1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T G.8031/Y.1342 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2015) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects Ethernet over Transport aspects SERIES Y: GLOBAL I
2、NFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Transport Ethernet linear protection switching Recommendation ITU-T G.8031/Y.1342 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELE
3、PHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-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 RA
4、DIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION 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 DIGIT
5、AL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS 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.80
6、99 MPLS over Transport aspects G.8100G.8199 Synchronization, quality and availability targets G.8200G.8299 Service Management G.8600G.8699 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.8031/Y.1342 (01/2015) i Recommendation ITU-T G.
7、8031/Y.1342 Ethernet linear protection switching Summary Recommendation ITU-T G.8031/Y.1342 describes the specifics of linear protection switching for Ethernet VLAN signals. Included are details pertaining to ETH linear protection characteristics, architectures and the automatic protection switching
8、 (APS) protocol. The protection scheme considered in this Recommendation is: VLAN-based Ethernet subnetwork connection linear protection with sublayer monitoring. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.8031/Y.1342 2006-06-06 15 11.1002/1000/8779 1.1 ITU-T G.8031/Y
9、.1342 (2006) Amd. 1 2007-10-07 15 11.1002/1000/9174 1.2 ITU-T G.8031/Y.1342 (2006) Cor. 1 2008-06-06 15 11.1002/1000/9392 2.0 ITU-T G.8031/Y.1342 2009-11-13 15 11.1002/1000/10429 2.1 ITU-T G.8031/Y.1342 (2009) Cor. 1 2010-09-06 15 11.1002/1000/10901 3.0 ITU-T G.8031/Y.1342 2011-06-22 15 11.1002/1000
10、/11138 3.1 ITU-T G.8031/Y.1342 (2011) Cor. 1 2012-02-13 15 11.1002/1000/11513 3.2 ITU-T G.8031/Y.1342 (2011) Amd.1 2013-08-29 15 11.1002/1000/12031 4.0 ITU-T G.8031/Y.1342 2015-01-13 15 11.1002/1000/12383 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of yo
11、ur web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.8031/Y.1342 (01/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information
12、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 telecommunications on a worldwide
13、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 procedure laid down in WTSA Re
14、solution 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 telecommunication administrati
15、on 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 these mandatory provisions
16、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 RIGHTSITU draws attention to the p
17、ossibility 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 members or others outside of t
18、he 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 represent the latest informa
19、tion and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 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.8031/Y.1342 (01/2015) iii Table of
20、 Contents Page 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 4 4 Abbreviations and acronyms 4 5 Conventions 5 5.1 Representation of octets . 5 6 Introduction . 5 7 Network objectives . 6 8 Protection characteristics 7 8.1 Monito
21、ring methods and conditions . 7 9 Protection group commands . 8 9.1 End-to-end commands and states . 8 9.2 Local commands . 8 10 Protection architectures 8 10.1 Unidirectional and bidirectional switching 9 10.2 Need for APS communication 9 10.3 Revertive and non-revertive switching . 9 10.4 Provisio
22、ning mismatches 10 10.5 Protection switching trigger . 10 10.6 Protection switching models . 10 11 APS Protocol 17 11.1 APS format . 17 11.2 1-phase APS protocol . 19 11.3 Request type . 22 11.4 Protection types and bridge type 22 11.5 Requested signal . 23 11.6 Bridged signal . 23 11.7 Control of b
