ITU-T I 366 1-1998 Segmentation and Reassembly Service Specific Convergence Sublayer for the AAL Type 2 - Series I Integrated Services Digital Network - Overall Network Aspects anddy .pdf

1、STDmITU-T SECMN I.3bb.L-ENGL A998 4862591 0651647 034 INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STAN DARD I ZATI O N SECTOR OF ITU 1.366.1 (06/98) SERIES i: INTEGRATED SERVICES DIGITAL NETWORK Overall network aspects and functions - Protocol layer requirements Segmentation and Re

2、assembly Service Specific Convergence Sublayer for the AAL type 2 ITU-T Recommendation 1.366. I (Previously CCITT Recommendation) %. ITU-T I-SEMES RECOMMENDATIONS INTEGRATED SERVICES DIGITAL NETWORK GENERAL STRUCTURE Terminology Description of ISDNs General modelling methods Telecommunication networ

3、k and service attributes General description of asynchronous transfer mode Scope General aspects of services in ISDN Common aspects of services in the ISDN Bearer services supported by an ISDN Teleservices supported by an ISDN Supplementary services in ISDN SERVICE CAPABILITIES OVERALL NETWORK ASPEC

4、TS AND FUNCTIONS Network functional principles Reference models Numbering, addressing and routing Connection types Performance obiectives I. 1 10-1.1 19 1.120-1.129 I. 130-1.139 I. 140-1.149 I. 150-1.199 1.200-1.209 1.2 10-1.2 19 1.220-1.229 1.230-1.239 1.240-1.249 1.250-1.299 I. 3 1 0-1.3 19 I. 3 2

5、0-1.3 29 1.330-1.339 I. 340-1.349 1.350-1.359 Protocol layer requirements 1.360-1.369 General network requirements and functions ISDN USER-NETWORK INTERFACES Application of I-series Recommendations to ISDN user-network interfaces Layer 1 Recommendations Layer 2 Recommendations Layer 3 Recommendation

6、s Multiplexing, rate adaption and support of existing interfaces Aspects of ISDN affecting terminal requirements INTERNETWORK INTERFACES MAINTENANCE PRTNCIPLES B-ISDN EQUIPMENT ASPECTS ATM equipment Transport functions Management of ATM equipment I. 370-1.399 1.420-1.429 1.430-1.439 1.440-1.449 1.45

7、0-1.459 1.460-1.469 1.470-1.499 1.500-1.599 1.600-1.499 1.730-1.739 1.740-1.749 1.750-1.799 For fitrther details, please refer to ITU-T List of Recommendations. 4 ITU-T RECOMMENDATION 1.366.1 SEGMENTATION AND REASSEMBLY SERVICE SPECIFIC CONVERGENCE SUBLAYER FOR THE AAL TYPE 2 Summary This Recommenda

8、tion specifies the Segmentation and Reassembly Service Specific Convergence sublayer of the ATM Adaptation Layer (AAL) type 2 which provides for the bandwidth-efficient transmission of low-rate, short, and variable length packets in delay sensitive applications. On one or more AAL type 2 user inform

9、ation streams, the Segmentation and Reassembly Service Specific Convergence sublayer may be deployed. In this Recommendation, the sublayer structure and the procedures for the segmentation and reassembly process, as well as the optional transmission error detection and assured data transfer, are def

10、ined in depth. Source ITU-T Recommendation 1.366.1 was prepared by ITU-T Study Group 13 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 1st of June 1998. Recommendation 1.366.1 (06198) i STD-ITU-T RECMN 1.3bb-L-ENGL 1998 W 4862591 0651652 629 = FOREWORD ITU (Internation

11、al Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The IT Telecommunication Standardization Sector (IT-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendatio

12、ns on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the IT-T Study Groups which, in their turn, produce Recommendations on these topics. The a

13、pproval of Recommendations by the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within IT-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation,

14、the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a c

15、laimed Intellectual Property Right. The 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 Recommendation, th

16、e ITU had 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. O ITU 1998 All

17、 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 the ITU. 11 Recommendation 1.366.1 (06/98) 1 2 8 9 10 STD-ITU-T RECIIN I.36b-L-ENGL 1798 4862571

18、 Ob53653 565 H CONTENTS Scope Normative References Definitions Abbreviations . General framework of the segmentation and Reassembly Service Specific Convergence Sublayer . 5.1 Structure of the Segmentation and Reassembly Service Specific Convergence sublayer . 5.2 Primitives provided by AAL type 2 f

19、or higher layer 5.3 Information flow across the SEG-SSCS - AAL type 2 CPS boundary 5.4 The system and block structure of the Segmentation and Reassembly Service Specific Convergence Sublayer Interaction with Management and Control Plane . 6.1 Management plane 6.1.1 Management plane interaction with

20、AAL type 2 CPS user plane . 6.2 Control Plane . Service Specific Segmentation and Reassembly Sublayer (SSSAR) . 7.1 Service provided by the SSSAR . 7.2 Primitives between the SSSAR and SSSAR user entities . 7.3 Format and coding of the SSSAR . 7.4 Procedure ofthe SSSAR . 7.4.1 SSSAR transmitter 7.4.

