ISO/IEC TR 9575:1995
(Main)Information technology — Telecommunications and information exchange between systems — OSI Routeing Framework
Information technology — Telecommunications and information exchange between systems — OSI Routeing Framework
Provides a framework in which OSI protocols for routeing may be developed and to expedite the progression of routeing protocols through the standardisation process. Reflects the current state of OSI routeing and does not preclude future extensions and developments. Replaces the first edition, which has been technically revised.
Technologies de l'information — Communication de données et échange d'information entre systèmes — Cadre général de routage OSI
General Information
Relations
Standards Content (Sample)
TECHNICAL
ISO/IEC
REPORT
TR 9575
Second edition
1995-I O-l 5
Information technology -
Telecommunications and information
exchange between systems - OSI
Routeing Framework
Technologies de /‘information
- Communication de don&es et bchange
d ‘information en tre syst&mes - Cadre g&Wal de routage OS1
Reference number
ISO/l EC TR 9575: ‘I 995(E)
---------------------- Page: 1 ----------------------
ISOhEC TR 95751995 (E)
Page
Contents
...
111
Foreword .
iv
Introduction .
1
1 Scope .
1
..................................................................................................
2 References
1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Definitions
...................................................................... 2
4 Symbols and Abbreviations
2
5 Routeing Concepts .
................................................................ 6
6 Environment for OS1 Routeing
6
7 Goals for OS1 Routeing .
8
............................................................
8 Structure of Global OS1 Routeing
@ ISO/IEC 1995
All rights reserved. Unless otherwise specified, 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.
ISO/IEC Copyright Office l Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
---------------------- Page: 2 ----------------------
lSO/IEC TR 9575:1995 (E)
o ISO/IEC
Foreword
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized system for worldwide standardiza-
tion. National bodies that are members of IS0 or IEC participate in the development 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.
The main task of technical committees is to prepare International Standards, but in
exceptional circumstances a technical committee may propose the publication of a
Technical Report of one of the following types:
- type 1, when the required support cannot be obtained for the publication of an
International Standard, despite repeated efforts
- type 2, when the subject is still under technical development or where for any
other reason there is the future but not immediate possibility of an agreement on
an International Standard;
- type 3, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for
example).
Technical Reports of types 1 and 2 are subject to review within three years of
publication, to decide whether they can be transformed into International Standards.
Technical Reports of type 3 do not necessarily have to be reviewed until the data they
provide are considered to be no longer valid or useful.
ISOLEC TR 9575, which is a Technical Report of type 3, was prepared by Joint
Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 6,
Telecommunications and inform&ion exchange between systems.
This second edition cancels and replaces the first edition (ISO/IEC TR 9575:1990),
which has been technically revised.
0.0
111
---------------------- Page: 3 ----------------------
lSO/IEC TR 9575:1995 (E) 0 ISOhEC
Introduction
In the OS1 environment (OSIE), the possibility exists for any End System (ES) to communicate with any other
ES. The physical path (or paths) over which this communication takes place may
include multiple Intermediate Systems (IS);
- include multiple subnetwork types; and
- traverse multiple, independent organisations .
Furthermore, one instance of communications may follow a different path from another instance of
communications.
Within the Network Layer, the Internal Organisation of the Network Layer (IS0 8648) identifies two
functions, Routeing and Relaying, as being central to the ability for End Systems to communicate through an
arbitrary concatenation of subnetworks and Intermediate Systems.
Part of the overall function of routeing and relaying is to allow ESs and ISs to find an appropriate path
between two or more ESs for a given instance of communications.
Relaying is concerned primarily with the actual transformation and manipulation of Network Protocol Data
Units (NPDUs) as they transit Intermediate Systems. Routeing, on the other hand, is primarily concerned
with the maintenance and selection of paths through multiple subnetworks and Intermediate Systems which
allow NPDUs to flow smoothly between End Systems.
There are four important aspects to routeing, i.e.:
a) the information required by ESs and ISs (5.1.1) ,
b) the techniques used by ESs and ISs to collect that information (5.1.2),
c) the techniques used by ESs and ISs to distribute that information (5 .1.3), and
d) the functions executed by ESs and ISs on that information to determine the paths over which NPDUs
flow between pairs of NSAPs (5 .1.4).
