1、 International Telecommunication Union ITU-T G.8021.1/Y.1341.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2012) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Packet over Transport aspects Ethernet over Transport aspects SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, IN
2、TERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Transport Types and characteristics of Ethernet transport network equipment Recommendation ITU-T G.8021.1/Y.1341.1 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL
3、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 TELEPHONE SYSTEMS O
4、N 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 DIGITAL SECTIONS AND D
5、IGITAL 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 Transport aspects G.8000
6、G.8099MPLS over Transport aspects G.8100G.8199 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.8021.1/Y.1341.1 (10/2012) i Recommendation ITU-T G.8021.1/Y.1
7、341.1 Types and characteristics of Ethernet transport network equipment Summary Recommendation ITU-T G.8021.1/Y.1341.1 describes examples of Ethernet equipment types derived from IEEE 802.1Q bridge types. History Edition Recommendation Approval Study Group 1.0 ITU-T G.8021.1/Y.1341.1 2012-10-29 15 K
8、eywords Bridge, Ethernet equipment. ii Rec. ITU-T G.8021.1/Y.1341.1 (10/2012) 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 Standardiza
9、tion 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 me
10、ets 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
11、 purview, 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
12、 voluntary. 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“
13、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. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may i
14、nvolve 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 R
15、ecommendation, 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 databas
16、e 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 the prior written permission of ITU. Rec. ITU-T G.8021.1/Y.1341.1 (10/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 4 Abbrevia
17、tions and acronyms 2 5 Conventions 3 6 ETH layer hierarchy, domains, topology and connections . 4 6.1 MEF global interconnect 4 6.2 Ethernet maintenance entities . 5 7 Interface ports on Ethernet transport network equipment 6 7.1 User to network interface (UNI) . 7 7.2 Network to network interface (
18、NNI) 10 8 Basic Ethernet MAC layer network (ETH) equipment types . 12 8.1 Provider edge bridge (PEB) 14 8.2 Provider edge bridge with remote customer service interface (RCSI PEB) 16 8.3 Provider bridge (PB) . 18 8.4 I-type backbone edge bridge (I-BEB) 19 8.5 B-type backbone edge bridge (B-BEB) 21 8.
19、6 IB-type backbone edge bridge (IB-BEB) . 23 8.7 IB-BEB with customer edge port (CEP) 25 8.8 I-BEB with CEP . 27 8.9 RCSI IB-type backbone edge bridge (RCSI IB-BEB) . 29 8.10 RCSI I-type backbone edge bridge (RCSI I-BEB) . 31 8.11 T-type backbone edge bridge (T-BEB) 33 8.12 TB-type backbone edge bri
20、dge (TB-BEB) . 35 8.13 Backbone core bridge (BCB) . 37 9 Operations, administration, maintenance and provisioning . 38 10 Protection switching . 38 11 Control plane 38 Appendix I Examples of IEEE 802.1Q equipment . 39 Appendix II IEEE 802.1Q provider network considerations 44 II.1 OAM . 44 II.2 Netw
21、ork hierarchy and scalability 44 Appendix III Layer processor and edge processor to ITU-T G.8021 atomic functions expansion 45 Bibliography. 46 Rec. ITU-T G.8021.1/Y.1341.1 (10/2012) 1 Recommendation ITU-T G.8021.1/Y.1341.1 Types and characteristics of Ethernet transport network equipment 1 Scope Th
22、is Recommendation provides an overview of the functions of Ethernet equipment and gives examples of various Ethernet equipment types. The Recommendation is based on the Ethernet transport network architecture specified in ITU-T G.8010, the bridge types specified in IEEE 802.1Q, and equipment functio
23、nal blocks specified in ITU-T G.8021. It is by no means intended to lay down restrictions on the way in which equipment may be built. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommen
24、dation. 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 the Recommendations and other reference
25、s 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.800 Recommendation ITU-T G.800 (2012), Unified functional architectu
26、re of transport networks. 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.1307 (2009), Ethernet service characteristics. ITU-T G.8012 Recommendation ITU-T G.8012/Y.1308 (2004), Ethernet UNI and Ethernet NNI.
