1、INTERNATIONAL TELECOMMUNICATION UN ION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES X: DATA NETWORKS COM M U N I CATI ON S X.86ff.1323 (02/200 1 ) AND OPEN SYSTEM Public data networks - Transmission, signalling and switching SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE AND INTERNET PR
2、OTOCOL ASPECTS Internet protocol aspects - Transport Ethernet over LAPS ITU-T Recommendation X.86N. 1323 ITU-T X-SERIES RECOMMENDATIONS PUBLIC DATA NETWORKS Services and facilities Interfaces Transmission, signalling and switching Network aspects Maintenance Administrative arrangements Model and not
3、ation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS proformas Protocol Identification Security Protocols Layer Managed Objects Conformance testing General Satellite data transmission systems IP-based networks MESSAGE HANDLING SYSTEMS DIR
4、ECTORY OS1 NETWORKING AND SYSTEM ASPECTS Networking Efficiency Quality of service Naming, Addressing and Registration Abstract Syntax Notation One (ASN. 1) Systems Management framework and architecture Management Communication Service and Protocol Structure of Management Information Management funct
5、ions and ODMA functions OPEN SYSTEMS INTERCONNECTION INTERWORKING BETWEEN NETWORKS OS1 MANAGEMENT SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS I X.l-X.19 X.20-X.49 X.50
6、-X.89 X.90-X. 149 X. 150-X. 179 X. 180-X. 199 X.200-X.209 X.2 1 O-X.2 19 X.220-X.229 X.230-X.239 X.240-X.259 X.260-X.269 X.270-X.279 X.280-X.289 X.290-X.299 X.300-X.349 X.350-X.369 X.370-X.399 X.400-X.499 X.500-X.599 X.600-X.629 X.630-X.639 X.640-X.649 X.650-X.679 X.680-X.699 X.700-X.709 X.7 10-X.7
7、19 X.720-X.729 X.730-X.799 X.800-X.849 X.850-X.859 X.860-X.879 X.880-X.899 X.900-X.999 Il For further details, please refer to the list of ITU-T Recommendations. ITU-T Recommendation X.86N.1323 Ethernet over LAPS Summary This Recommendation specifies how to operate Ethernet (defined by IEEE WG 802.3
8、) over LAPS (Link Access Procedure- 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 capabili
9、ty, remote fault indication 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 proced
10、ure on 2 February 200 1. ITU-T Rec. X.86N.1323 (02/2001) 1 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
11、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 meets every four years, establishes the topics for study by the ITU-T st
12、udy 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 purview, the necessary standards are prepared on a collaborative basi
13、s with IS0 and IEC. NOTE In 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 t
14、his 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 others outside of the Recommendation development process. As of the da
15、te 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 the latest information and are therefore strongly urged to consul
16、t the TSB patent database. O ITU 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. 11 ITU-T Rec. X.86lY.1323 (02/2001) CONTENTS 1 2 2
17、.1 3 4 4.1 4.2 4.3 4.4 5 6 7 8 9 10 Scope . References . Normative references 2.1.1 ITU-T Recommendations 2.1.2 ISO/IEC Standards Definitions Abbreviations Abbreviations specified in ISO/IEC 23 82-25 . Abbreviations specified in ITU-T G.707/Y. 1322 . Abbreviations specified in ITU-T 4.92 1 Abbreviat
18、ions specified in this Recommendation The protocol framework of Ethernet over LAPS The SDH physical layers Service facilities and protocol specifications of LAPS Encapsulation Functional elements of Gigabit Ethernet over LAPS . Rate adaptation . Appendix I . An example of data processing I . 1 The L
