1、 International Telecommunication Union ITU-T G.8121.2/Y.1381.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2013) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects MPLS over Transport aspects SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERN
2、ET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Transport Characteristics of MPLS-TP equipment functional blocks supporting ITU-T G.8113.2/Y.1372.2 OAM mechanisms Recommendation ITU-T G.8121.2/Y.1381.2 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL
3、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 METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERN
4、ATIONAL 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 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORK
5、S 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.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 Eth
6、ernet over Transport aspects G.8000G.8099 MPLS over Transport aspects G.8100G.8199Quality 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.8121.2/Y.1381.2 (11/2013)
7、i Recommendation ITU-T G.8121.2/Y.1381.2 Characteristics of MPLS-TP equipment functional blocks supporting ITU-T G.8113.2/Y.1372.2 OAM mechanisms Summary Recommendation ITU-T G.8121.2/Y.1381.2 specifies both the functional components and the methodology that should be used in order to specify the MP
8、LS-TP layer network functionality of network elements based on the protocol-neutral constructs defined in Recommendation ITU-T G.8121/Y.1381 and on the tools defined in Recommendation ITU-T G.8113.2/Y.1372.2. History Edition Recommendation Approval Study Group Unique ID*1.0 ITU-T G.8121.2/Y.1381.2 2
9、013-11-06 15 11.1002/1000/12018-en Keywords Atomic functions, equipment functional blocks, MPLS-TP, MPLS-TP layer network. _ *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:/handl
10、e.itu.int/11.1002/1000/ 11830-en. ii Rec. ITU-T G.8121.2/Y.1381.2 (11/2013) 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 Standardizati
11、on 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 basis. The World Telecommunication Standardization Assembly (WTSA), which meet
12、s 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 Resolution 1. In some areas of information technology which fall within ITU-Ts p
13、urview, 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 administration and a recognized operating agency. Compliance with this Recommendation is v
14、oluntary. 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 are met. The words “shall“ or some other obligatory language such as “must“ an
15、d 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 draws attention to the possibility that the practice or implementation of this Recommendation may inv
16、olve 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 the Recommendation development process. As of the date of approval of this Rec
17、ommendation, ITU had not 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
18、at http:/www.itu.int/ITU-T/ipr/. ITU 2014 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.8121.2/Y.1381.2 (11/2013) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms de
19、fined elsewhere 2 3.2 Terms defined in this Recommendation . 3 4 Abbreviations and acronyms 3 5 Conventions 5 6 Supervision . 5 6.1 Defects 5 7 Information flow across reference points . 5 8 MPLS-TP processes 5 8.1 G-ACh process . 5 8.2 TC/Label processes 5 8.3 Queueing process 5 8.4 MPLS-TP-specifi
20、c GFP-F processes 5 8.5 Control word (CW) processes 5 8.6 OAM-related processes used by server adaptation functions . 5 8.7 OAM-related processes used by adaptation functions . 8 8.8 Proactive and on-demand OAM-related processes 8 8.9 Data-plane loopback processes . 50 9 MPLS-TP layer functions . 50
21、 9.1 Connection functions (MT_C) . 50 9.2 Termination functions 50 9.3 Adaptation functions 57 9.4 MT diagnostic functions . 57 10 MPLS-TP to non-MPLS-TP client adaptation functions . 67 11 Non-MPLS-TP server to MPLS-TP adaptation functions 68 Appendix I OAM process and subprocesses . 69 Rec. ITU-T
