rfc941.txt

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Network Working Group                                                ISO
Request for Comments: 941                                     April 1985

          Addendum to the Network Service Definition Covering
                        Network Layer Addressing


                            ISO/DP8348/DAD2
                        (also TC 97/SC 6/N 3444)

Status of this RFC:

 This document is distributed as an RFC for information only.  It does
 not specify a standard for the ARPA-Internet.  Distribution of this
 document is unlimited.

Note:

 This document has been prepared by retyping the text of ISO/DP8348/DAD2
 of October 1984 (also numbered SC 6/N 3444), which is currently
 undergoing voting within ISO as a Draft Proposed Addendum to the
 Network Service Definition.  Although this RFC has been reviewed after
 typing, and is believed to be substantially correct, it is possible
 that typographic errors not present in the ISO document have been
 overlooked.

Alex McKenzie
BBN Laboratories





























ISO/TC-97/SC-6                                                  [Page 1]
RFC 941                                                       April 1985
Network Layer Addressing


ISO Statement on the Status of this Document.

At its meeting in Zurich, April 2-11, 1984, SC 6/WG 2 produced document
SC 6 N 3134 and, in accordance with Resolution 49 of the SC 6 meeting in
Tianjin (September 19-30, 1983), forwarded it to the SC 6 Secretariat
for registration and ballot as a first Draft Proposed Addendum to the
Network Service Definition (ISO DP 8348/DAD2).

The letter ballot on SC 6/N 3134 closed on August 20, 1984. The results
of the ballot were 10-4-0-3 [approve-disapprove-abstain-no vote]; the
summary of voting is contained in document SC 6/N 3229 (late votes are
contained in documents SC 6/N 3333 and 3360). These ballot results were
reviewed at the SC 6/WG 2 meeting in Washington, October 15-25, 1984,
and document SC 6/N 3444 was produced as a progression of SC 6/N 3134,
taking into account as many of the ballot comments as possible.  The
Editor's report, contained in document SC 6/N 3445, describes the
disposition of member body comments on the DP 8348/DAD2 letter ballot.

A resolution of the SC 6 meeting in Washington, October 22-26, 1984,
instructs the SC 6 Secretariat to register document SC 6/N 3444 as a
second Draft Proposed Addendum to ISO 8348, and to circulate it for a
two-month letter ballot.

Introduction

This Addendum to the Network Service Definition Standard, ISO 8348,
defines the abstract syntax and semantics of the Network Address
(Network Service Access Point Address).  The Network Address defined in
this Addendum is the address that appears in the primitives of the
connection-mode Network Service as the calling address, called address,
and responding address parameters, and in the primitives of the
connectionless-mode  Network  Service  as  the source address and
destination address parameters.




















ISO/TC-97/SC-6                                                  [Page 2]
RFC 941                                                       April 1985
Network Layer Addressing


  SCOPE AND FIELD OF APPLICATION

The scope of this Addendum is the definition of the abstract syntax and
semantics of the Network Address.  This Addendum does not specify the
way in which the semantics of the NSAP address are encoded in Network
Layer protocols.  The field of application of this Addendum is the same
as the field of application described in Clause 1 of the Network Service
Definition (ISO 8348).

2  REFERENCES

ISO 7498        Information Processing Systems - Open Systems
                Interconnection - Basic Reference Model [Note:  See also
                CCITT Recommendation X.200]

DP 7498/DAD1    Information Processing Systems - Open Systems
                Interconnection - Addendum to the Basic Reference Model
                Covering Connectionless Data Transmission

DP 8509         Information Processing Systems - Open Systems
                Interconnection - Service Conventions

ISO 8348        Information Processing Systems - Data Communications -
                Network Service Definition [Note:  See also CCITT
                Recommendation X.213]

DIS 8348/DAD1   Information Processing Systems -  Data Communications -
                Addendum to the Network Service Definition Covering
                Connectionless Data Transmission

DP 8648         Information Processing Systems - Data Communications -
                Internal Organization of the Network Layer

ISO 6523        Data Interchange - Structure for the Identification of
                Organizations

ISO 646         7-bit Coded Character Set for Information Processing
                Interchange

ISO 2375        Procedure for the Registration of Escape Sequences

CCITT X.121     International Numbering Plan for Public Data Networks

CCITT E.163     Numbering Plan for the International Telephone Service

CCITT E.164     The Numbering Plan for the ISDN Era

CCITT F.69      Plan for Telex Destination Codes





ISO/TC-97/SC-6                                                  [Page 3]
RFC 941                                                       April 1985
Network Layer Addressing


Temporary Note

 The  list  of  References  in  the  published Addendum will contain
 only approved ISO Standards and CCITT Recommendations; items may need
 to  be subtracted from, or added to, the current list.
















































ISO/TC-97/SC-6                                                  [Page 4]
RFC 941                                                       April 1985
Network Layer Addressing


SECTION ONE - GENERAL
---------------------

3  DEFINITIONS

3.1  Reference Model Definitions

 This Addendum makes use of the following terms defined in ISO 7498:

 a)  Network layer

 b)  Network service

 c)  Network service access point

 d)  Network service access point address

 e)  Network entity

 f)  Routing

 g)  Network address

 h)  Network protocol control information

 i)  Network protocol data unit

3.2  Service Conventions Definitions

 This Addendum makes use of the following terms defined in ISO 8509:

 j)  Service user

 k)  Service provider

3.3  Network Layer Architecture Definitions

 This Addendum makes use of the following terms defined in ISO 8648
 (Internal Organization of the Network Layer):

 l)  Subnetwork

 m)  Real subnetwork

 n)  Subnetwork service

 o)  Real end system

 p)  Interworking unit

 q)  Intermediate system


ISO/TC-97/SC-6                                                  [Page 5]
RFC 941                                                       April 1985
Network Layer Addressing


3.4  Network Addressing Definitions

 This Addendum makes use of the following terms as defined below:

 r)  DTE address: information used to identify a point of attachment to
     a public data network.

 s)  Subnetwork point of attachment: a point at which a real end system,
     interworking unit, or real subnetwork is attached to a real
     subnetwork, and a conceptual point at which a subnetwork service is
     offered within an end or intermediate system.

 t)  Subnetwork address (Subnetwork point of  attachment  address):
     information used in the context of a particular real subnetwork to
     identify a subnetwork point of attachment, or information used in
     the context of a particular subnetwork to identify the point at
     which the subnetwork service is offered within  an  end  or
     intermediate system.

 u)  Network protocol address information:  information encoded in a
     network protocol data unit to carry the semantics of an NSAP
     address. (This is known as an "address signal" or as the "coding of
     an address signal" in the Public Data Network environment.)

 v)  Domain (of the OSI environment): a subset of the OSI environment
     within which identifiers for OSI environment entities of the same
     type are unambiguous.

 w)  Global network addressing domain: the set of all Network Service
     Access Point addresses in the OSI environment.

 x)  Network addressing subdomain; a subset of the global network
     addressing domain.

 y)  Authority (for a domain or subdomain): that which ensures that
     identifiers within the corresponding domain or subdomain  are
     unambiguous.
















ISO/TC-97/SC-6                                                  [Page 6]
RFC 941                                                       April 1985
Network Layer Addressing


4  ABBREVIATIONS

This Addendum makes use of the following abbreviations:

a)  NSAP - Network Service Access Point

b)  NPAI - Network Protocol Addressing Information

c)  DCC  - Data Country Code

d)  CC   - Country Code