This Technical Report discusses these aspects of routeing, and describes how various protocols may be
employed to effect the OS1 routeing functions. It does not discuss relaying, except where relaying functions
are closely allied with routeing functions.
This second edition of ISO/IEC TR 9575 adds the option of interconnecting Routeing Domains using multicast
subnetworks, interconnecting Administrative Domains using multicast subnetworks, and providing
connectivity within Routeing Domains using multicast subnetworks.
iv
---------------------- Page: 4 ----------------------
ISO/lEC TR 95751995 (E)
TECHNICAL REPORT 0 ISO/IEC
- Telecommunications and information exchange
Information technology
OS1 Routeing Framework
between systems -
1 Scope
23 0 Additional references
This Technical Report provides a framework in which OS1
IS0 8648: 1988, Information processing systems -
protocols for routeing may be developed and to expedite the
Open Systems Interconnection - Internal
progression of routeing protocols through the standardisation
organization of the Network Layer.
process. At the time of publication, this report reflected the
IS0 9542: 1988 l, Information processing systems
current state of OS1 Routeing, and does not preclude future
- Telecommunications and information exchange
extensions and developments.
between systems
- End system to intermediate
system ruuteing exchange protocol for use in
2 References
conjunction with the protocol for providing the
connection-less mode network service.
The following International Standards I ITU-T Recommenda-
tions contain provisions which, through reference in this text,
ISODEC 10030: 1995, Information technology -
constitute provisions of this Technical Report. At the time of
Telecommunications and information exchange
publication, the editions indicated were valid. All Standards 1
between systems - End System Routeing
Recommendations are subject to revision, and parties to agree-
Information Exchange Protocol for use in
ments based on this Technical Report are encouraged to inves-
conjunction with ISO/IEC 8878.
tigate the possibility of applying the most recent editions of the
Standards I Recommendations listed below. Members of IEC
ISOAEC 10589: 1992, Information technology -
and IS0 maintain registers of currently valid International Stan-
Telecommunications and information exchange
dards. The Telecommunication Standardization Bureau of the between systems - Intermediate system to intermediate
ITU maintains a list of currently valid ITU-T Recommenda- system intra-domain-routeing routine information
exchange protocol for use in conjunction with the
tions.
protocol for providing the connectionless-mode
Network Service (IS0 8473).
21 Identical International Standards I
Recommendations
ISO/IEC 10747: 1994, Information technology -
Telecommunications and information exchange
ITU-T Recommendation X.200 (1994) I ISO/IEC
between systems - Protocol for exchange of inter-
7498- 1: 1994, Information technology - Open
domain routeing information among intermediate
Systems Interconnection - Basic Reference
systems to supportforwarding of IS0 8473 PDUs.
Model: The Basic Model.
RFC 1629, Guidelines for OSI NSAP allocation
CCITT Recommendation X.21 3 (1992) I ISO/IEC
in the Internet.
8348: 1993, Information technology - Open
I
Currently under revision.
Systems Interconnection - Network service
definition.
ITU-T Recommendation X.233 (1993) I ISODEC
8473- 1: 1994, Information technology - Protocol for
3 Definitions
providing the connectionless-mode network service:
Protocol spec@cation.
3.1 Reference Model Definitions
2.2 Paired International Standards I
This Technical Report makes use of the following terms
Recommendations
defined in ITU-T Rec. X.200 I IS0 7498-l :
ITU-T Recommendation X.223 (1993), Use of
a) Network Layer
X.25 to Provide the OSI Connection-mode
b) Network Service Access Point
Network Service for ITU-T Applications.
c) Network Service Access Point address
ISOIIEC 8878: 1992, Information technology -
* Telecommunications and information exchange
d) Network entity
Use of X.25 to provide the OH
between systems -
e) Routeing
Connection-mode Network Service.
---------------------- Page: 5 ----------------------
0 ISO/IEC
ISO/IEC TR 9575:1995 (E)
multiple hierarchies, with the common domain as the
f) Network protocol
highest element of each hierarchy.
g) Network relay
Where there are multiple common domains, they co-operate
h) Network protocol data unit
as peers to make it possible to route to any NSAP in the
OSIE.
i) System management
3.4.4 hop: The traversal of a single subnetwork by a
j) Layer management
PDU.
