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.8132/Y.1383 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (08/2017) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects MPLS over Transport aspects SERIES Y: GLOBAL INFOR
2、MATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS, NEXT-GENERATION NETWORKS, INTERNET OF THINGS AND SMART CITIES Internet protocol aspects Transport MPLS-TP shared ring protection Recommendation ITU-T G.8132/Y.1383 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NET
3、WORKS 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 METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER
4、 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 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DI
5、GITAL 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.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 Ethernet over Tran
6、sport 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 the list of ITU-T Recommendations. Rec. ITU-T G.8132/Y.1383 (08/2017) i
7、 Recommendation ITU-T G.8132/Y.1383 MPLS-TP shared ring protection Summary Recommendation ITU-T G.8132/Y.1383 provides architecture and mechanisms for shared ring protection for multi-protocol label switching-transport profile (MPLS-TP) networks. It describes the MPLS-TP shared ring protection (MSRP
8、) mechanisms and the ring protection switch (RPS) protocol. The mechanisms defined herein protect point-to-point MPLS-TP label switched paths (LSPs) against failures at the MPLS-TP section layer. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.8132/Y.1383 2017-08-13 15 11.
9、1002/1000/13318 Keywords MPLS-TP shared ring protection. * To access the Recommendation, type the URL http:/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.8132/Y.1383 (08/20
10、17) 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 permanent organ of ITU. ITU-T is responsible for
11、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, establishes the topics for study by the ITU-T study
12、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 standards are prepared on a collaborative basis wi
13、th 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 Recommendation may contain certain mandatory prov
14、isions (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 equivalents are used to express requirements. The use of
15、such words does not suggest that compliance with the Recommendation is required of any party. 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 posit
16、ion 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 received notice of intellectual property, protec
17、ted 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-T/ipr/. ITU 2017 All rights reserved. No part of
18、 this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.8132/Y.1383 (08/2017) 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 . 2 4 Abbreviat
19、ions and acronyms 2 5 Conventions 3 6 Overview . 3 7 Network objectives . 4 8 Functional model 5 8.1 Label operations . 6 9 Protection architecture types . 10 10 Switching types . 10 11 Operation types . 10 12 Ring interconnection and its functional model . 10 12.1 Interconnection node 11 13 Failure
20、 detection . 13 14 Ring protection switch protocol 13 14.1 Transmission and acceptance of ring protection switch requests . 13 14.2 RPS PDU format 13 14.3 Ring node ring protection switch state . 14 14.4 Ring protection switch state transition . 14 15 Misconnection avoidance . 14 16 Ring protection
21、switch initiation criteria 14 16.1 Administrative commands 14 16.2 Automatically initiated commands . 14 Annex A State transition tables of protection switching. 15 Annex B Bandwidth sharing . 16 Appendix I Wrapping and Steering examples 17 I.1 Wrapping 17 I.2 Short wrapping . 17 I.3 Steering . 17 R
22、ec. ITU-T G.8132/Y.1383 (08/2017) 1 Recommendation ITU-T G.8132/Y.1383 MPLS-TP shared ring protection 1 Scope This Recommendation provides architecture and mechanisms for shared ring protection for multi-protocol label switching-transport profile (MPLS-TP) networks. It describes the MPLS-TP shared r
23、ing protection (MSRP) mechanisms and the ring protection switch (RPS) protocol defined in IETF RFC 8227. The mechanisms defined herein protect point-to-point MPLS-TP label switched paths (LSPs) against failures at the MPLS-TP section layer. This Recommendation provides a representation of the MPLS-T
24、P technology using the methodologies that have been used for other transport technologies e.g., synchronous digital hierarchy (SDH), optical transport network (OTN) and Ethernet.1 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in thi
25、s text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edit
26、ion 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 this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T G.805 Recommendation ITU
27、-T G.805 (2000), Generic 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 Recommendation ITU-T G.808 (2016), Terms and definitions for network protection
28、 and restoration. ITU-T G.808.2 Recommendation ITU-T G.808.2 (2013), Generic protection switching Ring protection. ITU-T G.8110.1 Recommendation ITU-T G.8110.1 (2011), Architecture of the Multi-Protocol Label Switching transport profile layer network. ITU-T G.8121 Recommendation ITU-T G.8121 (2016),
29、 Characteristics of MPLS-TP equipment functional blocks. IETF RFC 5654 IETF RFC 5654 (2009), Requirements of an MPLS transport profile. IETF RFC 6371 IETF RFC 6371 (2011), Operations, administration, and maintenance framework for MPLS-based transport networks. IETF RFC 6372 IETF RFC 6372 (2011), MPL
30、S transport profile (MPLS-TP) survivability framework. IETF RFC 8227 IETF RFC 8227 (2017), MPLS-TP shared-ring protection (MSRP) mechanism for ring topology. 1 This ITU-T Recommendation is intended to be aligned with the IETF MPLS RFCs it cites as normative references. 2 Rec. ITU-T G.8132/Y.1383 (08
