ISO 8802-2:1989
(Main)Information processing systems — Local area networks — Part 2: Logical link control
Information processing systems — Local area networks — Part 2: Logical link control
Systèmes de traitement de l'information — Réseaux locaux — Partie 2: Contrôle de liaison logique
General Information
Standards Content (Sample)
I NTER NAT1 O NAL
IS0
STANDARD 8802-2
ANSI/IEEE
Std 802.2
First edition
1989-1 2-31
Information processing systems -
Local area networks -
Part 2 :
Logical link control
Systèmes de traitement de Pinformation - Réseaux locaux -
Partie 2 : Contrôle de liaison logique
Reference number
IS0 8802-2 : 1989 (E)
ANSI/IEEE
Std 802.2-1989
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First Printing
December 1989
Ism 1-55937419-x
Library of Congress Catalog Card Number 8846183
Copyright O 1989 by
TheInstituteofElectricalandELecb.onicsEngineem,Inc
345 East 47th Street, New York, NY 10017-2394, 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.
December 31,1989 @I2930
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rnternatiod standard Is0 8802-2 : 1989
ANSI/IEEE Std 802.2-1989
(Revision of ANsI/IEEE Stü 8022-1986)
Information processing systems-
Local area networks-
Part 2:
Logical link control
Sponsor
Technical Committee on Computer Communications
oftbt!
IEEEComputmSociety
Approved August 17,1989
IEExstandardsBoard
Approved January 12, 1990
American National Standards Institute
Approved 1989 by the
Jnternatiod ûrganhtion for Stan-ation
---------------------- Page: 3 ----------------------
International standard Is0 8802-2 : 1989
IS0 (the International Organization for Standardization) is a worlddide
federation of national standards bodies (IS0 member bodies). The wor of
preparing International Standards is normally carried out through IS0 ch-
nical committees. Each member body interested in a subject for which a t ~ ch-
nical committee has been established has the right to be represented on that
committee. International organizations, governmental and non-govebn-
mental, in liaison with ISO, also take part in the work. IS0 collabordtes
closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are ir-
culated to the member bodies for approval before their acceptance as Inter a-
tional Standards by the IS0 Council. They are approved in accordance it h
IS0 procedures requiring at least 75% approval by the member bodies votin
4-
In 1985, ANSUIEEE SM 802.2-1985 was adopted by IS0 Technical Commit&ee
97, Information processing systems, as draft International Standard I80
8802-2. Following the procedures described above, the Standard was subse-
quently approved by IS0 in the form of this new edition, which is published as
International Standard IS0 8802-2 : 1989.
International Organization for Standardization
Caeepoatale56 CH-1211GenèveZû . Switzerland
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Foreword to International Statldard IS0 8802.2 : 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
numbers.)
r I
8802-2
I DATA
LINK
LAYER
PHYSICAL
LAYER
E]
This family of standards deals with the physical and data link layers as
defined by the IS0 Open Systems Interconnection Reference Model (IS0 7498 :
1984). The access standards define four types of medium access technologies
and associated physical media, each appropriate for particular applications or
system objectives. The standards defining these technologies are:
(1) IS0 8802-3 [ANSVIEEE Std 802.3-19881, a bus utilizing CSWCD as the
access method,
(2) IS0 8802-4 [ANSIfiEEE Std 802.4-19851, a bus utilizing token passing as
the access method,
(3) IS0 8802-6 [IEEE Std 802.5-19891, a ring utilizing token passing as the
access method,
(4) IS0 8802-7, a ring utilizing slotted ring as the access method.
IS0 8802-2 [IEEE Std 802.2-19891, Logical Link Control protocol, is used in
conjunction with the medium access standards.
The reader of this document is urged to become familiar with the complete
family of standards.
The main body of this standard serves for both the IS0 8802-2 : 1989 and IEEE
802.2-1989 standards. IS0 and IEEE each have unique foreword sections.