3.2 Network Layer Architecture
3.4.5 black hole: A situation in which an Intermediate
Definitions
System, due to a breakdown of the routeing
procedures, malicious intent, or lack of
This Technical Report makes use of the following terms
information, discards or otherwise refuses to
defined in IS0 8648:
forward all traffic directed to it.
a) Subnetwork
A black hole may also be formed on a connectionless
b) End system
subnetwork when the intended recipient of traffic is
unavailable.
c) Intermediate system
3.4.6 Subnetwork Address Resolution Entity: A
d) Subnetwork service
network layer entity available on a subnetwork
which acts as a repository for, and source of,
3.3 Network Layer Addressing Definitions
routeing information for that subnetwork.
This Technical Report makes use of the following terms
3.4.7 multicast subnetwork: a subnetwork in which a
defined in CCITT Rec. X.213 I ISO/IEC 8348.
single data unit transmitted by a source is received
by multiple destinations.
a) Subnetwork address
3.4.8 multicast communication: the use of a
b) Subnetwork Point of Attachment
multicast subnetwork for data transmission.
3.4 Routeing Framework Definitions
4 Svmbols and Abbreviations
u
For the purpose of this Technical Report the following
definitions apply.
Border Intermediate System
BIS
3.4.1 Administrative Domain: A collection of End
End System
ES
systems, Intermediate systems, and subnetworks
IS Intermediate System
operated by a single organisation or administrative
authority.
LAN Local Area Network
The components which make up the domain are assumed to
NPDU Network Protocol Data Unit
interoperate with a significant degree of mutual trust among
NSAP Network Service Access Point
themselves, but interoperate with other Administrative
Domains in a mutually suspicious manner.
OSIE Open System Interconnection Environment
The term Administrative Domain is not intended to
NOTE:
PDU Protocol Data Unit
have any particular relationship to an Administration
as defined by the ITU-T. A ITU Administration may in
0 Quality of Service
QS
fact operate an Administrative Domain, but this would
SN Subnetwork
be no different from an Administrative Domain
operated by any organisation from the point of view
SNARE Subnetwork Address Resolution Entity
of this Routeing Framework.
SNPA Subnetwork Point of Attachment
A set of End Systems and
3.4.2 Routeing Domain:
Intermediate Systems which operate according to
WAN Wide Area Network
the same routeing procedures and which is wholly
contained within a single Administrative Domain.
5 Routeing Concepts
See 8.1.2.1 for a precise formal definition of this concept.
5.1 Functional Decomposition of Routeing
An Administrative Domain
3.4.3 common domain:
OS1 Routeing can be decomposed into four different but
which is not a member of a higher level domain.
interrelated aspects. The purposes of this division are to:
A common domain is the highest level in the routeing
- conceptually clarify the functions of routeing;
hierarchy. There is no single domain above the common
domain. In this sense, the routeing hierarchy is in fact
2
---------------------- Page: 6 ----------------------
0 ISOAEC lSO/IEC TR 9575:1995 (E)
simplify the design of routeing protocols by breaking - Network maps. These are complete topological
-
graphs of a portion of the global network. Such
routeing into its component parts; and
maps can be used to compute shortest paths to
- make the routeing functions as flexible as is practical
destination NSAPs using any of a number of routeing
by allowing for degrees of freedom in each aspect.
metrics.
The four aspects are described in the following clauses.
5.1.2 Information Collection
Figure 1 below illustrates the relationship among these four
aspects of routeing.
ESs and ISs build up their routeing information bases by
collecting information from their local environment and
5.1.1 Routeing Information Base
from other systems. Some example sources of information
are: measurement protocols, policy input from System
The Routeing Information Base comprises the complete
Management, directory lookup functions, and routeing
information required by a particular ES or IS to accomplish
protocols. The information collection function is illustrated
routeing. Such information might include:
in figure 1 by the box labelled Update Receive.