22、G.8121.2/Y.1381.2 (11/2013) 1 Recommendation ITU-T G.8121.2/Y.1381.2 Characteristics of MPLS-TP equipment functional blocks supporting ITU-T G.8113.2/Y.1372.2 OAM mechanisms 1 Scope This Recommendation describes both the functional components and the methodology that should be used in order to descr
23、ibe MPLS-TP layer network functionality of network elements; it does not describe individual MPLS-TP network equipment. This Recommendation provides protocol-specific extensions of the protocol-neutral constructs defined in ITU-T G.8121 to support the OAM tools defined in ITU-T G.8113.2. This Recomm
24、endation provides a description of the MPLS-TP functional technology using the same methodologies that have been used for other transport technologies (e.g., SDH, OTN and Ethernet)1.This Recommendation, along with ITU-T G.8121, specifies a library of basic building blocks and a set of rules by which
25、 they may be combined in order to describe digital transmission equipment. The library comprises the functional building blocks needed to specify completely the generic functional structure of the MPLS-TP layer network. In order to be compliant with this Recommendation, equipment needs to be describ
26、able as an interconnection of a subset of these functional blocks contained within this Recommendation. The interconnections of these blocks should obey the combination rules given. Not every atomic function defined in this Recommendation is required for every application. Different subsets of atomi
27、c functions may be assembled in different ways according to the combination rules given in this Recommendation to provide a variety of different capabilities. Network operators and equipment suppliers may choose which functions must be implemented for each application. 2 References The following ITU
28、-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 revision; users of this Recommendatio
29、n 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 this Recommendation does not give it,
30、 as a stand-alone document, the status of a Recommendation. ITU-T G.805 Recommendation ITU-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. I
31、TU-T G.8101 Recommendation ITU-T G.8101/Y.1355 (2013), Terms and definitions for MPLS transport profile. 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. _ 1This ITU-T Recommendation is intended to be al
32、igned with the IETF MPLS RFCs normatively referenced by this Recommendation. 2 Rec. ITU-T G.8121.2/Y.1381.2 (11/2013) ITU-T G.8113.2 Recommendation ITU-T G.8113.2/Y.1372.2 (2012), Operations, administration and maintenance mechanisms for MPLS-TP networks using the tools defined for MPLS. ITU-T G.812
33、1 Recommendation ITU-T G.8121/Y.1381 (2013), Characteristics of MPLS-TP equipment functional blocks. IETF RFC 4379 IETF RFC 4379 (2006), Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures. IETF RFC 5880 IETF RFC 5880 (2010), Bidirectional Forwarding Detection (BFD). IETF RFC 5884 IET
34、F RFC 5884 (2010), Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs). IETF RFC 6435 IETF RFC 6435 (2011), MPLS Transport Profile Lock Instruct and Loopback Functions. IETF RFC 6374 IETF RFC 6374 (2011), Packet Loss and Delay Measurement for MPLS Networks. IETF RFC 6375 IE
35、TF RFC 6375 (2011), A Packet Loss and Delay Measurement Profile for MPLS-Based Transport Networks. IETF RFC 6426 IETF RFC 6426 (2011), MPLS On-Demand Connectivity Verification and Route Tracing. IETF RFC 6427 IETF RFC 6427 (2011), MPLS Fault Management Operations, Administration, and Maintenance (OA
36、M). IETF RFC 6428 IETF RFC 6428 (2011), Proactive Connectivity Verification, Continuity Check and Remote Defect Indication for the MPLS Transport Profile. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 access point: ITU-T G.805 3.1.2 a
