ISO/IEC 10747:1994
(Main)Information technology — Telecommunications and information exchange between systems — Protocol for exchange of inter-domain routeing information among intermediate systems to support forwarding of ISO 8473 PDUs
Information technology — Telecommunications and information exchange between systems — Protocol for exchange of inter-domain routeing information among intermediate systems to support forwarding of ISO 8473 PDUs
Specifies a protocol to be used by boundary intermediate systems to acquire and maintain information for the purpose of routeing NPDUs between different routeing domains. Lays down the procedures for the exchange of inter-domain reachability and path information between BISs, the procedures for maintaining inter-domain routeing information bases within a BIS, the encoding of protocol data units used to distribute inter-domain routeing information between BISs, the functional requirements for implementations that claim conformance to this standard. The protocol described operates at the level of individual routeing domains. Does not cover the establishment of administrative domains.
Technologies de l'information — Télécommunications et échange d'information entre systèmes — Protocole pour échange d'information inter-domaine de routage parmi les systèmes intermédiaires supportant la transmission de PDUs de l'ISO 8473
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Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD
10747
First edition
1994-l o-01
Information technology -
Telecommunications and information
exchange between systems - Protocol for
exchange of inter-domain routeing
information among intermediate systems
to support forwarding of IS0 8473 PDUs
- T&&ommunications et Gchange
Technologies de /‘information
- Pro tocole pour kchange d ‘informa tion
d ‘information en tre systkmes
inter-domaine de routage parmi /es syst&mes intermgdiaires supportant la
transmission de PDlJs de I’ISO 8473
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ISOAEC 10747: 1994 (E)
0 ISOAEC
Contents
1 Scope . . . . . . . . . . . . . . . . . . . . . . 1
5.10 Routeing domain identifiers . . . . . . . . . 9
5.11 Formats of RDls, NETS, and NSAP addresses 10
2 Normative references . . . . . . . . . . . . . .
1 5.12 Design objectives
. . . . . . . . . . . . . . 10
5.12.1 Within the scope of the protocol . . . . 10
3 Definitions . 2
5.12.2 Outside the scope of the protocol
. . . 10
3.1 Reference model definitions . 2
6 Structure of BlSPDUs .
3.2 Network layer architecture definitions 11
.... 3
6.1 Header of BISPDU .
3.3 Network layer addressing definitions 11
.... 3
6.2 OPEN PDU . 12
3.4 Routeing framework definitions .
3
6.3 UPDATE PDU . 14
3.5 Intra-domain routeing definitions . 3
6.3.1 Path attribute encoding
3.6 Additional definitions . 14
............. 3
6.3.2 Network layer reachability information
. 19
6.4 IDRP ERROR PDU .
4 Symbols and abbreviations . 20
4
6.5 KEEPALIVE PDU . 21
4.1 Data unit abbreviations . 4
6.6 CEASE PDU . 21
4.2 Addressing abbreviations . 4
4.3 Other abbreviations 6.7 RIB REFRESH PDU . 21
.............. 5
7 Elements of procedure
5 General protocol information . 5 21
7.1 Naming and addressing conventions . . . . . 22
5.1 Inter-RD topology . 5
7.1.1 Interpretation of address information . . 22
5.2 Routeing policy . 6
7.1.2 NSAP address prefixes
............... . . . . . . . . . 22
5.3 Types of systems 7
7.2 Deployment guidelines . . . . . . . . . . . . 22
5.4 Types of routeing domains .
7
7.2.1 Minimum configuration of an RD . . . . 22
5.5 Routeing domain confederations . 7
7.2.2 Deployment of ISs and ESs . . . . . . . 22
5.6 Routes: advertisement and storage . 7
7.3 Domain configuration information . . . . . . 23
5.7 Distinguishing path attributes and RIB-Atts . 8
7.4 Advertising NLRI
5.8 Selecting the information bases . . . . . . . . . . . . . . . . 23
8
7.5 Receive process . . . . . . . . . . . . . . . . 24
5.9 Routeing information exchange .
8
7.6 BIS-BIS connection management
5.9.1 Internal neighbor BIS . 8 . . . . . . 24
7.6.1 BIS finite state machines
5.9.2 External neighbor BIS . 9 . . . . . . . . 24
0 lSO/lEC 1994
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 photocopyrng and
microfilm, without permission in writing from the publisher.
