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.8131/Y.1382 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1 (04/2016) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects MPLS over Transport aspects SERIES Y:
2、GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS, INTERNET OF THINGS AND SMART CITIES Internet protocol aspects Transport Linear protection switching for MPLS transport profile Amendment 1 Recommendation ITU-T G.8131/Y.1382 (2014) Amendment 1 ITU-T G-SERIES R
3、ECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE 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 META
4、LLIC 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 RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699
5、 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 ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.70
6、00G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 Ethernet over Transport aspects G.8000G.8099 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 t
7、he list of ITU-T Recommendations. Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) i Recommendation ITU-T G.8131/Y.1382 Linear protection switching for MPLS transport profile Amendment 1 Summary Recommendation ITU-T G.8131/Y.1382 provides architecture and mechanisms for subnetwork connection (SNC) pr
8、otection switching for MPLS transport profile (MPLS-TP) networks. It describes the SNC protection architectures type, the uni- and bidirectional switching types and the revertive/non-revertive operation types. It defines an automatic protection coordination protocol used to coordinate both ends of t
9、he protected domain. Amendment 1 provides the format of APC specific information, and descriptions about management (MI) signals and trail protection architecture. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.8131/Y.1382 2007-02-06 15 11.1002/1000/9008 1.1 ITU-T G.8131/
10、Y.1382 (2007) Amd. 1 2007-09-22 15 11.1002/1000/9179 2.0 ITU-T G.8131/Y.1382 2014-07-07 15 11.1002/1000/12188 2.1 ITU-T G.8131/Y.1382 (2014) Amd. 1 2016-04-13 15 11.1002/1000/12807 Keywords APC, APS, PSC, bridge, selector, SNC protection, MPLS-TP. _ * To access the Recommendation, type the URL http:
11、/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized
12、 agency in the field of telecommunications, 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
13、view to standardizing telecommunications 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 Recommen
14、dations 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 standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conci
15、seness to indicate both a telecommunication 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 Recommenda
16、tion is achieved when all of these 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.
17、INTELLECTUAL PROPERTY RIGHTSITU 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
18、, whether asserted by ITU members 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
19、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-T/ipr/. ITU 2016 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission
20、 of ITU. Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 3 4 Abbreviations and acronyms 3 5 Conventions 4 6 Protection architecture and characteristics . 4
21、 6.1 MPLS-TP protection architecture . 5 6.2 Switching types 5 6.3 Operation types . 5 6.4 Protection switching trigger mechanism 6 6.5 Provisioning mismatches 7 7 Protection group commands and state 7 7.1 End-to-end commands 7 7.2 Local commands . 8 7.3 States . 8 8 Automatic protection coordinatio
22、n protocol . 9 8.1 Automatic protection coordination specific information structure 9 8.2 Priorities of local and remote requests . 12 8.3 APC initiation criteria . 13 8.4 APC protocol type 13 8.5 Transmission and acceptance of APC messages 13 8.6 1-phase APC protocol . 14 8.7 Equal priority request
23、s 15 8.8 Control of bridge 16 8.9 Control of selector 16 8.10 Acceptance and retention of local requests 17 8.11 Hold-off timer . 17 8.12 Wait-to-restore timer 17 8.13 Exercise operation 18 8.14 Signal degrade processing 18 8.15 Failure of protocol defects 18 9 Application architectures 19 9.1 Unidi
24、rectional 1+1 SNC/S protection switching 19 iv Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) Page 9.2 Bidirectional 1+1 SNC/S protection switching 20 9.3 Bidirectional 1:1 SNC/S protection switching . 21 9.4 Relationship with ITU-T G.8131 (2007) 24 10 Security aspects 24 Annex A State transition t
25、ables of protection switching. 25 Appendix I Operation example of MPLS-TP linear protection protocol 26 Appendix II Format of APC specific information 27 Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) 1 Recommendation ITU-T G.8131/Y.1382 Linear protection switching for MPLS transport profile Amendm
26、ent 1 Editorial note: This is a complete-text publication. Modifications introduced by this amendment are shown in revision marks relative to Recommendation ITU-T G.8131/Y.1382 (2014). 1 Scope This Recommendation provides architecture and mechanisms for linear protection switching for MPLS transport
27、 profile (MPLS-TP) networks. The automatic protection coordination protocol, and 1+1 and 1:1 protection architecture are defined in this Recommendation. Other protection architecture types are for further study. This Recommendation describes the protection switching functionality for point-to-point
28、connections using the automatic protection switching (APS) mode defined in IETF RFC 7271. This Recommendation provides a representation of the MPLS-TP technology using the methodologies that have been used for other transport technologies (e.g., synchronous digital hierarchy (SDH), optical transport
