EN ISO/IEC 9314-3:1995
(Main)Information processing systems - Fibre distributed Data Interface (FDDI) - Part 3: Physical Layer Medium Dependent (PMD) (ISO/IEC 9314-3:1990)
Information processing systems - Fibre distributed Data Interface (FDDI) - Part 3: Physical Layer Medium Dependent (PMD) (ISO/IEC 9314-3:1990)
Migrated from Progress Sheet (TC Comment) (2000-07-10): First formal vote negative. Second formal vote to be launched asap.
Informationsverarbeitungssysteme - Verteilte Datenschnittstelle mit Lichtwellenleitern (FDDI) - Teil 3: Mediumspezifische Festlegungen für die Bitübertragungsschicht (PMD) (ISO/IEC 9314-3:1990)
Systèmes de traitement de l'information - Interface de données distribuées sur fibre - Partie 3: Spécification pour la couche physique déterminée par le milieu (ISO/IEC 9314-3:1990)
Information processing systems - Fibre distributed Data Interface (FDDI) - Part 3: Physical Layer Medium Dependent (PMD) (ISO/IEC 9314-3:1990)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO/IEC 9314-3:1997
01-december-1997
Information processing systems - Fibre distributed Data Interface (FDDI) - Part 3:
Physical Layer Medium Dependent (PMD) (ISO/IEC 9314-3:1990)
Information processing systems - Fibre distributed Data Interface (FDDI) - Part 3:
Physical Layer Medium Dependent (PMD) (ISO/IEC 9314-3:1990)
Informationsverarbeitungssysteme - Verteilte Datenschnittstelle mit Lichtwellenleitern
(FDDI) - Teil 3: Mediumspezifische Festlegungen für die Bitübertragungsschicht (PMD)
(ISO/IEC 9314-3:1990)
Systemes de traitement de l'information - Interface de données distribuées sur fibre -
Partie 3: Spécification pour la couche physique déterminée par le milieu (ISO/IEC 9314-
3:1990)
Ta slovenski standard je istoveten z: EN ISO/IEC 9314-3:1995
ICS:
35.100.10 )L]LþQLVORM Physical layer
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
SIST EN ISO/IEC 9314-3:1997 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO/IEC 9314-3:1997
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SIST EN ISO/IEC 9314-3:1997
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SIST EN ISO/IEC 9314-3:1997
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SIST EN ISO/IEC 9314-3:1997
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SIST EN ISO/IEC 9314-3:1997
ISO/IEC
INTERNATIONAL
9314-3
STANDARD
First edition
1990-10-15
Information processing systems - Fibre
distributed Data Interface (FDDI) -
Part 3:
Physical Layer Medium Dependent (PMD)
Reference number
ISO/IEC 9314-3 : 1990 (E)
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SIST EN ISO/IEC 9314-3:1997
ISO/IEC 9314-3 : 1990 (E)
Contents
Page
Foreword. vi
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
1 scope. 1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4 Conventions and abbreviations. . . . . . . . . . . . . . . . . . . . . 5
4.1 Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2 Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1 Ring Overview . . . . . . . . . . . . . . . . . o . . . . . . . . . . . 6
6.2 Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Services. . . . . . . a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1 PMD-to-PHY services. . . . . . . . . . . . . . . . . . . . . . . 10
6.2 PMD-to-SMT services . . . . . . . . . . . . . . . . . . . . . . 13
7 Media attachment. . . . . . . . . . . . . . . . . . . ‘ . . . . . . . . . 14
7.1 Media Interface Connector (ML) . . . . . . . . . . . . . . . 15
7.2 MIC intermateability detail. . . . . . . . . . . . . . . . . . . . 20
8 Media signal interface. . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.1 Active output interface. . . . . . . . . . . . . . . . . . . . . . 20
8.2 Active input interface. . . . . . . . . . . . . . . . , . . . . . . 22
8.3 Station bypass interface . . . . . . . . . . . . . . . . . . . . 23
0 ISO/IEC 1990
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronic or mechanical, including photocopying and microfilm, without permission in
writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
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ISOAEC 9314-3 : 1990 (E)
8.4 Station bypass timing definitions. . . l . . . . . . . . . . . 23
9 interface signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
9.1 Optical Receiver. . . . . . . . . . D . . . . . . . . . . . . . . . . 26