---------------------- Page: 5 ----------------------
1
IEEE Std 802.2-1989
IEEE Stanurds documents are developed within the Technical Committees
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Use of an IEEE Standard is wholly voluntary. The existence of an IEEE
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or reaffirmation. When a document is more than five years old, and h4 not
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been reaffirmed, it is reasonable to conclude that its contents, although sal1 of
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to check to determine that they have the latest edition of any IEEE Standard,
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gether with appropriate supp
Interpretations: Occasion stions may arise regarding the
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---------------------- Page: 6 ----------------------
FO~WO~ to IEEE md 8022-1989
(Revision OfANSVIEXE SM 802.2-31985)
("his Foreword is not a part of IS0 8802-2 : 1989 or of IEEE Std 802.2-1989.)
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.)
1
802.1 I
DATA LINK LAYER
-
PHYSICAL LAYER
This family of standards deals with the physical and data link layers as
defined by the IS0 Open Systems Interconnection Reference Model. The ac-
cess standards define three types of medium access technologies and associ-
ated physical media, each appropriate for particular applications or system
objectives. The standards defining these technologies are:
(1) ANSYIEEE Std 802.3-1988 [IS0 8802-31, a bus utilizing CSWCD as the
access method,
(2) ANSIDEEE Std 802.4-1985 [IS0 8802-41, a bus utilizing token passing as
the access method,
(3) IEEE Std 802.6-1989 [IS0 8802-51, a ring utilizing token passing as the
access method.
IEEE Std 802.2-1989 [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.
---------------------- Page: 7 ----------------------
j
I
At the time of approval of this standard in 1983, the following members vriere
participants of IEEE Project 802 Working Group:
David E. Carlson, Chairman
Juan Pimente1
Om Agrawal Maris Graube
Phi1 Arneth Ed Harada Lavern Pope
Jeff Bobzin Lo Hsieh Dave Potter
Karen Hsing DeMis Quy
Mark Bauer
Le Biu Kevin Hughes John Rance
Clyde Boenke Marco Hurtado Dan Ratner
Bob Bowen Bob Husak Richard Read
Bob Bridge* Dittmar Janetzky Ted Rebenko
Chuck Brill Ross Jaibaji John Ricketson
Wayne Brodd* George Jelatis Edouard Rocher
Werner Bux Gabor Kardos Rob Rosenthal*
Jim Campbell Chip Schnarel
Pegu KarP*
Tony Cape1 Kristin Kocan Waiter Schreuer
Ron Cates Zak Kong* Gerard Segarra
Rao Cherukuri Sy Korowitz Dennis Sosnoski
Po Chen* George Koshy Robert C. Smith
Jade Chien Don Kotas Mark Stahlman
Mike Clader Tony Kozlii Steve Stem
Mike Kryskow*
Jeny Clang* Carry Stephem*
Rich Collins Dave Laffitte Mark Steiglitz*
Steve Cooper Terry Lawell* Kathleen Sturgis
Bob Crowder* Ron Leuchs Bob &over*
Kirit Davé Peter Lin Bart Stuck
John Davidson Jim Lindgren Dave Sweeton*
Em Delahostria* Laurie Lindsey* Dan Sze*
Jan Dolphin Bill Livingaton* Vic Tarassov*
Bob DOM^ Then Tang Liu Angus Telfer*
Bob Douglas Don C. Loughry Dave ThomDson
Bill Durrenberger Don J. Loughry Fouad Tobâ~
Rich Fabbri Bruce Loyer Jean-Marie Tourret '
Jeny Lurtz Bo Viklund
Eldon Feist*
Bill Miller Bruce Watson
Jim Field*
Lamy Foltzer Ken Miller Don Weir*
Ron Floyd Lou Mitta Dan Wendling
Darrell Furlong Bob Moles Walter Wheeler