23、ridge 23 11.8 Control of selector 23 11.9 Signal fail of the protection transport entity . 24 11.10 Equal priority requests 24 11.11 Command acceptance and retention . 24 11.12 Hold-off timer . 25 11.13 Wait-to-restore timer 25 11.14 Exercise operation 25 iv Rec. ITU-T G.8031/Y.1342 (01/2015) Page 1
24、1.15 Failure of protocol defects 26 11.16 Signal degrade of the protection transport entity . 26 Annex A State transition tables of protection switching. 27 A.1 State transition for 1:1 bidirectional switching with revertive mode . 27 A.2 State transition for 1:1 bidirectional switching with non-rev
25、ertive mode 31 A.3 State transition for 1+1 bidirectional switching with revertive mode 36 A.4 State transition for 1+1 bidirectional switching with non-revertive mode . 40 A.5 State transition for 1+1 unidirectional switching with revertive mode 45 A.6 State transition for 1+1 unidirectional switch
26、ing with non-revertive mode . 47 Appendix I Operation example of 1-phase APS protocol . 50 I.1 Introduction 50 I.2 Example scenario 50 I.3 APS protocol examples 50 Appendix II Interaction between Ethernet protection switching and STP 53 Appendix III MIPs for protection switching environment 55 III.1
27、 Introduction 55 III.2 Considerations 55 III.3 Configuration examples 56 Appendix IV State transition diagrams using SDL . 58 IV.1 Introduction 58 IV.2 SDL diagrams . 58 Rec. ITU-T G.8031/Y.1342 (01/2015) 1 Recommendation ITU-T G.8031/Y.1342 Ethernet linear protection switching 1 Scope This Recommen
28、dation defines the automatic protection switching (APS) protocol and linear protection switching mechanisms for point-to-point VLAN-based ETH subnetwork connection (SNC) in Ethernet transport networks. All other protection schemes including point-to-multipoint and multipoint-to-multipoint are for fu
29、rther study. Linear 1+1 and 1:1 protection switching architectures with unidirectional and bidirectional switching are defined in this version of the Recommendation. The APS protocol and protection switching operation for all other Ethernet network architectures (e.g., ring, mesh) are for further st
30、udy. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to re
31、vision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within th
32、is Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T G.780 Recommendation ITU-T G.780/Y.1351 (2010), Terms and definitions for synchronous digital hierarchy (SDH) networks. ITU-T G.805 Recommendation ITU-T G.805 (2000), Generic functional architecture
33、of transport networks. ITU-T G.806 Recommendation ITU-T G.806 (2012), Characteristics of transport equipment Description methodology and generic functionality, plus Corrigendum 1 (2012). ITU-T G.808.1 Recommendation ITU-T G.808.1 (2014), Generic protection switching Linear trail and subnetwork prote
34、ction. ITU-T G.870 Recommendation ITU-T G.870/Y.1352 (2012), Terms and definitions for Optical Transport Networks, plus Corrigendum 1 (2013). ITU-T G.8010 ITU-T Recommendation G.8010/Y.1306 (2004), Architecture of Ethernet layer networks, plus Erratum 1 (2007), Erratum 2 (2007), Amendment 1 (2006),
35、Amendment 2 (2010). ITU-T G.8013 Recommendation ITU-T G.8013/Y.1731 (2013), OAM functions and mechanisms for Ethernet based networks, plus Amendment 1 (2015). ITU-T G.8021 Recommendation ITU-T G.8021/Y.1341 (2015), Characteristics of Ethernet transport network equipment functional blocks. IEEE 802.1
36、Q IEEE Std 802.1Q-2014, IEEE Standard for Local and Metropolitan Area networksBridges and Bridged Networks. 2 Rec. ITU-T G.8031/Y.1342 (01/2015) 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: Terms defined in ITU-T G.780: 3.1.1 bidirectional
37、 protection switching 3.1.2 unidirectional protection switching Terms defined in ITU-T G.805: 3.1.3 adapted information 3.1.4 characteristic information 3.1.5 link 3.1.6 link connection 3.1.7 tandem connection 3.1.8 trail 3.1.9 trail termination Terms defined in ITU-T G.806: 3.1.10 atomic function 3
