1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Q.2111TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (12/1999) SERIES Q: SWITCHING AND SIGNALLING Broadband ISDN Signalling ATM adaptation layer (SAAL) B-ISDN ATM adaptation layer Service specific connection oriented protocol in a multilink and connectio
2、nless environment (SSCOPMCE) ITU-T Recommendation Q.2111 (Formerly CCITT Recommendation) ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND INFORMATION FLOWS FOR SERVIC
3、ES IN THE ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 Q.120Q.249 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 Q.250Q.309 SPECIFICATIONS OF SIGNALLING SYSTEM R1 Q.310Q.399 SPECIFICATIONS OF SIGNALLING SYSTEM R2 Q.400Q.499 DIG
4、ITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWORK Q.120
5、0Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799 BROADBAND ISDN Q.2000Q.2999 General aspects Q.2000Q.2099 Signalling ATM adaptation layer (SAAL) Q.2100Q.2199 Signalling network protocols Q.2200Q.2299 Common aspects of B-ISDN application protocols for access signalling and netw
6、ork signalling and interworking Q.2600Q.2699 B-ISDN application protocols for the network signalling Q.2700Q.2899 B-ISDN application protocols for access signalling Q.2900Q.2999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Q.2111 (12/1999) i ITU-T Recommendation Q.21
7、11 B-ISDN ATM adaptation layer Service specific connection oriented protocol in a multilink and connectionless environment (SSCOPMCE) Summary The protocol defined in this Recommendation is called the Service Specific Connection Oriented Protocol in a Multilink and Connectionless Environment (SSCOPMC
8、E) and provides assured data delivery between AAL connection endpoints. SSCOPMCE is a peer-to-peer protocol which provides the following functions: transfer of user data with sequence integrity; error correction by selective retransmission; flow control; connection control; error reporting to layer
9、management; connection maintenance in the prolonged absence of data transfer; local data retrieval by the user; error detection of protocol control information; status reporting; and out-of-sequence delivery. This Recommendation enhances the specification in ITU-T Q.2110 to allow the SSCOPMCE mechan
10、ism to be deployed not only on a single ATM connection but also: on multiple ATM connections between the same endpoints; or on a connectionless network. When deployed on a single ATM connection, the protocol defined in this Recommendation is interoperable with the protocol specified in ITU-T Recomme
11、ndation Q.2110. This Recommendation describes the necessary elements for layer to layer communication, the elements for peer-to-peer communication, a detailed protocol specification, and examples of assured data operation. Source ITU-T Recommendation Q.2111 was prepared by ITU-T Study Group 11 (1997
12、-2000) and approved under the WTSC Resolution 1 procedure on 3 December 1999. Keywords ATM Adaptation Layer (AAL), Asynchronous Transfer Mode (ATM), Broadband Integrated Services Digital Network (B-ISDN), Connectionless (CL), Multilink (ML), Network Node Interface (NNI), Signalling AAL (SAAL), Servi
13、ce Specific Coordination Function (SSCF), Service Specific Connection Oriented Protocol (SSCOP), Service Specific Connection Oriented Protocol in a Multilink and Connectionless Environment (SSCOPMCE), Service Specific Convergence Sublayer (SSCS), User-to-Network Interface (UNI). ii ITU-T Q.2111 (12/
14、1999) 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, operating and tariff question
15、s and issuing Recommendations 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 ITU-T study groups which, in turn, produce Recommendations
16、on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSC 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, th
17、e 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 involve the use of a claimed
18、 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 Recommendation, ITU had not
19、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. Ge3 ITU 2001 All rights
20、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, except as noted in footnote 1) in Appendix I. ITU-T Q.2111 (12/1999) iii CONTENTS Page 1 Scope. 1 2