Me1 Gable Jim Mollenauer Hugh White
Ware Myers
Mike Gamey Steve Whiteside I
Earl Whitaker* I
Bud Glick Gene Nines
Arie Goldberg Bill Northup
Ping Wu 1
Esin Ulug i
Pat Gonia Brian O'Neil*
Gordon Griffit Ku1 Padda Hiroshi Yoshida
Bob Grow Mahendra Pate1 Hank Zannini
Tom Phinney*
* Principal contributors to Project 802.2
,
---------------------- Page: 8 ----------------------
Additional individuals who made significant contributions were the fol-
lowing:
Wendel1 Nakamine
Don Andrews Andrew Huang
Phi1 Arst Hal Keen Liston Neely
Ron Crane Tony Lauck Lee Neitzel
Dan Pitt
Walt Elden Andy Luque
Dan Maltbie Robert Printis
Ingrid Fromm
Atul Garg Jane Munn Stephen Soto
Bryan Hoover Joshua Weiss
The following persons were on the balloting committee that approved this
document for submission to the IEEE Standards Board
William B. Adams Mike Lawler Robert Rosenthal
Kit Athul Jaiyong Lee Floyd Ross
Chih-Tsai Chen F. C. Lim S. I. Samoylenko
Julio Sanz Gonzalez
R. S. Little
Michael H. Coden
Robert S. Crowder William D. Livingston Norman Schneidewind
George S. Curon Donald C. Loughry D. A. Sheppard
Andy J. Luque John Spragins
Mitchell Duncan
Richard Miller Care1 M. Stillebroer
John E. Emrich
Nirode C. Mohanty Fred Strauss
John W. Fendrich
Hal Folts John E. Montague Peter Sugar
Kiqji Mori Efstathios D. Sykas
Harvey Freeman
D. G. Gan David J. Morris Daniel Sze
Patrick Gonia M. Ravindranath Nayak Nathan Tobol
Ambuj Goya1 Arne A. Nileson L. David Umbaugh
Charles Oestereicher Thomas A. Varetoni
Maria Graube
James Vorhies
J. Scott Haugdahl Young Oh
Paul L. Hutton Udo W. Pooch Don Weir
Raj Jain John P. Riganati Earl J. Whitaker
Gary S. Robinson George B. Wright
David M. Kollm
Anthony B. Lake Oren Yuen
When the IEEE Standards Board approved this standard on August 17,1989,
it had the following membership:
Marco W. Migliaro,Vice Chairman
Dennis Bodson, Chairman
Andrew G. Salem, Secretary
John E. May, Jr.
Kenneth D. Hendrix
Arthur A. Blaisdell
Lawrence V. McCall
Theodore W. Hissey, Jr.
Fletcher J. Buckley
L. Bruce McClung
John W. Horch
Allen L. Clapp
Donald T. Michael*
David W. Hutchins
James M. Daly
Richard E. Mosher
Frank D. Kirschner
Stephen R. Dillon
Stig Nilsson
Frank C. Kitzantides
Donald C. Fleckenstein
L. John Rankine
Joseph L. Koepfingee
Eugene P. Fogarty
Gary S. Robinson
Edward Lohse
Jay Forster*
Donald W. Zipse
L. Hannan
Thomas
*Member emeritus
---------------------- Page: 9 ----------------------
. . . . .
contents
SE PAGE
CTION
1 . Introduction . 13
1.1 Scope and Purpose . 13
1.2 Standards Compatibility . 15
1.3 References . 15
1.4 Acronyms and Definitions . 16
1.4.1 Acronyms . 16
1.4.2 Definitions . 17
LLC Sublayer Service Specifications . 21
2 .
2.1 Network LayerLLC Sublayer Interface Service Specification . 22
2.1.1 Overview of Interactions . 24
2.1.2 Detailed Service Specifications . 26
2.2 LLC Sublayer/MAC Sublayer Interface Service Specification . 35
2.2.1 Overview of lnteractions . 35
2.2.2 Detailed Service Specification., . 35
2.3 LLC SublayedLLC Sublayer Management Function Interface
Service Specification . 38
3 . LLC PDU Structure . 39
3.1 General . 39
3.2 LLC PDU Fomiat . 39
3.3 Elements of the LLC PDU . 39
3.3.1 Address Fields . 39
3.3.2 Control Field .
........ 41
3.3.3 Information Field .
........ 41
3.3.4 Bit Order .
........ 41
3.3.5 Invalid LLC PDU .
........ 42
LLC Types and Classes of Procedure .