I SO/I EC Copyright Off ice l Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
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........... 29
7.6.2 Closing a connection 7.20.4 IDRP ERROR PDU error handling
. . _ 59
7.7 Validation of BISPDUs . 29 7.20.5 Hold timer expired error handling . . . 59
7.7.1 Authentication type I . 29 7.20.6 KEEPALIVE PDU error handling
. . . . 59
7.7.2 Authentication type 2 . 29 7.20.7 CEASE PDU error handling . . . . . . . 59
.......... 29
7.7.3 Authentication type 3 7.20.8 RIB REFRESH PDU error handling . . . 59
7.7.4 Sequence numbers . 31
7.7.5 Flow control . 31
8 Forwarding process for CLNS . . . . . . . . . 59
7.8 Version negotiation . 33
8.1 Forwarding to internal destinations
. . . . . 60
............. 33
7.9 Checksum algorithm
8.2 Determining the NPDU-derived distinguishing
7.10 Routeing information bases . 33
attributes . . . . . . . . . . . . . . . . . . . . . 60
33
7.10.1 Identifying an information base .
8.3 Matching RIB-Att to NPDU-derived
............ 34
7.10.2 Validation of RIBS
distinguishing attributes . . . . . . . . . . . . . 60
..... 35
7.10.3 Use of the RIB REFRESH PDU
8.4 Forwarding to external destinations . . . . . 61
7.11 Path attributes . 35
7.11.1 Categories of path attributes . 35
7.11.2 Handling of distinguishing attributes . 37
9 Interface to IS0 8473 . . . . . . . . . . . . . . 62
7.11.3 Equivalent distinguishing attributes . . 37
9.1 Use of network layer security protocol over
7.12 Path attribute usage . 37
IS0 8473. . . . . . . . . . . . . . . . . . . . . . 62
7.12.1 ROUTE-SEPARATOR . 37
................ 38
7.12.2 EXT-INFO
7.12.3 RD-PATH . 38
10 Constants . . . . . . . . . . . . . . . . . . . . 63
7.12.4 NEXT-HOP . 40
7.12.5 DIST-LIST-INCL . 41
11 System management and GDMO definitions . 63
42
7.12.6 DIST-LIST-EXCL .
11.1 Name binding
................ 63
7.12.7 MULTI-EXIT-DISC . 43
11.2 Managed objects for IDRP
.......... 63
7.12.8 TRANSIT DELAY . 43
11.3 Packages for IDRP 63
..............
7.12.9 RESIDUAL ERROR . 43
11.4 Attribute definitions . 67
................ 44
7.12.10 EXPENSE
11.5 Parameter definitions
............ 71
7.12.11 LOCALLY DEFINED QOS . 44
11.6 Behaviour
.................. 72
7.12.12 HIERARCHICAL RECORDING . 44
11.7 ASN.1 modules 72
................
7.12.13 RD-HOP-COUNT . 45
............... 45
7.12.14 SECURITY
7.12.15 CAPACITY . 45
12 Conformance . . . . . . . . . . . . . . . . . . 74
7.12.16 PRIORITY . 46
12.1 Static conformance for all BISs . . . . . . . 75
......
7.13 Routeing domain confederations 46
12.2 Conformance to optional functions . . . . . 75
7.13.1 RDC policies . 46
12.2.1 Generation of information in reduced
7.13.2 RDC configuration information . 46
form . . . . . . . . . . . . . . . . . . . . . . 75
7.13.3 Detecting confederation boundaries . . 46
12.2.2 Generation of well-known discretionary
.......... 46
7.14 Update-Receive process
attributes . . . . . . . . . . . . . . . . . . . 75
7.15 Information consistency . 47
12.2.3 Propagation of well-known discretionary
7.15.1 Detecting inconsistencies . 47
attributes . . . . . . . . . . . . . . . . . . . 75
7.16 Decision process . 47
12.2.4 Peer entity authentication . . . . . . . 76
7.16.1 Phase 1: calculation of degree of
...................
