1、 International Telecommunication Union ITU-T Series GTELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 52(09/2012) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Ethernet ring protection switching ITU-T G-series Recommendations Supplement 52 ITU-T G-SERIES RECOMMENDA
2、TIONS 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 METALLIC LINE
3、S 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 DIGITAL
4、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.7000G.7999
5、PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. G series Supplement 52 (09/2012) i Supplement 52 to ITU-T G-series Recommendations Ethernet ring protection switching Summary Supplement 52 to ITU-T G-serie
6、s Recommendations provides supplemental information to Recommendation ITU-T G.8032/Y.1344, Ethernet ring protection switching. It provides examples of network application scenarios, Ethernet service support, ring interconnection examples, guidelines for configuration and management procedures, prote
7、ction switching for multiple Ethernet ring protection (ERP) instances and end-to-end network/service resiliency involving ITU-T G.8032. History Edition Recommendation Approval Study Group 1.0 ITU-T G Suppl. 52 2012-09-21 15 ii G series Supplement 52 (09/2012) FOREWORD The International Telecommunica
8、tion 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 studying technical, operating and tariff que
9、stions 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 groups which, in turn, produce Recommendatio
10、ns 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 with ISO and IEC. NOTE In this publication, th
11、e expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure, e.g., interoperability or applicab
12、ility) and compliance with the publication 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 pub
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14、imed Intellectual Property Rights, whether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication
15、. 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 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without
16、the prior written permission of ITU. G series Supplement 52 (09/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Terms and definitions . 2 3.1 Terms defined elsewhere 2 4 Abbreviations and acronyms 3 5 Introduction 5 6 ITU-T G.8032 network applications . 5 7 ITU-T G.8032 support of Ether
17、net services . 6 7.1 Introduction 6 7.2 ITU-T G.8032 ring concepts in support of E-services . 8 7.3 ITU-T G.8032 support of E-Line services . 10 7.4 ITU-T G.8032 support of E-Tree services . 11 7.5 ITU-T G.8032 support of E-LAN services . 12 7.6 ITU-T G.8032 support of mixed E-services . 13 8 Interc
18、onnected rings 14 8.1 Configuration for interconnected rings 16 8.2 Topology examples for interconnected Ethernet rings . 19 9 Guidelines for management procedures . 20 9.1 An example procedure for removing an Ethernet ring node 20 9.2 Management procedures to exit the FS state in case of failure of
19、 an Ethernet ring node under an FS condition 21 9.3 Replacing an ITU-T G.8032 (2008) v1 Ethernet ring node with an ITU-T G.8032 (2010) v2 Ethernet ring node . 22 10 End-to-end service resilience 23 10.1 Generic end-to-end service resilience 23 10.2 Layering ITU-T G.8031 protection over ITU-T G.8032
20、23 10.3 Access sub-ring connected to major ring . 24 10.4 Non-ERP node connected in major ring . 25 11 Protection switching for multiple ERP instances . 28 11.1 Multiple ERP instances 28 11.2 Applying protection mechanisms to multiple ERP instances . 28 11.3 Protection switching model for multiple E
21、RP instances 29 11.4 Multiple instances of interconnected rings . 29 12 Guidelines for the configuration of VIDs and ring IDs of R-APS channels 31 12.1 Sub-ring with R-APS virtual channel . 31 12.2 Sub-ring without R-APS virtual channel 34 12.3 Backward compatibility 35 iv G series Supplement 52 (09
22、/2012) Page 13 Minimizing segmentation in interconnected rings . 36 13.1 Characterization of the segmentation issue 36 13.2 Class of double faults addressed . 37 13.3 Procedure for minimization of segmentation . 39 G series Supplement 52 (09/2012) 1 Supplement 52 to ITU-T G-series Recommendations Et