9.2 Optical Transmitter. . . . . . . . . . . . . . . . . . . . . . . . . 28
10 Cable Plant interface Specification 28
10.1 Cable plant specification . . . . . . . . . . . . . l l . . l l l 28
10.2 Bypassing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
10.3 Connectors and splices. . D . . . . . . . . . . . . . . . . . . 30
Tables
Table 1 Characteristics of active output interface . . . . 21
Table 2 Characteristics of active input interface. . . . . 24
Table 3 Characteristics of station bypass interface. . . 24
Table 4 Summary of assertion and deassertion
requirements. . . . . . . . . . . . . . . . . . . . . . . . 28
Table 5 Suggested fibre for a Cable plant . . . . . . . . . 29
Table 6 Bandwidth and attenuation values. . . . . . l . l . 2Q
Figures
Figure 1 FDDI links and connections. . . . . . . . . . . . l l l l 7
FDDI topology example . . . . . . . . . . . . . . . . . . 8
Figure 2
Figure 3 Dual attachment PMD services. . . . . . . . . . . . 11
Figure 4 Example of Media interface
Connector (MIC) plug. . . . . . . . . . . . . . . l . . 15
Figure 5 MIC receptacle - fibre/device. . . . . . . . . . . . 16
Figure 6 MIC receptacle - fibre/fibre . . . . . . . . . . . . . 17
Figure 7 MIC ferrule geometry. . . . . . . . . . . . . . . . . . . 18
Figure 8 Receptacle keying detail m . . . . . . . . . . . . . . . 19
Figure 9 Source spectral width and centre
wavelength requirements . . . . . . . . . . . . . . . 21
Figure 10 Pulse envelope . . . . . . . . . . . . . . . . . . . . . . . 22
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ISO/IEC 9314-3 : 1990 (E)
Figure 11 Expanded pulse envelope. . . . . . . . . . . . . . . . 23
Figure 12 Station bypass timing characteristics . . . . . . . 25
Figure 13 Signal detect thresholds and timing . . . . . . l . 27
Figure 14 Minimum dispersion wavelength and
slope limits. . . . . . . . . . . . . . . . . . . . . . . . . 30
Figure 15 Cable plant example . . . . . . . . . . . . . . . . . . . 31
Annexes
Annex A Test methods. . . . . . . . . . . . . . . . . . . . . . . . 32
A.1 Active output interface . . . . . . . . . . . . . . . . . . . 32
A.2 Active input interface . . . . . . . . . . . . . . . . . . . . 33
A.3 Distortion and jitter contributions. . . . . . l l l l l . 33
A.4 Distortion and jitter measurements. . . . . . . . . . . 34
A.5 DDJ test pattern for jitter measurements. . . . . . 35
Annex B Optical test procedures . . . . . . . . . . . . . . . . 37
Annex C Alternative cable plant usage . . . . . . . . l l l l 38
C.l Alternative fibre sizes . . . . . . . . . . . . . . . . . . . . 38
C.2 Theoretical connection losses . . . . . . . . . . . . . . 38
C.3 Optical bypass switCh8s. . . . . . . . . . . . . . . . . . 39
Table C.l Alternative fibre typ8.s. . . . . . . . . . . . . . . . . 38
Table C.2 Theoretical connection losses for
mixed fibre types. . . . . . . . . . . . . . . . . . 38
Table C.3 Summary of loss budget remaining. . l l l l l . 39
Annex D Electrical interface considerations . . . . . . . . . 40
Figure D.l Test configuration for dc-coupled
components. . . . . . . . . . . . . . . . . . . . . . . . 40
Figure D.2 Test configuration for ac-coupled
components. . . . . . . . . . . . . . . . . . . . . . . . 41
Annex E Exampie of system jitter allocation . . . . . . . . 42
E.l Jitter sources . . . . . . . . . . . . . . . . . . . . . . . . a . 42
IV
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ISOAEC 9314-3 : 1990 (E)
................. 42
E.2 Jitter calculation example
........... 43
Table E.l System jitter budget example
.................. 44
Annex F Keying considerations
....................... 44
F.l Receptacle keying
........................... 44
F.2 Plug keying.
........................ 45
F.3 Cabling systems
..... 46
Annex G Reference non-precision MIC test plug.
47
.........
Figure G.l Reference non-precision MIC plug
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SIST EN ISO/IEC 9314-3:1997
ISOAEC 9314-3 : 1990 (E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) together form a system for worldwide standardization as
a whole. National bodies that are members of IS0 or IEC participate in the develop-
ment of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. IS0 and IEC
technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with IS0 and IEC, also
take part in the work.