- Next hop routeing tables. These are tables which
relate destination NSAPs to the potential next
5.1.3 Information Distribution
subnetwork hops (e.g. local and remote SNPAs)
Systems may inform other systems of pertinent information
which might be used to forward the PDU closer to its
in their local routeing information base by distributing this
destination.
information. Some examples of information distribution
- Lists of neighbour ESs and ISs. These lists enable
techniques include: routeing protocols and interactions
an ES or IS to ascertain the local topology.
through the management information bases. The
information distribution function is illustrated in figure 1 by
- Measured QoS characteristics of a datalink or
the box labelled Update Send.
These measurements allow the
subnetwork path.
routeing functions to adapt to QoS changes.
Update
Send
_.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.:::::.:.
. . . . . . . . . . . . . . . . . . .i. q::::::,,
,&$:::.
. . . Routeing
..:::y
. .L.i
.gg:
:$$
:::::::
i. Information Base
. . . . . . .
.:.:.:.
$:#
.,. :: . .:.
Decision
.:.:.:.
. . . . . . .
g$ Forwarding
.:.:.:.
:;$
y:::.
yg.,
Information Base 1
‘::z&.,
‘+:+:+;. .
..:.:.:.:.:.:.:.:.:.:.~:.:.:.:.:.:.:.:.~:.:.~~:.:.:.:.:.:.:~:.~~~.~.:.:~:.:.:.:.:~:.:.:.:.:.:.:.:.:.:..
‘.‘.:.:.:.:.:.:.:.~.:.:.:.:.:.:.~.~:.:.~~:.:.~~:.~:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:. .
Forward
Figure 1 - Decomposition of the Routeing Function
3
---------------------- Page: 7 ----------------------
lSO/lEC TR 9575:1995 (E) 0 lSO/IEC
sequence of network entity titles or network entity
5.1.4 Route Calculation and Maintenance
title prefixes which identify Network relay systems.
These are the internal functions executed by ESs and ISs on See, for example, the source routing function of
the routeing information base to accomplish routeing. The ITU-T Rec. X.233 I ISO/IEC 8473-l. In a complete
major function in this category is the generation of the source route the next network entity title in the
forwarding information base which is used to actually relay sequence is the output of Fl. In a partial source
NPDUs. This function is illustrated in figure 1 by the box route, the next network entity title or network entity
labelled Decision. Other examples of these internal title prefix in the sequence is used to determine the
functions include: timing functions such as ageing old
network entity title of a Network relay system used to
reach the Network relay identified by the source route.
routeing information base entries, and the functions Fl and
F2 described below.
e) Quality of service (QoS) parameters (optional);
5.1.4.1 Functions Fl and F2
f) the Forwarding Information Base.
The functions Fl and F2 are two functions required by every
For each NPDU that is routed, Fl determines
ES and IS to route an NPDU. The inputs to Fl are
f) The Network entity title of a Network relay system
a) the called or destination NSAP address;
on the path to the destination NSAP or else,
b) the calling or source NSAP address;
g) The title of the destination Network entity, if no relay
function is necessary to reach the destination. The
c) a source route (optional). A source route is a
~~~~~~~~~~~~~~~~~~
al System Remote End
or Intermediate
System
OS1
Management
Application
Local
Information
Base
, ,:::_:,:,:,:_:.:.:_:.:.:.: :.:.:.:.:_: :.:+:_:.: :_:_.:_:.:_:_: :.:.:.:.:::f , :_ :::: :_:.,_:_:_:.:: ____. . . . . . . . . . . . . .~._.~. :.:.y.:.:
- .,:
N-Routeing Protocol _:
w ,z Routeing :i( 4
b $ Routeing $
$ Info Base 2 :# Info Base $
2.:
::: . . i:: :.
:j: .:.
:::
._._. ._. _. _. ,. .(.I .,.,. ., : ._., :.:.:.:.:: :.:.:.:: :___:.::.: :_: .:.:.:.:_::‘::
. . . . . . . ._. _. .z. .z. . . . . . . ::::. ‘.‘.
Figure 2 - Routeing Exchange using Network Layer Protocols
---------------------- Page: 8 ----------------------
ISO/IEC TR 9575:1995 (E)
0 ISO/IEC
title may be the same as the destination NSAP address.