21、 References. 1 2.1 Normative references 1 2.2 Additional references (informative) 1 3 Definitions 2 4 Abbreviations 2 5 General 4 5.1 History. 4 5.2 Services provided 4 5.3 Modes of operation . 5 5.4 Addition and removal of “links“. 8 6 Functions of the SSCOPMCE. 8 7 Elements for layer to layer comm
22、unication 9 7.1 Signals between SSCOPMCE and its user . 10 7.1.1 Signal definition 10 7.1.2 Parameter definition 11 7.1.3 State transition diagram for sequences of signals 11 7.2 Signals between SSCOPMCE and SSCS layer management . 13 7.2.1 Signal definition 14 7.2.2 Parameter definition 14 7.3 Sign
23、als between SSCOPMCE and CPCS. 15 7.3.1 Signal definition 15 7.3.2 Parameter definition 15 7.3.3 Connectionless environment 15 8 Protocol elements for peer-to-peer communications 16 8.1 SSCOPMCE PDUs. 16 8.2 SSCOPMCE PDU formats . 18 8.2.1 Coding conventions . 20 8.2.2 Padding (PAD) field 21 8.2.3 R
24、eserved field 21 8.2.4 PDU length 21 8.2.5 STAT and USTAT PDU codings 22 8.3 States of SSCOPMCE protocol entity 22 8.4 SSCOPMCE state variables 23 8.4.1 Value range and arithmetic 23 iv ITU-T Q.2111 (12/1999) Page 8.4.2 State variables at the transmitter 23 8.4.3 State variables at the receiver 26 8
25、.4.4 Common state variables. 28 8.5 SSCOPMCE PDU parameters 28 8.6 SSCOPMCE timers 29 8.7 SSCOP parameters 31 8.8 SSCOPMCE credit and flow control 32 8.8.1 Credit and peer-to-peer flow control . 32 8.8.2 Local flow control 32 8.8.3 Network congestion. 33 9 Specification of SSCOPMCE . 33 9.1 Overview
26、. 33 9.1.0 Guard . 33 9.1.1 Idle . 33 9.1.2 Establishment and release 34 9.1.3 Bidirectional resynchronization. 34 9.1.4 Recovery 34 9.1.5 Data transfer. 34 9.2 SDL diagrams . 35 Annex A Management error indications. 76 Annex B SDL diagrams for the ancillary process TRSP 77 Annex C Convergence funct
27、ion for SSCOPMCE above IP or UDP 81 C.1 General description . 81 C.2 Functions of the convergence function . 81 C.3 Specification of the convergence function 81 C.3.1 The IP interface to its users . 81 C.3.2 The UDP interface to its users. 87 C.4 Layer Management 88 Appendix I Protocol Implementatio
28、n Conformance Statement (PICS) Proforma 91 I.1 Introduction. 91 I.1.1 Scope . 91 I.1.2 Normative references. 91 I.1.3 Definitions . 91 I.1.4 Conformance Statement 92 ITU-T Q.2111 (12/1999) v Page I.2 PICS Proforma 92 I.2.1 Identification of the PICS Proforma Corrigenda . 92 I.2.2 Instructions for Co
29、mpleting the PICS Proforma 92 I.2.3 Identification of the Implementation . 93 I.2.4 Global Statement of Conformance 94 I.2.5 Supported values 99 Appendix II Examples of SSCOPMCE operation 101 II.1 Semantics of the list elements. 101 II.2 Error-free operation 101 II.3 Error recovery by STAT and USTAT
30、 PDUs 103 II.4 Error recovery of PDUs received in a different order than transmitted 107 II.5 Early acknowledgment of SD PDUs. 108 Appendix III Summary of buffer and state variable management 110 Appendix IV Default window size for SSCOP. 112 ITU-T Q.2111 (12/1999) 1 ITU-T Recommendation Q.2111 B-IS
31、DN ATM adaptation layer Service specific connection oriented protocol in a multilink and connectionless environment (SSCOPMCE) 1 Scope This ITU-T Recommendation describes the Service Specific Connection Oriented Protocol (SSCOP 6) enhanced to operate in a multilink or connectionless environment. It
32、specifies the peer-to-peer protocol for the transfer of information and control between any pair of SSCOPMCE entities, the interactions between the SSCOPMCE and its user, the interactions between the SSCOPMCE and the layer below, and the interactions between the SSCOPMCE and layer management. 2 Refe
33、rences 2.1 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
34、 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 currently valid ITU-T Recommendations is regularly published. 1 ITU-T Recommendation
35、X.200 (1994) | ISO/IEC 7498-1:1994, Information technology Open Systems Interconnection Basic Reference Model: The Basic Model. 2 ITU-T Recommendation X.210 (1993) | ISO/IEC 10731:1994, Information technology Open Systems Interconnection Basic Reference Model Conventions for the definition of OSI se