19、APS transmit processing . 1.2 The LAPS receive processing . 1.3 Erroneous frame handling . Appendix II - The possible application area of this technology . ITU-T Rec . X.86N.1323 (02/2001) Page 1 2 2 2 2 2 3 3 3 3 3 3 5 6 6 8 8 9 9 10 10 11 . 111 Introduction The Internet market has been growing at
20、a great rate, Growth is an important issue and 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 Reconmendatiion expands the scope of LAPS wliicli
21、 was introduced in ITU-T X.85h. I321 to adapt Ethernet 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. iv
22、 ITU-T Rec. X.86N.1323 (02/2001) ITU-T Recommendation X.86N.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 o
23、f ITU-T X.200, and applies to Synchronous Digital 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 enca
24、psulate IEEE 802.3 Ethernet MAC frame as shown in Figure 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 on
25、e or more Ethernet switch ports are connected. The relationship between LAPS and Ethernet and SDH physical layer, together with the Rate Adaptation are presented in the following diagram (see Figure 1). IEEE 802.3 MAC frame Reconciliation sublayer Rate Adaptation SDH TO733570-00 Figure 1K.86N.1323 -
26、 The relationship between Ethernet frame and 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,
27、 in future amendments, to support additional new types of data service. NOTE 2 - LAPS used in this Recommendation is not used to coexist with HDLC (ISO/IEC 3309 or RFC 1662), LAPBITU-T X.25, LAPDITU-T 4.921 and LAPFITU-T 4.922 within the same physical layer in future. NOTE 3 - This Recommendation sh
28、all be applied to SDH sub-rates for IEEE 802.3 Ethernet. ITU-T Rec. X.86N.1323 (02/2001) 1 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 edi
29、tions indicated were valid. All Recommendations and other references are subject to revision; users of his 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 vali
30、d ITU-T Recommendations is regularly published. 2.1 2.1.1 il i21 31 41 51 FI 2.1.2 i71 3 Normative references ITU-T Recommendations ITU-T X.85N. 132 1 (200 i), IP over SDH using LAPS. ITU-T G.703 (1 998), Physical/electrical characteristics of hierarchical digital interfaces. ITU-T G.707N. 1322 (200
31、0), Network node interface for the synchronous digital hierarchy (SDH) . ITU-T G.708 (1999), Sub STM-O network node interface for the synchronous digital hierarchy (SOH). ITU-T G.957 (1999), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. ITU-T X.200 (1 9
32、94) I ISO/IEC 7498- 1 : 1994, Information technology - Open System Interconnection - Basic Reference Model: The Basic Model. ISO/IEC Standards ISO/IEC 8802-3 :2000, Information technologv - Telecommunications and information exchange between systems -Local and metropolitan area networks - Specific r
33、equirements -Part 3: Carrier sense multiple access with collision detection (CSMCD) access method andphysical layer specijkations. (Equivalent to IEEE 802.3 .) Definitions This Recommendation defines the following terms: 3.1 Ethernet over LAPS: The data communication architecture of combination Ethe
34、rnet (IEEE 802.3) with LAPS network. The physical layer is defined as 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 LA
35、PS: Destination address, source address, lengthhype, MAC client data, 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 MI1 to SDH VC rate since SDH and MAC are operated in the way of period and burst respectively. 2 ITU-
36、T Rec. X.86N.1323 (02/2001) 4 Abbreviations High Order VC Multiplex Section Regenerator Section . . ElectricaVOptical Section 4.1 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 Abbreviatio
37、ns specified in ISODEC 2382-25 4.2 This Recommendation makes use of the following abbreviations specified in ITU-T G.707N. 1322: SDH Synchronous Digital Hierarchy STM Synchronous Transfer Module Abbreviations specified in ITU-T G.707N.1322 sSTM Sub-STM vc Virtual Container 4.3 SAP1 Service Access Po
