1、 International Telecommunication Union ITU-T G.8251TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 3(10/2012) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects Quality and availability targets The control of jitter and wander within the op
2、tical transport network (OTN) Amendment 3 Recommendation ITU-T G.8251 (2010) Amendment 3ITU-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 CARRIER-TRANS
3、MISSION 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 COORDINATION OF RADIOT
4、ELEPHONY 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 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPEC
5、TS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 Ethernet over Transport aspects G.8000G.8099 MPLS over Transport aspects G.8100G.8199 Quality and availability targets G.8200G.8299Service Manag
6、ement G.8600G.8699 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) i Recommendation ITU-T G.8251 The control of jitter and wander within the optical transport network (OTN) Amendment 3 Summary Amendment 3 t
7、o Recommendation ITU-T G.8251 (2010) contains text additions to include support of a new client in the optical transport network (OTN) History Edition Recommendation Approval Study Group 1.0 ITU-T G.8251 2001-11-29 15 1.1 ITU-T G.8251 (2001) Cor. 1 2002-06-13 15 1.2 ITU-T G.8251 (2001) Amd. 1 2002-0
8、6-13 15 1.3 ITU-T G.8251 (2001) Cor. 2 2008-05-22 15 1.4 ITU-T G.8251 (2001) Amd.2 2010-01-13 15 2.0 ITU-T G.8251 2010-09-22 15 2.1 ITU-T G.8251 (2010) Amd. 1 2011-04-13 15 2.2 ITU-T G.8251 (2010) Cor. 1 2012-02-13 15 2.3 ITU-T G.8251 (2010) Amd. 2 2012-02-13 15 2.4 ITU-T G.8251 (2010) Amd. 3 2012-1
9、0-29 15 ii Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a p
10、ermanent 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 Telecommunication Standardization Assembly (WTSA), which meets every four years, esta
11、blishes 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 some areas of information technology which fall within ITU-Ts purview, the necessary st
12、andards 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 recognized operating agency. Compliance with this Recommendation is voluntary. However, the R
13、ecommendation 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 “shall“ or some other obligatory language such as “must“ and the negative equivalen
14、ts 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 practice or implementation of this Recommendation may involve the use of a claime
15、d 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 development process. As of the date of approval of this Recommendation, ITU had not
16、 received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU
17、-T/ipr/. ITU 2013 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.8251 (2010)/Amd.3 (10/2012) iii Table of Contents Page 1) Scope 1 2) Clause 2, References . 1 3) Clause 4, Abbreviations and acrony
18、ms 1 4) Clause 6.2, Jitter and wander tolerance of client interfaces . 1 5) Clause A.1, Scope . 1 6) Clause A.3, Frequency accuracy 6 7) Clause A.4, Pull-in and pull-out ranges 6 8) Clause A.7.3, Jitter transfer for ODCp . 6 9) Clause A.8, Jitter transfer for ODCp 7 Rec. ITU-T G.8251 (2010)/Amd.3 (1
19、0/2012) 1 Recommendation ITU-T G.8251 The control of jitter and wander within the optical transport network (OTN) Amendment 3 1) Scope This amendment contains modified text to be added to Recommendation ITU-T G.8251, The control of jitter and wander within the optical transport network (OTN). 2) Cla
20、use 2, References Add the following references to clause 2: EN 50083-9 EN 50083-9:2002, European Committee for Electrotechnical Standardization (CENELEC), Cable networks for television signals, sound signals and interactive services Part 9: Interfaces for CATV/SMATV headends and similar professional
21、 equipment for DVB/MPEG-2 transport streams. ETSI TR 101 290 ETSI TR 101 290 V1.2.1 (2001), Digital Video Broadcasting (DVB); Measurement guidelines for DVB systems. ETSI TR 101 891 ETSI TR 101 891 V1.1.1 (2001), Digital Video Broadcasting (DVB); Professional Interfaces: Guidelines for the implement
22、ation and usage of the DVB Asynchronous Serial Interface (ASI). 3) Clause 4, Abbreviations and acronyms Add the following new abbreviations: ASI Asynchronous Serial Interface DVB Digital Video Broadcast 4) Clause 6.2, Jitter and wander tolerance of client interfaces Add the following text underneath
23、 the existing text of clause 6.2: The DVB_ASI client mapped into ODU0 according to clause 17.7.1 of ITU-T G.709 shall support the parameters as given in the DVB_ASI specification contained in ETSI TR 101 891 V1.1.1 and EN 50083-9. 5) Clause A.1, Scope Insert the changes indicated below into Table A.