23、hernet ring protection switching 1 Scope This supplement describes how ITU-T G.8032 can support the various Ethernet services and how it can be used in various network applications. Additionally, examples of Ethernet ring interconnection, guidelines for configuration and management procedures, prote
24、ction switching for multiple Ethernet ring protection (ERP) instances and end-to-end network/service resiliency involving ITU-T G.8032, are described. This supplement is intended to consolidate and expand upon related material that is current in ITU-T G.8032. 2 References ITU-T G.805 Recommendation
25、ITU-T G.805 (2000), Generic functional architecture of transport networks. ITU-T G.806 Recommendation ITU-T G.806 (2009), Characteristics of transport equipment Description methodology and generic functionality. ITU-T G.808.1 Recommendation ITU-T G.808.1 (2010), Generic protection switching Linear t
26、rail and subnetwork protection. ITU-T G.809 Recommendation ITU-T G.809 (2003), Functional architecture of connectionless layer networks. ITU-T G.870 Recommendation ITU-T G.870/Y.1352 (2010), Terms and definitions for optical transport networks ITU-T G.8001 Recommendation ITU-T G.8001/Y.1354 (2010),
27、Terms and definitions for Ethernet frames over transport. ITU-T G.8010 Recommendation ITU-T G.8010/Y.1306 (2004), Architecture of Ethernet layer networks. ITU-T G.8011 Recommendation ITU-T G.8011/Y.1306 (2004), Ethernet service characteristics. ITU-T G.8011.1 Recommendation ITU-T G.8011.1/Y.1307.1 (
28、2009), Ethernet private line service. ITU-T G.8011.2 Recommendation ITU-T G.8011.2/Y.1307.2 (2009), Ethernet virtual private line service. ITU-T G.8013 Recommendation ITU-T G.8013/Y.1731 (2008), OAM functions and mechanisms for Ethernet based networks: Amendment 1 (2010). ITU-T G.8021 Recommendation
29、 ITU-T G.8021/Y.1341 (2011), Characteristics of Ethernet transport network equipment functional blocks. ITU-T G.8031 Recommendation ITU-T G.8031/Y.1342 (2011), Ethernet linear protection switching. ITU-T G.8032 Recommendation ITU-T G.8032/Y.1344 (2012), Ethernet ring protection switching. 2 G series
30、 Supplement 52 (09/2012) IEEE 802.1ag IEEE Std 802.1ag-2007, IEEE Standard for Local and Metropolitan Area Networks Virtual Bridged Local Area Networks Amendment 5: Connectivity Fault Management. IEEE 802.1D IEEE Std 802.1D-2004, IEEE Standard for Local and Metropolitan Area Networks: Media Access C
31、ontrol (MAC) Bridges. IEEE 802.1Q IEEE Std 802.1Q-2005, IEEE Standard for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks. IEEE 802.3 IEEE Std 802.3-2008, Information Technology Local and Metropolitan Area Networks Part 3: Carrier Sense Multiple Access with Collision Detect
32、ion (CSMA/CD) Access Method and Physical Layer Specifications. MEF 6.1 The Metro Ethernet Forum, MEF Technical Specification (2008), Ethernet Services Definitions Phase 2, April, 2008. 3 Terms and definitions 3.1 Terms defined elsewhere This supplement uses the following terms defined elsewhere: 3.1
33、.1 Terms defined in ITU-T G.806: a) defect b) failure c) server signal fail (SSF) d) signal degrade (SD) e) signal fail (SF) f) trail signal fail (TSF) 3.1.2 Terms defined in ITU-T G.809: a) adaptation b) flow c) layer network d) network e) port f) transport g) transport entity 3.1.3 Terms defined i
34、n ITU-T G.870: a) APS protocol b) hold-off time c) non-revertive operation d) protection e) protected domain f) revertive operation g) signal h) switch i) switching time G series Supplement 52 (09/2012) 3 j) transport entity: a. protection transport entity b. working transport entity k) wait-to-rest
35、ore time 3.1.4 Terms defined in ITU-T G.8001: a) maintenance entity (ME) b) maintenance entity group (MEG) c) Ethernet ring d) Ethernet ring node e) ERP instance f) interconnection node g) major ring h) R-APS virtual channel i) ring MEL j) ring protection link (RPL) k) RPL neighbour node l) RPL owne
36、r node m) sub-ring n) sub-ring link o) wait to block timer 3.1.5 Terms defined and described in ITU-T G.8010 and ITU-T G.8013: a) maintenance entity group end point (MEP) b) maintenance entity group level (MEL) 3.1.6 Terms defined and described in ITU-T G.8011: a) Ethernet virtual connection (EVC) 4
