ISO 8473:1988/Add 3:1989

IS0
INTERNATIONAL
STANDARD
First edition
1988-12-1 5
ADDENDUM 3
1989-09-01
Information processing systems - Data
communications - Protocol for providing the
connectionless-mode network service
ADDENDUM 3 : Provision of the underlying service
assumed by IS0 8473 over subnetworks which
OS1 data link service
provide the
Systèmes de traitement de l'information - Communications de données -
Protocole fournissant le service de réseau en mode sans connexion
ADDITIF 3: Fourniture du service sous-jacent assuré par l'IS0 8473 sur des sous-
réseaux point à point fournissant le service de liaison de données OS1
Reference number
IS0 8473 : 1988lAdd.3 : 1989 (E)

IS0 8473 : 1988/Add.3 : 1989 (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 re-
quiring at least 75 % approval by the national bodies voting.
International Standard ISO/IEC 8473lAdd.3 was prepared by Joint Technical Com-
mittee ISO/IEC JTC 1, Information technology.
Users should note that all International Standards undergo revision from time to time
and that any reference made herein to any other International Standard implies its
latest edition, unless otherwise stated.
O ISO/IEC 1989
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Printed in Switzerland
II
IS0 8473 : 1988/Add.3 : 1989 (E)
Introduction
The Protocol for Providing the Connectionless-mode Network Service (IS0 8473)
is one of a set of International Standards produced to facilitate the interconnec-
tion of open systems. This Addendum 3 to IS0 8473 defines the provision of the
underlying service assumed by the protocol described in IS0 8473 over subnet-
works which provide the OS1 Data Link Service.
The material in this Addendum will be incorporated into the body of IS0 8473
when the next revision of the Standard is produced. This Addendum has a çtruc-
ture which is similar to that of IS0 8473 and previous Addenda in order to facili-
tate cross reference between the documents and their eventual incorporation into
IS0 8473.
INTERNATIONAL STANDARD IS0 8473 : 19WAdd.3 : 1989 (E)
Information processing systems - Data communications
- Protocol for providing the connectionless-mode
network service
ADDENDUM 3: Provision of the underlying service assumed by
IS0 8473 over subnetworks which provide the OS1 data link
service
"In the case of an underlying subnetwork which provides a
1 Scope
connection-mode service, the Transit Delay value provided to
the CLNP must take into consideration any processing or
queueing delay incurred as a result of an attempt to establish a
This addendum to IS0 8473 defines a set of Subnetwork De-
connection."
pendent Convergence Functions (SNDCFs) that relate the OS1
Data Link Service defined in IS0 8886 to the abstract "under-
lying service" defined in subclause 5.5 of IS0 8473. The SND- Adda new subclause 8.4.4:
CFs defined in this Addendum complement the set of SNDCFs
aiready defined in clawe 8. Provision of the 1Jnderlying Serv-
8.4.4 Subnetwork Dependent Conyergeiice
ice.
Functions used with IS0 8886
The scope of this addenduni is strictly limited to configurations
This clause defines a mapping of the OS1 Data Link Service to
in which the IS0 8473 protocol is used in conjunction with one
the underlying service assumed by IS0 8473. The OS1 Data
or more subnetworks to provide the OS1 Connectionless-mode
Link Service Definition defines two types of Data Link Serv-
Network Seivice. When the IS0 8473 protocol is used for this
ices: a connectioniess-mode service and a connection-mode
purpose. the appropriate subnetwork-dependent convergence
service. SNDCFs are defined for subnetworks which provide
functions defined in this addendum are applied to each subnet-
either of these two modes of service.
work that participates in the transmission of IS0 8473 protocol
data units from a ço!ir'ce Network Service Access Point to a
destination Network Service Access Point.
8.4.4.1 SNDCF used with the Connectionless-
mode Data Link Service
The field of application of this addendum is the operation of
the IS0 8473 protocol ove] subnetworks which provide the
The primitives defined for provision of the underlying service
OS1 Data Link Sciivce. For certain types of subnetworks, a cir-
assumed by the CLNP map directly onto the UNITDATA Re-
cuit niwt be opened between end-points before communication
quest and Indication primitives defined for the Connectionless-
can kghi. The piocedures for opeiiing and closing circuit5 are
mode Data Link Service. Subnetwork Dependent Convergence
defined hi the standards pertaining to the particular subnet-
Functions perform a mapping of the Connectionless-mode
to open a circuit and to which end-
work. The choice of when
Data Link Service onto the underlying service assumed by the
point the circuit w opened are a local matter. This addendum
CLNP. The mapping is as follows. The generation of an SN-
defines the convergence fiinctions to be used once the circuit
UNITDATA request by the CLNF' results in the generation of
exiqts.
a DL-UNITDA
...