1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STAN DARD IZATI ON SECTOR OF ITU (03/200 1 ) SERIES X: DATA NETWORKS AND OPEN SYSTEM COM M U N I CAT I ON S Public data networks - Transmission, signalling and switching SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE AND INTERNET PROTOCOL AS
2、PECTS Internet protocol aspects - Transport IP over SDH using LAPS ITU-T Recommendation X.85Y.1321 (Formerly CCITT Recommendation) ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS PUBLIC DATA NETWORKS Services and facilities X.1-X.19 Interfaces X.20-X.49 Network aspects X.
3、90-X.149 Maintenance Administrative arrangements Model and notation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS proformas Protocol Identification Security Protocols Layer Managed Objects Conformance testing General Satellite data trans
4、mission systems IP-based networks MESSAGE HANDLING SYSTEMS DIRECTORY OS1 NETWORKING AND SYSTEM ASPECTS Networking Efficiency Quality of service Naming, Addressing and Registration Abstract Syntax Notation One (ASN.l) Systems Management fi-amework and architecture Management Communication Service and
5、 Protocol Structure of Management Information Management functions 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 X.150-X.
6、179 X. 180-X. 199 X.200-X.209 x.2 1 0-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.710-X.719 X.720-X.729 x.730-x.799 X.8
7、00-X.849 X.850-X.859 X.860-X.879 X.880-X.899 X.900-X.999 For further details, please refer to the list of ITD-T Recommendations. ITU-T Recommendation X.85N.1321 IP over SDH using LAPS Summary This Recommendation provides a simple HDLC specification named LAPS to adapt IP directly to SDH. The Service
8、 Access Point Identifier (SAPI) is introduced to encapsulate IPv4, IPv6, PPP and other upper layer protocols. The LAPS is fully compatible with RFC 2615 when the Address field is set to “1 11 11 11 1 I and the data link is set to operate as the way RFC 2615 defines. Source ITU-T Recommendation X.85N
9、.1321 was revised by ITU-T Study Group 7 (2001-2004) and approved under the WTSA Resolution 1 procedure on 15 March 2001. ITU-T X.85N.1321 (03/2001) i FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The U Telecommu
10、nication Standardization Sector (U-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 Assembl
11、y (WTSA), which meets every four years, establishes the topics for study by the U-T study groups which, in turn, produce Recommendations on these topics. The approval of U-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall
12、 within ITU-Ts purview, the necessary standards are prepared on a collaborative basis 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 RI
13、GHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. U takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by U m
14、embers or others outside of the Recommendation development process. As of the date of approval of this Recommendation, U 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 n
15、ot represent the latest information and are therefore strongly urged to consult the TSB patent database. o mu 2001 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 permi
16、ssion in writing from U. 11 ITU-T X.85N.1321(03/2001) CONTENTS 1 Scope . 1 2 2.1 References . Normative references 2.1.1 Identical Recommendations I International Standards 2.1.2 Other normative references . 2.2 Informative references 3 Definitions 4 Abbreviations 5 The protocol framework of IP over
17、 SDH using LAPS . 6 7 7.1 Physical layer and its primitives . Service facilities and protocol specifications of data link UITS and its specification . Annex A . The LAPS specification . A.l General A.2 Frame structure for peer-to-peer communication . A.2.1 General . A.2.2 Flag sequence A.2.3 Address
18、 field A.2.4 Control and SAPI field A.2.5 Information field A.2.6 Transparency . A.2.7 Frame Check Sequence (FCS) field A.2.8 Format convention . A.2.9 Invalid frames A.3 Elements of procedures and formats of fields for data link layer . A.3.1 General . A.3.2 Address field and data link SAPI A.3.3 D
19、efinition of the peer-to-peer procedures of the data link layer . A.4.1 Transmission of unacknowledged information . A.4.2 Receipt of unacknowledged information . A.4.3 Service access point identifier (SAPI) . A.4 Procedure on the Connection management entity . ITU-T X.85N.1321 (03/2001) 1 2 2 2 2 2
20、 3 4 5 7 7 8 8 8 8 8 8 8 8 8 8 9 10 11 11 11 11 11 11 12 12 . 111 Page Annex B . Primitives between Layer 3 or other upper protocols and link layer. Layer 1 and link layer B.l General B.2 Layer 3 or other upper protocol entity - Data link layer primitives . B.3 Layer 1 - Data link layer primitives .
