ISO 8802-3:1989

INTER NATIONAL
IS0
STANDARD
ANSVIEEE
Std 802.3
First edition
1989-02-24
Information processing systems -
Local area networks -
Part 3 :
Carrier sense multiple access with collision
detection (CSMA/CD) access method and
physical layer specifications
Systèmes de traitement de I’information - Réseaux locaux -
Partie 3 : Accès muIt&ie par surveillance du signal et détection de collision et
spécifications pour la couche physique
Reference number
IS0 8802-3 : 1989 (E)
ANSIIIEEE
Std 802.3-1 988
First Printing
ISBN 1-55937-005-X
Library of Congress Catalog Card Number 88-046183
Copyright 1989 by
The Institute of Electrid and Electronics Engineers, Inc
345 East 47th Street, New York, NY 10017, USA
No part of this publication may be reproduced in any form,
in an electronic retrieval system or otherwise,
without the prior written permission of the publisher.
SH11726
February 24,1989
Information processing systems-
Local area networks-
Part 3:
Carrier sense multiple access with
collision detection (CSMNCD)
access method and
physical layer specifications
Sponsor
Technical Committee on Computer Communications
od‘the
IEEXcOmputerSaciety
Approved June 9,1988 (ANSIIIEEE Std 802.3-1988)
Approved October 20,1988 (ANSMEEE Std 802.3a-1988)
lEEEStanW-
Approved January 12,1989
American Nationai Standards Institute
Approved 1988 by the
International organization for Standardization
n
I
8802-3 : 1989
zation for Standardizati is a worldwide
bodies (IS0 member bodies). The work of
s is normally carried out through IS0 tech-
ber body interested in a subject for which a tech-
nical committee has been established has the right to be represented on that
committee. Internation
mental, in liaison with I
closely with the Interna
matters of electrotechnic
Draft Intern
culated to the
tional Standards by the IS0 Council. They are approved in accordance with
IS0 procedures requiring at least 75% approval by the member bodies voting.
1985, ANSVIEEE Std 802.3-1985 was adopted by IS0 Technical Committee
In
97, Information processing systems, as draft International Standard ISO/DIS
8802-3. Following the proc described above, the ard was subse-
of this new edition, is published as
also includes IS0 8802-
ANSUIEEE SM 802.3a-
For the purpose of assigning global addresses, the Institute of
Electronics Engineers, Inc., USA, has been designated by the I
the Registration Authority. Communications on this subject
ation Authority for IS0 88023
c/o The Institute of Electrical and Electro
445 Hoes Lane
PO Box 1331
Piscataway, NJ 08855-133
USA
During the preparation of this Internation tandard, information was
gathered on patents upon which application e standard might depend.
Relevant patents were ide belonging to Xerox Corporation. However,
mprehensive information about evidence,
rights. The patent-holder has stated that
easonable terms and conditions and com-
munications on this subject be addressed to
P.O. Box 1600
ford, CT 06904
I
-1 1
International Organization for Standardization
Case postale 56 CH-1211 Genève 20 * Switzerland
i
Fomordto IntermtiodSt;andairdISo 88023 : 1989
This standard is part of a family of standards for Local Area Networks
(LANs). The relationship between this standard and the other members of the
family is shown below. (The numbers in the figure refer to IS0 Standard
mbers.)
IS0 8802-2 [ANSVII
used in conjunction with the medium access standaras.
The reader of this document is urged to become familiar wit11
w~~~~~~~~
The main body of this standard serves fo
Oth the ISO 8802-3 : 1989 and
ANSVIEEE 802.3-1988 standards. IS0 and IEEE each have unique foreword
sections. The Annex applies to the IEEE standard only. The Appendices serve
as useful reference material to both standards.

ANSYIEEE std m3-1988
lyl
IEEE Standards documents are developed within the Technical Committees
of the IEEE Societies and the Standards Coordinating Committees of the IEEE
..
Standards Board. Members of the committees serve voluntarily and without
compensation. They are not necessarily members of the Institute. The stan-
dards developed within IEEE represent a consensus of the broad expertise on the
subject within the Institute as well as those activities outside of IEEE which have
expressed an interest in participating in the development of the standard.
Use of an IEEE Standard is wholly voluntary. The existence of an IEEE
Standard does not imply that there are no other ways to produce, test, measure,
purchase, market, or provide other goods and services related to the scope of the
IEEE Standard. Furthermore, the viewpoint expressed at the time a standard is
approved and issued is subject to change brought about through developments in
the state of the art and comments received from users of the standard. Every
IEEE Standard is subjected to review at least once every five years for revision
or reaffirmation. When a document is more than five years old, and has not
been reaffirmed, it is reasonable to conclude that its contents, although still of
some value, do not wholly reflect the present state of the art. Users are cautioned
to check to determine that they have the latest edition of any IEEE Standard.
