1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Y.1730TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2004) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT GENERATION NETWORKS Internet protocol aspects Operation, administration and maintenance Requirements for OAM fu
2、nctions in Ethernet-based networks and Ethernet services ITU-T Recommendation Y.1730 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT GENERATION NETWORKS GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.199 Services, applications and middleware Y.2
3、00Y.299 Network aspects Y.300Y.399 Interfaces and protocols Y.400Y.499 Numbering, addressing and naming Y.500Y.599 Operation, administration and maintenance Y.600Y.699 Security Y.700Y.799 Performances Y.800Y.899 INTERNET PROTOCOL ASPECTS General Y.1000Y.1099 Services and applications Y.1100Y.1199 Ar
4、chitecture, access, network capabilities and resource management Y.1200Y.1299 Transport Y.1300Y.1399 Interworking Y.1400Y.1499 Quality of service and network performance Y.1500Y.1599 Signalling Y.1600Y.1699 Operation, administration and maintenance Y.1700Y.1799 Charging Y.1800Y.1899 NEXT GENERATION
5、NETWORKS Frameworks and functional architecture models Y.2000Y.2099 Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Service aspects: Interoperability of services and networks in NGN Y.2250Y.2299 Numbering, naming and address
6、ing Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. Y.1730 (01/2004) i ITU-T Recommendation Y.1730 Requirem
7、ents for OAM functions in Ethernet-based networks and Ethernet services Summary This Recommendation provides the motivations and requirements for user-plane operation, administration, and maintenance (OAM) functionality for ETH layer in Ethernet-based networks and Ethernet services. This Recommendat
8、ion includes the requirements for OAM functions for the point-to-point and multipoint-to-multipoint maintenance entities (MEs) including both dedicated and shared access. It is noted that this Recommendation does not address the administration aspects of OAM. Source ITU-T Recommendation Y.1730 was a
9、pproved on 10 January 2004 by ITU-T Study Group 13 (2001-2004) under the ITU-T Recommendation A.8 procedure. Keywords ETH, Ethernet, EPL, EPLAN, ETY, EVPL, EVPLAN, maintenance entity, OAM. ii ITU-T Rec. Y.1730 (01/2004) FOREWORD The International Telecommunication Union (ITU) is the United Nations s
10、pecialized agency in the field of telecommunications. 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 them with a view to standardizing telecommunications
11、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-T Recommendations is covered by the procedure laid
12、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 for conciseness to indicate both a telecommunicati
13、on 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 Recommendation is achieved when all of these mandator
14、y 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 any party. INTELLECTUAL PROPERTY RIGHTS ITU draws atte
15、ntion 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 Property Rights, whether asserted by ITU members or other
16、s outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent
17、the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2004 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. Y.1730 (01/2004) iii CONTENTS Page 1 Scope 1 2 Ref
18、erences. 1 3 Definitions 1 4 Symbols and abbreviations. 2 5 Reference networks 3 6 Point-to-point and LAN service types 11 7 Motivation for OAM functionalities for Ethernet-based networks 11 8 General requirements for Ethernet ETH layer OAM functions 12 9 Requirements for ETH maintenance entities 13
19、 10 Required OAM functions . 14 10.1 Point-to-point services 14 10.2 Multipoint-to-multipoint services. 14 11 Security aspects 14 Appendix I Examples of the protocol stack reference model . 15 Appendix II Service description . 16 II.1 Ethernet service 16 II.2 Private service 16 II.3 Virtual private
20、service 16 II.4 Line service 16 II.5 LAN service 17 BIBLIOGRAPHY 18 ITU-T Rec. Y.1730 (01/2004) 1 ITU-T Recommendation Y.1730 Requirements for OAM functions in Ethernet-based networks and Ethernet services 1 Scope This Recommendation provides the motivations and requirements for user-plane operation
21、, administration, and maintenance (OAM) functionality for ETH layer in Ethernet-based networks and Ethernet services. This Recommendation includes the requirements for OAM functions for the point-to-point and multipoint-to-multipoint maintenance entities (MEs) including both dedicated and shared acc
22、ess. It is noted that this Recommendation does not address the administration aspects of OAM. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the
23、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 references listed below. A list of the currently
24、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. 1 ITU-T Recommendation G.805 (2000), Generic functional architecture of transport networks. 2 ITU-T Recommendation G
25、.806 (2000), Characteristics of transport equipment Description methodology and generic functionality. 3 ITU-T Recommendation G.809 (2003), Functional architecture of connectionless layer networks. 4 ITU-T Recommendation G.8010/Y.1306 (2004), Architecture of Ethernet layer networks. 3 Definitions 3.