21、2 SSSAR receiver . 7.4.3 Summary of error indications to Layer Management by the SSSAR Service Specific Transmission Error Detection sublayer (SSTED) . 8.1 Service provided by the SSTED . 8.2 Primitives between the SSTED and SSTED user entities . 8.3 Format and coding ofthe SSTED . 8.4 Procedure oft

22、he SSTED . 8.4.1 SSTED transmitter 8.4.2 SSTED receiver . 8.4.3 Summary of error indications to Layer Management by the SSTED Service Specific Assured Data Transfer sublayer (SSADT) 9.1 . Information about the service provided by the SSADT 9.2 Primitives between the SSADT and SSADT user entities 9.3

23、 Format, coding, and procedure of the SSADT 9.4 Interaction with management plane Summary of parameters and values for the Segmentation and Reassembly Service Specific Convergence sublayer . . Page 1 1 2 2 3 3 3 3 5 8 8 9 9 9 11 13 14 14 14 16 17 18 18 20 20 20 23 23 23 23 24 . Recommendation 1.366.

24、1 (06/98) 111 STDmITU-T RECMN 1-3bb.L-ENGL 1998 4862593 0b5Lb54 4TL Annex A . Data unit naming convention Appendix I - Protocol Implementation Conformance Statement (PICS) proforma I . 1 Introduction . 1.1.1 Scope . 1.1.2 Normative References . 1.1.3 Definitions . 1.1.4 Conformance statement . 1.2 P

25、ICS proforma 1.2.1 Identification of the PICS proforma comgenda 1.2.2 Instructions for completing the PICS proforma 1.2.3 1.2.4 Global statement of conformance 1.2.5 Timers Identification of the implementation . Page 25 26 26 26 26 26 27 27 27 27 28 29 30 iv Recommendation 1.366.1 (06/98) Recommenda

26、tion 1.366.1 SEGMENTATION AND REASSEMBLY SERVICE SPECIFIC CONVERGENCE SUBLAYER FOR THE AAL TYPE 2 (Geneva, 199%) 1 Scope This Recommendation specifies the Segmentation and Reassembly Service Specific Convergence sublayer for the AAL type 2 which provides for the bandwidth-efficient transmission of l

27、ow-rate, short, and variable length packets in delay sensitive applications. On one or more AAL type 2 user information streams, the Segmentation and Reassembly Service Specific Convergence sublayer may be deployed. This Recommendation covers the specification of the sublayer structure, the frame st

28、ructures of the various layered parts of this sublayer, and the mechanisms for the segmentation and reassembly process, as well as the optional transmission error detection and assured data transfer features. With this Segmentation and Reassembly Service Specific Convergence sublayer applied for a S

29、ervice Specific Convergence sublayer for the AAL type 2, it is possible to transport a packet size of more than the maximum length specified in the CPS and also to multiplex with low-rate and short length packets in delay sensitive application. This Recommendation describes the interactions between

30、the Segmentation and Reassembly Service Specific Convergence sublayer for the AAL type 2 and the next higher layer, between this Service Specific Convergence sublayer and the AAL type 2, and between this sublayer and Layer Management, as well as Segmentation and Reassembly Sublayer peer-to-peer oper

31、ations. 2 Normative 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 Recommendations and other references are

32、subject to revision; all 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-Recommendations is regularly published. ITU-T Recommendation 1

33、.361 (1999, B-ISDN ATM layer specijcation. IT-T Recommendation 1.363.2 (1997), B-ISDN ATMadaptation layer specification: type 2 AAL. IT-T Recommendation 4.21 1 O (1994), B-ISDN ATM adaptation layer - service specific connection oriented Protocol (SSCOP). ITU-T Recommendation 1.363.5 (1999, B-ISDN AT

34、Madaptation layer specijcation: type 5 AAL. IT-T Recommendation X.200 (1994) I ISO/IEC 7498-1: 1994, Information technology - Open Systems Interconnection - Basic reference model: The basic model. ITU-T Recommendation X.2 1 O ( 1993) I ISOhEC 1073 1 : 1994, Information technology - Open Svsrems Inte

35、rconnection - Basic reference model: Conventions for the definition of OSI services. Recommendation 1.366.1 (06/98) 1 3 Definitions This Recommendation is based upon the concepts developed in Recommendations X.200 5 and X.210 6. Details of the data unit naming convention used in this Recommendation

