1、 STD-ITU-T RECMN 1.3b5.2-ENGL 1995 E 48b2591 Ob21437 85b = INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF TU INTEGRATED SERVICES DIGITAL NETWORK (ISDN) OVERALL NETWORK ASPECTS AND FUNCTIONS 1.365.2 (1 1/95) B-ISDN ATM ADAPTATION LAYER SUBLAYERS: SERVICE SPECI
2、FIC COORDINATION FUNCTION TO PROVIDE THE CONNECTION ORIENTED NETWORK SERVICE ITU-T Recommendation 1.365.2 (Previously “CCITT Recommendation”) STD-ITU-T RECMN 1-3b5-2-ENGL 1775 L1db2571 0b211i3d 772 M FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the Internatio
3、nal Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets ev
4、ery four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics, The approval of Recommendations by the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). ITU-T Reco
5、mmendation 4.365.2 was prepared by ITU-T Study Group 13 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 2nd of November 1995. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a r
6、ecognized operating agency. O ITU 1996 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 the IT. 1 2 3 4 5 6 7 8 9 10 11 CONTENTS Scope Normati
7、ve references . Definitions Abbreviations . Conventions General description Services provided by the SSCF-CONS Functions of the SSCF-CONS Elements for Layer-to-Layer Communication . 9.1 Primitives between SSCF-CONS and SCF . 9.2 Signals between SSCF-CONS and SSCF-CONS Layer Management . 9.3 Signals
8、between SSCF-CONS and SSCOP 9.4 State transition diagram for sequences of signais at the layer boundaries of SSCF-CONS . Protocol elements for Peer-to-Peer Communication 10.1 SSCF-CONS PDUS 10.2 SSCF-CONS PDU formats . 10.3 SSCF-CONS PDU fields 10.4 SSCF-CONS state variables . 10.5 SSCF-CONS timers
9、10.6 SSCF-CONS protocol parameter Specification of the SSCF-CONS 1 1.1 Overview 1 1.2 State Transition Table . 11.3 SDL diagrams . Annex A . Management error indications Annex B -Default values for SSCOP parameters and timers . Annex C . Expedited Data Transfer Service . Protocol elements for peer-t
10、o-peer communication Specification of the Expedited Data service procedure Protocol elements for peer-to-peer communication Specification of the Receipt Confirmation service procedure Parameters and their negotiation for the “Empty” QOS set C . 1 C.2 Annex D - Receipt Confirmation service D . 1 D.2
11、Annex E - Quality of Service parameter negotiation Parameters and their negotiation for the “Standard CONS” QOS set Annex F - Supplementary specification for the SCF (Recommendation 4.923) . F.l Selection of predicates F.2 Mapping of the C-plane Sub-N-Service . E.l E.2 Recommendation 1.365.2 (11/95)
12、 Page 1 1 2 2 3 3 4 6 7 1 10 11 13 15 16 17 17 22 22 22 23 23 25 25 52 53 54 54 58 66 66 69 75 75 75 78 79 79 1 Page Appendix I . N(u)-primitive sequences at the UNI for connection establishment. reset. and release within the U-plane and their relationship to AA-signals and SSCOP PDU sequences . App
13、endix II - Further considerations for the default values for the SSCOP parameters and timers 11.1 Definitions 11.2 Goal . 11.3 Frame size . 11.4 Qualitative analysis . 11.5 Conclusion 80 94 94 94 95 95 97 11 Recommendation 1.365.2 (1U95) STD-ITU-T RECMN I-Ib5.2-ENGL 1995 = 4db259L Ob21441 287 = SUMM
14、ARY The ATM Adaptation Layer (AAL) is defined to enhance the services provided by the ATM layer to support the functions required by the next higher layer. One particular type of service supported by the AAL is the Connection Oriented Network Service (CONS). The AAL for CONS comprises functions nece
15、ssary to support CONS data communications between peer entities in the user plane. The AAL for CONS consists of a Segmentation And Reassembly (SAR) function, and a Convergence Sublayer which is specified as two sublayers: a Common Part Convergence Sublayer (CPCS) and a Service Specific Convergence S
16、ublayer (SSCS). The CPCS is defined in Clause 64.363 2, and is used as the underlying protocol for the service specific part for CONS. The SSCS is functionally divided into two parts: the Service Specific Connection Oriented Protocol (SSCOP), which provides an assured data transfer service, and the
17、Service Specific Coordination Function (SSCF). The SSCOP is defined in Recommendation 4.2110 4 and is suitable for use by various SSCFs. This Recommendation specifies the SSCF for CONS. This Recommendation describes for the SSCF-CONS the mapping of primitives from the Synchronization and Coordinatio