Comments for revision of IEEE Standards are welcome from any interested
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changes in documents should be in the form of a proposed change of text, to-
gether with appropriate supporting comments.
Interpretations: Occasionally questions may arise regarding the meaning of
portions of standards as they relate to specific applications. When the need for
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tion to prepare appropriate responses. Since IEEE Standards represent a con-
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pretation has also received the concurrence of a balance of interests. For this
reason IEEE and the members of its technical committees are not able to provide
an instant response to interpretation requests except in those cases where the
matter has previously received formal consideration.
Comments on standards and requests for interpretations should be addressed
to:
Secretary, IEEE Standards Board
345 East 47th Street
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IEEE Standards documents are adopted by the Institute of Electrical and
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any liability to any patent owner, nor does it assume any obligation whatever to
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lparties adopting the standards documents.

Foreword to ANSUIEXE Std 8û2.%1988
(EditoriaiRevisionof ANSWEEE Stü8û.28-198ti and
e. ANSI/iEEE Std ûû2Sa-1988)
("his Foreword is not a part of IS0 8802-3 : 1989 or of ANSïAEEE Std 802.3-1988.)
This standard is part of a family of standards for Local Area Networks
(LANs). The relationship between this standard and other members of the
family is shown below. (The numbers in the figure refer to IEEE standard
numbers.)
I
I
802.1
I
I i
1 DATA LINK LAYER
802.2
802.4 I 1802.5 I PHYSICAL LAYER
This family of standards deals with the Physical and Data Link Layers a8
defined by the IS0 Open Systems Interconnection Reference Model. The ac-
cess standards define three types of medium access technologies and associ-
or system
ated physical media, each appropriate for particular applications
objectives. The standards defining these technologies are:
(1) ANSIAEEE Std 802.3-1988 [IS0 8802-31, a bus utilizing CSWCD as the
access method,
(2) ANSUIEEE Std 802.4-1985 [IS0 8802-43, a bus utilizing token passing as
O
the access method,
(3) ANSIAEEE Std 802.5-1985 CIS0 8802-51, a ring utilizing token passing as
the access method.
ANSIAEEE SM 802.2-1985 [IS0 8802-21, the Logical Link Control standard,
is used in conjunction with the medium access standards.
IEEE P802.1 describes the relationship among these standards and their re-
lationship to the IS0 Open Systems Interconnection Reference Model in more
detail. This companion document also will contain networking management
standards and information on internetworking. The reader of this standard
is urged to become familiar with the complete family of standards.
The local area network access mechanism specified by this standard may

rk access mechanism
m
O position with re-
d implementation
t is anticipated tha 8
of revisions should con
the following membership I
f
l
e
the development of this standard
Individuals who contributed actively in
roughout its elaboration were
Dean Lindsa Mark Townsend
Juan Bulnes
Roger Van Brunt
Ron Crane Then. T. Liu
h
Robert Moles Bo Vicklund
Dane Elliot
Chris Wargo
Alan Flatman Tony Lauck
Richard William
Joseph St. Amand
Maris Graube
Richard Seifert Ron Yara
Nathan Tobol
TC24 Committee on Communication Protocols also provided
helpful input in the development of this standard.
The IEEE 802.3 Working Group acknowledges and appreciates that many
concepts embodied in this standard are based largely upon the CSMNCD
access method earlier described in The Ethernet specification as written
jointly viduals from Xerox Corporation, Digital Equipment
Corpora Intel Corporation. Appreciation is also expressed to Robert
M. Metcalfe and David R. Boggs for their pioneering work in establishing the
original concepts.