27、ITU-T G.8012.1 Recommendation ITU-T G.8012.1/Y.1308.1 (2012), Interfaces for the Ethernet transport network. ITU-T G.8013 Recommendation ITU-T G.8013/Y.1731 (2011), OAM functions and mechanisms for Ethernet based networks. ITU-T G.8021 Recommendation ITU-T G.8021/Y.1341 (2012), Characteristics of Et
28、hernet 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. IEEE 802.1aq IEEE Std. 802.1aq-2012, Shortest Path Bridging.
29、 IEEE 802.1Q IEEE Std. 802.1Q-2011, Local and Metropolitan Area Networks Virtual Bridged Local Area Networks. IEEE 802.1Qbc IEEE Std. 802.1Qbc-2011, Provider Bridging Remote Customer Service Interface. IEEE 802.3 IEEE Std. 802.3-2008, Part 3: Carrier sense multiple access with Collision Detection (C
30、SMA/CD) Access Method and Physical Layer Specifications. 2 Rec. ITU-T G.8021.1/Y.1341.1 (10/2012) IETF RFC 6060 IETF RFC 6060 (2011), Generalized Multiprotocol Label Switching (GMPLS) Control of Ethernet Provider Backbone Traffic Engineering (PBB-TE). MEF 6.1 Metro Ethernet Forum (MEF) (2008), Techn
31、ical Specification 6.1 Ethernet Services Definitions Phase 2. MEF 26.1 Metro Ethernet Forum (MEF) (2012), Technical Specification 26.1 External Network Network Interface (ENNI) Phase 2. MEF 30 Metro Ethernet Forum (MEF) (2011), Technical Specification 30 Service OAM Fault Management Implementation A
32、greement. MEF 35 Metro Ethernet Forum (MEF) (2012), Technical Specification 35 Service OAM Performance Monitoring Implementation Agreement. 3 Definitions This Recommendation does not define any terms. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: B-B
33、EB B-type Backbone Edge Bridge BCB Backbone Core Bridge B-MAC Backbone MAC address CBP Customer Backbone Port CE Customer Equipment IEEE 802.1, Customer Edge MEF CEP Customer Edge Port CEP IB-BEB IB-BEB with Customer Edge Port CEP I-BEB I-BEB with Customer Edge Port CFM Connectivity Fault Management
34、 CNP Customer Network Port DSL Digital Subscriber Line EC Ethernet Connection ENNI External Network to Network Interface ESP Ethernet Switched Path ETH Ethernet MAC layer network EVC Ethernet Virtual Connection FD Flow Domain GMPLS Generalized Multiprotocol Label Switching IB-BEB IB-type Backbone Ed
35、ge Bridge I-BEB I-type Backbone Edge Bridge I-SID Backbone Service Identifier field in an I-TAG MAC Media Access Control MD Maintenance Domain Rec. ITU-T G.8021.1/Y.1341.1 (10/2012) 3 MEF Metro Ethernet Forum MEG Maintenance Entity Group MPLS Multiprotocol Label Switching MPLS-TP MPLS Transport Prof
36、ile NNI Network to Network Interface OAM Operations, Administration and Maintenance OTN Optical Transport Network OVC Operator Virtual Connection PAP Provider Access Port PB Provider Bridge PBB Provider Backbone Bridging PBB-TE Provider Backbone Bridging with Traffic Engineering PDH Plesiochronous D
37、igital Hierarchy PEB Provider Edge Bridge PHY Physical layer PIP Provider Instance Port PNP Provider Network Port PON Passive Optical Network RCAP Remote Customer Access Port RCSI IB-BEB IB-type Backbone Edge Bridge with Remote Customer Service Interface RCSI I-BEB I-type Backbone Edge Bridge with R
38、emote Customer Service Interface RCSI PEB Provider Edge Bridge with Remote Customer Service Interface RCSI Remote Customer Service Interface SDH Synchronous Digital Hierarchy SPB Shortest Path Bridging TAG The attributes of priority information, and optionally, VLAN identification information, assoc