preference 48
7.16.2 Phase 2: route selection . 48
Annex A PICS proforma . . . . . . . . . . . . . 77
7.16.3 Phase 3: route dissemination . 49
A.1 Introduction . . . . . . . . . . . . . . . . . . 77
7.16.4 Interaction with update process . 50
A.2 Abbreviations and special symbols . . . . . 77
7.17 Update-Send process . 51
A.2.1 Status symbols . . . . . . . . . . . . . 77
7.17.1 Internal updates . 51
A.3 Instructions for completing the PIGS proforma 77
7.17.2 External updates . 52 A.3.1 General structure of the PIGS proforma 77
7.17.3 Controlling routeing traffic overhead . 52 A.3.2 Additional information . . . . . . . . . . 78
7.18 Efficient organization of routeing information 53 A.3.3 Exception information . . . . . . . . . . 78
7.18.1 Information reduction . 53 A.3.4 Conditional status . . . . . . . . . . . . 78
7.18.2 Aggregating routeing information . 53
A.4 Identification . . . . . . . . . . . . . . . . . 79
7.19 Maintenance of the forwarding information
A.4.1 PIGS proforma: IDRP implementation
bases . 56 identification . . . . . . . . . . . . . . . . . . 79
7.20 Error handling for BISPDUs . 56 A.4.2 PIGS proforma: IDRP protocol summary 80
7.20.1 BISPDU header error handling . 56 A.4.3 PIGS proforma: IDRP general . . . . . . 80
7.20.2 OPEN PDU error handling . 57 A.4.4 PIGS proforma: IDRP update send
......
7.20.3 UPDATE PDU error handling 57 process . . . . . . . . . . . . . . . . . . . . 81
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Annex H Processor overload . . . . . . . . . . . 94
A.45 PIGS proforma: IDRP update receive
process . . . . . . . . . . . . . . . . . . . . 81
A.4.6 PIGS proforma: lDRP decision process . 81
Annex J Formation of RDCs
. . . . . . . . . . . 95
A.4.7 PIGS proforma: IDRP receive process . 81
J.l Forming a new lower level confederation . . 95
A.4.8 PIGS proforma: IDRP CLNS forwarding . 82
J.2 Forming a higher level confederation
. . . . 95
A.4.9 PIGS proforma: IDRP authentication . . 82
J.3 Deleting a lowest level confederation
. . . . 96
A.4.10 PIGS proforma: IDRP optional transitive
J.4 Deleting a higher level confederation
. . . . 96
attributes . . . . . . . . . . . . . . . . . . . 82
A.4.1 1 PICS proforma: Generating IDRP
Annex K Exa of MULTI-EXIT-DISC
well-known discretionary attributes . . . . . 83
attrib ute . . . . . . . . . . . . . . . 97
A.4.12 PIGS proforma: Propagating IDRP
well-known discretionary attributes . . . . . 84
A.4.13 PICS proforma: Receiving IDRP
Annex L Syntax and semantics for policy . 99
well-known discretionary attributes . . . . . 85
99
L.l Overview .
L.l.l Preference statement . 99
Annex B IDRP checksum generation algorithm . 86
L.1.2 Aggregation statement . 100
B.l Mathematical notation . . . . . . . . . . . . 86
L.1.3 Distribution statement . 101
B.2 Algorithm description . _ . . . . . . . . . . . 86
L.2 Policy configuration language BNF . 102
L.2.1 PREF statement BNF . 102
Annex C Bibliography . . . . . . . . . . . . . . . 88
L.2.2 AGGR statement BNF . 102
102
1.2.3 DIST statement BNF .
. . . 89
Annex D Examp of authentication type 2
......... 103
L.2.4 Common BNF symbols
mechanism . . . . . . . . . . 89
D.l Auth enticati
L.3 Simple example . 104
L.3.1 Transit domain 3 . 104
. . . . . . . . . . . . . 91
Annex E Jitter algorithm
L.3.2 Policy configuration example . 105
L.3.3 Discussion . 106
92
Annex F Computing a checksum for an Adj-RIB
Index . . . . . . . . . . . . . . . . . . . . . . . 110
Annex G RIB overload . . . . . . . . . . . . . . 93
iv
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0 ISOAEC
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Figures
Tables
1. Field of Application 2
............. 1. The IDRP Information Bases ........ 9
2. intermediate Routeing Domains and End 2.
