1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T X.86/Y.1323 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2001) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS Public data networks Transmission, signalling and switching SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE AND INTERNET PROTOCOL ASPE
2、CTS Internet protocol aspects Transport Ethernet over LAPS ITU-T Recommendation X.86/Y.1323 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS PUBLIC DATA NETWORKS Services and facilities X.1X.19 Interfaces X.20X.49 Transmission, signalling and switching X.50X.89 Network asp
3、ects X.90X.149 Maintenance X.150X.179 Administrative arrangements X.180X.199 OPEN SYSTEMS INTERCONNECTION Model and notation X.200X.209 Service definitions X.210X.219 Connection-mode protocol specifications X.220X.229 Connectionless-mode protocol specifications X.230X.239 PICS proformas X.240X.259 P
4、rotocol Identification X.260X.269 Security Protocols X.270X.279 Layer Managed Objects X.280X.289 Conformance testing X.290X.299 INTERWORKING BETWEEN NETWORKS General X.300X.349 Satellite data transmission systems X.350X.369 IP-based networks X.370X.399 MESSAGE HANDLING SYSTEMS X.400X.499 DIRECTORY X
5、.500X.599 OSI NETWORKING AND SYSTEM ASPECTS Networking X.600X.629 Efficiency X.630X.639 Quality of service X.640X.649 Naming, Addressing and Registration X.650X.679 Abstract Syntax Notation One (ASN.1) X.680X.699 OSI MANAGEMENT Systems Management framework and architecture X.700X.709 Management Comm
6、unication Service and Protocol X.710X.719 Structure of Management Information X.720X.729 Management functions and ODMA functions X.730X.799 SECURITY X.800X.849 OSI APPLICATIONS Commitment, Concurrency and Recovery X.850X.859 Transaction processing X.860X.879 Remote operations X.880X.899 OPEN DISTRIB
7、UTED PROCESSING X.900X.999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. X.86/Y.1323 (02/2001) i ITU-T Recommendation X.86/Y.1323 Ethernet over LAPS Summary This Recommendation specifies how to operate Ethernet (defined by IEEE WG 802.3) over LAPS (Link Access Pr
8、ocedure SDH) and provides a simple technique to connect LANs and provides Ethernet LAN extension over Wide Area Network (WAN) within a private and/or public network. The characteristics of this technique include low latency variance, remote performance monitoring capability, remote fault indication
9、capability, active flow control in burst traffic condition and ease of use and maintenance, especially in the area of SDH transmission. Source ITU-T Recommendation X.86/Y.1323 was prepared by ITU-T Study Group 7 (2001-2004) and approved under the WTSA Resolution 1 procedure on 2 February 2001. ii IT
10、U-T Rec. X.86/Y.1323 (02/2001) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized 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, oper
11、ating 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 meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, p
12、roduce 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 purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In
13、this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may invol
14、ve 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 Recom
15、mendation, 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 the latest information and are therefore strongly urged to consult the TSB patent database. I
16、TU 2002 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. ITU-T Rec. X.86/Y.1323 (02/2001) iii CONTENTS Page 1 Scope. 1 2 References. 2 2.
17、1 Normative references 2 2.1.1 ITU-T Recommendations 2 2.1.2 ISO/IEC Standards 2 3 Definitions 2 4 Abbreviations 3 4.1 Abbreviations specified in ISO/IEC 2382-25. 3 4.2 Abbreviations specified in ITU-T G.707/Y.1322. 3 4.3 Abbreviations specified in ITU-T Q.921 3 4.4 Abbreviations specified in this R
18、ecommendation 3 5 The protocol framework of Ethernet over LAPS 3 6 The SDH physical layers 5 7 Service facilities and protocol specifications of LAPS 6 8 Encapsulation 6 9 Functional elements of Gigabit Ethernet over LAPS . 8 10 Rate adaptation . 8 Appendix I An example of data processing 9 I.1 The
19、LAPS transmit processing . 9 I.2 The LAPS receive processing. 10 I.3 Erroneous frame handling. 10 Appendix II The possible application area of this technology . 11 iv ITU-T Rec. X.86/Y.1323 (02/2001) Introduction The Internet market has been growing at a great rate. Growth is an important issue and