38、.1.11 defect 3.1.12 failure 3.1.13 server signal degrade (SSD) 3.1.14 server signal fail (SSF) 3.1.15 signal degrade (SD) 3.1.16 signal fail (SF) 3.1.17 trail signal degrade (TSD) 3.1.18 trail signal fail (TSF) Terms defined in ITU-T G.808.1: 3.1.19 transfer time (Tt) Terms defined in ITU-T G.870: 3
39、.1.20 APS protocol 3.1.20.1 1-phase 3.1.21 protection class 3.1.21.1 individual 3.1.21.2 group 3.1.21.3 network connection protection 3.1.21.4 subnetwork connection protection 3.1.21.4.1 sublayer monitored (/S) 3.1.21.4.2 non-intrusive monitored 3.1.21.4.3 inherent monitored Rec. ITU-T G.8031/Y.1342
40、 (01/2015) 3 3.1.21.4.4 test monitored (/T) 3.1.21.5 trail protection 3.1.22 switch 3.1.23 component 3.1.23.1 protected domain 3.1.23.2 bridge 3.1.23.2.1 permanent bridge 3.1.23.2.2 broadcast bridge 3.1.23.2.3 selector bridge 3.1.23.3 selector 3.1.23.3.1 selective selector 3.1.23.4 head end 3.1.23.5
41、 tail end 3.1.23.6 sink node 3.1.23.7 source node 3.1.23.8 intermediate node 3.1.24 architecture 3.1.24.1 1+1 protection architecture 3.1.24.2 1:n protection architecture 3.1.24.3 (1:1)n protection architecture 3.1.25 signal 3.1.25.1 traffic signal 3.1.25.2 normal traffic signal 3.1.25.3 extra traff
42、ic signal 3.1.25.4 null signal 3.1.26 time 3.1.26.1 detection time 3.1.26.2 hold-off time 3.1.26.3 wait-to-restore time 3.1.26.4 switching time 3.1.27 transport entity 3.1.27.1 protection transport entity 3.1.27.2 working transport entity 3.1.27.3 active transport entity 3.1.27.4 standby transport e
43、ntity 3.1.28 protection 3.1.29 impairment 4 Rec. ITU-T G.8031/Y.1342 (01/2015) 3.1.30 protection ratio 3.1.31 revertive (protection) operation 3.1.32 non-revertive (protection) operation Terms defined in ITU-T G.8010: 3.1.33 Ethernet characteristic information (ETH_CI) 3.1.34 Ethernet flow point (ET
44、H_FP) 3.1.35 maintenance entity 3.1.36 maintenance entity group 3.1.37 maintenance entity group end point (MEP) 3.1.38 maintenance entity group level Terms defined in ITU-T G.8021: 3.1.39 Ethernet flow forwarding function (ETH_FF) 3.2 Terms defined in this Recommendation None. 4 Abbreviations and ac
45、ronyms This Recommendation uses the following abbreviations and acronyms: AI Adapted Information APS Automatic Protection Switching CCM Continuity Check Message CI Characteristic Information DNR Do Not Revert EC Ethernet Connection ETH Ethernet layer network ETH-AIS Ethernet Alarm Indication Signal
46、function ETH-APS Ethernet Automatic Protection Switching function ETH-CC Ethernet Continuity Check function EXER Exercise FS Forced Switch FT Flow Termination LCK Locked LO Lockout of protection LOC Loss of Continuity LSB Least Significant Bit MEP Maintenance Entity Group End Point MI Management Inf
47、ormation MIP Maintenance Entity Group Intermediate Point Rec. ITU-T G.8031/Y.1342 (01/2015) 5 MS Manual Switch MSB Most Significant Bit NR No Request OAM Operation, Administration and Maintenance PDU Protocol Data Unit PS Protection Switching RR Reverse Request RSTP Rapid Spanning Tree Protocol SD S
48、ignal Degrade SF Signal Fail SF-P Signal Fail on Protection SNC Subnetwork Connection SNC/I Subnetwork Connection with Inherent monitoring SNC/N Subnetwork Connection with Non-intrusive monitoring SNC/S Subnetwork Connection with Sublayer monitoring SNC/T Subnetwork Connection with Test trail monito
49、ring STP Spanning Tree Protocol TCM Tandem Connection Monitoring TLV Type Length Value VID VLAN Identifier VLAN Virtual Local Area Network WTR Wait-to-Restore 5 Conventions 5.1 Representation of octets Octets are represented as defined in IEEE 802.1Q. When consecutive octets are used to represent a binary number, the lower octet number has the most significant value. The bits in an octet are numbered from 1 to 8, where 1 is the least significant bi