In the field of information technology, IS0 and IEC have established a joint technical
committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint
technical committee are circulated to national bodies for approval before their accep-
tance as International Standards. They are approved in accordance with procedures
requiring at least 75 % approval by the national bodies voting.
International Standard ISO/IEC 9314-3 was prepared by Joint Technical Committee
ISO/IEC JTC 1, Information technology.
ISO/IEC 9314-3 consists of the following parts, under the general title information pro-
cessing systems - Fibre distributed Data Interface (FDDII
- Part I: Token Ring Physical Layer Protocol (PHY)
- Part 2: Token Ring Media Access Control MAC
- Part3: Token Ring Physical Layer Medium Dependent (PMD)
Annexes A to G are for information only.
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Introduction
This part of ISOAEC 9314 on the FDDI token ring physical layer,
medium dependent is intended for use in a high-performance
multistation network. This protocol is designed to be effective
at 100 Mbit/s using a token ring architecture and fibre optics as
the transmission medium over distances of several kilometres in
extent.
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SIST EN ISO/IEC 9314-3:1997
ISO/IEC 9314-3 : 1990 (El
INTERNATIONAL STANDARD
Information processing systems - Fibre distributed Data
Interface (FDDI) -
Part 3:
Physical Layer Medium Dependent (PMD)
1 scope
PMD) requirements for
This part of ISO/IEC 9314 specifies Physical Layer, Medium Dependent
the Fibre Distributed Data Interface (FDDI).
high-bandwidth (100 Mbit/s) general-purpose interconnection among
The FDDI provides a
The FDDI
computers and peripheral equipment using fibre optics as the transmission medium.
may be configured to support a sustained transfer rate of approximately 80 Mbit/s (10
Mbyte/s). It may not meet the response time requirements of all unbuffered high-speed
devices. The FDDI establishes the connection among many FDDI nodes (stations) distributed
over distances of several kilometres in extent. Default values for FDDI were calculated on
the basis of 1 000 physical connections and a total fibre path length of 200 km.
The FDDI consists of
(a) A Physical Layer (PL) which is divided into two sublayers:
(1) A Physical Layer, Medium Dependent (PMD), which provides the digital baseband
point-to-point communication between nodes in the FDDI network. PMD shall provide
all services necessary to transport a suitably coded digital bit stream from node to
node.
PMD specifies the point of interconnection requirements for conforming FDDI
stations and cable plants at both sides of the Media Interface Connector (MIC). PMD
includes the following:
I
The optical power budgets for cable plants using 62,5/125 pm fibre optic
cables and optical bypass switches.
I
The MIC receptacle mechanical mating requirements including the keying
features.
I
The 62,5/125 pm fibre optic cable requirements.
-
The services provided by PMD to PHY and SMT.
(2) A Physical Layer Protocol (PHY), which provides connection between PMD and
the Data Link Layer (DLL). PHY establishes clock synchronization with the upstream
code-bit data stream 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 clocks, and the
delineation of octet boundaries as required for the transmission of information to or
1
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ISO/IEC 9314-3 : 1990 (E)
from higher layers. Information to be transmitted on the interface medium is encoded
by the PHY into a grouped transmission code.
(b) A Data Link L ayer (DLL), which controls the accessing of the medium and the
generation and verification of frame check sequences to ensure the proper delivery of
valid data to the other layers. DLL also concerns itself with the generation and
within the FDDI
recognition of device addresses and the peer-to-peer associations
network.
For the purposes of this part of ISOAEC 9314, references to DLL are made in
terms of the Media Access Control (MAC) entity, which is the lowest sublayer of DLL.
(C) A Station Management (SMT)‘) which provides the control necessary at the node level
to manage the processes underway in the various FDDI layers such that a node may work
co-operatively on a ring. SMT provides services such as control of configuration
management, fault isolation and recovery, and scheduling procedures.
This part of ISO/IEC 9314 is a supporting document to ISO/IEC 9314-I which should be read
in conjunction with it.
The SMT document should be consulted for information pertaining to supported FDDI node and
network configurations.
ISO/IEC 9314 specifies the interfaces, functions, and operations necessary to insure
interoperability between conforming FDDI implementations. This part of ISO/IEC 9314 is a
functional description. Conforming implementations may employ any design technique which does
not violate interoperability.