29、 network (OTN) and Ethernet).1 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 re
30、ferences are subject to revision; 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 referen
31、ce to a document within this 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), Generi
32、c functional architecture of transport networks. ITU-T G.806 Recommendation ITU-T G.806 (2012), Characteristics of transport equipment Description methodology and generic functionality. ITU-T G.808.1 Recommendation ITU-T G.808.1 (2014), Generic protection switching Linear trail and subnetwork protec
33、tion. ITU-T G.870 Recommendation ITU-T G.870/Y.1352 (2012), Terms and definitions for optical transport networks. ITU-T G.8031 Recommendation ITU-T G.8031/Y.1342 (2011), Ethernet linear protection switching. _ 1 This ITU-T Recommendation is intended to be aligned with the IETF MPLS RFCs normatively
34、referenced by this Recommendation. 2 Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) ITU-T G.8110.1 Recommendation ITU-T G.8110.1/Y.1370.1 (2011), Architecture of the Multi-Protocol Label Switching transport profile layer network. ITU-T G.8121 Recommendation ITU-T G.8121/Y.1381 (2013), Characteristi
35、cs of MPLS-TP equipment functional blocks. IETF RFC 5586 IETF RFC 5586 (2009), MPLS Generic Associated Channel IETF RFC 6378 IETF RFC 6378 (2011), MPLS Transport Profile (MPLS-TP) Linear Protection. IETF RFC 7271 IETF RFC 7271 (2014), MPLS Transport Profile (MPLS-TP) Linear Protection to Match the O
36、perational Expectations of Synchronous Digital Hierarchy, Optical Transport Network, and Ethernet Transport Network Operators. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 1+1 protection architecture ITU-T G.870 3.1.2 1:n protection
37、architecture ITU-T G.870 3.1.3 1-phase ITU-T G.870 3.1.4 2-phase ITU-T G.870 3.1.5 3-phase ITU-T G.870 3.1.6 active transport entity ITU-T G.870 3.1.7 APS protocol ITU-T G.870 3.1.8 architecture ITU-T G.870 3.1.9 bidirectional protection switching ITU-T G.780 3.1.10 bridge ITU-T G.870 3.1.11 defect
38、ITU-T G.806 3.1.12 failure ITU-T G.806 3.1.13 forced switch ITU-T G.870 3.1.14 hold-off time ITU-T G.870 3.1.15 manual switch ITU-T G.870 3.1.16 non-revertive (protection) operation ITU-T G.870 3.1.17 normal traffic signal ITU-T G.870 3.1.18 permanent bridge ITU-T G.870 3.1.19 protected domain ITU-T
39、 G.870 3.1.20 protection ITU-T G.870 3.1.21 protection group ITU-T G.870 3.1.22 protection transport entity ITU-T G.870 3.1.23 revertive (protection) operation ITU-T G.870 Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) 3 3.1.24 selector ITU-T G.870 3.1.25 selector bridge ITU-T G.870 3.1.26 signal I
40、TU-T G.870 3.1.27 signal degrade (SD) ITU-T G.806 3.1.28 signal fail (SF) ITU-T G.806 3.1.29 standby transport entity ITU-T G.870 3.1.30 subnetwork connection protection ITU-T G.870 3.1.31 switch ITU-T G.870 3.1.32 traffic signal ITU-T G.870 3.1.33 trail ITU-T G.805 3.1.34 trail protection ITU-T G.8
41、70 3.1.35 transport entities ITU-T G.870 3.1.36 unidirectional protection switching ITU-T G.780 3.1.37 wait-to-restore time ITU-T G.870 3.1.38 working transport entity ITU-T G.870 3.2 Terms defined in this Recommendation This Recommendation defines the following term: 3.2.1 PSC protocol: A means to
42、coordinate the two ends of the protected domain via the exchange of a single message as defined in IETF RFC 6378. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ACH Associated Channel Header APC Automatic Protection Coordination APS Automatic Protecti
43、on Switching dFOP Failure of Protocol defect DNR Do-not-Revert DPath Data Path EXER Exercise FPath Fault Path FS Forced Switch G-ACh Generic Associated Channel LO Lockout of protection LSP Label Switched Path MPLS-TP MPLS Transport Profile MS Manual Switch MS-P Manual Switch to Protection transport
44、entity 4 Rec. ITU-T G.8131/Y.1382 (2014)/Amd.1 (04/2016) MS-W Manual Switch to Working transport entity MT_C MPLS-TP Connection MT_CP MPLS-TP Connection Point MT_TT_Sk MPLS-TP Trail Termination Sink NR No Request OAM Operations, Administration and Maintenance OC Operator Clear OTN Optical Transport
45、Network PDU Protocol Data Unit PSC Protection State Coordination PT Protection Type RR Reverse Request SD Signal Degrade SDH Synchronous Digital Hierarchy SD-P Signal Degrade on Protection transport entity SD-W Signal Degrade on Working transport entity SF Signal Fail SF-P Signal Fail on Protection
46、transport entity SF-W Signal Fail on Working transport entity SNC Subnetwork Connection SNCP Subnetwork Connection Protection SNC/S SNCP with Sublayer monitoring TLV Type Length Value WTR Wait-to-Restore 5 Conventions In this Recommendation, the term automatic protection coordination (APC) protocol
47、is used to describe the means to coordinate the two ends of the protected domain via the exchange of a single message and represents the protection state coordination (PSC) protocol in automatic protection switching (APS) mode as defined in IETF RFC 7271. This protocol is developed to provide the sa
48、me operator control and experience of APS protocol by modifying and enhancing the PSC protocol as described in IETF RFC 6378. 6 Protection architecture and characteristics Protection switching is a fully allocated protection mechanism that can be used on any topology. It is fully allocated in the se
49、nse that the route and bandwidth of the protection connection is reserved for a selected working connection. To be effective under all possible failures of the working connection however, the protection connection must be known to have complete physical diversity over all common-failure modes. This may not always be possible. Also, this might require the working connection not to