BIS Finite State Machine . 26
Routeing Domains
.............. 4 3. Path Attribute Characteristics 36
.......
3. Position of IDRP within Network Layer . 6
4. NPDU-Derived Attribute Set . 61
4. Inter-domain Routeing Components . 7 5. IDRP-CL Primitives
............. 63
5. Structure of the UPDATE PDU . 15 6. Architectural Constants of IDRP
...... 64
Illustration of Authentication Types 1 and 3
6. 30
7. Routeing Information Base 34
.........
8. A Transitive Fully Connected Subnetwork . 41
9. IDRP Naming and Containment Hierarchy _ 65
D.l An Example of the Authentication Type 2 . 90
Example 1 Configuration
K.l . 98
K.2 Example 2 Configuration
.......... 98
L.l A Portion of an Internet . 105
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0 ISOAEC
ISOIIEC 10747: 1994 (E)
_-
Foreword
IS0 (the International Organization for Standardization) and IEC (the Inter-
national Electrotechnical Commission) form the specialized system for
worldwide standardization. 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 commit-
tees collaborate in fields of mutual interest. Other international organiza-
tions, 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, lSO/IEC JTC 1. Draft International Standards adopted
by the joint technical committee are circulated to national bodies for vot-
ing. Publication as an International Standard requires approval by at least
75 % of the national bodies casting a vote.
International Standard ISO/IEC 10747 was prepared by Joint Technical
Committee lSO/IEC JTC 1, Information technology, Subcommittee SC 6,
Telecommunications and information exchange between systems.
Annexes A and B form an integral part of this International Standard. An-
nexes C, D, E, F, G, H, J, K and L are for information only.
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0 ISOAEC
ISOAEC 10747: 1994 (E)
the BIS, using the methods of this inter-domain
Introduction
routeing protocol, will calculate a path to a Boundary
Intermediate system in an adjacent routeing domain
This Protocol is one of a set of International Stand-
lying on a path to the destination. After arriving at
ards which facilitate the interconnection of open
the next routeing domain, the NPDU may also travel
systems. They cover the services and protocols
within that domain on its way towards a BIS located
required to achieve such interconnection.
in the next domain along its path. This process will
continue on a hop-by-hop basis until the NPDU arrives
This Protocol is positioned with respect to other
at a BIS in the routeing domain which contains the
related standards by the layered structure defined in
destination End system. The Boundary IS in this
IS0 7498, and by the Network layer organization
routeing domain will hand the incoming NPDU over to
defined in IS0 8648. It is located at the top of the
the domain’s intra-domain routeing protocol, which
Network layer and relies on the services of IS0 8473.
will construct a path to the destination End system.
This protocol permits a routeing domain to exchange
information with other routeing domains to facilitate
This inter-domain IS-IS routeing protocol places
the operation of the routeing and relaying functions of
requirements on the type of information that a
the Network Layer. It applies to the following catego-
routeing domain must provide and on the methods by
ries of routeing, which are described in
which this information will be distributed to other
ISO/IEC TR 9575, making no distinction between
routeing domains. These requirements are intended
them:
to be minimal, addressing only the interactions
- Intra-Administrative Domain routeing between between Boundary ISs; all other internal operations of
routeing domains each routeing domain are outside the scope of this
- Inter-Administrative Domain routeing between protocol. That is, this Inter-domain routeing protocol
does not mandate that a routeing domain run a par-
routeing domains.
ticular intra-domain routeing protocol: for example, it
Within the hierarchical relations between routeing would be a local choice as to whether a domain
protocols, as described in ISO/IEC TR 9575, this pro- implements a standard intra-domain protocol (such as
tocol is situated above the intra-domain routeing pro- ISO/IEC 10589) or a private protocol.
tocols. That is, this Inter-domain IS-IS protocol:
The methods of this protocol differ from those gener-
- maintains information about the interconnections
ally adopted for an intra-domain routeing protocol
between routeing domains, but does not require
because they emphasize the interdependencies
detailed information about their internal struc-
between efficient route calculation and the preserva-
tures
tion of legal, contractual, and administrative concerns.