4 . . 43
4.1 General . . 43
4.2 Classes of LLC . . . 44
4.2.1 Class I LLC . . . 44
4.2.2 Class II LLC . . 45
...........
LLC Elements of Procedure . . . 47
5 .
5.1 General . . . 47
5.2 Control Field Formats .
...................... 47
5.2.1 Information Transfer Format-I., . . 48
5.2.2 Supervisory Format-S . . 48
5.2.3 Unnumbered Format-U . . 48
5.3 Control Field Parameters .
...................... 48
5.3.1 Type 1 Operation Parameters . . 48
_-
5.3.2 Type 2 Operation Parameters . 48
5.4 Commands and Responses .
Type 1 Operation Commands and Responses . 51
5.4.1
---------------------- Page: 10 ----------------------
SECTION
p*cE
5.4.2 Type 2 Operation Commands and Responses . 53
6 . LLC Description of the Type 1 Procedures., . 161
6.1 Modes of Operation . 61
6.2 Procedure for Addressing . 61
6.3 Procedure for the Use of the P/F Bit . 61
6.4 Procedures for Logical Data Link Set-Up and Disconnection . 61
6.5 Procedures for Information Transfer . 161
Sending U1 PDUs . 161
6.5.1
Receiving U1 PDUs .
6.5.2
6.6 Uses of the XID Command and Response PDU . la
6.7 Uses of the TEST Command and Response PDU . !62
6.8 List of Logical Data Link Parameters . -64
6.8.1 Maximum Number of Octets in a U1 PDU . 64
6.8.2 Minimum Number of Octets in a PDU . 64
6.9 Precise Description of the Type 1 Procedures . :64
6.9.1 LLC Precise Specification . 164
6.9.2 Station Component Overview . .I 67
6.9.3 Service Access Point (SAP) Component Overview . 170
I
LC Description of the Type 2 Procedures . J75
7.1 Modes . 75
7.1.1 Operational Mode . 75
7.1.2 Non-operational Mode . 75
7.2 Procedure for Addres . 76
7.3 Procedures for the Use P/F Bit . 76
Set-Up and Disconnection . 176
7.4 Procedures for Data
7.4.1 Data Link tion Phase . 1 76
1
7.4.2 Information Transfer Phase. . 177
I
7.4.3 Data Link Disconnection Phase . J77
7.4.4 Data Link Disconnected Phase . 78
7.4.5 Contention of Unnumbered Mode Setting Command PDUs . 78
O
7.5 Procedures for Information Transfer . J78
Sending I PDUs . 78
7.5.1
7.6.2 Receiving an I PDU . J79
O
7.5.3 Reception of Incorrect PDUs . 179
ption of Out-of-Sequence PDU~ . 179
I
7.5.5 Receiving Acknowledgment. . 180
I
7.5.6 Receiving a REJ PDU . 80
7.5.7 Receiving an RNR PDU . 80
7.5.8 LLC Busy Condition . 80
7.5.9 Waiting Acknowledgment . 81
7.6 Procedures for Resetting . 81
7.7 FRMR Exception Condition .
7.8 List of Data k Connection Parameters .
I
l
l
1:
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SECTION PAGE
7.8.1 Timer Functions . . 83
7.8.2 Maximum Number of Transmissions N2 . 84
7.8.3 Maximum Number of Octets in an I PDU N1 . 84
7.8.4 Maximum Number of Outstanding I PDUs k . 84
7.8.6 Minimum Number of Octets in a PDU . 84
7.9 Precise Description of the Type 2 Procedures . 84
7.9.1 General . 84
Connection Service Component Overview . 84
7.9.2
FIGURES
Fig 1-1 Relationship to LAN Reference Model . 13
Service Primitives . 21
Fig 2-1
Time-Sequence Diagrams . 23
Fig 2-2
Fig 3-1 LLC PDU Format . 39
DSAP and SSAP Address Field Formats . 40
Fig 3-2a
Global DSAP Address Field Format . 40
Fig 3-2b
Balanced Data Link Connection Configuration . 44
Fig 4-1
Classes of LLC . 44
Fig 4-2
LLC PDU Control Field Formats . 47
Fig 6-1
Fig 6-2 Type 1 Operation Command Control Field Bit
Assignments . 51
XID Information Field Basic Format . 62
Fig 6-3
Fig 6-4 Type 1 Operation Response Control Field Bit Assignments . 53