21、 The connection management entity - Data link layer primitive . B.3.1 PH-DATA B.4 B.4.1 MDL-ERROR B.5 Parameter definition B.6 Primitive relationship description . Annex C - The self-synchronous scrambling/descrambling (x43 + 1) function description C . 1 The self-synchronous (x + 1) scrambler/descr
22、ambler 43 Appendix I . The main differences between LAPS and PPP/HDLC 12 12 12 12 12 12 12 13 13 13 13 15 iv ITU-T X.85N.1321(03/2001) Introduction Currently IPv4 is transported largely over telecommunications facilities or channels to support IP protocols and to provide IP-related applications. One
23、 of the best channels is SDH. SDH and related WDM (Wavelength Division Multiplex) optical transport network are considered to be the foundation for the physical layer of the broadband IP and B-ISDN. SDH had been deployed all over the world in recent years. How to fully make use of these existing hug
24、e broadband resources effectively to provide Internet data communication services? How to combine IP-based network with SDH to establish the lower cost and high-speed based protocol model? This Recommendation provides LAPS (a type of HDLC) to adapt directly IP to SDH. The model of IP directly over S
25、DH is particularly well suited for existing IPv4 and forthcoming IPv6 Internet engineering applications. ITU-T X.85N.1321 (03/2001) V ITU-T Recommendation X.85N.1321 IP over SDH using LAPS 1 Scope This Recommendation: builds the simple HDLC protocol model of the IP over SDH in light of IT-T X.200; s
26、pecifies multiple logical links specified by the Service Access Point Identifier (SAPI) to defines the various physical interfaces and primitives to be used in the “IP over SDH using encapsulate IPv4-based, IPv6-based, PPP and other upper protocol packets; and LAPS“ network. The relationship between
27、 LAPS and IP and SDH physical layer, along with relative primitives are presented as the following diagram (see Figure 1). SAP of Data Link Layer Data Link Primitives Protocol - SAP of Physical Layer Physical Layer Primitives qPc I SDH. I I I T0733690-01 Figure l/X.85N.1321- The relationship between
28、 LAPS and IP, LAPS and SDH This Recommendation does not specifj the mapping LAPS to SDH, and it does not specifj either any LAN accessing to “IP over SDH using LAPS“ network. No change is made for all IP-based protocols (including RFC 791 and RFC 2460) and all SDH standards. IP over SDH using LAPS c
29、an be extended, in future amendments, to support additional new types of Internet service. LAPS is not used to coexist with HDLC (ISOAEC 3309 or RFC 1662), LAPBATU-T X.25 and LAPDATU-T 4.921 within the same physical layer in future, and is limited within the area of this IP over SDH using LAPS. 2 Re
30、ferences 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 Recommendations and other references are subject to revision; u
31、sers 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 published. ITU-T X.85N.1321 (03/2001) 1 Normative referen
32、ces Identical Recommendations I International Standards ITU-T X.200 (1994) I ISO/IEC 7498-1: 1994, Information technology - Open Systems Interconnection - Basic reference model: The basic model. ITU-T X.2 1 1 (1 995) I ISO/IEC 10022: 1996, Information technology - Open Systems Interconnection - Phys
33、ical service deflnition. ITU-T X.212 (1995) I ISO/IEC 8886: 1996, Information technology - Open Systems Interconnection - Data link service deflnition. Other normative references ITU-T G.703 (1 998), Physical/electrical characteristics of hierarchical digital interfaces. ITU-T G.707N. 1322 (2000), N
34、etwork node inteflace for the Synchronous Digital Hierarchy (SDH) . ITU-T G.708 (1999), Sub-STM-O network node inteflace for the synchronous digital hierarchy (SDH). ITU-T G.957 (1999), Optical interfaces for equipments and systems relating to the synchronous digital hierarchy. IETF RFC 79 1 (1 98 1
35、 ), Internet Protocol - DARPA Internet Program - Protocol Speczjkation. IETF RFC 2460 (1998), Internet Protocol, Version 6 (IPv6) - Speczjkation. IETF RFC 261 5 (1 999), PPP over SONETEDH. NOTE - The reference to a document within this Recommendation does not give it, as a stand-alone document, the
36、status of a Recommendation. 2.2 Informative references 1 i 121 ITU-T 4.921 (1997), ISDN user-network inteflace -Data link layer speczjkation. ITU-T X.25 (1996), Interface between Data Terminal Equipment (DTE) and Data Circuit- terminating Equipment (DCE) for terminals operating in the packet mode an