.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this part of ISO/IEC 9314. At the time of publication, the editions indicated
were valid. All standards are subject to revision, and parties to agreements based on this
part of ISOAEC 9314 are encouraged to investigate the possibility of applying the most recent
editions of the standards listed below. Members of IEC and IS0 maintain registers of
currently valid International Standards.
IS0 9314-l: 1989, information processing systems - Fibre Distributed Data interface (FDDl) -
Part t Token Ring Physical Layer Protocol (PHY).
IS0 9314-2: 1989, Information processing systems - Fibre Distributed Data Interface (FDDI) -
Part 2: Token Ring Media Access Control (MAC).
3 Definitions
For the purposes of this part of ISOIIEC 9314, the following definitions apply. Other parts of
lSO/lEC 9314, e.g., MAC and PHY, may contain additional definitions of interest.
3.1 attenuation: Level of optical power loss, expressed in decibels.
3.2 average power: The optical power measured using an average reading power meter when
the FDDI station is transmitting a stream of Halt symbols.
‘1 SW will form the subject of a future part of ISOAEC 9314.
2
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ISO/IEC 9314-3 : 1990 (E)
3.3 bypass: The ability of a station to isolate itself optically from the FDDI network while
maintaining the continuity of the cable plant.
3.4 centre wavelength: The average of the two wavelengths measured at the half amplitude
points of the power spectrum.
3.5 code bit: The smallest signalling element used by the Physical Layer for transmission on
the medium.
3.6 concentrator: An FDDI node that has additional PHY/PMD entities beyond those required
for its own attachment to an FDDI network. These additional PHY/PMD entities are for the
attachment of other FDDI nodes (including other concentrators) in a tree topology.
3.7 connector plug: A device used to terminate an optical conductor(s) cable.
3.8 connector receptacle: The fixed or stationary half of a connection that is mounted on a
panel/bulkhead. Receptacles mate with plugs.
3.9 counter-rotating: An arrangement whereby two signal paths, one in each direction, exist in
a ring topology.
A concentrator that offers two attachments to the FDDI
3.10 dual attachment concentrator:
network which are capable of accommodating a dual (counter-rotating) ring.
3.11 dual attachment station: A station that offers two attachments to the FDDI network
which are capable of accommodating a dual (counter-rotating) ring.
3.12 dual ring (FDDI dual ring): A pair of counter-rotating logical rings.
3.13 entity: An active service or management element within an Open Systems Interconnection
(OSI) layer, or sublayer.
3.14 extinction ratio: The ratio of the low, or off optical power level (PL) to the high, or on
optical power level (PH) when the station is transmitting a stream of Halt symbols.
Extinction ratio (%) = (P~1Pr-r) x 100
3.15 fibre: Dielectric material that guides light; waveguide.
3.16 fibre optic cable: A cable containing one or more optica I fibres.
3.17 Interchannel isolation: The ability to prevent undesired optical energy from appearing in
one signal path as a result of coupling from another signal path; cross talk.
Jitter that is related to the transmitted symbol sequence.
3.18 jitter, data dependent (DDJ):
DDJ is caused by the limited bandwidth characteristics and imperfections 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.
3.19 jitter, duty cycle distortion (DCD): 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.
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3.20 jitter, random (RJ):
RJ is due to thermal noise and may be modelled as a Gaussian
process. The peak-peak value of RJ is of a probabilistic nature and thus any specific value
requires an associated probability.
3.21 loglcal ring: The set of MACs serially connected to form a single ring.
3.22 media Interface connector (MIC): A mated connector pair that provides an attachment
The MIC consists of two parts; a MC
between an FDDI node and a fibre optic cable plant.
plug and a MIC receptacle.
3.23 MIC plug: The male part of the MIC which terminates a fibre optical cable.
3.24 MIC receptacle: The female part of the MIC which is contained in an FDDI node.
3.26 network (FDDI network): A collection of FDDI nodes interconnected to form a trunk, or
a tree, or a trunk with multiple trees. This topology is sometimes called a dual ring of trees.
3.26 node: A generic term applying to any FDDI ring attachment (station or concentrator).
3.27 numerical aperture (NA): The sine of the radiation or acceptance half angle of an
optical fibre, multiplied by the refractive index of the material in contact with the exit or
entrance face.
3.28 optical fall time: The time interval for the falling edge of an optical pulse to transition
from 90 % to 10 % of the pulse amplitude.
The plane that defines the optical boundary between the MlC
3.29 optical reference plane:
Plug and the MIC Receptacle.
