1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T I.356TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(02/2004) SERIES I: INTEGRATED SERVICES DIGITAL NETWORK Overall network aspects and functions Performance objectives B-ISDN ATM layer cell transfer performance Amendment 1: New Appendix V Sup
2、port of Y.1541 QoS classes 0 and 2 in ATM-based networks ITU-T Recommendation I.356 (2000) Amendment 1 ITU-T I-SERIES RECOMMENDATIONS INTEGRATED SERVICES DIGITAL NETWORK GENERAL STRUCTURE Terminology I.110I.119 Description of ISDNs I.120I.129 General modelling methods I.130I.139 Telecommunication ne
3、twork and service attributes I.140I.149 General description of asynchronous transfer mode I.150I.199 SERVICE CAPABILITIES Scope I.200I.209 General aspects of services in ISDN I.210I.219 Common aspects of services in the ISDN I.220I.229 Bearer services supported by an ISDN I.230I.239 Teleservices sup
4、ported by an ISDN I.240I.249 Supplementary services in ISDN I.250I.299 OVERALL NETWORK ASPECTS AND FUNCTIONS Network functional principles I.310I.319 Reference models I.320I.329 Numbering, addressing and routing I.330I.339 Connection types I.340I.349 Performance objectives I.350I.359 Protocol layer
5、requirements I.360I.369 General network requirements and functions I.370I.399 ISDN USER-NETWORK INTERFACES Application of I-series Recommendations to ISDN user-network interfaces I.420I.429 Layer 1 Recommendations I.430I.439 Layer 2 Recommendations I.440I.449 Layer 3 Recommendations I.450I.459 Multi
6、plexing, rate adaption and support of existing interfaces I.460I.469 Aspects of ISDN affecting terminal requirements I.470I.499 INTERNETWORK INTERFACES I.500I.599 MAINTENANCE PRINCIPLES I.600I.699 B-ISDN EQUIPMENT ASPECTS ATM equipment I.730I.739 Transport functions I.740I.749 Management of ATM equi
7、pment I.750I.759 Multiplexing aspects I.760I.769 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. I.356 (2000)/Amd.1 (02/2004) i ITU-T Recommendation I.356 B-ISDN ATM layer cell transfer performance Amendment 1 New Appendix V Support of Y.1541 QoS classes 0 and 2 in
8、 ATM-based networks Source Amendment 1 to ITU-T Recommendation I.356 (2000) was agreed on 12 February 2004 by ITU-T Study Group 13 (2001-2004). ii ITU-T Rec. I.356 (2000)/Amd.1 (02/2004) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of
9、 telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World T
10、elecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In som
11、e areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognize
12、d operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “
13、shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the
14、 practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation d
15、evelopment process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are theref
16、ore strongly urged to consult the TSB patent database. ITU 2004 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. I.356 (2000)/Amd.1 (02/2004) 1 ITU-T Recommendation I.356 B-ISDN ATM layer cell transfe
17、r performance Amendment 1 New Appendix V Support of Y.1541 QoS classes 0 and 2 in ATM-based networks ITU-T Rec. Y.1541 defines a set of QoS classes for IP-based networks. Two of the Y.1541 classes have an IP packet transfer delay (IPTD) objective of 400 ms (class 1 and class 3) and two have a more s
18、tringent IPTD objective of 100 ms (class 0 and class 2). When supporting the transfer of IP packets over an ATM network, I.356 class 1 (stringent class) and class 5 (stringent bi-level class), both of which have a CTD objective of 400 ms, are obvious candidates for supporting Y.1541 classes 1 and 3.
19、 As there are no I.356 classes with an end-to-end CTD of 100 ms, support of Y.1541 QoS classes 0 and 2 requires more consideration. This appendix offers guidance on how ATM networks conforming to ITU-T Rec. I.356 can be configured to support the stringent delay Y.1541 QoS classes. NOTE All the assum
20、ptions and conditions regarding the applicability of the Y.l541 and I.356 QoS classes, including minimum line speeds, apply to the calculations in this appendix. Both ITU-T Rec. Y.1541 and the related ITU-T Rec. M.2301 indicate that the stringent delay IP QoS classes will not be achievable across th
21、e whole set of global IP paths. M.2301 goes so far as to use a 10 000 km reference connection for Y.1541 classes 0 and 2 rather than the more usual 27 500 km reference connection. A subset of ATM connections employing I.356 QoS classes 1 and 5 will be able to support the transfer of IP packets withi
22、n the delay limits specified by Y.1541 classes 0 and 2. Examples of such connections are given below. Table V.1/I.356 Example one: A direct VPC between two national portions directly interconnected by an undersea cable Portion Route length No. of switches I.356 classes 1 and 5 delay allocation Natio
23、nal portion 1 700 km 4 5.6 ms IIP 4000 km 0 25 ms National portion 2 1500 km 4 10.6 ms Total VPC delay 41.2 ms NOTE The delay figures have been rounded up to one decimal place. 2 ITU-T Rec. I.356 (2000)/Amd.1 (02/2004) Table V.2/I.356 Example two: A VCC between two national portions interconnected v
24、ia two international transit portions Portion Route length No. of switches I.356 classes 1 and 5 delay allocation National portion 1 1200 km 8 9.9 ms IIP(0) 50 km 0 0.3 ms ITP 1 300 km 3 2.8 ms IIP(0) 700 km 0 4.4 msITP 2 2000 km 3 13.4 ms IIP(0) 80 km 0 0.5 ms National portion 2 3500 km 8 24.3 ms T
25、otal VCC delay 55.6 ms NOTE The delay figures have been rounded up to one decimal place. Printed in Switzerland Geneva, 2004 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series B Means of expression: definitions, symbols, classification Series C General telecommunicatio
26、n statistics Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia syste
27、ms Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M TMN
28、and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality,
29、telephone installations, local line networks Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communications Series Y Global information infrastructure, Internet protocol aspects and Next Generation Networks Series Z Languages and general software aspects for telecommunication systems