- calculates path segments on a hop-by-hop basis This protocol calculates routes which will be efficient,
loop-free, and in compliance with the domain’s local
routeing policies. IDRP may be used when routeing
This protocol calculates path segments which consist
of Boundary Intermediate systems and the links that domains do not fully trust each other; it imposes no
interconnect them. An NPDU destined for an End upper limit on the number of routeing domains that
system in another routeing domain will be routed via can participate in this protocol; and it provides iso-
lation between its operations and the internal oper-
Intra-domain routeing to a Boundary Intermediate
ations of each routeing domain.
system (BIS) in the source routeing domain. Then,
vii
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0 ISOAEC
ISOAEC 10747: 1994 (E)
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INTERNATIONAL STANDARD 0 MMEC
ISO/IEC 10747: 1994 (E)
Information technology - Telecommunications and information
exchange between systems -
Protocol for exchange of inter-
domain routeing information among intermediate systems to
support forwarding of is0 8473 PDUs
1 Scope
2 Normative references
This International Standard specifies a protocol to be The following standards contain provisions which,
used by Boundary Intermediate systems (defined in
through reference in this text, constitute provisions of
3.6) to acquire and maintain information for the
this International Standard. At the time of publica-
purpose of routeing NPDUs between different routeing
tion, the editions indicated were valid. All standards
domains. Figure 1 illustrates the field of application are subject to revision, and parties to agreements
of this International Standard. based on this International Standard are encouraged
to investigate the possibility of applying the most
This International Standard specifies:
recent editions of the standards listed below.
Members of IEC and IS0 maintain registers of cur-
the procedures for the exchange of inter-domain
rently valid International Standards.
reachability and path information between BlSs
the procedures for maintaining inter-domain IS0 7498: 1984, Information processing systems -
routeing information bases within a BIS Open Systems Interconnection - Basic Reference
the encoding of protocol data units used to dis- Model.
tribute inter-domain routeing information between
IS0 7498lAdd. 1: 1984, Information processing systems -
BlSs
Open Systems Interconnection - Basic Reference Model -
the functional requirements for implementations
Addendum 7: Connectionless-mode transmission.
that claim conformance to this International
Standard IS0 7498-3:1989, Information processing systems - Open
Sys terns Interconnection - Basic Reference Model - Part 3:
Naming and addressing.
The procedures are defined in terms of:
- interactions between Boundary Intermediate lSO/IEC 7498-4:1989, Information processing systems -
Open Systems Interconnection - Basic Reference Model -
systems through the exchange of protocol data
Part 4: Management frame work.
units
- interactions between this protocol and the under-
ISO/IEC 8208:1990, Information technology - Data
lying Network Service through the exchange of
communjcations - X.25 Packet Layer Protocol for Data
service primitives
Terminal Equipment.
- constraints on policy feasibility and enforcement
ISO/IEC 8348:i 993, Information technology - Network
which must be observed by each Boundary Inter-
mediate system in a routeing domain Service Definition.
IS0 8473:1988, Information processing systems - Data
The boundaries of Administrative Domains are real-
communjcations - Protocol for providing the
ized as artifacts of the placement of policy constraints
connectionless-mode network service.
and the aggregation of network layer reachability
IS0 8648: 1988, Information processing systems -
information; they are not manifested explicitly in the
Telecommunications and information exchange
protocol. The protocol described in this International
between systems - internal organiza tjon of the
Standard operates at the level of individual routeing
domains. The establishment of administrative Network Layer.
domains is outside the scope of this International
IS0 9542:1988, Information processing systems -
Standard.
Telecommunications and information exchange
between systems - End system to Intermediate system
routeing exchange protocol for use in conjunction with
the Protocol fos providing the connectionless-mode
network service (IS0 8473).