31、/2017) 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 adaptation function (A): ITU-T G.806 3.1.2 atomic function: ITU-T G.806 3.1.3 clear: ITU-T G.808 3.1.4 connection function (C): ITU-T G.806 3.1.5 connection point (CP): ITU-T G.806
32、3.1.6 defect: ITU-T G.806 3.1.7 exercise signal: ITU-T G.808 3.1.8 extra traffic: ITU-T G.808.2 3.1.9 failure: ITU-T G.806 3.1.10 forced switch: ITU-T G.808 3.1.11 layer network: ITU-T G.805 3.1.12 manual switch: ITU-T G.808 3.1.13 nonpre-emptible unprotected traffic: ITU-T G.808.2 3.1.14 normal tra
33、ffic: ITU-T G.808.2 3.1.15 revertive (protection) operation: ITU-T G.808 3.1.16 ring map: IETF RFC 8227: NOTE Ring map defined in IETF RFC 8227 is slightly different in meaning from the one that ITU-T G.808.2 uses. The ring map in ITU-T G.808.2 includes only the ring topology map information, while
34、the ring map in IETF RFC 8227 also includes the ring connectivity status information. 3.1.17 section: ITU-T G.806 3.1.18 server signal fail (SSF): ITU-T G.806 3.1.19 steering: ITU-T G.808 3.1.20 termination connection point (TCP): ITU-T G.806 3.1.21 trail termination function (TT): ITU-T G.806 3.1.2
35、2 wrapping: ITU-T G.808 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: A Adaptation function C Connection function CIR Committed Information Rate CP Connection Point Rec. ITU-T G.8132/Y.1383 (08/2017) 3 E
36、IR Excess Information Rate LSP Label Switched Path LSR Label Switched Router MEP Maintenance Entity Point MPLS Multi-Protocol Label Switching MPLS-TP Multi-Protocol Label Switching-Transport Profile MSRP MPLS-TP Shared Ring Protection MT MPLS-TP NUT Non-pre-emptible Unprotected Traffic OAM Operation
37、, Administration and Maintenance OTN Optical Transport Network PDU Protocol Data Unit PW Pseudowire RPS Ring Protection Switch SDH Synchronous Digital Hierarchy SF Signal Fail SSF Server Signal Fail Sk Sink So Source TCP Termination Connection Point TT Trail Termination 5 Conventions The naming and
38、diagrammatic conventions for the atomic functions used in this Recommendation follow the rules specified in ITU-T G.806. The following syntax is used to describe the contents of the label stack: 1) The label stack is enclosed in square brackets (“). 2) Each level in the stack is separated by the | c
39、haracter. Note that the label stack can contain additional layers. However, the layers that are related to the protection mechanism are presented in this Recommendation. 3) If the label is assigned by node X, the node name is enclosed in parentheses (“(X)“) RaW_X and RcW_X denote anticlockwise worki
40、ng ring tunnel terminating on node X and clockwise working ring tunnel terminating on node X, respectively. Similarly, RaP_X and RcP_X denote anticlockwise protection ring tunnel terminating on node X and clockwise protection ring tunnel terminating on node X, respectively. 6 Overview This Recommend
41、ation specifies MPLS-TP Shared Ring Protection (MSRP) switching mechanisms to be applied to MPLS-TP layer networks as described in ITU-T G.8110.1. Clause 4.1 of IETF RFC 8227 provides an overview of MSRP. 4 Rec. ITU-T G.8132/Y.1383 (08/2017) 7 Network objectives Clause 2.5.6.1 of IETF RFC 5654 descr
42、ibes the requirements for MPLS-TP ring protection as well as some optimization criteria. Clause 3 of IETF RFC 8227 describes how MSRP meets those optimization criteria. This clause describes the network objectives that MSRP supports: 1) Operation in both a single ring topology and single rings of in
43、terconnected ring topology as stated in Requirement 92 of IETF RFC 5654. 2) Identical protection mechanisms for both logical and physical rings as stated in Requirement 101 of IETF RFC 5654. 3) Interconnection with other MPLS-TP domains without precluding the operations of other recovery mechanisms
44、in the rest of the network as stated in Requirement 99 of IETF RFC 5654. 4) Protection of unidirectional and bidirectional point-to-point LSPs as stated in Requirement 94 of IETF RFC 5654. 5) Sharing of the reserved protection bandwidth as stated in Requirement 109 of IETF RFC 5654. 6) Allowing the
45、bandwidth of a physical link to be shared with best-effort traffic as stated in Requirement 108 of IETF RFC 5654. 7) Transfer time 50 ms (Tt in ITU-T G.808.2) as specified in Requirement 96 of IETF RFC 5654. Note that transfer time in ITU-T G.808.2 is considered to be the same as switching time in I
46、ETF RFC 5646. 8) Hold-off time as specified in Requirement 61 of IETF RFC 5654. 9) Wait-to-restore time as specified in Requirement 107 of IETF RFC 5654. 10) Protection against a single failure and multiple failures when recovery is possible as per Requirement 106 of IETF RFC 5654. 11) Revertive mod
47、e of operation as described in Requirement 103 of IETF RFC 5654. 12) Bidirectional protection switching type as described in Requirement 102 of IETF RFC 5654. 13) Interconnected rings as specified in Requirement 93 of IETF RFC 5654. 14) MPLS-TP ring protection shall protect against the following eve
48、nts: a) MPLS-TP section layer failures. b) Node failures. 15) Traffic types: a) Normal traffic as defined in ITU-T G.808.2 shall be supported. b) Non-pre-emptible unprotected traffic (NUT) as defined in ITU-T G.808.2 shall not be supported, as described in Annex B. c) Extra traffic as defined in ITU
49、-T G.808.2 shall not be supported, as described in Annex B. 16) Ring protection switch (RPS) protocol and algorithm: a) The switching protocol shall be able to accommodate, as minimum, up to 127 nodes on a ring Rec. ITU-T G.8132/Y.1383 (08/2017) 5 b) The RPS protocol and associated section operation, administration and maintenance (OAM) functions shall accommodate the capability to upgrade the ring (node