24、1-1, Summary of ODUk clock (ODC) types. 2 Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) Table A.1-1 Summary of ODUk clock (ODC) types ODCa (Note 4) ODCb (Note 4) ODCr ODCp (Note 4) Atomic function ODUkP/CBRx-a_A_So ODUkP/GFP_A_So ODUkP/NULL_A_So ODUkP/PRBS_A_So ODUkP/RSn-a_A_So ODUkP/VP_A_So ODUkP/ODUij_
25、A_So ODUkP/ODUj_A_So ODUkP/ODUij_A_Sk (AIS clock) OTUk/ODUk_A_Sk (AIS clock) OTUkV/ODUk_A_Sk (AIS clock) ODUk_C (OCI clock) ODUkP/CBRx-b_A_So ODUkP/RSn-b_A_So OTUk/ODUk_A_So and OTUk/ODUk_A_Sk (i.e., the clocks of these atomic functions are concentrated in a single ODCr; see ITU-T G.798) ODUkP/CBRx_
26、A_Sk ODUkP/ODUij_A_Sk ODUkP/ODUj_A_Sk Frequency accuracy 20 ppm 20 ppm for ODUk (k = 0, 1, 2, 3, 4) 20 ppm for CBRx (x = 2G5, 10G, 40G) 100 ppm for ODU2e, ODUflex, 10GE, and FC-x (x = 100, 200, 400, 800, 1200), IB SDR; IB DDR, IB QDR 20 ppm 20 ppm for ODUk (k= 0, 1, 2, 3, 4) 20 ppm for CBRx (x = 0G1
27、55, 0G622, 2G5, 10G, 40G) 100 ppm for 1GE, 10GE, 40GE, 100GE, FC-x, IB SDR; IB DDR, IB QDR; DVB_ASI, ODUflex, and ODU2e 200 ppm for SBCON Free-run mode supported Yes Yes Yes Yes Locked mode supported No Yes Yes Yes Holdover mode supported No No No No 3 Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) Table
28、A.1-1 Summary of ODUk clock (ODC) types ODCa (Note 4) ODCb (Note 4) ODCr ODCp (Note 4) Pull-in range NA 20 ppm (SDH clients) 100 ppm (Ethernet and FC-x (x = 100, 200, 400, 800, 1200), IB SDR; IB DDR, IB QDR clients) 20 ppm 20 ppm (SDH clients) 100 ppm (Ethernet and FC-x (x = 100, 200, 400, 800, 1200
29、), IB SDR; IB DDR, IB QDR clients) 200 ppm for SBCON clients Pull-out range NA 20 ppm (SDH clients) 100 ppm (Ethernet and FC-x (x = 400, 800, 1200), IB SDR; IB DDR, IB QDR clients) 20 ppm 20 ppm (SDH clients) 100 ppm (Ethernet and FC-x (x = 100, 200, 400, 800, 1200), IB SDR; IB DDR, IB QDR clients)
30、200 ppm for SBCON clients Jitter generation Table A.5-1 Table A.5-1 Table A.5-1 Table A.5-2 Wander generation NA NA (Note 1) NA NA (Note 2) Jitter tolerance NA ITU-T G.825 for SDH clients IEEE 802.3 for Ethernet clients Table 6.1-1, Figure 6.1-1 (OTU1) Table 6.1-2, Figure 6.1-2 (OTU2) Table 6.1-3, F
31、igure 6.1-3 (OTU3) Table 6.1-4, Figure 6.1-4 (OTU3/ OTL3.4) Table 6.1-5, Figure 6.1-5 (OTU4/ OTL4.4) Table 6.1-1, Figure 6.1-1 (OTU1) Table 6.1-2, Figure 6.1-2 (OTU2) Table 6.1-3, Figure 6.1-3 (OTU3) Table 6.1-4, Figure 6.1-4 (OTU3/OTL3.4) IEEE 802.3 for Ethernet clients Wander tolerance NA ITU-T G.
32、825 Clause 6.1 Clause 6.1 4 Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) Table A.1-1 Summary of ODUk clock (ODC) types ODCa (Note 4) ODCb (Note 4) ODCr ODCp (Note 4) Jitter transfer NA Maximum bandwidth: ODU0: 0.5 kHz ODU1: 1 kHz ODU2: 4 kHz ODU2e: 4 kHz ODU3: 16 kHz ODUflex: FFS Maximum gain peaking: 0
33、.1 dB for ODU0, 1, 2, 2e, and 3 FFS for ODUflex (see Table A.7-1 and Figure A.7-1) Maximum bandwidth: OTU1: 250 kHz OTU2: 1000 kHz OTU3: 4000 kHz OTU4: 10000 kHz Maximum gain peaking: 0.1 dB for OTU1, 2, 3 and 4 (see Table A.7-2 and Figure A.7-1) Maximum bandwidth: 300 Hz for ODUk (k=0, 1, 2, 2e, 3,
34、 flex) 300 Hz for CBRx (x = 0G155, 0G622, 2G5, 10G, 40G), 10GE, 40GE, 100GE, FC-x (x =100, 200, 400, 800, 1200), IB SDR; IB DDR, IB QDR; SBCON 100 Hz for 1GE 200 Hz for DVB_ASI Maximum gain peaking: 0.1 dB (see clause A.7.3) Output when input signal is lost AIS (CBRx client) OTUk: no frame hit OTUk
35、frequency unchanged AIS (CBRx client) Local Fault (Ethernet and FC-x (x = 100, 200, 400, 800, 1200) clients) OTUk: no frame hit OTUk initial frequency change 9 ppm (See clause A.8) AIS (OTUk) OTUk: frame hit allowed Temporary OTUk frequency offset 20 ppm allowed AIS (CBRx client), AIS (ODUj/i client
36、) Frequency offset 20 ppm Local Fault (Ethernet and FC-x (x = 100, 200, 400, 800, 1200) clients) Frequency offset 100 ppm NOS for SBCON Frequency offset 200 ppm 5 Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) Table A.1-1 Summary of ODUk clock (ODC) types ODCa (Note 4) ODCb (Note 4) ODCr ODCp (Note 4) NA