18、n Function (SCF) (defined in Recommendation Q.923 3) to signais of the SSCOP and vice versa. It also specifies the exchange of signals between Layer Management and the SSCF-CONS. KEYWORD Asynchronous Transfer Mode (ATM), ATM Adaptation Layer (AAL), Broadband Integrated Services Digital Network (B-IS
19、DN), Connection Oriented Network Service (CONS), Service Specific Coordination Function (SSCF). Recommendation 1.365.2 (11/95) iii STD*ITU-T RECMN 1-3b5-2-ENGL 1775 m 48b2571 Ob211142 113 m i - STD*ITU-T RECMN 1-3b5.2-ENGL 1775 48b2571 0621443 05T Recommendation 1.365.2 B-ISDN ATM ADAPTATION LAYER S
20、UBLAYERS: SERVICE SPECIFIC COORDINATION FUNCTION TO PROVIDE THE CONNECTION ORIENTED NETWORK SERVICE (Geneva, 1995) 1 Scope This Recommendation specifies a function that is part of the ATM Adaptation Layer to support the OS1 Connection Oriented Network Service (CONS) within the B-ISDN. This function
21、is used to map the service of the Service Specific Connection Oriented Protocol (SSCOP) of the AAL to the requirements of a Network Service user as defined in Recommendation X.213 7. This function is called Service Specific Coordination Function to provide CONS (SSCF-CONS). This Recommendation cover
22、s the specification of the SSCF identified in the complete AAL structure for connection oriented data communications defined in Recommendation 1.363 2, and describes the relationship to the protocol entity providing the Network Service defined in Recommendation X.213 7, the Service Specific Connecti
23、on Oriented Protocol defined in Recommendation Q.2110 4, and Layer Management. This Recommendation is applicable to equipment to be attached to a B-ISDN User Network Interface (UNI) or B-ISDN Network Node Interface (“I) when the OS1 Connection Oriented Network Service is to be supported. 2 Normative
24、 references The following Recommendations and other references contain provisions which, through reference in this text, constitue provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision: ail u
25、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 IT-T Recommendations is regularly published. ITU-T Recommendation 1.361 (1993), B-ISDN ATM l
26、ayer specification. IT-T Recommendation 1.363 (1993), B-ISDN ATM Adaptation Layer (AAL) specification. ITU-T Recommendation 4.923 (1995), Specification of a synchronization and coordination function for the provision of the OSI connection-mode network service in an XSDN environment. ITU-T Recommenda
27、tion Q.2110 (1994), B-ISDN ATM Adaptation Layer - Service Specijic Connection Oriented Protocol (SSCOP). ITU-T Recommendation X.200 (1 994), Information technology - Open Systems Interconnection - Basic reference model: The basic model. ITU-T Recommendation X.210 (1993), information technology - Ope
28、n Systems Interconnection - Basic reference model: Conventions for the definition of OSX services. ITU-T Recommendation X.2 13 (1995), Information technology - Open Systems Interconnection Network service definitions - Amendment 1: Addition of group network addressing and connectionless-mode multica
29、st services. ITU-T Recommendation X.223 (1993). Use of X.25 to provide the OS1 connection-mode network service for ITU- T applications. Recommendation 1.365.2 (11/95) 1 STD-ITU-T RECMN I*IbC-Z-ENGL 1995 48b257L Ob21444 T9b = 9 ITU-T Recommendation 4.295 1 (1993, Stage 3 description for number identi
30、fication supplementary services using D-ISDN Digital Subscriber Signalling System No. 2 - Basic Call - Clause 8 - Sub-addressing (SUB). ITU-T Recommendation 4.2957 (1995), Stage 3 description for additional information transfer supplementary services using B-ISDN Digital Subscriber Signalling System
31、 No. 2 (DSS2) - Basic Call - Clause I - User-to-User Signalling (UUS). 101 3 Definit ions This Recommendation is based upon the concepts developed in Recommendation X.200 5, and makes use of the following terms defined in that Recommendation: a) connection oriented; b) expedited data transfer; c) Ne
32、twork Layer; d) Network Service; e) Network Service Access Point; f) receipt confirmation. This Recommendation is based upon the concepts developed in Recommendation 1.363 2, and makes use of the following terms defined in that Recommendation: a) b) Common Part Convergence Sublayer; c) Segmentation
