1、 International Telecommunication Union ITU-T G.8121/Y.1381TELECOMMUNICATION 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, INTERNET P
2、ROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Transport Characteristics of MPLS-TP equipment functional blocks Recommendation ITU-T G.8121/Y.1381 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS A
3、ND 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 RADIO-RELAY OR SATELL
4、ITE 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 DIGITAL LINE SYSTEM G.90
5、0G.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.8099 MPLS over Transp
6、ort 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/Y.1381 (11/2013) i Recommendation ITU-T G.8121/Y.1381 Characteristics of MPLS-T
7、P equipment functional blocks Summary Recommendation ITU-T G.8121/Y.1381 specifies both the functional components and the methodology that should be used in order to specify the multi-protocol label switching transport profile (MPLS-TP) layer network functionality of network elements. It does not sp
8、ecify individual MPLS-TP network equipment. History Edition Recommendation Approval Study Group Unique ID*1.0 ITU-T G.8121/Y.1381 2006-03-29 15 11.1002/1000/8785 1.1 ITU-T G.8121/Y.1381 (2006) Cor. 1 2006-12-14 15 11.1002/1000/9007 1.2 ITU-T G.8121/Y.1381 (2006) Amd. 1 2007-10-22 15 11.1002/1000/917
9、8 2.0 ITU-T G.8121/Y.1381 2012-09-21 15 11.1002/1000/115172.1 ITU-T G.8121/Y.1381 (2012) Amd. 1 2012-12-22 15 11.1002/1000/118003.0 ITU-T G.8121/Y.1381 2013-11-06 15 11.1002/1000/12020Keywords Atomic functions, equipment functional blocks, MPLS-TP layer network, MPLS-TP. _ *To access the Recommendat
10、ion, 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.8121/Y.1381 (11/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nations s
11、pecialized 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 th
12、em 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 groups which, in turn, produce Recommendations on these topics. The approval of ITU-
13、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 with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used
14、 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 provisions (to ensure, e.g., interoperability or applicability) and compliance with the
15、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 such words does not suggest that compliance with the Recommendation is required of a
16、ny party. INTELLECTUAL PROPERTY RIGHTS ITU 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 Prop
17、erty 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 received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implem
18、enters 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 2014 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written
19、 permission of ITU. Rec. ITU-T G.8121/Y.1381 (11/2013) iii Table of Contents Page 1 Scope 1 2 References. 2 3 Definitions 4 3.1 Terms defined elsewhere 4 3.2 Terms defined in this Recommendation . 5 4 Abbreviations and acronyms 5 5 Conventions 7 6 Supervision . 7 6.1 Defects 7 6.2 Consequent actions
20、 . 13 6.3 Defect correlations 13 6.4 Performance filters . 13 7 Information flow across reference points . 13 8 MPLS-TP processes 13 8.1 G-ACh process . 13 8.2 TC/Label processes 15 8.3 Queueing process 17 8.4 MPLS-TP-specific GFP-F processes 18 8.5 Control word (CW) processes 20 8.6 OAM-related pro
21、cesses used by server adaptation functions . 21 8.7 OAM-related processes used by adaptation functions . 23 8.8 Proactive and on-demand OAM-related processes 29 8.9 Data-plane loopback processes . 37 9 MPLS-TP layer functions . 39 9.1 Connection functions (MT_C) . 40 9.2 Termination functions 42 9.3
22、 Adaptation functions 50 9.4 MT diagnostic functions . 55 10 MPLS-TP to non-MPLS-TP client adaptation functions . 66 10.1 MPLS-TP to ETH adaptation function (MT/ETH_A) . 66 10.2 MPLS-TP to SCC and MCC adaptation functions . 71 11 Non-MPLS-TP server to MPLS-TP adaptation functions 77 11.1 SDH to MPLS
23、-TP adaptation function (S/MT_A) . 77 11.2 OTH to MPLS-TP adaptation function (O/MT_A) 99 11.3 PDH to MPLS-TP adaptation function (P/MT_A) . 117 11.4 Ethernet to MPLS-TP adaptation function . 127 Appendix I Examples of processing packets with expired TTL . 131 iv Rec. ITU-T G.8121/Y.1381 (11/2013) P
24、age Appendix II Flow of PHB information through MEP and MIP . 135 Appendix III Examples of MPLS-TP linear protection 137 Bibliography. 139 Rec. ITU-T G.8121/Y.1381 (11/2013) 1 Recommendation ITU-T G.8121/Y.1381 Characteristics of MPLS-TP equipment functional blocks11 Scope This Recommendation descri
25、bes both the functional components and the methodology that should be used in order to describe the multi-protocol label switching transport profile (MPLS-TP) layer network functionality of network elements. It does not describe individual MPLS-TP network equipment. This Recommendation provides a re
26、presentation of MPLS-TP technology which uses the methodologies that have been used for other transport technologies (e.g., synchronous digital hierarchy (SDH), optical transport network (OTN) and Ethernet).2This Recommendation forms part of a suite of Recommendations covering the full functionality
27、 of network equipment. These Recommendations are ITU-T G.806, ITU-T G.798, ITU-T G.783, ITU-T G.705 and ITU-T G.8021. This Recommendation also follows the principles defined in ITU-T G.805. These Recommendations specify a library of basic building blocks and a set of rules by which they may be combi