When the IEEE 802.3 Working Group approved ANSYIEEE Std 802.3a-1988
I (Section 10) in November 1984, it had the following membership:
Don Lou&, Chairman
Alan Flatman, Chairman, Type 10BASE2 Task Force
Joseph Rickert
Menachem Abraham Guy Harkins
Gary Robinson
R.V. Balakriehnan Greg Hopkins
Robert Rosenthal
William Belkiiap Joe Kennedy
Joseph St. Amand
Charles Brill Hiroshi Kobayashi
Walter Schreuer
Juan Bulnes Tony Lauck
Stephen Soto
Stephen Cooper William Livingston
Gary Spencer
Ronald Crane Hugh Logan
Robert Summers
John Davidson Leland Long
Pat Thaler
Mark Devon Andy Lugue
Daniel Maltbie Geoff Thompson
Phil Edholm
Wendell Turner
Gregory Emis Steven Moustakas
David White
Wendell Nakamine
Judy Estrin
Lawrence White
Richard Fransen Lloyd Oliver
Rich Williams
Ingrid Fromm Aidan Paul
Ronald Yara
David Potter
Robert Galin
Eugene Reilly Mo Zonoun
Rich Graham
I
,
The following persons were on the balloting committee that approved
ANSI/IEEE Std 802.3-1985 for submission to the IEEE Standards Board:
W. Adams
R. Harrington
C. Ostereicher
R. Appleby
H. Heilborn
M. Palpa
r<
G. Arnold
L. Heeelton
S. Peter
Y. Baeg
D. Hislop
D. Phiioc
E. Beauregard
C. Hobbs
T. Phinney
J. Becker
S. Hollander
G. Power
E. Bergaimini
P. Hutton
A. Retldi
Boorstyn
P. Induiago
M. Repko
A. Carrato
T. Ishida
F. Restivo
G. Carson
J. Jelemenshy
L. Rich
S. Chakradarti
O. Kahn
D. Rine
S. Chandra
S. Kak
R. Rosenthal
F. Chang
K. Katzeff
P. Ruoisadri
C. Chao
C. Kessler
S. Sanioylenko
C. Chen
D. Kirschen
B. Saslhi
P. Chen
R. Kolm
A. Sauler 8
K. Chon
T. Kuki
N. Schuieidewind
R. Chow
R. Kunkel
O. Serlin
G. Clinque
W. Lai
D. Shqpard
I. Cotton
V. Lasker
D. Slojrer
D. Cox
N. Lau
H. Solomon
R. DeJardins
R. Laughlin
G. Stephens
D. Dickel
F. Lim
C. Stillebroer
C. Eldridge
T. Liu
K. Suniner
P. Enslow
J. Loo
E. Sykiss
J. Fendirch
K. Loughner
A. Tantawi
M. Figuerea
D. Loughry
D. Tether
D. Fisher
T. Louhenkillbi
J. Tourret
J. Fletcher
D. Manchester
K. Tu
W. Franta
M. Marco
D. Umbaugh
R. Gagliano
D. Matters
J. Vorhies
D. Gan
D. McInode
A. Weissberger
M. Graube
D. Michels
W. Wenker
M. Greene
L. Moraes
T. Wicklund
R. Gustin
D. Morriss
T. Wolf
K. Harbaugh
J. Murayama
F. Wolff
0. Harkins
R. Nelson
R. Youif
D. Ofsevit
The following persons were on the balloting committee that approved
ANSUIEEE Std 802.3a-1988 for submission to the IEEE Standards Board:
Marco Meli
Keith W. Harbaugh
Marshall Abram
David S. Millman
S.M. Harris
John Adams
Aditya N. Mishra
William B. Adams J. Scott Haugdahl
Richard J. Moff
Sharon Healy
S.R. Ahuja
David E. Morgan
C.W. Hobbs
Kit Athul
Mike Morganti
Jim P. Hong
William Ayen
Kiqji Mori
Paul L. Hutton
Yong-Myung Baeg
D.J. Morris
Richard Iliff
Wesley A. Ballenger, Jr
H.T. Mouftah
Edwardo W. Bergamini George D. Jelatis
Dale A. Murray
Guy Juanole
Henk F. Boley
Ruth Nelson
Siegel L. Junker
Betty Brannick
J. Duane Northcutt
Karl H. Kellermayr
George S. Carson
Charles Ostereicher
Mladen Kezunovic
Po Chen
David Ofsevit
Samuel Kho
L. Y. Cheung
Young Oh
David Kollm
Kilnam Chon
George Parowski
Sastri L. Kota
T. Ricky Chow
Thomas L. Phinney
Hirayr M. Kudyan
David Cohen
Nikitas Pimopoulos
Takahiko Kuki
Allen F. Conrad
David Potter
Lee LaBarre L
Ira W. Cotton
John Potvcek
Wai-Sum Lat
Robert S. Crowder
Gary S. Robinson
Valerie Lasker
Michel Diaz
Marya Repko
Lanse M. Leach
Mitchell 0. Duncan
Robert Rosenthd
Edward YS. Lee
Philip H. Endow, Jr
Gian Paolo Rossi
Stephen E. Levin
Judith Estrin
David J. Rypka
F.C. Lim
John W. Fendrich
S.I. Samoylenko
A. Freeman Don C. Loughry
Harvey
Norman F. Schneidewind
Joseph F.P. Luhukay
Patrick Gonia
Oscar Sepulveda
Wo-Shun Luk
Ambuj Goyal
Serlin
Omri
Marco Marsan
Michael D. Graebner
D. Sheppard
Joseph Massi
Maris Graube
R.M. Simmons
Darrell B. McIndoe
Nobuhiro Hamada
David W. Sloyer
Patrick S. McIntosh
Joseph L. Hammond
When the IEEE Standards Board approved this standard on June 9,1988, it
had the following membership:
Marco Migliar0,Vice Chairman
Donald C. Fleckenstein, Chairman
Andrew G. Salem, Secretary
L. Bruce McClung
John W. Horch
Arthur A. Blaisdell
Donald T. Michael*
Jack M. Kinn
Fletcher J. Buckley
Richard E. Moaher
Frank D. Kirschner
James M. Daly
L. John Rankine
Frank C. Kitzantides
Stephen R. Dillon
Gary S. Robinson
Joseph L, Koepfmger*
Eugene P. Fogarty
Frank L. Rose
Jay Forster* Irving Kolodny
Helen M. Wood
L. Hannan Edward Lohee
Thomas
Karl H. Zaininger
John E. May, Jr.