39、iated with an Ethernet frame TB-BEB TB-type Backbone Edge Bridge T-BEB T-type Backbone Edge Bridge UNI User to Network Interface VID VLAN Identifier VLAN Virtual Local Area Network 5 Conventions There are no special conventions in this Recommendation. 4 Rec. ITU-T G.8021.1/Y.1341.1 (10/2012) 6 ETH l
40、ayer hierarchy, domains, topology and connections Figure 6-1 shows a much simplified view of an Ethernet network consisting of two domains (depicted by the cloud edges) and showing generic Ethernet bridge equipment within each domain. IIG.8021.1-Y.1341.1(12)_F6-1BBBB BSB-BEBB-BEB I-BEBI-BEB I-BEBBCB
41、I-BEBSPEBCECECECECEPEBPEBPBI-BEBBBBOther providerbackbone bridgednetworksI-TAGboundaryLANMEF-ENNIProvider backbonebridged networkProvider bridgednetworkMEF-UNIIFigure 6-1 Simplified Ethernet network Ethernet is an extremely flexible technology and it is virtually impossible to illustrate in a diagra
42、m the many possible deployments. In Figure 6-1, the network is constructed from Ethernet provider bridges (PBs) interconnected by Ethernet links. See Appendix II for additional IEEE 802.1Q considerations on the provider network. A provider edge bridge (PEB) provides for connection to Ethernet custom
43、er equipment (CE) via an MEF user network interface (UNI). G.8021.1-Y.1341.1(12)_F6-2SDH LTE SDH XC SDH LTEIB-BEB BCB B-BEBSDH serverFigure 6-2 Example of Ethernet over synchronous digital hierarchy (SDH) The links between bridges are not necessarily optical fibres and may be provided by Ethernet ov
44、er X technology networks. For example, a link could be provided by Ethernet over synchronous digital hierarchy (SDH) or by Ethernet over an optical transport network (OTN). The generic equipment would then also contain some SDH or OTN components, ranging from a simple termination to a complete cross
45、-connect function. 6.1 MEF global interconnect The Metro Ethernet Forum MEF 6.1 defines three basic Ethernet service types E-Line, E-LAN and E-Tree (Figure 6-3) which can be offered by a single service provider in a single metro network or between multiple metro networks, or by multiple service prov
46、iders. In the latter case, the UNI ports may be distributed globally. Rec. ITU-T G.8021.1/Y.1341.1 (10/2012) 5 G.8021.1-Y.1341.1(12)_F6-3CECECE CECECECECE CEMEF-UNI MEF-UNIMEF E-Line serviceethernet virtual connectionMEF E-LAN MEF E-TreeFigure 6-3 Examples of MEFs E-Line, E-LAN and E-Tree service Th
47、e Ethernet service connectivity between UNIs is referred to as an Ethernet virtual connection (EVC). There are point-to-point EVCs, rooted multipoint EVCs and multipoint-to-multipoint EVCs. G.8021.1-Y.1341.1(12)_F6-4PB PBPB PBPBCEPBSCEENNIService provider 2Service provider 1Operator virtualconnectio
48、nsEthernet virtual connectionUNIUNIFigure 6-4 Connections across multiple operators An EVC starts and ends at midpoints of UNI links and spans one or more service provider/carrier networks. When an EVC spans multiple service provider/carrier networks, these carrier networks are interconnected via ME
49、F 26.1-based Ethernet external network to network interface (ENNI) links. Interconnection may be direct or via a carrier Ethernet exchange. The segment of an EVC within one service provider/carrier network is referred to as an operator virtual connection (OVC). An OVC starts and ends at the midpoints of the user network interface (UNI) and ENNI links. 6.2 Ethernet maintenance entities Ethernet virtual connections are supported by Ethernet connections (ECs)