37、 Abbreviations and acronyms This supplement uses the following abbreviations and acronyms: APS Automatic Protection Switching CCM Continuity Check Message CE Customer Equipment CPE Customer Premises Equipment E-LAN Ethernet LAN Service E-Line Ethernet Line Service EPL Ethernet Private Line ERP Ether
38、net Ring Protection E-services Ethernet services E-Tree Ethernet Tree Service EVC Ethernet Virtual Connection 4 G series Supplement 52 (09/2012) FDB Filtering Database FS Forced Switch ID Identification IP Internet Protocol IPTV Internet Protocol Television LAN Local Area Network MAC Media Access Co
39、ntrol MEF Metro Ethernet Forum MEG Maintenance Entity Group MEL Maintenance Entity Group Level MEP Maintenance Entity Group End Point MI Management Information MIP Maintenance Entity Group Intermediate Point MPLS Multiprotocol Label Switching MPLS-TP MPLS Transport Profile MS Manual Switch NR No Req
40、uest OAM Operations, Administration and Maintenance OTN Optical Transport Network PBB-TE Provider Backbone Bridge Traffic Engineering PDU Protocol Data Unit RAN Radio Access Network R-APS Ring APS RB RPL Blocked RPL Ring Protection Link RSTP Rapid Spanning Tree Protocol SDH Synchronous Digital Hiera
41、rchy SF Signal Fail SONET Synchronous Optical Network STP Spanning Tree Protocol TDM Time Division Multiplexing UNI User Network Interface VID VLAN Identifier VLAN Virtual LAN VPLS Virtual Private LAN Service VR Virtual Ring G series Supplement 52 (09/2012) 5 5 Introduction This supplement provides
42、supplemental information to ITU-T G.8032, Ethernet ring protection switching. It describes ITU-T G.8032 suitability to many network applications (e.g., mobile backhaul, business services, etc.), and how ITU-T G.8032 can be used to support the various Ethernet services (e.g., E-Line, E-LAN and E-Tree
43、 services), as defined by MEF MEF 6.1, using a common ERP protection switching mechanism. Ring interconnections examples involving ITU-T G.8032 major-rings and sub-rings, and configuration and management procedures in support of service provider network requirements and network applications, are als
44、o described. 6 ITU-T G.8032 network applications The fundamental network requirement to operate an ITU-T G.8032 ring is the existence of a sub-network of network elements interconnected in a closed loop1, such that there are diversely routed forwarding paths between any two network elements. Network
45、s are often composed of both diversely routed paths and spurs. A network spur exists when there is only a single network path providing connectivity between network elements. Consequently, spurs by their very nature do not provide diversely routed paths and thus could not leverage ITU-T G.8032. Howe
46、ver, spurs typically connect network elements to redundant access or aggregation sub-networks. When these redundant sub-networks use diverse routing for redundancy, ITU-T G.8032 can be deployed to provide all the value propositions of this technology. The existence of diversely routed sub-networks c
47、an be found in network architectures for various applications, such as business services, mobile/wireless backhaul and residential services. These applications can make use of ITU-T G.8032 as an access sub-network or as an aggregation transport infrastructure sub-network. For example, ITU-T G.8032 i
48、s suitable for mobile backhaul network applications. As illustrated in Figure 1, ITU-T G.8032 can be used in the backhaul access, as well as the aggregation network, to provide service connectivity with (sub-50 ms) resiliency. _ 1A “closed loop“ is a data path through the network that would result i
49、n data traffic looping, without a loop prevention mechanism. A closed loop requires diversely routed paths between two nodes within the network. It should be noted that both a major ring and a sub-ring, from a data path perspective, form a closed loop. However, the R-APS channel of a major ring forms a closed loop while the R-APS channel of a sub-ring does not. 6 G series Supplement 52 (09/2012) AggregationG suppl.52(12)_F01eNodeBNodeBBTSB