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ISO/IEC 10747: 1994 (E)
0 ISOAEC
:ps c=apa.
f
>
End
Pnmm+a4mam End
~f%ll+~l~u
End
Eoutelng
Damin
Eoutelng
Dulnti
I
Figure 1 - Field of Application: The inter-domain Routeing Protocol operates between routeing domains; intra-
domain routeing is not within its scope.
ISO/I EC TR 9575: 1990, information techndogy - Me-
3 Definitions
communications and information exchange between
systems - OS/ Routeing Framework.
For the purposes of this International Standard, the
ISO/I EC TR 9577: 1993, Information technology - Tele- following definitions apply.
communications and information exchange between
systems - Protocol identification in the Network Layer.
3.1 Reference model definitions
ISO/IEC 10030: 1990, Information technology - Tele-
communications and information exchange between
This International Standard uses the following terms
systems - End System Routeing Information Exchange
defined in IS0 7498:
Protocol for use in conjunction with IS0 8878.
a) Network entity
ISO/I EC 10589: 1992, Information technology - 7%/e-
b) Network Layer
communications and information exchange between
c) Network Protocol
systems - Intermediate system to intermediate system
d) Network Protocol Data Unit
intra-domain routeing routine information exchange
e) Network relay
protocol for use in conjunction with the protocol for
f) Network Service Access Point
providing the connectionless-mode Network Service
g) Network Service Access Point Address
(IS0 8473).
h) Real system
ISO/IEC 10165-4: 1992, Information technology - Open ’
i) Routeing
- Structure of management
Sys terns Interconnection
information: Guidelines for the definition of managed
This International Standard uses the following term
objet ts.
defined in IS0 7498-3:
ISO/IEC 10165-2:1992, Information technology - Open
a) (N)-entity title
Systems Interconnection - Structure of management
information: Definition of management information.
2
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0 ISOAEC
ISO/IEC 10747: 1994 (E)
3.2 Network layer architecture definitions 3.6.3 Boundary Intermediate system: An intermediate
system that runs the protocol specified in this lnterna-
This International Standard uses the following terms tional Standard, has at least one inter-domain link
defined in IS0 8648: attached to it, and may optionally have intra-domain
links attached to it.
a) End system
b) Intermediate System 3.6.4 End Routeing Domain: A routeing domain whose
local policies permit its BISs to calculate inter-domain
c) Subnetwork
path segments only for PDUs whose source is located
within that routeing domain. There are two varieties
3.3 Network layer addressing definitions
of End routeing domains: stub and multi-homed. A
stub ERD has inter-domain links to only one adjacent
This International Standard uses the following term
routeing domain, while a multi-homed ERD has inter-
defined in lSO/IEC 8348:
domain links to several adjacent routeing domains.
a) Subnetwork point of attachment
For example, the domains labelled as multi-homed
ERDs in Figure 2 have policies which prohibit them
from providing relaying functions; it is these policies,
3.4 Routeing framework definitions
not the topology of their interconnections, that make
them ERDs.
This International Stan dard uses the foll owin g terms
defin ed in IS0 95 75: 3.6.5 Transit Routeing Domain: A routeing domain
whose policies permit its BlSs to calculate inter-
a) Administrative Domain
domain path segments for PDUs whose source is
b) Common Domain
located either in the local routeing domain or in a dif-
c) Fire wall
ferent routeing domain. That is, it can provide a
d) Routeing Domain
relaying service for such PDUs. See Figure 2 for an
illustration of TRDs.
3.5 Intra-domain routeing definitions
3.6.6 Adjacent RDs: Two RDs (“A” and “B”) are adja-
cent to one another if there is a at least one pair of
This International Standard uses the following terms
BISs, one located in “A” and the other in “B”, that are
defined in IS0 10589:
attached to each other by means of a real subnet-
work.
a) Adjacency
b) Link
3.6 Additional definitions
3.6.8 Routeing Domain Confederation: A set of
For pu rpos es of this International Stan dard, the fol-
routeing domains which have agreed to join together
lowing defi nitions apply:
and to conform to the rules in 7.13 of this Interna-
tional Standard. To the outside world, a confeder-
3.6.1 Intra-domain IS-IS routeing protocol: A routeing
ation is indistinguishable from a routeing domain.
protocol that is run between Intermediate systems in
a single routeing domain to determine routes that
pass through only systems and links wholly contained
within the domain.