26、1 This Recommendation uses the terms defined in ITU-T Rec. G.805: a) link b) trail 3.2 This Recommendation uses the terms defined in ITU-T Rec. G.806: a) anomaly b) defect c) failure d) fault cause 3.3 This Recommendation uses the terms defined in ITU-T Rec. G.809: a) CLPS b) CO-CS c) CO-PS d) flow
27、domain 2 ITU-T Rec. Y.1730 (01/2004) e) flow point f) link flow g) termination flow point 4 Symbols and abbreviations This Recommendation uses the following abbreviations: AP Access Point BPDU Bridge Protocol Data Unit CBR Constant Bit Rate CLPS Connectionless Packet Switched CO-CS Connection-Orient
28、ed Circuit Switched CO-PS Connection-Oriented Packet Switched DoS Denial of Service EPL Ethernet Private Line EPLAN Ethernet Private LAN ETH Ethernet MAC layer network (connectionless) ETH_CI ETH Characteristic Information as defined in ITU-T Rec. G.8010/Y.1306 ETY Ethernet PHY layer network (connec
29、tion-oriented) EVPL Ethernet Virtual Private Line EVPLAN Ethernet Virtual Private LAN FD Flow Domain FP Flow Point FT Flow Termination GARP Generic Attribute Registration Protocol LACP Link Aggregation Control Protocol LAN Local Area Network LF Link Flow MAC Media Access Control ME Maintenance Entit
30、y NC Network Connection NMS Network Management System NNI Network Node Interface OAM Operation, Administration and Maintenance PHY Ethernet Physical layer entity SLA Service Level Agreement ITU-T Rec. Y.1730 (01/2004) 3 TFP Termination Flow Point TT Trail Termination UNI User Network Interface 5 Ref
31、erence networks This Recommendation specifies the requirements for OAM functions which are applied to point-to-point and multipoint-to-multipoint ETH flows. Figure 1 provides a layered network perspective of a point-to-point flow according to the methodology of ITU-T Rec. G.8010/Y.1306. In this part
32、icular example, network elements A and D, which are placed in customer premises, are associated with ETH TFPs and the ingress and egress of a network flow. ETYTTETYTTETY/ETHSTTETY/ETHETHFTETH/clientETH connectionless trailS trailETH APETH TFPETH FPETYNCETHLFETHLFETYtrailA DCBNNIUNIETH TFP ETH TFPETH
33、 FP ETH FPETHLF ETH LF ETH LFUNI link flow UNI link flowTransit link flowNetwork flowUNI-UNI flowS/ETHETYNCETHLFETYtrailUNIETYTTSTTETY/ETHETH FPS/ETHETYTTETY/ETHETHFTETH/clientETH TFPETH APFigure 1/Y.1730 Example of point-to-point ETH flow reference model (1) Note that between the network elements B
34、 and C, which are placed at the edges of the providers network, the ETH link flow is supported by a single server layer technology S. S may be connection-oriented circuit switched, connection-oriented packet switched, or connectionless. S may itself be supported by lower layer networks. Also note th
35、at although ETY is used for the server layer from A to B and from C to D in this example, it does not preclude the use of other server layers for these portions. This flexibility applies to all the examples in this Recommendation. 4 ITU-T Rec. Y.1730 (01/2004) A second case of a flow is illustrated
36、in Figure 2. Here the network elements A and D, which are placed in user premises, are associated with ETH FPs, indicating that they are associated with bridging. In this case the “UNI-UNI“ flow is between flow points rather than termination flow points. As such the UNI-UNI flow is not the same as t
37、he network flow. ETYTTETYTTETYTTETY/ETHSTTETY/ETHETY/ETHS trailETH FPETH FPETH FPETYNCETHLFETHLFETYtrailA DCBNNIUNIETH FP ETH FPETH FP ETH FPETH LF ETH LF ETH LFUNI link flow UNI link flowTransit link flowNetwork flowUNI-UNI flowS/ETHETYNCETHLFETYtrailUNIETYTTSTTETY/ETHETH FPS/ETHFigure 2/Y.1730 Exa
