents to the publisher. However, neither the deve
10、lopers nor the publisherhave undertaken a patent search in order to identify which, if any, patents may apply to this standard. As of the date ofpublication of this standard and following calls for the identification of patents that may be required for the implementationof the standard, no such clai
11、ms have been made. No further patent search is conducted by the developer or publisher inrespect to any standard it processes. No representation is made or implied that licenses are not required to avoidinfringement in the use of this standard.Published byAmerican National Standards Institute11 West
12、 42nd Street, New York, New York 10036Copyright 1996 by Information Technology Industry Council (ITI)All rights reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of ITI, 1250 Eye Street NW,Washington, DC
13、 20005.Printed in the United States of Americad_ .-_. _ I_. ,s _ ,. . ,. -m Contents Page Foreword . iv 1 Scope .1 2 Normative references . .2 3 Definitions . .3 4 Conventions and abbreviations . .5 5 General description .6 6 Services .I1 7 Media interface connector specification 16 8 Media signal i
14、nterface .19 9 Interface signals . .21 10 Cable plant interface specification .23 Figures 1 FDDI links and connections .7 2 FDDI topology example ,9 3 FDDI representative distribution environment example .lO 4 Dual attachment LCF-PMD services .12 5 LCF-PMD duplex receptacle . .18 6 LCF-MIC plug . .1
15、8 7 LCF-MIC ferrule . .19 8 Signal detect thresholds and timing . .22 Tables 1 Characteristics of active output interface . .20 2 Characteristics of active input interface . .21 3 Summary of assertion and deassertion requirements . .22 4 Bandwidth and attenuation values . .23 Annexes A Test methods
16、. .25 B Optical test procedures . .30 C Alternative cable plant usage .31 D Electrical interface considerations .33 E Example of system jitter allocation .35 F LCF-MIC requirements and testing .37 G Alternate optical interface connector . .41 H Labeling considerations .44 J Bibliography . .46 Forewo
17、rd (This foreword is not part of American National Standard X3.237-1995.) The Fibre Distributed Data Interface (FDDI) is intended for use in a high-per- formance general purpose multi-station network and is designed for efficient operation with a peak data rate of 100 Mbit/s. It uses a Token Ring ar
18、chitec- ture with optical fibre as the primary transmission medium. FDDI provides for hundreds of stations operating over an extent of tens of kilometers. The FDDI Part: Token ring low-cost physical layer medium dependent (LCF-PMD) standard specifies the lower sublayer of the Physical Layer for FDDI
19、. As such, it specifies the power levels and characteristics of the opti- cal transmitter and receiver, and the interface optical signal requirements including jitter. LCF-PMD also specifies the connector receptacle footprint, the requirements of conforming FDDI optical fibre cable plants, and the p
20、ermissible bit error rates. LCF-PMD is one of a set of American National Standard alternative PMDs being developed, or already developed, for FDDI. This set includes the original PMD, the Single Mode Fibre PMD (SMF-PMD), and the Twisted- Pair PMD (TP-PMD). The set of FDDI standards, when completed,
21、will include the following standards: (a) A FDDI Part: Token ring physical layer protocol (PHY), which spec- ifies the upper sublayer of the physical layer for the FDDI, including the data encode/decode, framing and clocking, as well as the elasticity buffer, smoothing, and repeat filter functions;
22、(b) A FDDI Part: Token ring media access control (MAC), which speci- fies the lower sublayer of the data link layer for FDDI, including the access to the medium, addressing, data checking, and data framing; (c) A FDDI Part: Token ring station management (SMT), which specifies the local portion of th
23、e system management application process for FDDI, includ- ing the control required for proper operation of a station in an FDDI ring. American National Standards for FDDI MAC (ANSI X3.139-1987), FDDI PHY (ANSI X3.148-1988), and FDDI PMD (ANSI X3.166-1990) have been approved and published. In additio
24、n, FDDI standards are being processed as International Standards by standards committee ISO/IEC JTC l/SC 25. International standards for FDDI PHY, FDDI MAC, and FDDI PMD (IS0 9314-1: 1989, 9314-2: 1989 and ISO/IEC 9314-3: 1990, respectively) have also been published. An extension to the basic FDDI i
25、s now in the X3 approval process. The standard FDDI HRC, commonly known as FDDI-II, will extend the capability of FDDI to handle isochronous data streams at a multiplicity of data rates. A standard for an enhancement to MAC is in process. This standard will be referred to as FDDI MAC-2 when it is ne
26、cessary to distinguish it from the approved FDDI MAC standard ANSI X3.139-1 987. Changes to be consid- ered for this update of the FDDI MAC standard include those identified in footnotes in the published standard on MAC as areas that the standards committee intended to change as well as changes that
27、 may be required for any proposed extensions to FDDI, such as FDDI-II or MAC Bridging. A similar enhancement project is in process for the FDDI PHY standard. This standard will be referred to as FDDI PHY-2. ii The text and format of this FDDI LCF-PMD standard is based upon the International FDDI PMD
28、 standard ISO/IEC 9314-3. As a consequence, cer- tain conventions, references, spelling, and units commonly used in International Standards have been used in this standard. These are differ- ent from those normally used in American National Standards, but are not expected to cause difficulty in unde
29、rstanding or use. This standard contains nine annexes. Annexes A-J are informative and are not considered part of this standard. Requests for interpretation, suggestions for improvement or addenda, or defect reports are welcome. They should be sent to the X3 Secretariat, Infor- mation Technology Ind