5.2 Relationship of Routeing to OS1
Management
The inputs to F2 are:
h) The network entity title of the Network relay or Operation of the Network Layer, in fulfilment of the role
destination End system determined by Fl. assigned to it in the OS1 Reference Model, requires shared
knowledge concerning the location of NSAPs and routes
i) QoS.
through the available subnetworks.
j) the Forwarding information base.
As shown in figures 2 and 3, the routeing function intersects
with OS1 management through information stored in, and
This function is performed after Fl to determine which
retrieved from, the management information base (the boxes
subnetwork point of attachment (SNPA) to use when
labelled Local Information Base in the figures). Routeing
sending an NPDU to the Network relay or destination
information is placed in the management information base
network entity. The information yielded by this function is:
either through interaction with Network Layer entities or
k) identification of the selected SNPA.
through interaction with System Management (the box
labelled OSI Management Application).
1) values of parameters which are input to the
subnetwork service provider associated with that
It may be desirable to collect and distribute routeing
SNPA.
information automatically through the operation of OS1
Routeing protocols; these protocols may be located at the
Remote End
Local System
or Intermediate
System
OS1
OS1
Routeing Information
Management Management
----VI
Application Application
Local
Information
System Management Protocol
A-Entity A-Entity
Base
N-Entity
N-Entity 1
I
I
:::::::::::::~.::~.:::j:::~.::::::::::::::::::~::::::~::::::::::
:::
:;:
$ Routeing $
:::
:::
$ Info Base $
:::
:;:
:c.s
.~.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:
Figure 3 - Routeing Exchange using System Management
5
---------------------- Page: 9 ----------------------
ISO/IEC TR 9575:1995 (E)
0 ISO/IE@
Network Layer (Layer management) or the application layer private networks may be interconnected using public
(System management). network facilities. Routeing functions shall be capable of
efficient routeing within both the private and public
The use of a “network layer teing information exe hange
rou
domains, while providing the organisational isolation
protocol ” has (among others) following advantages
the
necessary for the separate management of these domains.
Further, the routeing methods, metrics, and policies may be
- it confines the generation, exchange, and
very different in the public domain than in the private
synchronisation of routeing information within the
domain. Routeing functions shall be capable of successfully
Network layer. This keeps routeing a “closed
dealing with the limited control and data flow across these
system” and avoids difficult issues in cross-layer co-
sorts of boundaries.
ordination.
- it permits the efficient and direct use of subnetwork
6.3 Factory and Campus Networks
capabilities which may be available, such as inherent
The use of networks in factories and campus environments
multicast.
such as universities, corporate headquarters, government
Figure 2 illustrates the use of a layer management protocol
ministries, and research establishments is growing rapidly.
to exchange routeing information. Use of an “application
These environments are characterised by large numbers of
layer routeing information exchange protocol” has (among
systems (sometimes in the thousands) connected by rich
others) the following advantage:
topologies. In these environments, the configuration of the
network tends to change rapidly and the exercise of
- context negotiation and the establishment of
centralised control over the installation and operation of
management associations over a reliable end-to-end
systems minimal. Routeing schemes for this kind of
transport service is possible.
environment need to be robust against unanticipated
illustrates use of a syste m management
Figure 3 the
configuration changes and be able to adapt to changes in
exchange routei ng i nformation.
protocol to
network usage, applications, and traffic patterns without the
need for the extensive intervention of a centralised
In general, it is likely that a complete and realistic solution
administrative function.
to the global routeing problem in the OS1 environment will
require a combination of techniques, involving both
6.4 Multi-vendor Subnetworks
Network layer management protocols and System
management protocols.
Networks are inherently a multi-vendor environment. It is
extremely rare for a consumer to acquire an entire
6 Environment for OS1 Routeing
subnetwork (LAN or WAN) from a single vendor, since
systems are purchased at different times for different
OS1 Routeing shall be capable of operating effectively in a
applications.