3.30 optical rise time: The time interval for the rising edge of an optical pulse to transition
from 10 % to 90 % of the pulse amplitude.
3.31 physical connectlon: The full-duplex physical layer association between adjacent PHY
entities (in concentrators or stations) in an FDDI network, i.e., a pair of Physical Links.
3.32 physical link: The simplex path (via PMD and attached medium) from the transmit
function of one PHY entity to the receive function of an adjacent PHY entity (in concentrators
or stations) in an FDDI network.
3.33 primitive: An element of the services provided by one entity to another.
3.34 receiver (optical): An opto-electronic circuit that converts an optical signal to an
electrical logic signal.
3.36 ring: A set of stations wherein information is passed sequentially between stations, each
station in turn examining or copying the information, finally returning it to the originating station.
In FDDI usage, the term “ring” or ‘FDDI ring” refers to the a dual (counter-rotating) ring.
3.36 services: The services provided by one entity to another. Data services are provided
to a higher layer entity; management services are provided to a management entity in the
same or another layer.
A concentrator that offers one attachment to the FDDI
3.37 single attachment concentrator:
network.
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ISO/IEC 9314-3 : 1990 (E)
3.38 single attachment station: A station that offers one attachment to the FDDI network
The absolute difference between the
3.39 spectral width, full width half maxlmum (FWHM):
wavelengths at which the spectral radiant intensity is 50,O % of the maximum power.
3.40 statlon: An addressable node on an FDDI network capable of transmitting, repeating, and
receiving information. A station has exactly one SMT and at least one MAC, one PHY, and
one PMD.
An opto-electronic circuit that converts an electrical logic signal to
3.41 transmltter (optical):
an optical signal.
3.42 trunk: A physical loop topology, either open or closed, employing two optical fibre signal
paths, one in each direction (i.e., counter-rotating), forming a sequence of peer connections
between FDDI nodes. When the trunk forms a closed loop it is sometimes called a trunk ring.
3.43 tree: A physical topology consisting of a hierarchy of master-slave connections between
a concentrator and other FDDI nodes (including subordinate concentrators).
4 Conventions and abbreviations
4.1 Conventlons
The terms SMT, MAC, PHY, and PMD, when used without modifiers, refer specifically to the
local instances 0 If these entities.
control,-action) are used as a convenience to mark the name of signals,
Low lines (e.g.,
functions, and the like, which might otherwise be misinterpreted as independent individual words
if they were to appear in text.
The use of a period (e.g., PM,UNITDATA.request) is equivalent to the use of low lines except
that a period is used as an aid to distinguish modifier words appended to an antecedent
expression.
The use of a colon (e.g., N:PM-UNITDATA.request) distinguishes between two or more instances
of the same signal where N designates the other source/destination entity.
4.2 Abbreviations
All Active Input Interface
Active Output Interface
AOI
ANS-Max Maximum acquisition time (no signal)
AS-Max Maximum acquisition time (signal)
BER Bit Error Rate
BERT Bit Error Rate Tester
Duty Cycle Distortion (jitter)
DCD
DDJ Data Dependent Jitter
FOTP Fibre Optic Test Procedure
FWHM Full Width Half Maximum
Maximum switching insertion/deinsertion time
I-Max
LS-Max Maximum line state change time
MIC Media Interface Connector
MI-Max Maximum media interruption time
NA Numerical Aperture
NRZI Non Return to Zero, Invert on ones
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ISO/IEC 9314-3 : 1990 (E)
RJ Random Jitter
SAE Static Alignment Error (clock offset error)
Difference delay time
l-00
Media interruption time
-hAI
Optical switching speed
Tos
Switching insertion/deinsertion time
TSI
5 General description
6.1 Ring Overview
A ring consists of a set of stations logically connected as a serial string of stations and
transmission media to form a closed loop. Information is transmitted sequentially, as a stream
of suitably encoded symbols, from one station to the next. Each station generally regenerates
and repeats each symbol and serves as the means for attaching one or more devices to the
ring for the purpose of communicating with other devices on the ring.
The method of actual
physical attachment to the FDDI ring may vary and is dependent on specific application
requirements as described in subsequent paragraphs.