20、creates the need to expand the scope of Ethernet area. Transferring Ethernet (defined by IEEE WG 802.3) over LAPS is a simple and cheap technique to connect LANs within a private and public network. This Recommendation expands the scope of LAPS which was introduced in ITU-T X.85/Y.1321 to adapt Ethe
21、rnet frame to LAPS. The full transparency is guaranteed for mapping Ethernet frame to LAPS, and mapping LAPS to SDH. The model of Ethernet over LAPS shall be particularly well suited for the network resource of the existing network infrastructure. ITU-T Rec. X.86/Y.1323 (02/2001) 1 ITU-T Recommendat
22、ion X.86/Y.1323 Ethernet over LAPS 1 Scope This Recommendation specifies a protocol suite structure of Ethernet frame (defined by IEEE WG 802.3) over LAPS for the purpose of providing the future protocol compatibility among peer systems in the light of ITU-T X.200, and applies to Synchronous Digital
23、 Hierarchy (ITU-T G.707/Y.1322). LAPS protocol and specification introduced in ITU-T X.85/Y.1321 continue to be used to address its capabilities of providing the adaptation from Ethernet to LAPS. LAPS describes an HDLC-like framing structure to encapsulate IEEE 802.3 Ethernet MAC frame as shown in F
24、igure 7, provide a point-to-point full-duplex simultaneous bidirectional operation. Connecting Ethernet Switches to a SDH network is a very attractive way to provide Ethernet over a Wide Area Network. It is transparent to the Ethernet switch that one or more Ethernet switch ports are connected. The
25、relationship between LAPS and Ethernet and SDH physical layer, together with the Rate Adaptation are presented in the following diagram (see Figure 1). T0733570-00IEEE 802.3 MAC frameReconciliation sublayerMII/GMIILAPSRate AdaptationSDHFigure 1/X.86/Y.1323 The relationship between Ethernet frame and
26、 LAPS and SDH This Recommendation does not specify the method of mapping LAPS to SDH. No change is made for all Ethernet-based protocols (including IEEE 802.3 Ethernet) and all SDH standards. NOTE 1 It is intended that Ethernet over LAPS can be extended, in future amendments, to support additional n
27、ew types of data service. NOTE 2 LAPS used in this Recommendation is not used to coexist with HDLC (ISO/IEC 3309 or RFC 1662), LAPB/ITU-T X.25, LAPD/ITU-T Q.921 and LAPF/ITU-T Q.922 within the same physical layer in future. NOTE 3 This Recommendation shall be applied to SDH sub-rates for IEEE 802.3
28、Ethernet. 2 ITU-T Rec. X.86/Y.1323 (02/2001) 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 editions indicated were valid. All Recommendation
29、s 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 valid ITU-T Recommendations is regularly publishe
30、d. 2.1 Normative references 2.1.1 ITU-T Recommendations 1 ITU-T X.85/Y.1321 (2001), IP over SDH using LAPS. 2 ITU-T G.703 (1998), Physical/electrical characteristics of hierarchical digital interfaces. 3 ITU-T G.707/Y.1322 (2000), Network node interface for the synchronous digital hierarchy (SDH). 4
31、 ITU-T G.708 (1999), Sub STM-0 network node interface for the synchronous digital hierarchy (SDH). 5 ITU-T G.957 (1999), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. 6 ITU-T X.200 (1994) | ISO/IEC 7498-1:1994, Information technology Open System Interco
32、nnection Basic Reference Model: The Basic Model. 2.1.2 ISO/IEC Standards 7 ISO/IEC 8802-3:2000, Information technology Telecommunications and information exchange between systems Local and metropolitan area networks Specific requirements Part 3: Carrier sense multiple access with collision detection
33、 (CSMA/CD) access method and physical layer specifications. (Equivalent to IEEE 802.3.) 3 Definitions This Recommendation defines the following terms: 3.1 Ethernet over LAPS: The data communication architecture of combination Ethernet (IEEE 802.3) with LAPS network. The physical layer is defined as
34、SDH, the second layer is the combination of three elements: LLC/MAC/LAPS. 3.2 LAPS: A type of HDLC, including data link service and protocol specification which have been used to IP over SDH using LAPS. 3.3 information field of LAPS: Destination address, source address, length/type, MAC client data,
35、 PAD field (if any) and FCS field of the intact MAC frame. 3.4 rate adaptation: A mechanism that adjusts the rate of Ethernet MAC MII to SDH VC rate since SDH and MAC are operated in the way of period and burst respectively. ITU-T Rec. X.86/Y.1323 (02/2001) 3 4 Abbreviations 4.1 Abbreviations specif