Kenneth D. Hen&
Donald W. Zipse
Lawrence V. McCall
Theodore W. Hissey, Jr.
*Member emeritus
confents
PAGE
...................................................................
1.1 Overview 17
1.1.1 Basic Concepts . 17
1.1.2 Architectural Perspectives . 17
..................................................
1 J.3 Layer Interfaces 19
1.1.4 Application Areas . 19
1.2 Notation . 20
State Diagram Conventions . 20
1.2.1
Service Specification Method and Notation . 21
1.2.2
Physical Layer and Media Notation . 22
1.2.3
Physical Layer Message Notation . 22
1.2.4
.................................................................
1.3 References 22
1.4 Definitions . 23
-2.2.1 General Description of Services Provided by the Layer . 25
2.2.2 Model Used for the Service Specification . 26
2.2.3 Overview of Interactions . 26
01 Frame Structure . 29
MAC Frame Format . 29
3.1.1
3.2 Elements of the MAC Frame . 30
.......................................................
3.2.6 Length Field 32
Data and PAD Fields . 32
3.2.7
Frame Check Sequence Field . 32
3.2.8
3.3 Order of Bit Transmission .
4.1 Functional Model of the Media Access Control Method . 35
4.1.1 Overview . 35
4.1.2 CSMMCD Operation .
Relationships to LLC Sublayer and Physical Layer . 38
4.1.3
CSMMCD Access Method Functional Capabilities. . 38
4.1.4
.
SECTION PAGE
4.2 CSMNCD Media Access Control Method (MAC): Precise
Specification . 40
4.2.1 Introduction . 40
4.2.2 Overview of the Procedural Model . 40
4.2.3 Frame Transmission Model . 43
4.2.4 Frame Reception Model . 47
4.2.5 Preamble Generation . 48
4.2.6 Start Frame Sequence . 49
4.2.7 Global Declarations . 49
4.2.8 Frame Transmission . 52
4.2.9 Frame Reception . 57
4.2.10 Common Procedures . 60
4.3 Interfaces to/from Adjacent Layers . 60
4.3.1 Overview . 60
Services Provided by the MAC Sublayer . 60
4.3.2
Services Required from the Physical Layer . 61
4.3.3
4.4 Specific Implementations . 63
4.4.1 Compatibility Overview . 63
4.4.2 Allowable Implementations . 63
Network Management .
5 .
PLS Service Specifications.,. . 67
6 .
6.1 Scope and Field of Application . 67
6.2 Overview of the Service . 67
6.2.1 General Description of Services Provided by the Layer . 67
6.2.2 Model Used for the Service Specification . 67
6.2.3 Overview of Interactions . 67
6.2.4 Basic Services and Options . 67
Detailed Service Specification . 68
6.3
6.3.1 Peer-to-Peer Service Primitives . 68
6.3.2 Sublayer-to-Sublayer Service Primitives . 68
7 . Physical Signaling (PLS) and Attachment Unit Interface
(AUI) Specifications . 71
7.1 Scope . 7l
7.1.1 Definitions . 72
7.1.2 Summary of Major Concepts . 72
7.1.3 Application . 73
7.1.4 Modes of Operation . 73
7.1.5 Allocation of Function . 73
7.2 Functional Specification . 73
7.2.1 PLS-PMA (DTE-MAU) Interkace Protocol . 73
7.2.2 PLS Interface to MAC and Management Entities . 80
7.2.3 Frame Structure .
7.2.4 PLS Functions . 83
7.3 Signal Characteristics . û6
7.3.1 Signal Encoding . û6

PAGE
SECTION
7.3.2 Signaling Rate . 91
7.3.3 Signaling Levels . 91
7.4 Electrical Characteristics . 9l
7.4.1 Driver Characteristics . 92
7.4.2 Receiver Characteristics . 95
7.4.3 AU1 Cable Characteristics . 97
Functional Description of Interface Circuits . 99
7.5
7.5.1 General . 99
7.5.2 Definition of Interchange Circuits . 100
7.6 Mechanical Characteristics . 103
7.6.1 Definition of Mechanical Interface . 103
7.6.2 Line Interface Connector . 103
7.6.3 Contact Assignments . 104
8 . Medium Attachment Unit and Baseband Medium Specifications,
...................................................................
