1、 International Telecommunication Union ITU-T G.992.3TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 2(07/2010) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Access networks Asymmetric digital subscriber line transceivers 2 (
2、ADSL2) Amendment 2: Retrain on eoc protocol timeout Recommendation ITU-T G.992.3 (2009) Amendment 2 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE C
3、ARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATI
4、ON OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 General G.900G.909 Parameters for optical fibre cable systems G.
5、910G.919 Digital sections at hierarchical bit rates based on a bit rate of 2048 kbit/s G.920G.929 Digital line transmission systems on cable at non-hierarchical bit rates G.930G.939 Digital line systems provided by FDM transmission bearers G.940G.949 Digital line systems G.950G.959 Digital section a
6、nd digital transmission systems for customer access to ISDN G.960G.969 Optical fibre submarine cable systems G.970G.979 Optical line systems for local and access networks G.980G.989 Access networks G.990G.999MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999
7、TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.992.3 (2009)/Amd.2 (07/2010) i Recommendation
8、ITU-T G.992.3 Asymmetric digital subscriber line transceivers 2 (ADSL2) Amendment 2 Retrain on eoc protocol timeout Summary This amendment contains: Retrain on eoc protocol timeout (addition to existing functionality). History Edition Recommendation Approval Study Group 1.0 ITU-T G.992.3 2002-07-29
9、15 1.1 ITU-T G.992.3 (2002) Amend. 1 2003-05-22 15 1.2 ITU-T G.992.3 (2002) Cor. 1 2003-12-14 15 1.3 ITU-T G.992.3 (2002) Cor. 2 2004-02-22 15 1.4 ITU-T G.992.3 (2002) Amend. 2 2004-04-30 15 1.5 ITU-T G.992.3 (2002) Amend. 3 2004-06-13 15 1.6 ITU-T G.992.3 (2002) Amend. 4 2004-06-13 15 2.0 ITU-T G.9
10、92.3 2005-01-13 15 2.1 ITU-T G.992.3 (2005) Amend. 1 2005-09-22 15 2.2 ITU-T G.992.3 (2005) Amend. 2 2006-03-29 15 2.3 ITU-T G.992.3 (2005) Amend. 3 2006-12-14 15 2.4 ITU-T G.992.3 (2005) Amend. 4 2007-07-29 15 2.5 ITU-T G.992.3 (2005) Amend. 5 2008-06-22 15 3.0 ITU-T G.992.3 2009-04-22 15 3.1 ITU-T
11、 G.992.3 (2009) Cor. 1 2009-11-13 15 3.2 ITU-T G.992.3 (2009) Amend. 1 2010-03-01 15 3.3 ITU-T G.992.3 (2009) Amend. 2 2010-07-29 15 ii Rec. ITU-T G.992.3 (2009)/Amd.2 (07/2010) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecomm
12、unications, information and communication technologies (ICTs). 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 telecommun
13、ications on a worldwide basis. The World Telecommunication 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 proced
14、ure laid down in WTSA Resolution 1. In some 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 teleco
15、mmunication administration and a recognized 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 thes
16、e mandatory provisions are met. The words “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
17、draws attention to the possibility that the 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 member
18、s or others outside of the Recommendation development 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, implementers are cautioned that this may not repr
19、esent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.992.3 (200
20、9)/Amd.2 (07/2010) 1 Recommendation ITU-T G.992.3 Asymmetric digital subscriber line transceivers 2 (ADSL2) Amendment 2 Retrain on eoc protocol timeout Modify the fifth paragraph of clause 7.8.2.4.1 Transmitter protocol as shown below: When sending a new command message, the LSB of the control field
21、 shall be inverted from the previous command message, irrespective of the priority class. The transmitter shall send the command message one time and await a response message. No more than one command message of each priority value shall be awaiting a response message at any time. Upon receipt of a
22、response message, a new command message may be sent. If a response message is not received, a time-out occurs and the command message is repeated without inverting the LSB of the control field. Alternately, the ATU may abandon the command message aAfter an implementation-specific number of retransmi
23、ssions, the ATU shall take recovery actions to accomplish the eoc command/response exchange; those recovery actions are also vendor discretionary and may involve a re-initialization through the high_BER-hs condition (see Annex D, Figure D.1). There are different time-out durations for the different
24、priority messages and are displayed in Table 7-17. Timeouts are based starting from the instant the PMS-TC sends the last octet of the request message in a PMD.Bits.confirm primitive, until the instant the PMS-TC receives the first octet of the response message in a PMD.Bits.indicate primitive or a
25、PMD.Synchflag.indicate primitive (see Figures 7-5 and 8-4 and Table 8-1). Modify clause D.2.7 as shown below: D.2.7 high_BER-hs: High bit error ratio in received data, re-initialize through an ITU-T G.994.1 event. This event occurs when some algorithm, which may be vendor-specific, determines that a
26、 full re-initialization (including an ITU-T G.994.1 session) is required. This event is (but is not required to be) related to a high level of near-end LCD, CRC or FEC anomalies over some period of time or the SEF (severely errored frame) or LOM (loss-of-margin) defect (see clause 8.12.1). It may al
27、so relate to far-end performance primitives (see clause 8.12.1) or unsuccessful eoc command/response exchange (see clause 7.8.2.4.1). Printed in Switzerland Geneva, 2010 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall net
28、work 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 systems Series I Integrated services digital network Series J Cable netwo
29、rks 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 Telecommunication management, including TMN and network maintenance Seri
30、es N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Terminals and subjective and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services termina
31、l equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