38、mple of point-to-point ETH flow reference model (2) ITU-T Rec. Y.1730 (01/2004) 5 In both the cases above there is a single server technology between the network elements B and C. Reference models where ETH link flows are supported by different server layer technologies, S and Z, are as illustrated
39、in Figures 3 and 4. The difference between Figures 3 and 4 is whether the network elements A and E are associated with termination flow points or flow points. Transit flowETYTTETYTTETY/ETHSTTETY/ETHETHFTETH/clientETH connectionless trailETH APETH TFPETH FPETYNCETHLFETYtrailA EDBNNIUNIETH TFP ETH TFP
40、ETH LFETH FPETH LF ETH LFUNI link flow UNI link flowTransit link flowNetwork flowUNI-UNI flowS/ETHETYNCETHLFETYtrailUNIETYTTETY/ETHETHFTETH/clientETH TFPETH APTransit link flowETH LFETH FPNNICETHLFStrailETHLFZtrailSTTZTTS/ETHETH FPZ/ETHZTTETYTTZ/ETHETH FPETY/ETHETH FPFigure 3/Y.1730 Example of point
41、-to-point ETH flow reference model (3) 6 ITU-T Rec. Y.1730 (01/2004) ETYTTETYTTETY/ETHETY/ETHETH FPETH FPA ETransit flowETYTTSTTETY/ETHETH FPETYNCETHLFETYtrailDBNNIUNIETH FP ETH FPETH LFETH FPETH LF ETH LFUNI link flow UNI link flowTransit link flowNetwork flowUNI-UNI flowS/ETHETYNCETHLFETYtrailUNIT
42、ransit link flowETH LFETH FPNNICETHLFStrailETHLFZtrailSTTZTTS/ETHETH FPZ/ETHZTTETYTTZ/ETHETH FPETY/ETHETH FPFigure 4/Y.1730 Example of point-to-point ETH flow reference model (4) ITU-T Rec. Y.1730 (01/2004) 7 Figure 5 shows the functional model of the hand-off portion between two providers. A and B
43、denote the network elements placed at the boundary. It should be noted that the server layer between the hand-off points can be any ETH server layer although ETY is used in this example. STTETYTTS/ETHETH FPETHLFStrailANNIETYTTZTTETY/ETHETH FPBNNIETHLFETHLFETYtrailZtrailETH FPETH LFETH FPETH LF ETH L
44、FETY/ETHZ/ETHNNITransit link flow Transit link flowTransit flowTransit link flowFigure 5/Y.1730 Example of hand-off point reference model 8 ITU-T Rec. Y.1730 (01/2004) The view of the reference models in terms of layer networks and the relationships can be simplified by considering only the flows pr
45、esent in the ETH layer network (single layer network view). This is illustrated in Figures 6 and 7. Figure 6 is the ETH layer network view of Figures 1 and 2 while Figure 7 is the ETH layer network view of Figures 3 and 4 (different server layer technologies). Figure 6/Y.1730 Examples of point-to-po
46、int flow reference models (1 and 2) in the ETH layer network (single layer network view) ITU-T Rec. Y.1730 (01/2004) 9 Figure 7/Y.1730 Examples of point-to-point flow reference models (3 and 4) in the ETH layer network (different server layer technologies) 10 ITU-T Rec. Y.1730 (01/2004) This single
47、layer network view is used to describe the multipoint-to-multipoint case. This is illustrated in Figure 8. The ETH flow domain (FD) is present as a provider network. In this figure, network elements A, B, C, D, E and F are network elements owned by each user. A to E are end stations while F is a bri
48、dge (matrix FD). G, H and I are provider network elements placed at the edge of the provider FD. J is a network element placed in the core of the providers network. G to J are bridges (matrix FDs). TFPTFPTFPTFPFPFPFPFPFPFPFPFPFPFPFPFPTFPTFPTFP or FPUser or provider equipmentsupporting a matrix flow
49、domainProvidernetwork (= FD)FPFPFPTFPABCDEFGHIJFPFPFPFigure 8/Y.1730 Multipoint-to-multipoint reference model in the ETH layer network ITU-T Rec. Y.1730 (01/2004) 11 6 Point-to-point and LAN service types There are two point-to-point service classes: Ethernet private line (EPL) and Ethernet virtual private line (EVPL). These may be further classified as providing a full rate or fractional rate service. The reference model for these services is that of Figures 6 and 7. There are two LAN service classes provided by multipoint-to-mult