Type 10BASE5 107
8.1 Scope . 107
8.1.1 Overview . 107
8.1.2 Definitions . 108
Application Perspective: MAU and MEDIUM Objectives . 109
8.1.3
MAU Functional Specifications., . 110
8.2
MAU Physical Layer Functions . 111
8.2.1
MAU Interface Messages . 114
8.2.2
8.2.3 MAU State Diagrams . 115
8.3 MAU-Medium Electrical Characteristics . 116
8.3.1 MAU-to-Coaxial Cable Interface . 116
MAU Electrical Characteristics . 121
8.3.2
8.3.3 MAU-DTE Electrical Characteristics . 122
MAU-DTE Mechanical Connection . 122
8.3.4
Characteristics of the Coaxial Cable . 122
8.4
Coaxial Cable Electrical Parameters . 122
8.4.1
Coaxial Cable Properties . 123
8.4.2
8.4.3 Total Segment DC Loop Resistance . 125
0 Coaxial Trunk Cable Connectors . 125
8.5
..........................
8.5.1 Inline Coaxial Extension Connector 125
8.5.2 Coaxial Cable Terminator . 125
8.5.3 MAU-to-Coaxial Cable Connector . 126
8.6 System Considerations . 127
8.6.1 Transmission System Model . 127
8.6.2 Transmission System Requirements . 129
8.6.3 Labeling . 132
8.7 Environmental Specifications . 132
8.7.1 General Safety Requirements . 132
8.7.2 Network Safety Requirements . 133
8.7.3 Electromagnetic Environment . 134
8.7.4 Temperature and Humidity . 135

PAGE
8.7.5 Regulatory Requirements .
9. Repeater Unit .
9.1 Repeater Set and Repeater Unit Specification
9.1.1 Basic Repeater Set Configuration. .
9.1.2 Data Propagation .
Collision Detection and Jam Generat
9.1.3
9.1.4 Test Functions .
Repeater Unit State Diagram Input and Output Definitions . 140
9.2
10. Medium Attachment Unit and Baseband Med
Type 10BASE2 .
10.1 Scope .
...........................
10.1.1 Overview
10.1.2 Definitions .
10.1.3 Application Perspective: MAU and Medium Olbjectives . .la
10.2 References . .146
10.3 MAU Functional Specfications. . .146
10.3.1 MAU Physical Layer Functional Requirements. . .147
10.3.2 MAU Interface Messages. . .150
10.3.3 MAU State Diagrams . . 1%
10.4 MAU-Medium Electrical Charac .
10.4.1 MAU-to-Coaxial Cable Inter . .IS
10.4.2 MAU Electrical Characteristics . .155
10.4.3 MAU-DTE Electrical Characteristics . 156
10.5 Characteristics of Coaxial Cable System. . .156
10.5.1 Coaxial Cable Electrical Parameters . .156
10.5.2 Coaxial Cable Physical Parameters .
10.5.3 Total Segment DC Loop Resistance. .
Coaxial Trunk Cable Connectors .
10.6.1 In-Line Coaxial Extension Connector .
10.6.2 Coaxial Cable Terminator .
10.6.3 MAU-to-Coaxial Cable Connection. .
10.7 System Considerations. .
10.7.1 Transmission System Model . .1
10.7.2 Transmission System Requirements .
10.8 Environmental Specifications .
10.8.1 Safety Requirements .
etic Environment .