36、can be found in Annex A. 4 Abbreviations This Recommendation uses the following abbreviations. AAL ATM Adaptation Layer AAL-SDU AAL Service Data Unit ATM Asynchronous Transfer Mode CI Congestion Indication CPS Common Part Sublayer CPS-INFO CPS Interface Data CPS-UUI CPS-User-to-User Indication LP LS

37、B MSB Loss Priority Least Significant Bit Most Significant Bit PICS Protocol Implementation Conformance Statement SAP SDL SDU SEG-SSCS SSADT SSADT-SDU SSCOP sscs Service Access Point Specification and Description Language Service Data Unit Segmentation and Reassembly Service Specific Convergence Sub

38、layer Service Specific Assured Data Transfer sublayer SSADT Service Data Unit Service Specific Connection Oriented Protocol (see Recommendation Q.2 1 10 31) Service Specific Convergence Sublayer SSSAR s SSAR-INFO SSSAR Interface Data SS SAR-PDU S S SAR-SDU SSSAR-UUI SSSAR User-to-User Indication SST

39、ED SSTED-CI SSTED Congestion Indication SSTJZD-INFO SSTED Interface Data SSTED-LP SSTED Loss Priority SSTED-PDU SSTED Protocol Data Unit SSTED-SDU SSTED Service Data Unit SSTED-W SSTED User-to-User indication field SSTED-UUI SSTED User-to-User Indication Service Specific Segmentation and Reassembly

40、sublayer SSSAR Protocol Data Unit SSSAR Service Data Unit Service Specific Transmission Error Detection sublayer 2 Recommendation 1.366.1 (06/98) 5 General framework of the Segmentation and Reassembly Service Specific Convergence Su blayer CPS-UNITDATA. Parameter request 5.1 Structure of the Segment

41、ation and Reassembly Service Specific Convergence sublayer Comments CPS-UNITDATA. indication The Segmentation and Reassembly Service Specific Convergence sublayer is subdivided into the Service Specific Segmentation and Reassembly sublayer (SSSAR), the Service Specific Transmission Error Detection s

42、ublayer (SSTED), and the Service Specific Assured Data Transfer sublayer (SSADT) as shown in Figure 1. The minimum service provided by this sublayer is a segmentation and reassembly function as specified in clause 7. Optionally, a transmission error detection mechanism as specified in clause 8 may b

43、e deployed. When transmission errors are detected, the reassembled SDU is not delivered to the user. Also optionally, the user of the transmission error detection mechanism may be a further mechanism for assured data transfer specified in clause 9. NOTE -A corrupted data delivery option is for furth

44、er study. 5.2 Primitives provided by AAL type 2 for higher layer The primitives that cross the AAL type 2 SAP are dependent on the optional mechanisms that are selected. If neither the Service Specific Transmission Error Detection sublayer nor the Service Specific Assured Data Transfer sublayer is s

45、elected, the primitives for the AAL are equivalent to the SSSAR primitives (see 7.2) but identified as AAL-UNITDATA.request and AAL-UNITDATAindication consistent with the primitive naming convention at a SAP. On the other hand, if the transmission error detection mechanisms are selected but not the

46、assured data transfer mechanism, the primitives for the AAL are equivalent to the SSTED primitives (see 8.2) but identified as AAL-UNITDATA.request and AAL-UNITDATA.indication consistent with the primitive naming convention at a SAP. If both mechanisms, i.e. the transmission error detection and the

47、assured data transfer mechanism are selected, the primitives defined in clause 9 make the service of the AAL type 2 available to its users. 5.3 Information flow across the SEG-SSCS - AAL type 2 CPS boundary The Segmentation and Reassembly sublayer for the AAL type 2 makes use of the Common Pari Subl

48、ayer services as defined in Recommendation 1.363.2 2. The primitives that cross the boundary between the two sublayers are also defined in Recommendation 1.363.2 2; they are summarized in Table 1. In the event of any difference between the following summary and the definitions in Recommendation 1.36

49、3.2, the definitions in Recommendation 1.363.2 take precedence. Table 1B.366.1- Primitives and parameters of the Common Part Sublayer 1 ._. 45 (default) or i . 64 octets of CPS user Im Im CPS-Interface Data (CPS-INFO) I CPS-User-to-User Indication (CPS-Vvr) I m m 15 bits of CPS user information (Note) I I m Parameter mandatory - Parameter not present NOTE - Only values “O“ . “27“ are permitted. NOTE - Further pdmeters might be needed if the corrupted data delivery option is selected, however, this option is for further study. Recommendation 1.366.1 (06/