Information Transfer Format Control Field Bits . 64
Fig 5-6
Supervisory Format Control Field Bits . 65
Fig 6-6
Unnumbered Format Control Field Bits., . 66
Fig 6-7a
Fig 6-7b Unnumbered Command and Response Control Field Bit
Assignments . 66
FRMR Information Field Format . 58
Fig 6-8
Component Relationships . 66
Fig 6-1
Station Component State Diagram . 68
Fig 6-2
Service Access Point Component State Diagram . 72
Fig 6-3
Connection Component State Diagram . 95
Fig 7-1
TABLES
Station Component State Transitions . 63
Table 6-la
Station Component Options . 61)
Table 6-lb
Service Access Point Component State Transitions . 71
Table 6-2
Connection Component State Transitions . 96
Table 7-1
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I
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Information processing systems-
Local area networks-
Part 2:
Logical link control
1. Intraduction
1.1 Scope and Purpose, "his International Standard is one of a set of interna-
tional standards produced to facilitate the interconnection of computers and
terminals on a Local Area Network (LAN). It is related to the other interna-
tional standards by the Reference Model for Open Systems Interconnection.
NOTE: The exact relationship of the layers described in this International Standard to the layers
081 Reference Model is under study.
defined by the
"his International Standard describes the functions, features, protocol, and
services of the Logical Link Control (LLC) sublayer in the IS0 8802 Local Area
Network Protocol. The LLC sublayer constitutes the top sublayer in the data
link layer (see Fig 1-1) and is common to the various medium access methods
that are defined and supported by the IS0 8802 activity. Separate international
standards describe each medium access method individually and indicate the
additional features and functions that are provided by the Medium
Fig 1-1
RelationshiptoLANReferenceModel
DATA LINK
LAYER
I MAC I
I I
MEDIUM
---------------------- Page: 14 ----------------------
Is0 88022 : 1989
IEEE Std802.21989 LOCAL AREA NETWORP:
ontrol (MAC) sublayer in each case to complete the functionality; of
link layer as defined in the LAN architectural reference model. ~
This International Standard describes the LLC sublayer service specifi’ca-
tions to the network layer (Layer 31, to the MAC sublayer, and to the LLC saib-
layer management function. The service specification to the network layer
provides a description of the various services that the LLC sublayer, plus n-
derlying layers and sublayers, offer to the network layer, as viewed from he
P
network layer, The service specification to the MAC sublayer provides a de-
scription of the services that the LLC sublayer requires of the MAC subla er.
so as to be independent of the form of the medi m
These services are defined
U
access methodology, and of the nature of the medium itself. The service spqci-
fication to the LLC sublayer management function provides a description of
the management se that are provided to the LLC sublayer. All of the
above service speci s are given in the form of primitives that represent
in an abstract way the logical exchange of information and control betw en
the LLC sublayer e identified service function (network layer, k$C
sublayer, or LLC s r management function). They do not specify or
constrain the implementation of entities or interfaces.