30、ustry Council, 1250 Eye Street, NW, Washington DC 20005-3922. This standard was processed and approved for submittal to ANSI by the Accredited Standards Committee on Information Technology, X3. Committee approval of this standard does not necessarily imply that all committee members voted for its ap
31、proval. At the time it approved this standard, the X3 Committee had the following members: James D. Converse, Chair Donald C. Loughry, Vice-Chair Joanne Flanagan, Secretary Organization Represented Name of Representative American Nuclear Society Geraldine C. Main Sally Hartzell (Ah.) AMP, Inc . Edwa
32、rd Kelly Charles Brill (Alt.) Apple Computer, Inc David K. Michael AT 2) A Physical Layer Protocol (PHY) sublayer (ISO/IEC 9314-l), and its enhancement, (PHY-2), which provides connection between the PMD and the Data Link Layer. PHY establishes clock synchronization with the upstream code-bit data s
33、tream and decodes this incoming code-bit stream into an equivalent symbol stream for use by the higher layers. PHY provides encoding and decoding between data and control indicator symbols and code bits, medium conditioning and initializing, the synchronization of incoming and outgoing code-bit cloc
34、ks, and the delineation of octet boundaries as required for the transmission of information to or from higher layers. Information to be transmitted on the medium is encoded by the PHY using a group transmission code; 1 ANSI X3.237-i 995 b) a Data Link Layer (DLL), which is divided into two or more s
35、ublayers: 1) An optional Hybrid Ring Control (HRC) (ISO/IEC 93145), which provides multiplexing of packet and circuit switched data on the shared FDDI medium. HRC comprises two internal components, a Hybrid Multiplexer (H-MUX) and an lsochronous MAC (I-MAC). H-MUX maintains a synchronous 125 ps cycl
36、e structure and multiplexes the packet and circuit switched data streams, and I-MAC provides access to circuit switched channels; 2) A Media Access Control (MAC) (IS0 9314-2), and its enhancement (MAC-2), which provides fair and deterministic access to the medium, address recognition, and generation
37、 and verification of frame check sequences. Its primary function is the delivery of packet data, including frame generation, repetition, and removal; 3) An optional Logical Link Control (LLC), which provides a common protocol for any required packet data adaptation services between MAC and the Netwo
38、rk Layer. LLC is not specified by FDDI; 4) An optional Circuit Switching Multiplexer (CS-MUX), which provides a common protocol for any required circuit data adaptation services between I-MAC and the Network Layer. CS-MUX is not specified by FDDI; c) a Station Management (SMT), which provides the co
39、ntrol necessary at the node level to manage the processes under way in the various FDDI layers such that a node may work cooperatively on a ring. SMT provides services such as control of configuration management, fault isolation and recovery, and scheduling policies. FDDI LCF-PMD is a supporting doc
40、ument to FDDI PHY and FDDI PHYP which should be read in conjunction with it. The FDDI SMT document should be read for information pertaining to supported FDDI node and network configurations. The original FDDI PMD should be read for issues relating to FDDI LCF- PMD to FDDI PMD optical interoperabili
41、ty. ISO/IEC 9314 specifies the interfaces, functions, and operations necessary to ensure interoperability between conforming FDDI implementations. This standard provides a functional description. Conforming implementations may employ any design technique that does not violate interoperability. 2 Nor
42、mative references The following standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this
43、American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid international standards. Members of IEC and IS0 maintain registers of currently valid Internati
44、onal Standards. ANSVEWTIA 455-308-l 991, Frequency domain measurement of multimode optical fiber information transmission capacity ANSI/EIA/TIA 45551A-1991, Pulse distortion measurement of multimode glass optical fiber information transmission capacity ANSI/EIA/TIA 455-53A-1990, Attenuation by subst
45、itution measurement for multimode graded-index optical fibers or fiber assemblies used in long length communications systems ANSIIEIATTIA 455-54A-1990, Mode scrambler requirements for overfilled launching conditions to multimode fibers ANSI/EIAlTIA-492AAAA-1989 Detail specific waveguide. Available f
46、rom American National Standards Institute, 11 West 42nd Street, New York, NY 10036. ANSI X3.237-l 995 3.16 fibre optic cable: A cable containing one or more optical fibres. 3.17 interchannel isolation: The ability to prevent undesired optical energy from appearing in one signal path as a result of c
47、oupling from another signal path; cross talk. 3.18 jitter: The variation in synchronization between bits in the FDDI signalling bit stream. 3.19 jitter, data dependent (DDJ): Jitter that is related to the transmitted symbol sequence. DDJ is caused by the limited bandwidth characteristics and imperfe
48、ctions in the optical channel components. DDJ results from non-ideal individual pulse responses and from variation in the average value of the encoded pulse sequence which may cause base-line wander and may change the sampling threshold level in the receiver. 3.20 jitter, duty cycle distortion (DCD)
49、: Distortion usually caused by propagation delay differences between low-to-high and high-to-low transitions. DCD is manifested as a pulse width distortion of the nominal baud time. 3.21 jitter, random (RJ): RJ is due to thermal noise and may be modeled as a Gaussian process. The peak-peak value of RJ is of a probabilistic nature and thus any specific value requires an associated probability. 3.22 LCF-MIC plug: The male part of the LCF-MIC which terminates a fibre optical cable. 3.23 LCF-MIC receptacle: The female part of the LCF-MIC which is contained in an FDDI node. 3.24 logical