37、dapted information: ITU-T G.805 3.1.3 associated channel header: ITU-T G.8101 3.1.4 bottom of stack: ITU-T G.8101 3.1.5 characteristic information: ITU-T G.805 3.1.6 client/server relationship: ITU-T G.805 3.1.7 connection: ITU-T G.805 3.1.8 connection point: ITU-T G.805 3.1.9 explicitly TC-encoded-
38、PSC LSP: ITU-T G.8101 3.1.10 G-ACh label: ITU-T G.8101 3.1.11 generic associated channel: ITU-T G.8101 3.1.12 label: ITU-T G.8101 3.1.13 label inferred PHB scheduling class LSP: ITU-T G.8101 3.1.14 label stack: ITU-T G.8101 Rec. ITU-T G.8121.2/Y.1381.2 (11/2013) 3 3.1.15 label switched path: ITU-T G
39、.8101 3.1.16 label value: ITU-T G.8101 3.1.17 layer network: ITU-T G.805 3.1.18 matrix: ITU-T G.805 3.1.19 MPLS label stack: ITU-T G.8101 3.1.20 network: ITU-T G.805 3.1.21 network connection: ITU-T G.805 3.1.22 per-hop behaviour: ITU-T G.8101 3.1.23 reference point: ITU-T G.805 3.1.24 subnetwork: I
40、TU-T G.805 3.1.25 subnetwork connection: ITU-T G.805 3.1.26 termination connection point: ITU-T G.805 3.1.27 time to live: ITU-T G.8101 3.1.28 traffic class: ITU-T G.8101 3.1.29 trail: ITU-T G.805 3.1.30 trail termination: ITU-T G.805 3.1.31 transport: ITU-T G.805 3.1.32 transport entity: ITU-T G.80
41、5 3.1.33 transport processing function: ITU-T G.805 3.1.34 unidirectional connection: ITU-T G.805 3.1.35 unidirectional trail: ITU-T G.805 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AIS Alarm Indicati
42、on Signal APS Automatic Protection Switching BFD Bidirectional Forwarding Detection CC Continuity Check CCCV Continuity Check and Connectivity Verification CoS Class of Service CSF Client Signal Fail CV Connectivity Verification DLM Direct Loss Measurement DM Delay Measurement DSMap Downstream Mappi
43、ng 4 Rec. ITU-T G.8121.2/Y.1381.2 (11/2013) EMF Equipment Management Function FEC Forwarding Equivalence Class G-ACh Generic Associated Channel GAL G-ACh Label GFP Generic Framing Procedure ILM Inferred Loss Measurement LCK Locked LI Lock Instruct LKI Lock Instruct LKR Lock Report LM Loss Measuremen
44、t LStack Label Stack MCC Maintenance Communication Channel MEP Maintenance entity group (MEG) End Point MIP Maintenance entity group (MEG) Intermediate Point MPLS Multi-Protocol Label Switching MPLS-TP Multi-Protocol Label Switching Transport Profile MT Multi-Protocol Label Switching Transport Profi
45、le MTDe MPLS-TP MEP Diagnostic function MTU Maximum Transmit Unit OAM Operation, Administration and Maintenance ODCV On-Demand Connectivity Verification PDU Protocol Data Unit PHB Per Hop Behaviour PM Performance Monitoring QTF Queriers Timestamp Format RDI Remote Detect Indication Req Request Resp
46、Response RPTF Responders Preferred Timestamp Format RTF Responders Timestamp Format SCC Signalling Communication Channel SQI Session Query Interval SSF Server Signal Fail TC Traffic Class TLV Type Length Value TS Timestamp Rec. ITU-T G.8121.2/Y.1381.2 (11/2013) 5 TSFmt Timestamp Format TTL Time-To-L
47、ive 5 Conventions The diagrammatic convention for connection-oriented layer networks described in this Recommendation is that of ITU T G.805. 6 Supervision 6.1 Defects 6.1.1 Summary of entry/exit conditions for defects The defect entry and exit conditions are based on events. Occurrence or absence o
48、f specific events may raise or reset specific defects. The events used by this Recommendation are defined in Table 6-1 of ITU-T G.8121. The events, unexpPeriod, CSF-LOS, CSF-FDI and CSF-RDI that are described in Table 6-1 of ITU-T G.8121 are out of the scope of this Recommendation. 7 Information flo
49、w across reference points Information flow for MPLS-TP functions is defined in clause 9. A generic description of information flow is defined in clause 7 of ITU-T G.806. 8 MPLS-TP processes 8.1 G-ACh process In the case where OAM packets are encapsulated using a generic associated channel (G-ACh), the G-Ach process is described in clause 8.1 of ITU-T G.8121. Encapsulation of OAM packet