In many cases however, operators of private
variety of environments, which when considered together
(and in some cases public) networks are forced to acquire all
result in a number of difficult goals for any Routeing
of their ISs from a single source because of the lack of
scheme to satisfy. This clause discusses some of the
routeing standards. This situation limits the ability of
environments envisioned for OS1 routeing and points out
organisations to build cost-effective networks and severely
some of their salient features from the point of view of
constrains the ways in which their networks can be
routeing.
interconnected with those of other organisations. An
effective set of OS1 routeing standards will enable the
6.1 Interconnection of LANs
construction of practical multi-vendor subnetworks, much as
LANs may be connected either locally through an the rest of OS1 has enabled systems from multiple vendors
Interworking Unit, or across larger distances via point-to- to interoperate.
point subnetworks, multicast subnetworks, private leased-
line networks, or public data networks. In all cases routeing
7 Goals for OS1 Routeing
functions are needed to determine paths through the WAN
The environment identified for OS1 routeing in clause 6
that meet connectivity and/or QoS requirements. These
results in some difficult goals for any OS1 routeing scheme.
routeing functions may be arbitrarily complex, depending on
These goals are discussed in the following subclauses.
whether organisational boundaries are being crossed, the need
for optimal routes, resilience from failure, etc. In addition,
7.1 Multiple Subnetwork Types
the routeing functions for LAN-WAN interconnection need
to take account of the wide disparity of transmission
The routeing functions defined within this framework shall
bandwidth between the two environments.
be designed to operate without regard to any specific
underlying technology or transmission medium, to the
6.2 Public/Private Network
extent that they do not rely upon any technology specific
Interconnection
service for their correct operation. These functions shall
also be designed to operate correctly irrespective of the
Many organ sations already operate pri vate data networks.
geographic distribution of ESs and ISs which comprise the
communicate with other organisations their
In order to
6
---------------------- Page: 10 ----------------------
0 ISOAEC lSO/lEC TR 95731995 (E)
global Routeing Domain (i.e. they are not topology and illegal routeing (especially with regard to national
boundaries).
dependent). Furthermore, the routeing information
exchanged should provide a minimum of ancillary
7.2 Very Large Number of ESs and ISs information while providing a maximum of routeing
functionality. Examples of ancillary information about the
The global OSIE in which End System data are to be
internals of an administrative domain might include
transferred is assumed to consist of a very large number of
- topology information,
NSAPs (>107) which, in the most general situation, may be
logically interconnected by means of paths consisting of
- size,
concatenated intermediate systems. The total number of
intermediate systems is assumed to be one to two orders of
- level of activity,
magnitude fewer than the number of NSAPs (or End
- reliability,
Systems), but very large as well. Any routeing scheme
adopted for OS1 shall be capable of indefinite scaling.
quality and/or type of service, and
tariff structure.
7.2.1 End Systems Should be Kept Simple
Organisations operating administrative domains should be
A consequence of the preponderance of End-systems over
able to control the “leakage” of information outside their
Intermediate systems is the desire to keep the ESs simple,
administrative domain(s). That is, they should be able to
even at the expense of making the ISs more complicated.
control the amount and kind of information which enters or
This makes sense also because Intermediate systems are
leaves their administrative boundaries while still providing
often dedicated to routeing and relaying. End-systems, on the
and receiving some minimum global routeing capability.
other hand, perform routeing as an overhead function
necessary to enable them to do their real job of executing
When establishing administrative boundaries and exchanging
applications.
routeing information across those boundaries, strong
authentication of Network entities may be required.
7.3 Multiple Organisations
Authentication of Network entities is necessary to prevent
an IS belonging to one administrative domain from claiming
The presence of multiple organisations within the OS1
to be a different IS belonging to another (possibly the local)
environment will require the following attributes of OS1
administrative domain. Without authentication,
routeing.
administrative domains may be susceptible to a variety of
7.3.1 Distribution of Control external attacks, including the denial of service to large
numbers of systems”
Global routeing shall by necessity be able to operate
correctly under the distributed control of multiple
7.3.3 Routeing Domains
organisations. Furthermore, the control of routeing within a
The routeing functions shall be designed to operate across
single organisation may be distributed for reasons of
multiple Routeing Domains (see 8.1.2 for detailed
efficiency, economy, performance, etc.
informat
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.