This International Standard provides a description of the peer-to-peer pr to-
col procedures that are defined for the transfer of information and control I e-
tween any pair of data link layer service access points on a local area qet-
work. The LLC procedures are independent of the type of medium access
method used in the particular local area network.
broad range of potential applications, two types of data 1 nk
on are included (see Section 4). The first type of operation ( $I ee
ovides a data-link-connectionless-mode service across a d ta
imum protocol complexity. This type of operation may be us ful
when higher layers provide any essential recovery and sequencing servi es
so that these do not need replicating in the data link layer. In addition, t i is
type of operation may prove useful in applications where it is not essential to
guarantee the delivery of every data link layer data unit. This type of sefiice
e
is described in this International Standard in terms of “logical data lin&”.
The second type of operation (see Section 7) provides a data-link-connectibn-
mode service across a data link comparable to existing data link con
cedures provided in International Standards such as HDLC (see IS0
1987 ClIl). This service includes support of sequenced delivery of da
layer data units, and a comprehensive set of data link layer error rec
techniques, This second type of service is described in this internatio
standard in terms of “data link connections”.
This International Standard identifies two distinct “classes” of LLC opqra-
tion. Class I provides data-link-connectionless-mode service only, Class II
provides data-link-connection-mode service plus data-link-connectionldss-
mode service. Either class of operation may be supported.
The basic protocol escribed herein are peer protocols for use in m ti-
+
I
The numbers in brackets correspond to those of the references listed in 1.3.
---------------------- Page: 15 ----------------------
IS0 8802-2 : 1989
lEEE std 802.2-1989
LOGICAL LINK CONTROL
station, multiaccess environments. Because of the multistation, multiaccess
environment, it shall be possible for a station to be involved in a multiplicity
of peer protocol data exchanges with a multiplicity of different stations over a
multiplicity of different logical data links and/or data link connections that
are carried by a single physical layer (PHY) over a single physical medium.
Each unique to-from pairing at the data link layer shall define a separate
logical data link or data link connection with separate logical parameters
and variables. Except where noted, the procedures described in this chapter
shall relate to each data link layer logical data link or data link connection
separately and independently from any other logical data link or data link
connection that might exist at the stations involved.
19 Standards Compatibility. The peer protocol procedures defined in Section 5
utilize some of the concepts and principles, as well as commands and re-
sponses, of the balanced data link control procedures known as Asynchronous
Balanced Mode (ABM), as defined in IS0 7809 : 1984 [31. (The ABM procedures
provided the basis upon which the CCI'M! Recommendation X.26 Level 2 LAPB
[41 procedures were defined.) The frame structure defined for the data link
layer procedures as a whole is defined in part in Section 3 of this international
standard and in part in those International Standards that define the various
medium access control (MAC) procedures. The combination of a MAC
sublayer address and an LLC sublayer address is unique to each data link
layer service access point in the local area network.
NOTE: This division of data link layer addressing space into separate MAC and LLC address
fields is not presently a part of any present IS0 data link layer International Standard.
1.3 References
[il IS0 4336 : 1987, Information processing systems, Data communications,
High-level data link control elements of procedures.2
[21 IS0 7498 : 1984, Information processing systems, Open systems intercon-
nection, Basic reference model.
[31 IS0 7809 : 1984, Information processing systems, Data communications,
High-level data link control procedures, Consolidation of classes of proce-
dures.
[41 CCITT Recommendation X.25, Interface between data terminal equipment
(DTE) and data circuit-terminating equipment (DCE) for terminals operat-
ing in the packet mode and connected to public data networks by dedicated
circuit .3
IS0 documents are available in the US from the Sales Department, American National
Standards Institute, 1430 Broadway, New York, "Y 10018, USA. IS0 documents are also available
IS0 Oh, 1 rue de Varembé, Case Postale 66, CH-1211, Genève U), Switzerland/Suisse.
hm the
' CCplT documents are available in the US hm the US Dept. of Commerce, National Technical
6286 Port Royal Rd., Springfield, VA 22161. CCITT documents are also
Information Service,
available from CCITT General Secretariat, International Telecommunications Union, Sales
Sect
...
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