36、rvices. 3 ITU-T Recommendation I.150 (1999), B-ISDN asynchronous transfer mode functional characteristics. 4 ITU-T Recommendation I.361 (1999), B-ISDN ATM layer specification. 5 ITU-T Recommendation I.363.5 (1996), B-ISDN ATM adaptation layer (AAL) specification: Type 5 AAL. 6 ITU-T Recommendation Q
37、.2110 (1994), B-ISDN ATM adaptation layer Service specific connection oriented protocol (SSCOP). 7 IETF RFC 768, User Datagram Protocol. 8 IETF RFC 791, Internet Protocol. 9 IETF RFC 792, Internet Control Message Protocol. 10 IETF RFC 1122, Requirements for Internet Hosts Communication Layers. 2.2 A
38、dditional references (informative) The references listed in this subclause provide informative background information for the reader. 11 ITU-T Recommendation Q.2100 (1994), B-ISDN Signalling ATM Adaptation Layer (SAAL) Overview description. 2 ITU-T Q.2111 (12/1999) 12 ITU-T Recommendation Q.2130 (19
39、94), B-ISDN signalling ATM adaptation layer Service specific coordination function for support of signalling at the user-to-network interface (SSCF at UNI). 13 ITU-T Recommendation Q.2140 (1995), B-ISDN ATM adaptation layer Service specific coordination function for signalling at the network node in
40、terface (SSCF at NNI). 14 ITU-T Recommendation I.365.2 (1995), B-ISDN ATM adaptation layer sublayers Service specific coordination function to provide the connection oriented network service (SSCF-CONS). 15 ITU-T Recommendation I.365.3 (1995), B-ISDN ATM adaptation layer sublayers Service specific c
41、oordination function to provide the connection oriented transport service. 16 ITU-T Recommendation I.363.2 (1997), B-ISDN ATM adaptation layer (AAL) Specification: Type 2 AAL. 17 ITU-T Recommendation I.366.1 (1998), Segmentation and reassembly service specific convergence sublayer for the AAL Type 2
42、. 18 ITU-T Recommendation Q.2119 (1996), B-ISDN ATM adaptation layer Convergence function for SSCOP above the frame relay core service. 3 Definitions The definition of the SSCOPMCE takes into consideration the principles and terminology of ITU-T Recommendations X.200 1 and X.210 2 The reference mode
43、l and layer service conventions for Open Systems Interconnection (OSI). NOTE 1 The physical layer is currently defined in ITU-T Recommendations I.150 3 and I.361 4. NOTE 2 SSCOP is defined in ITU-T Recommendation Q.2110 6; it is deployed on top of an ATM adaptation layer common part on a single ATM
44、connection. The protocol defined in this ITU-T Recommendation is interoperable with the protocol specified in ITU-T Recommendation Q.2110 when deployed in the same environment. 4 Abbreviations AA ATM Adaptation AAL ATM Adaptation Layer ATM Asynchronous Transfer Mode BGAK Begin Acknowledge (PDU) BGN
45、Begin (PDU) BGREJ Begin Reject (PDU) B-ISDN Broadband Integrated Services Digital Network BR Buffer Release CP-AAL Common Part of the AAL CPCS Common Part Convergence Sublayer END End (PDU) ENDAK End Acknowledge (PDU) ER Error Recovery (PDU) ITU-T Q.2111 (12/1999) 3 ERAK Error Recovery Acknowledge (
46、PDU) ID Interface Data IP Internet Protocol LM Layer Management MAA Management ATM Adaptation MaxCC Maximum Connection Control (Count) MaxPD Maximum Poll Data (Count) MaxSTAT Maximum STAT (Count) MD Management Data (PDU) MSB Most Significant Bit MTP Message Transfer Part MU Message Unit NNI Network
47、Node Interface OSI Open Systems Interconnection PAD Padding PCI Protocol Control Information PD POLL Data PDU Protocol Data Unit PICS Protocol Implementation Conformance Statement PL Pad Length POLL Poll (PDU) QOS Quality of Service R Reserved (field) RN Retrieval Number RS Resynchronization (PDU) R
48、SAK Resynchronization Acknowledge (PDU) Rsvd Reserved (field) S Source (field) SAAL Signalling ATM Adaptation Layer SAP Service Access Point SAR Segmentation And Reassembly SD Sequenced Data (PDU) SDL Specification and Description Language SDU Service Data Unit SN Sequence Number SSCF Service Specif
49、ic Coordination Function SSCOP Service Specific Connection Oriented Protocol 4 ITU-T Q.2111 (12/1999) SSCOPMCE Service Specific Connection Oriented Protocol in a multilink and connectionless environment SSCS Service Specific Convergence Sublayer STAT Solicited Status (PDU) UD Unnumbered Data (PDU) UDP User Datagram Protocol UNI User Network Interface USTAT Unsolicited Status (PDU) UU User-to-User VR Receiver state Variable VT Transmitter state Variable 5 General 5.1 His