37、d connected to public data networks by dedicated circuit. ISO/IEC 3309: 1993, Information technology - Telecommunications and information exchange between Systems - High-level Data Link Control (?DLC) procedures - Frame structure. IETF RFC 1662 (1 994), PPP in HDLC-like Framing. 131 141 3 Definition
38、s This Recommendation defines the following terms: 3.1 IP over SDH: The data communication architecture of combination Internet protocols with SDH network. The physical, data link and network layer or other protocols are defined as SDH, LAPS and IP-based protocols or PPP protocols. 3.2 LAPS: A type
39、of HDLC, including data link service and protocol specification which are used to the network of IP over SDH. 2 ITU-T X.85N.1321(03/2001) 3.3 U1 frame: U1 fi-ame is a fi-ame which is used to transfer Layer 3 User data or user data of other protocols, including IPv4-based packet (refer to RFC 79 i),
40、IPv6-based packet (refer to RFC 2460) or PPP frames etc. in the way of unacknowledged information transferring. 4 Abbreviations This Recommendation uses the following abbreviations: CRC DS FCS HDLC ICMP IP over SDH IPv4 IPv6 LAN LAPB LAPS LLC MAC MRU PPP RFC SAP SAP1 SDH SDU SSTM STM TCP UDP u1 UITS
41、 vc Cyclic redundancy check Differentiated services Frame check sequence High-level data link control Internet control message protocol Internet protocol over SDH Internet protocol (version 4) Internet protocol (version 6) Local area network Link access procedure - Balanced Link access procedure - S
42、DH Logical link control Media access control Maximum receive unit Point-to-point protocol Request for comment Service access point Service access point identifier Synchronous digital hierarchy Service data unit Sub-STM Synchronous transfer module Transmission control protocol User datagram protocol
43、Unnumbered information (frame, transferring Layer 3 User data) Unacknowledged information transfer service Virtual container ITU-T X.85N.1321 (03/2001) 3 5 IP over SDH using LAPS is a type of data communication architecture of combination Internet protocol or other protocols with SDH network. The ph
44、ysical, link and network layer or other protocols are specified as SDH, LAPS and IPv4/IPv or PPP, etc. respectively as the layer/protocol stack for IP over STM-N shown in Figure 2 and the layer/protocol stack for IP over sSTM-n in Figure 3. Figures 4 and 5 illustrate protocol configuration and netwo
45、rk examples respectively. The protocol framework of IP over SDH using LAPS I I I TCPIUDP I LAPS G.7071Y.1322 High Order VC . I Multiplex Section I I Regenerator Section I I ElectricaVOptical Section I G.7031G.957 T0733700-01 Figure 2/X.85/Y.1321- Layer/Protocol Stack for IP over STM-N using LAPS I L
46、APS I I VC-11, VC-12, VC-2 I G.707N.1322 Multiplex Section Regenerator Section ElectricaVOpticaVRadio Section T0733710-0 G.707N. 1322 1 Figure 3/X.85/Y.1321- Layer/Protocol Stack for IP over sSTM-n using LAPS 4 ITU-T X.85N.1321(03/2001) TCPAJDP ;j TCPAJDP TCPAJDP TCPAJDP , 1 1 1 1 , 1 1 TCPAJDP IPv4
47、/IPv6 IPv4/IPv6 IPv4/IPv6 IPv4/IPv6 ij LLC LLC LLc LAPS LAPS LAPS SDH SDH SDH MAC MAC MAC I l l l l l l -u “IP over SDH using LAPS“ protocol T0733720-01 “IP over SDH using LAPS“ Network Figure 4/X.85/Y.1321- The Protocol Configuration of IP over SDH using LAPS LAN LAN “IP over SDH using LAPS“ Networ
48、k T0733730-01 0 Edge Node 0 Trunk Node SDH Physical Connection Routing protocol and IP packet Exchange Figure 5/X.85/Y.1321- “IP over SDH using LAPS“ network example 6 This Recommendation treats SDH transports as octet-oriented synchronous point-to-point links. The SDH fi-ames are an octet-oriented
49、synchronous multiplex mapping structure that specifies a series of standard rates, formats and mapping methods. Table 1 shows the bandwidth value of the VCs and Table 2 of the STMs that are currently specified. The use of control signals is not required. The self- synchronous scrambling/descrambling (x+ 1) function is applied during insertiodextraction into/fi-om the synchronous payload envelope (see Annex C). This Recommendation uses the future concatenation of virtual containers as defined in the new version of IT-T G.707N. 1322. Physical layer and its pri