28、ned 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 describable as an interco
29、nnection 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 atomic functions may be
30、 assembled in different ways according to the combination rules given in this Recommendation to provide a variety of different capabilities. _ 1Cisco Systems has expressed concerns that in the event of a difference between this ITU-T Recommendation and any of the normatively referenced IETF RFCs, in
31、teroperability issues may arise. To prevent interoperability issues, the behaviour defined in the IETF RFCs must be maintained, and any such differences must be resolved in coordination with the IETF in a timely manner. France Telecom Orange has expressed concerns that in the event of a difference b
32、etween this ITU-T Recommendation and any of the normatively referenced IETF RFCs, interoperability issues may arise. To prevent interoperability issues, the behaviour defined in the IETF RFCs must be maintained, and any such differences must be resolved in coordination with the IETF in a timely mann
33、er. Nokia Siemens Networks (NSN) is concerned that, in the event of a difference between this ITU-T Recommendation and any of the IETF RFCs to which it makes normative reference, interoperability issues may arise. This Recommendation contains no guidance on how to resolve such a situation. NSN belie
34、ves that in the case of such an event, differences should be resolved in coordination with the IETF and that the behaviour specified in the RFC(s) must be maintained. Verizon Communications has expressed concerns that in the event of a difference between this ITU-T Recommendation and the behaviour d
35、efined in the normatively referenced IETF RFCs, interoperability issues may arise. There is no guidance in this ITU-T Recommendation that describes how to address differences in behaviour between the Recommendation and the normatively referenced IETF RFCs. Verizon Communications feels that any diffe
36、rence should be resolved in coordination with the IETF in a timely manner and until the issue is resolved, the behaviour defined in the IETF RFCs should be maintained. 2This ITU-T Recommendation is intended to be aligned with the IETF MPLS RFCs normatively referenced by this Recommendation. 2 Rec. I
37、TU-T G.8121/Y.1381 (11/2013) Network operators and equipment suppliers may choose which functions must be implemented for each application. Figure 1 presents the set of atomic functions associated with the traffic signal transport. The functions are based on the functional architecture described in
38、ITU-T G.8110.1. It is noted that this Recommendation only defines Ethernet for the client of MPLS-TP as an MT/ETH adaptation function. Figure 1-1 MPLS-TP atomic functions 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, c
39、onstitute 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 edition of th
40、e 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.704 Recommendation ITU-T G.704
41、(1998), Synchronous frame structures used at 1544, 6312, 2048, 8448 and 44 736 kbit/s hierarchical levels. ITU-T G.705 Recommendation ITU-T G.705 (2000), Characteristics of plesiochronous digital hierarchy (PDH) equipment functional blocks. ITU-T G.707 Recommendation ITU-T G.707/Y.1322 (2003), Netwo
42、rk node interface for the synchronous digital hierarchy (SDH). ITU-T G.709 Recommendation ITU-T G.709/Y.1331 (2009), Interfaces for the Optical Transport Network (OTN). ITU-T G.780 Recommendation ITU-T G.780/Y.1351 (2004), Terms and definitions for synchronous digital hierarchy (SDH) networks. ITU-T
43、 G.783 Recommendation ITU-T G.783 (2006), Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks. Rec. ITU-T G.8121/Y.1381 (11/2013) 3 ITU-T G.798 Recommendation ITU-T G.798 (2012), Characteristics of optical transport network hierarchy equipment functional blocks. ITU-T
44、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. ITU-T G.832 Recommendation ITU-T G.832 (1998), Transport of SDH ele
45、ments on PDH networks Frame and multiplexing structures. ITU-T G.7041 Recommendation ITU-T G.7041/Y.1303 (2011), Generic framing procedure. ITU-T G.7043 Recommendation ITU-T G.7043/Y.1343 (2004), Virtual concatenation of plesiochronous digital hierarchy (PDH) signals. ITU-T G.7044 Recommendation ITU
46、-T G.7044/Y.1347 (2011), Hitless adjustment of ODUflex(GFP). ITU-T G.7712 Recommendation ITU-T G.7712/Y.1703 (2010), Architecture and specification of data communication network. ITU-T G.8021 Recommendation ITU-T G.8021/Y.1341 (2012), Characteristics of Ethernet transport network equipment functiona
47、l blocks. ITU-T G.8040 Recommendation ITU-T G.8040/Y.1340 (2005), GFP frame mapping into Plesiochronous Digital Hierarchy (PDH). ITU-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), Arc
48、hitecture of the Multi-Protocol Label Switching transport profile layer network. ITU-T G.8251 Recommendation ITU-T G.8251 (2010), The control of jitter and wander within the optical transport network (OTN). ITU-T Y.1415 Recommendation ITU-T Y.1415 (2005), Ethernet-MPLS network interworking User plan
49、e interworking. IETF RFC 4448 IETF RFC 4448 (2006), Encapsulation Methods for Transport of Ethernet over MPLS Networks. IETF RFC 4720 IETF RFC 4720 (2006), Pseudowire Emulation Edge-to-Edge (PWE3) Frame Check Sequence Retention. IETF RFC 5332 IETF RFC 5332 (2008), MPLS Multicast Encapsulations. IETF RFC 5586 IETF RFC 5586 (2009), MPLS Generic Associated Channel. IETF RFC 5718 IETF RFC 5718 (2010), An In-band Data Communication