37、No requirement because not applicable NOTE 1 The wander generation of ODCb is expected to be negligible compared to the wander on the input CBR (e.g., SDH) client signal, because the ODCb bandwidth is relatively wideband. NOTE 2 The intrinsic wander generation of the ODCp is negligible compared to t
38、he wander generated by the demapping process. NOTE 3 To achieve the compliance of STM-1 and STM-4 signals mapped with GMP into ODU0 with SDH jitter wander specification in addition to the ODCp clock filtering, the use of one bit additional phase information as specified in ITU-T G.709 and ITU-T G.79
39、8 is required. NOTE 4 An ODCa, ODCb, or ODCp for one client is not required to support another client simultaneously. 6 Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) 6) Clause A.3, Frequency accuracy Modify clause A.3 as indicated below: A.3 Frequency accuracy Under free-running conditions, the output fr
40、equency accuracy of ODCa and ODCr shall not be worse than 20 ppm with respect to a reference traceable to an ITU-T G.811 clock. Under free-running conditions, the output frequency accuracy of ODCb shall not be worse than 100 ppm for 1GE, 10GE, 40GE, 100GE, FC-x, and InfiniBand clients and ODU2e, and
41、 shall not be worse than 20 ppm for all other respective clients and ODUs (see Table A.1-1). Under free-running conditions, the output frequency accuracy of ODCp shall not be worse than 100 ppm for 1GE, 10GE, 40GE, 100GE, and FC-x, and DVB_ASI clients and ODU2e, shall not be worse than 200 ppm for S
42、BCON client, and shall not be worse than 20 ppm for all other respective clients and ODUs (see Table A.1-1). 7) Clause A.4, Pull-in and pull-out ranges Modify clauses A.4.1 and A.4.2 as indicated below: A.4.1 Pull-in range The minimum pull-in range of ODCb, ODCr, and ODCp shall be 100 ppm for 1GE, 1
43、0GE, 40GE, 100GE, and FC-x, and InfiniBand, and DVB_ASI clients and ODU2e. The minimum pull-in range of ODCp shall be 200 ppm for SBCON client. The minimum pull-in range of ODCb, ODCr, and ODCp shall be , and 20 ppm for all other clients and ODUs (see Table A.1-1), whatever the internal oscillator f
44、requency offset may be. There is no requirement for the pull-in range of ODCa because it is free-running. A.4.2 Pull-out range The minimum pull-out range of ODCb, ODCr, and ODCp shall be 100 ppm for 1GE, 10GE, 40GE, 100GE, and FC-x, InfiniBand, and DVB_ASI clients and ODU2e. The minimum pull-out ran
45、ge of ODCp shall be 200 ppm for SBCON client. The minimum pull-out range of ODCb, ODCr, and ODCp shall beand 20 ppm for all other clients and ODUs (see Table A.1-1), whatever the internal oscillator frequency offset may be. There is no requirement for the pull-out range of ODCa because it is free-ru
46、nning. 8) Clause A.7.3, Jitter transfer for ODCp Modify clause A.7.3 as indicated below: A.7.3 Jitter transfer for ODCp The jitter transfer requirements for ODCp are, essentially, the transfer requirements for a CBR (e.g., SDH) demapper (i.e., a desynchronizer) or ODUij demultiplexer. The demapper f
47、unction, including the ODCp, is contained in the ODUkP/CBRx_A_Sk and ODUkP/RSn_A_Sk atomic functions. The demultiplexer functions, including the ODCp, are contained in the ODUkP/ODUij_A_Sk atomic function. The ODCp performs filtering, which is necessary to control the mapping/demapping jitter and wa
48、nder accumulation over multiple OTN islands. The 3 dB bandwidth of the desynchronizer shall not exceed 300 Hz for: ODUk (k=0, 1, 2, 2e, 3, flex); CBRx (x = 0G155, 0G622, 2G5, 10G, 40G); 10GE, 40GE, 100GE; Rec. ITU-T G.8251 (2010)/Amd.3 (10/2012) 7 FC-x (x = 100, 200, 400, 800, 1200); IB SDR, IB DDR,
49、 IB QDR; SBCON. The 3 dB bandwidth of the desynchronizer shall not exceed 200 Hz for DVB_ASI. The 3 dB bandwidth of the desynchronizer shall not exceed 100 Hz for 1GE. The maximum gain peaking of the desynchronizer shall be 0.1 dB. These requirements apply to all ODUk rates. Additional information, on demapper phase error, is given in Appendix V. 9) Clause A.8, Jitter transfer for ODCp Modify clause A.8 as indicated below: A.8 Transient response When a C