36、ied in ISO/IEC 2382-25 This Recommendation makes use of the following abbreviations specified in IEEE 802.3: LAN Local area network LLC Logical link control MAC Media access control 4.2 Abbreviations specified in ITU-T G.707/Y.1322 This Recommendation makes use of the following abbreviations specifi
37、ed in ITU-T G.707/Y.1322: SDH Synchronous Digital Hierarchy STM Synchronous Transfer Module sSTM Sub-STM VC Virtual Container 4.3 Abbreviations specified in ITU-T Q.921 SAPI Service Access Point Identifier 4.4 Abbreviations specified in this Recommendation LAPS Link Access Procedure SDH 5 The protoc
38、ol framework of Ethernet over LAPS The layer/protocol stacks for Ethernet over LAPS in the STM-N sSTM-n are shown in Figures 2 and 3 respectively. Figures 4 and 5 illustrate protocol configuration and possible network examples of Ethernet over LAPS respectively. T0733580-00IEEE 802.3 MAC frameLAPSLo
39、w Order VCHigh Order VCMultiplex SectionRegenerator SectionElectrical/Optical SectionG.703/G.957G.707/Y.1322Ethernet SeriesFigure 2/X.86/Y.1323 Layer/protocol stack for Ethernet over LAPS in STM-N 4 ITU-T Rec. X.86/Y.1323 (02/2001) T0733590-00IEEE 802.3 MAC frameLAPSVC.11, VC.12, VC.2Multiplex Secti
40、onRegenerator SectionElectrical/Optical/Radio SectionG.708G.707/Y.1322Ethernet SeriesFigure 3/X.86/Y.1323 Layer/protocol stack for Ethernet over LAPS in sSTM T0733600-00IPv4/IPv6/IPXIPv4/IPv6/IPX IPv4/IPv6/IPXIPv4/IPv6/IPXLLCLLCLLCLLCMACMACMACMACLANLANLAPSLAPSSDH SDH“Ethernet over LAPS“ NetworkFigur
41、e 4/X.86/Y.1323 The protocol configuration of Ethernet over LAPS T0733610-00LAN LAN“Ethernet over LAPS“ NetworkEdge NodeSDH transmission equipmentSDH physical connectionFigure 5/X.86/Y.1323 “Ethernet over LAPS“ network example ITU-T Rec. X.86/Y.1323 (02/2001) 5 6 The SDH physical layers This Recomme
42、ndation treats SDH transport as an octet-oriented synchronous point-to-point full-duplex link. The SDH frame is an octet-oriented synchronous multiplex mapping structure which specifies a series of standard rates, formats and mapping methods. Table 1 shows the bandwidth value of the VCs and Table 2
43、of the STMs which is currently specified. The use of control signals is not required. The self-synchronous scrambling/descrambling (x43+ 1) function is applied during insertion/extraction into/from the synchronous payload envelope (see Annex C of ITU-T X.85/Y.1321). This Recommendation uses the futu
44、re concatenation of virtual containers as defined in the next version of ITU-T G.707/Y.1322. Table 1/X.86/Y.1323 The bandwidth of the VCs VC type VC bandwidth (kbit/s) VC payload (kbit/s) VC-11 1 664 1 600 VC-12 2 240 2 176 VC-2 6 848 6 784 VC-3 48 960 48 384 VC-4 150 336 149 760 VC-4-4c 601 344 599
45、 040 VC-4-16c 2 405 376 2 396 160 VC-4-64c* 9 621 504 9 584 640 *For further study. Table 2/X.86/Y.1323 STM interface rates STM type STM bit rate (kbit/s) sSTM-11 2 880 sSTM-12 5 184 sSTM-14 9 792 sSTM-18 19 792 sSTM-116 37 444 sSTM-21 7 488 sSTM-22 14 400 sSTM-24 28 224 STM-0 51 840 STM-1 155 052 S
46、TM-4 622 080 STM-16 2 488 320 STM-64 9 953 280 6 ITU-T Rec. X.86/Y.1323 (02/2001) The LAPS is a physical coding sublayer, which provides point-to-point transferring over SDH virtual containers and interface rates. The supported UITS is a connectionless-mode service. The rate adaptation between LAPS
47、and SDH is applied. It provides a mechanism that adjusts the rate of Ethernet MAC MII to SDH VC rate, and also prevents MAC frame going to SDH VC from being written to the SDH overhead since SDH and MAC are operated in the way of period and burst respectively. 7 Service facilities and protocol speci
48、fications of LAPS The default maximum frame size of LAPS shall be capable of supporting an information field of 1600 octets (at least) for Ethernet over LAPS. The SAPI of MAC is assigned to 0xfe01 (hexadecimal). The associated service facilities and protocol specifications of LAPS are included in An
49、nex A of ITU-T X.85/Y.1321. NOTE It is needed to replace “Layer 3 or network layer or IP based network“, “IP packet“ and “Layer 2 or data link layer“ with “MAC layer“, “MAC frame“ and “LAPS“ respectively in Annex A of ITU-T X.85/Y.1321. 8 Encapsulation LAPS link entity accepts frames from the MAC layer through the reconciliation sublayer and an equivalent MII (Media Independent Interface). No address filtering function is used here. The format of LAPS information field is defined in the shaded regi