The basic building block of an FDDI ring is a physical connection as shown in figure 1. A
physical connection consists of the Physical Layers (each composed of a PMD and a PHY
entity) of two stations that are connected over the transmission medium by a Primary Link and
a Secondary Link. A Primary Link consists of an output, called Primary Out, of a Physical
Layer, communicating over a Primary medium to the input, called Primary In, of a second
Physical Layer. The Secondary Link consists of the output, called Secondary Out, of the
second Physical Layer communicating over a Secondary medium to the input, called Secondary
In, of the first Physical Layer. Physical connections may be subsequently logically connected
within stations, via attached MACs or other means, to create the network. As such, the
function of each station is implementer-defined and is determined by the specific application or
site requirements.
TWO classes of stations are defined: dual (attachment) and single (attachment). FDDI trunk
rings may be composed only of dual attachment stations which have two PMD entities (and
associated PHY entities) to accommodate the dual ring. Concentrators provide additional PMD
entities beyond those required for their own attachment to the FDDI network, for the
attachment of single attachment stations which have only one PMD and thus cannot directly
attach to the FDDI trunk ring.
A dual attachment station, or one-half of it, may be substituted
for a single attachment station in attaching to a concentrator. The FDDI network consists of
all attached stations.
The example of figure 2 shows the concept of multiple physical connections used to create
logical rings. As shown, the logical sequence of MAC connections is stations 1, 3, 5, 8, 9, 10,
and 11. Stations 2, 3, 4, and 6 form an FDDI trunk ring. Stations 1, 5, 7, 10, and 11 are
attached to this ring by lobes branching out from the stations that form it. Stations 8 and 9
are in turn attached by lobes branching out from station 7. Stations 2, 4, 6, and 7 are
concentrators, serving as the means for attaching multiple stations to the FDDI ring.
Concentrators may or may not have MAC entities and stai
tion functionality. The concentrator
examples of figure 2 do not show any MACs although
their presence is implied by the
designation of these concentrators as stations.
Connection to the physical medium as established by PMD i:
s controlled by the station insertion
and removal algorithms of Station Management (SMT) which
are beyond the scope of this part
of ISO/IEC 9314.
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SIST EN ISO/IEC 9314-3:1997
HYSICAL CONNECTION
t-
PHYSICAL LINK
. , \
PHJNITDATA.request PHJNITDATA.indication
,
OUT
PHY
PHY PMD PMD
Optical
PHJNITDATA.request
PHJNITDATA.indication
urn
a
,0UT14 ‘i-----i=
-- I-
I I
I
STATION M STATION N
-----II------------------- ---m-w----- L -------s-w- ------------------------
_I
i
t
IF PHYSICAL LINK ,
-
cf)
0
\
m
0
Figure 1 - FDDI links and connections
---------------------- Page: 21 ----------------------
SIST EN ISO/IEC 9314-3:1997
ISO/IEC 9314-3 : 1990 (E)
STATION 5
SINGLE
STATION 3 STATION 4
MAC G
DUAL CONCENTRATOR
I
I 1 I I
D E F I
- I
A
I
STATION 6
CONCENTRATOR
-J
STATION 9
SINGLE
I 4
STATION 7
STATION 2 I-,
MAC L
CONCENTRATOR
NCENTRATOR
co
I
w---II
I I1
M
P 0
v
.
N
1
MAC
MAC
*
STATION 11 STATION 10 STATION 8
STATION 1
SINGLE
SINGLE SINGLE SINGLE
Figure 2 - FDDI topology example
---------------------- Page: 22 ----------------------
SIST EN ISO/IEC 9314-3:1997
ISO/IEC 9314-3 : 1990 (E)
6.2 Environment
As shown in figure 2 and as described 5.1, an FDDI network consists of a virtually unlimited
number of connected stations. SMT establishes the physical connections between stations, and
the correct internal station configurations, to create an FDDI network.
it is understood that restrictions of the transmission media as defined (i.ea, dynamic range and
bandwidth) may place limits on realizable physical configurations. Trade-offs may be made
within specific site applications, such as distance versus optical bypassing, consistent with
these limitations. While not intended to be limiting, the FDDI has been defined to serve three
major application environments including:
6.2.1 Data centre environment
The data centre environment is characterized by a relatively few number of stations, typically
mainframe computers and peripheral equipment, where a high degree of reliability and fault
tolerance is required. The FDDI network in a data centre environment is often typically
comprised of a preponderance of dual stations with relatively few, if any, concentrators. In
this environment, it is desirable that two stations maintain unimpaired operation even under the
circumstance where up to four intervening stations are powered down, thereby causing their
optical bypass switches to be in the active connection path between the communicating
stati
...
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