equirements . .165
cations, Type 10B
........................... ................... .I67
12. Baseband Medium Spec
FIGURES
Figl-1 LAN Standar nship to the OS1 Reference M[odel. 18
Fig 1-2 State Dia Example. . ,.a

PAGE
Fig 1-3 Service Primitive Notation . !Z2
Fig 2-1 Service Specification Relation to the LAN Model . 25
Fig 3-1 MAC Frame Format . 29
Fig 3-2 Address Field Format . 30
dia Access Control Functions . 39
Among CSMNCD Procedures . M
..................................................... ?7
..................................................... 78
ense Function . 85
Fig 7-15 Common-Mode Input Test . Yi
Fig 7-16 Receiver Fault Conditions . 98
Fig 7-17 Common-Mode Transfer Impedance . 99
Fig 8-6 Typical Coaxial Trunk Cable Signal Waveform . 120
Fig 8-7 Maximum Coaxial Cable Transfer Impedance . 123
Fig 8-8 Coaxial Tap Connector Configuration Concepts . 128
Fig 8-9 Typical Coaxial Tap Connection Circuit . 128
Fig 8-10 Maximum Transmission Path . 129
Fig 8-11 Minimal System Configuration . 130
Fig 8-12 Minimal System Configuration Requiring a Repeater Set . 130

FIGURES PAGE
Fig8-13 An Example of a Large System with Maximum Transmission
Paths . 131
Fig 8-14 An Example of a Large Point-to-Point Link System (5140 ns) . 131
Fig 9-1 Repeater Set. Coax-to-Coax Configuration . 137
Fig 9-2 Repeater Set. Coax-to-Link Configuration . 138
Fig 9-3 Repeater Unit State Diagram . 140
Fig 9-4 Collision-Gone State Diagram . 141
Fig 9-5 96 State Diagram . 141
Fig 10-1 Physical Layer Partitioning; Relationship to the IS0 Open
System Interconnection (OSI) Reference Model . 143
Fig 10-2 MAU Interface Function . 148
Fig 10-3 Jabber Function State Diagram . 151
Fig 10-4 Driver Current Signal Levels . 154
Fig 10-5 Coaxial Trunk Cable Waveform . 155
Fig 10-6 Maximum Coaxial Cable Transfer Impedance . 158
Fig lO-7 Examples of Insulated Connector Cover . 160
Fig 10-8 Maximum Transfer Path . 161
Fig 10-9 The Minimum System Configuration . 163
Fig 10-10 The Minimum System Configuration Requiring a Repeater Set . 163
Fig 10-11 An Example of a Large Hybrid System . 164
TABLES
Table 8-1 Generation of Collision Presence Signal . 113
Table 9-1
Repeater Set and Repeater Unit Speuifxation . 139
Table 10-1 Generation of Collision Presence &pal . 149
ANNEX
Additional Reference Material . 169
APPENDICES
A System Guidelines . 171
B State Diagram. MAC Sublayer . 179
C Application Context. Selected Medium Specifications . 185
APPENDIX FIGURES
Fig Al Maximal. System Configuration Bit Budget Apportionments . 173
Fig A2 Typical Signal Waveforms . 176
Fig A3 Worst-Case Signal Waveform Variations . 176
Fig B1 Transmit Component State Diagram . 180
Fig B2 Receive Component State Diagram . 183
APPENDIX TABLES
Table B1 Transmit Component State Transmission . 181
Table B2 fieceive Component State Transmission . 183

Information processing systems-
Local area networks-
Part 3:
Carrier sense multiple access with
(CSWCD)
collision detection
access method and
physical layer specifications
1. Introduction
1.1 Overview
1.1.1 Basic Concepts. The Carrier Sense Multiple Access with Collision De-
tection (CSMMCD) media access method is the means by which two or more
stations share a common transmission medium. To transmit, a station waits
(defers) for a quiet period on the medium (that is, no other station is transmit-
ting) and then sends the intended message in bit-serial form. If, after initiat-
ing a transmission, the message collides with that of another station, then
each transmitting station intentionally sends a few additional bytes to ensure
propagation of the collision throughout the system. The station remains silent
for a random amount of time (backoff) before attempting to transmit again.
Each aspect of this access method process is specified in detail in subsequent
sections of this standard.
This is a comprehensive standard for Local Area Networks employing
CSMNCD as the access method. This standard is intended to encompass sev-
eral media types and techniques for signal rates of Erom 1 Mb/s to 20 Mb/s.
e
This edition of the standard provides the necessary specification and related
10 Mb/s baseband implementations. It is expected that
parameter values for
subsequent editions of this standard will provide similar specifications for
additional implementations (for example, other data rates and physical me-
dia).
1.1.2 Architectural Perspectives. There are two important ways to view local
area network design corresponding to
(1) Architecture. Emphasizing the logical divisions of the system and how
they fit together.
(2) Implementation. Emphasizing actual components, their packaging and
interconnection.
This standard is organized along architectural lines, emphasizing the
IS0 8802-3 : 1989
ANSIAEE Std 802.3-1988 u>cALAREANETwoRKs:
large-scale separation of the system into two parts: the Media Access Control
"
(MAC) sublayer of the Data Link Layer, and the Physical Layer. These layers
are intended to correspond closely to the st layers of the IS0 Model for
Open Systems Intercon e reference The Logical
Link Control (LLC) sub together encompass the func-
tions intended for the D as defined in the OS1 model.
1.1.2.1 An architectural organization of the standard has two main ad-
vantage 8: 1
n of the design along architectural lines
(1) Clarity. A clean overall di
makes the standard clearer.
(2) Flexibility. Segregation O ium-dependent aspects in the Physical 1
Layer allows the LLC and MAC ily of transmission
media.
Partitioning the Data Link Layer a access methods
V
within the family of Local Area Network standards.