38、int Identifier Abbreviations specified in ITU-T 4.921 4.4 LAPS Abbreviations specified in this Recommendation Link Access Procedure - SDH 5 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 configuratio
39、n and possible network examples of Ethernet over LAPS respectively. The protocol framework of Ethernet over LAPS IEEE 802.3 MAC frame LAPS Low Order VC TO733580-00 Ethernet Series 1 G.707E.1322 I G.703lG.957 Figure 2K86N.1323 - Layer/protocol stack for Ethernet over LAPS in STM-N ITU-T Rec. X.86N.13
40、23 (02/2001) 3 IEEE 802.3 MAC frame Ethernet Series LAPS LLC MAC MAC LAPS LAPS SDH SDH MAC VC.11, vc.12, vc.2 . r- Multiplex Section IPv4 APv6 APX LLC MAC Regenerator Section ElectricaVOpticalRadio Section . G.707N. 1322 * G.708 TO733590-W Figure 3K.86N.1323 - Layer/protocol stack for Ethernet over
41、LAPS in sSTM I I I I I l I 1 I LAN LAN “Ethernet over LAPS“ Network 4 b TO7336W-00 Figure 4K.86N.1323 - The protocol configuration of Ethernet over LAPS “Ethernet over LAPS“ Network 0 EdgeNode 0 SDH transmission equipment SDH physical connection Figure 5K.86N.1323 - “Ethernet over LAPS“ network exam
42、ple 4 ITU-T Rec. X.86N.1323 (02l2001) 6 The SDH physical layers This Recommendation 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 an
43、d mapping methods. Table 1 shows the bandwidth value of the VCs and Table 2 of the STMs which is currently specified. The use of control signals is not required. The self-synchronous scramblingldescrambling (x43 + 1) function is applied during insertiodextraction into/from the synchronous payload en
44、velope (see Annex C of ITU-T X.85N. 1321). This Recommendation uses the future concatenation of virtual containers as defined in the next version of ITU-T G.707N. 1322. VC bandwidth (kbith) Table lK.86N.1323 - The bandwidth of the VCs VC payload (kbith) VC-4-64* I vc-11 I 1 664 I 1600 I 9 621 504 9
45、584 640 I vc-12 I 2 240 I 2 176 I sSTM-2 1 sSTM-22 sSTM-24 STM-O STM- 1 STM-4 STM- 16 I vc-2 I 6 848 I 6784 I 7 488 14 400 28 224 51 840 155 052 622 O80 2 488 320 I vc-3 I 48 960 I 48384 I I vc-4 I 150 336 I 149760 I I vc-4-4c I 601 344 I 599040 I I VC-4-16c I 2405376 I 2396 160 I Table 2K.86N.1323
46、- STM interface rates STM type I STM bit rate (kbith) I I I sSTM-11 I 2 880 1 I sSTM-12 I 5 184 1 I sSTM-14 I 9 792 1 I sSTM-18 I 19 792 1 I sSTM-116 I 37 444 1 I4 9 953 280 1 ITU-T Rec. X.86N.1323 (02/2001) 5 The LAPS is a physical coding sublayer, which provides point-to-point transferring over SD
47、H virtual containers and interface rates. The supported UITS is a connectionless-mode service. The rate adaptation between LAPS and SDH is applied. It provides a mechanism that adjusts the rate of Ethernet MAC MI1 to SDH VC rate, and also prevents MAC frame going to SDH VC from being written to the
48、SDH overhead since SDH and MAC are operated in the way of period and burst respectively. 7 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 SAP1 of MAC is assigned to OxfeO1 (hexadecimal). The associated
49、service facilities and protocol specifications of LAPS are included in Annex A of ITU-T X.85/Y.1321. NOTE - It is needed to replace “Layer 3 or network layer or IF based network“, “IP packet“ and “Layer 2 or data link layer“ with “MAC layer“, “MAC frame“ and “LAPS“ respectively in AnnexA of Service facilities and protocol specifications of LAPS ITU-T X.85N. 1321. 8 Encapsulation LAPS link entity accepts frames from the MAC layer through the reconciliation sublayer and an equivalent MI1 (Media Independent Interface). No address filtering function is used here. The format of L