NOTE 1: Unless reference is made to a specific protocol,
a) all members of RDC-A are also members of
this term is used as a general designator, encom-
RDC-B
passing both private and internationally standard-
b) there are some members of RDC-B that are not
ized protocols.
members of RDC-A
3.6.2 Inter-domain link: A real (physical) or virtual
(logical) link between two or more Boundary Interme-
diate systems (see Figure 2). A link between two
BlSs in the same routeing domain carry both intra-
domain traffic and inter-domain traffic; a link between
a) there are some members of RDC-A that are also
two BISs located in adjacent routeing domains can
members of RDC-B, and
carry inter-domain traffic, but not intra-domain traffic.
b) there are some members of RDC-A that are not
members of RDC-B, and
c) there are some members of RDC-B that are not
members of RDC-A.
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ISO/IEC 10747: 1994 (E)
0 ISOAEC
Stub
ERD
adjacent routaing domcrina
------ Links between BEs in
the wrne routeing domain
@;li-homad)
Bcrundcwy IS
0
lEi!F J
irdsrd
Figure 2 - Intermediate Routeing Domains and End Routeing Domains: The classification of a routeing domain
as an TRD or an ERD depends upon its relaying policies.
3.6.11 Disjoint RDCs: Two routeing domain confeder-
4.1 Data unit abbreviations
ations, RDC-A and RDC-B, are disjoint from one
BISPDU Boundary Intermediate System PDU
another when there are no routeing domains which
are simultaneously members of both RDC-A and
DT PDU IS0 8473 Data Protocol Data Unit
RDC-B.
ER PDU IS0 8473 Error Protocol Data Unit
3.6.12 Policy Information Base: The collection of
NPDU Network Protocol Data Unit
routeing policies that a BIS will apply to the routeing
information that it learns using this International
NSDU Network Service Data Unit
standard. It is not required that all routeing domains
PDU Protocol Data Unit
use the same syntax and semantics to express policy;
that is, the format of the Policy Information Base is
left as a local option.
4.2 Addressing abbreviations
3.6.13 Route Origin: Each route or component of an
AFI Authority and Format Identifier
aggregated route has a single unique origin. This is
DSP Domain Specific Part
the RD or RDC in which the route’s destinations are
located.
IDI Initial Domain Identifier
IDP Initial Domain Part
LSAP Link Service Access Point
4 Symbols and abbreviations
NET Network Entity Title
NPAI Network Protocol Address information
The symbols, acronyms, and abbreviations listed in
the following clauses are used in this International
Standard.
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Network Service Access Point IDRP relies on the underlying Network service to
provide for fragmentation and reassembly of
Subnetwork Point of Attachment
BISPDUs. IDRP queues Outbound BISPDUs as input
to the underlying Network Layer service, retaining a
copy of each BISPDU until an acknowledgement is
received. Similarly, inbound BlSPDUs are queued as
Boundary Intermediate System
input to the BISPDU-Receive process.
csnnectisnless ode
IDRP exchanges BlSPDUs in a reliable fashion. It pro-
Connectionfess Mode Network Service
vides mechanisms for the ordered delivery of
BlSPDUs and for the detection and retransmission of
Confederation ember
lost or corrupted BlSPDUs. The mechanisms for
End Routeing Domain
achieving reliable delivery of BlSPDUs are described
in 7.7; methods for establishing BIS-BIS connections
ES End System
are described in 7.6.
FIB Forwarding Information Base
IDRP is consistent with the routeing model presented
FSM Finite State Machine
in IS0 TR 9575. To emphasize its policy-based
IDRP Inter-domain Routeing Protocol (an acronym
nature, the IDRP routeing model includes a Policy
for the protocol described in this Interna-
Information Base, as shown in Figure 4. IDRP can be
tional Standard)
described in terms of four major components:
IPI Initial Protocol Identifier
BISPDU-Receive Process: responsible for
a)
accepting and processing control and routeing
MIB Management Information Base
information from the local environment and from
...
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