Fig 1-1
LANStandardReiationshiptothe
CSMA/CD
LAYERS LAYERS
i
PRESENTATION
i
I
I
I
MDI = MEDIUM DEPENDE
PMA = PHYSICAL MEDIUM
-4
i
they correspond to those listed in the Annex.
i
i
.i
IS0 8802-3 : 1989
CSMAm ANSUIEEE Std 802.3-1988
I
The architectural model is based on a set of interfaces that may be different
t-
I
from those emphasized in implementations. One critical aspect of the design,
however, shall be add ssed largely in terms of the implementation inter-
rtant compatibility inteflaces are defined within what is
Medium-Dependent Interface (MOI). To communicate in a compatible
manner, all stations shall adhere rigidly to the exact specification of physical
media signals defined in Section 8 (and beyond) in this standard, and to the
procedures that define correct behavior of a station. The medium-independent
aspects of the LLC sublayer and the MAC sublayer should not be taken as de-
tracting from this point; communication by way of the IS0 8802-3 [IEEE 802.31
Local Area Ne requires complete compatibility at the Physical Medium
e coaxial cable interface).
VI). It is anticipated that most DTEs will be
located some dist connection to the coaxial cable. A small
amount of circuitry will exist in the Medium Attachment Unit (MAU) directly
adjacent to the coaxial cable, while the majority of the hardware and all of the
is defined as a second com-
be placed within the DTE. The AU1
is not strictly
erface. While conformance with this interface
unication, it is highly recommended, since it al-
intermixing MAUs and DTEs. The AU1 may be
specified for some implementations of this standard that are
connected directly to the medium and so do not use a separate
MAU or its interconnecting AU1 cable. The PLS and PMA are then part of a
single unit, and no explicit AU1 specification is required.
1.1.3 Layer Interfaces. In the architectural model used here, the layers in-
teract by way of well defined interfaces, providing services as specified in
2 and 6. In general, the interface requirements are as follows:
Sections
(1) The interface between the MAC sublayer and the LLC sublayer includes
facilities for transmitting and receiving frames, and provides per-operation
status information for use by higher-layer error recovery procedures.
e between the MAC sublayer and the Physical Layer in-
cludes signals for framing (carrier sense, transmit initiation) and con-
tention resolution (collision detect), facilities for passing a pair of serial bit
nsmit, receive) between the two layers, and a wait function for
These interfaces are described more precisely in 4.3. Additional interfaces
to allow higher level network management facilities to interact
are necessary
to rform operation, maintenance, and planning functions.
with these layers
Network management functions will be discussed in Section 5.
1.1.4 Application Areas. The app ations environment for the Local Area
Network is intended to be commerci nd light industrial. Use of CSWCD
LANs in home or heavy industrial environments, while not precluded, is not
considered within the scope of this standard.
IS0 8802-3 : 1989
ANSUreEE Std 802.3-1988 LOCALAREAIWIWORK%
U Notation
1.2.1 State Diagram Conventions. The operation of a protocol can be de-
scribed by subdividing the protocol into a number of interrelated functions.
The operation of the functions can be described by state diagrams. Each dia-
a function and consists of a group of connected,
gram represents the domain of
at any given
mutually exclusive states. Only one state of a function is active
1-2).
time (see Fig
Each state that the function can assume is represented by a rectangle. These
are divided into two parts by a horizontal line. In the upper part the state is
identified by a name in capital letters. The lower part contains the name of
any ON signal that is generated by the function. Actions are described by
short phrases and enclosed in brackets.
All permissible transitions between the states of a function are represented
graphically by arrows between them. A transition that is global in nature (for
example, an exit condition from all states to the IDLE or RESET state) is indi-
cated by an open arrow. Labels on transitions are qualifiers that must be ful-
filled before the transition will be taken. The label UCT designates an
unconditional transition. Qualifiers described by short phrases are enclosed
in parentheses.
State transitions and sending and receiving of messages occur instanta-
neously. When a state is entered and the condition to leave that state is not
immediately fulfilled, the state executes continuously, sending the messages
and executing the actions contained in the state in a continuous manner.
Fig 1-2
State Diagram Notation Example

I
O I
TERMS TO ENTER
STATE
>
[ACTIONS TAKEN]
l
Key: ( ) = condition, for example, (if no-collision)
action, for example, [reset PLS functions]
[I =
*= logical AND
+= logical OR
Tw = Wait Time, implementation dependent
Td = Delay Timeout
Tb = Backoff Timeout
UCT = unconditional transition

IS0 8802-3 : 1989
ANSIJEEE Std 802.3-1988
The state diagrams contain the authoritative statement of the functions they
!-
depict; when apparent conflicts between descriptive text and state diagrams
to take precedence. This does not override, how-
arise, the state diagrams are
I
II
ever, any explicit description in the text that has no parallel in the state dia-
grams.
