ISO_9542_1988_Amd_1_1999E.pdf

Reference numberISO 9542:1988/Amd.1:1999(E)INTERNATIONALSTANDARDISO9542First edition1988-08-15AMENDMENT 11999-09-15Information processing systems Telecommunications and informationexchange between systems End systemto Intermediate system routeing exchangeprotocol for use in conjunction with theProtocol for providing the connectionless-mode network service(ISO 8473)AMENDMENT 1:Addition of groupcomposition informationSystmes de traitement de linformation Tlinformatique Protocolede routage dun systme dextrmit un systme intermdiaire utiliserconjointement avec le protocole fournissant le service de rseau en modesans connexion(ISO 8473)AMENDEMENT 1:Addition dinformation de composition de groupeISO 9542:1988/Amd.1:1999(E)ISO/IEC 1999All rights reserved.Unless otherwise specified,no part of this publication may be reproducedor utilized in any form or by any means,electronic or mechanical,including photocopying andmicrofilm,without permission in writing from the publisher.ISO/IEC Copyright Office?Case postale 56?CH-1211 Genve 20?SwitzerlandPrinted in SwitzerlandiiISO/IECISO 9542:1988/Amd.1:1999(E)iiiForewordISO(the International Organization for Standardization)and IEC(the Inter-national Electrotechnical Commission)form the specialized system forworldwide standardization.National bodies that are members of ISO or IECparticipate in the development of International Standards through technicalcommittees established by the respective organization to deal withparticular fields of technical activity.ISO and IEC technical committeescollaborate in fields of mutual interest.Other international organizations,governmental and non-governmental,in liaison with ISO and IEC,also takepart in the work.International Standards are drafted in accordance with the rules given inthe ISO/IEC Directives,Part 3.In the field of information technology,ISO and IEC have established a jointtechnical committee,ISO/IEC JTC 1.Draft International Standards adoptedby the joint technical committee are circulated to national bodies for voting.Publication as an International Standard requires approval by at least 75%of the national bodies casting a vote.Amendment 1toISO 9542:1988waspreparedbyJointTechnicalCommittee ISO/IEC JTC 1,Information technology,Subcommittee SC 6,Telecommunications and information exchange between systems.ISO 9542:1988/Amd.1:1999(E)ISO/IEC1Add the following new annex D.Annex D(normative)Group composition informationIntroductionThis annex adds optional functionality relating to the exchange of information about groupmembership,in support of known-group multicast transfer.The entire ES-IS protocol is contained inISO 9542:1988.There are two modes defined for exchange of this group composition information.Inone mode,the extended mode,End systems are informed about all existing address groups and theirmembers.This information is necessary to implement a known-group multicasting on End systems.Since the distribution of this group information for larger groups means a not negligible usage ofnetwork bandwidth,the main field of application of this mode will be smaller networks with demands ona known-group multicasting facility.In the second mode,the basic mode,an End system has neitherthe information about any existing groups nor about their composition.End systems have only thepossibility to join or leave existing address groups.Since this mode enforces a minimum amount ofgroup information to be exchanged between End systems and Intermediate systems,it is also suitablefor large networks.ISO 9542:1988 provides the capability to support the routing of non-multicast NPDUs;however,itdoes not directly support the exchange of multicast NPDUs.The capabilities required to support EndSystems sourcing or sinking multicast NPDUs include the means for Intermediate Systems to findwhich multicast NPDUs are needed on which subnetworks.This annex defines the optional additional functionality to the ES-IS Routing Protocol(ISO 9542:1988)which supports the transfer of multicast NPDUs.It is an explicit goal of this Amendment that ESs andISs,some of which will have known-group multicast capabilities and some without,will be able to fullyfunction on the same networks.This annex does not change any aspect of a currently defined(i.e.non-multicast)ISO 9542:1988 implementation;it adds new optional functionality without modifyingcurrent functionality.Note:The rationale for this annex is based on the following considerations:The information exchanged between systems has also a security aspect.In the case of unicastinformation exchange both originator and recipient are identified by their NSAP address.Thisinformation can be used as one element for the identification of the communication partners(e.g.the NLSP uses this information for address mapping).In the case of a multicast recipient addresswith information hiding about group members(basic case in the following description)an originatoris not able to determine concrete members within a group address.In the case of