The models presented by state diagrams are intended as the primary speci-
fications of the functions to be provided. It is important to distinguish, how-
ever, between a model and a real implementation. The models are optimized
for simplicity and clarity of presentation, while any realistic implementation
may place heavier emphasis on efficiency and suitability to a particular im-
plementation technology. It is the functional behavior of any unit that must
match the standard, not its internal structure. The internal details of the
model are useful only to the extent that they specify the external behavior
clearly and precisely.
122 Service Specincation Method and Notation. The service of a layer or
sublayer is the set of capabilities that it offers to a user in the next higher
(sub)layer. Abstract services are specified here by describing the service
primitives and parameters that characterize each service. This definition of
service is independent of any particular implementation (see Fig 1-31,
Specific implementations may also include provisions for interface inter-
actions that have no direct end-to-end effects. Examples of such local interac-
tions include interface flow control, status requests and indications, error
notifications, and layer management. Specific implementation details are
omitted from this service specification both because they will differ from im-
plementation to implementation and because they do not impact the peer-to-
peer protocols.
19.2.1 Classification of Service Primitives. Primitives are of two generic
types:
(1) REQUEST. The request primitive is passed from layer N to layer N-1 to
request that a service be initiated.
(2) INDICATION. The indication primitive is passed from layer N-1 to
layer N to indicate an internal layer N-1 event that is significant to layer N.
This event may be logically related to a remote service request, or may be
caused by an event internal to layer N-1.
The service primitives are an abstraction of the functional specification
and the user-layer interaction. The abstract definition does not contain local
detail of the user/provider interaction. For instance, it does not indicate the
local mechanism that allows a user to indicate that it is awaiting an incoming
call. Each primitive has a set of zero or more parameters, representing data
elements that shall be passed to qualisl the functions invoked by the primitive.
Parameters indicate information available in a usedprovider interaction; in
any particular interface, some parameters may be explicitly stated (even
though not explicitly defined in the primitive) or implicitly associated with the
service access point. Similarly, in any particular protocol specification,
to a service primitive may be explicitly defined or
functions corresponding
implicitly available.
IS0 8802-3 : 1989
ANSIAEEE Std 802.3-1988 LOCALAREANEIWORKS:
LAYER N
LAYER N
SERVICE USER
SERVICE US
LAYER N-1
,
"I
RVlCE PROVIDER
-
W REQUEST
+
I
I
INDICATION
!
Fig 1-3
Service Primitive Notation
sical Layer and Media Notation. Users is standard need to
reference which particul mplementation is bei sed or identified.
Therefore, a means of ide ing each implementation is given by a simple,
is explicitly stakd at the beginning of each rele-
three-field, type notation that
vant section. In general, the Physic ified by these fields:
nt length ( x 100 m)>
r example, the s
rd contains a 10 Mb/s baseband specification
5," meaning a 10 Mb/s baseband medium whose
maximum segment le 500 m. Each successive Physical Layer specifi-
cation will state its O ue TYPE identifier along similar lines.
19.4 Physical L sage Notation. Messages generated within
Physical Layer, either within or between PLS and the MAU (that is, PMA
cuitry), are designated by an italic type to designate either form of physical O
O
logical message used to execute the physical layer signaling process (for ex-
18 References
[il CISPR Publication 22 (19851, d Meth surement of Radio
Interference Characteristics of I n Tech ipment.2
lication 96-1 (1971) (3rd Edition), Radio Frequency Cable, Part 1:
uirements and Measuring Methods.
available in the US from the Sales Department, American
rds institute, 1430 Broadway, New York, NY 10018, USA. These documents are
from International Electrotechnicai Commission, 3 me de Varembé, Case Postale
, Genève 20, Switzerland/Suisse.

IS0 8802-3 : 1989
ANSUIBEB Std 802.3-1988
[31 IEC Publication 96 (19761, 1st Supplement, Radio Frequency Cable, Part
1: Appendix Section , Terminated Triaxial Test Method for Transfer
Impedance up to 100 MHz.
E41 IEC Publication 169-8 and -16, Radio Frequency Coaxial Connections with
Screw Coupling, 50 SZ (Type BNC and Type N).
[51 IEC Publication 380 (1985) (3rd Edition), Safety of Electrically Energized
Office Machines.
ation 435 (1983) (2nd Edition), Safety of Data Processing Equip-
[71 IEC Publication 807-2 (1985) (1st Edition), Detail Specification for a Range
of Connectors with Round Contacts-Fixed Solder Contact Types.
950 (19861, Safety of Information Technology Equipment
C81 IEC Publication
Inclu
...