33、and Reassembly Sublayer; d) Service Specific Convergence Sublayer. Asynchronous Transfer Mode Adaptation Layer; Furthermore, this Recommendation is based upon the concepts developed in Recommendation 4.21 10 4, and makes use of the following terms defined in that Recommendation: a) Service Specific
34、Coordination Function; b) Service Specific Connection Oriented Protocol. 4 Abbreviations For the purposes of this Recommendation, the following abbreviations are used. AAL ATM Adaptation Layer ATM Asynchronous Transfer Mode cc CONS Connection Oriented Network Service CP Common Part CPCS Common Part
35、Convergence Sublayer CR DATA (normal) Data (PDU) DR ED Expedited Data (PDU) EDAK Expedited Data Acknowledgement (PDU) NS (OSI) Network Service NSAP N-SDU Network Service Data Unit Connection Establishment - Confirmation (PDU) Connection Establishment - Request (PDU) Connection Release - Disconnect (
36、PDU) (OSI) Network Service Access Point 2 Recommendation 1.365.2 (1U95) STD-ITU-T RECMN 1-365.2-ENGL 1775 m LibZ591 Ob21LiLi5 722 m PCI PDU QOS RC RCAK SAAL SAP SAR SCF SDL SDU SSCF sscs SSCOP SSCOP-uu Protocol Control Information Protocol Data Unit Quality of Service Receipt Confirmation (PDU) Rece
37、ipt Confirmation Acknowledgement (PDU) AAL for Signalling Service Access Point Segmentation And Reassembly Synchronization and Coordination Function Specification and Description Language Service Data Unit Service Specific Coordination Function Service Specific Convergence Sublayer Service Specific
38、Connection Oriented Protocol SCOP User-to-User parameter 5 Conventions The primitives at the AAL type 5 SAP are conventionally called “AAL-primitives”. However, as defined in the General Descriptions (see clause 6) and shown in Figure 2 the SCF as defined in Recommendation 4.923 3 is the immediate u
39、ser of this AAL type 5 and the primitives there are defined in terms of N(u)-primitives, this Recommendation defines the primitives across the AAL type 5 SAP also as N(u)-primitives. 6 General description The Service Specific Coordination Function providing the Connection Oriented Network Service (S
40、SCF-CONS) resides in the Service Specific Convergence Sublayer (SSCS) of the ATM Adaptation Layer (AAL). It deploys the services provided by the Service Specific Connection Oriented Protocol (SSCOP) defined in Recommendation Q.2110 4. SSCOP also resides in the SSCS. Figure 1 illustrates the structur
41、e of the AAL. The SSCF-CONS provides for the service that is requested by the Synchronization and Coordination Function (SCF) defined in Recommendation 4.923 3. This SCF in turn provides the Connection Oriented Network Service (CONS) as defined in Recommendation X.213 7. The SCF also utilizes the si
42、gnalling capabilities defined for the C-plane. Figure 2a illustrates the B-ISDN structure of the U-plane and C-plane for switched ATM connections. For permanent ATM connections, the SCF interfaces with the M-plane instead of with the C-plane; this situation is shown in Figure 2b. Supplementary speci
43、fications for the SCF as required by Recommendation 4.923 3 are defined in Annex F. The definition of the SSCF-CONS takes into consideration the principles and terminology of the Recommen- dationsX.200 5 and X.210 6, the reference model and the service conventions for Open Systems Intercon- nection
44、(OSI). This Recommendation specifies: 0 the interactions between the SSCF-CONS and the SCF sublayer; the interactions between the SSCF-CONS and the SSCOP sublayer; the interactions between the SSCF-CONS and the AAL management; and the peer-to-peer protocol that enhances the SSCOP service to provide
45、the Connection Oriented Network Service (CONS). Recommendation 1.365.2 (11/95) 3 STD * ITU-T RECMN SAP 1 I Service Specific Coordination Function Service Specific Connection Oriented Prctccol v) 4 1 Signals t Cmmon Part Convergence Sublayer v) o 4 1 Signals k Cegmentation and Reassembly Sublayer SAP
46、 T130476(195/dl Fr n m $ K B w FIGURE 1A.365.2 AAL structure 7 Services provided by the SSCF-CONS The SSCF-CONS provides for the transparent transfer of data, i.e. SSCF-CONS user data between SSCF-CONS users. The supporting communication resources to achieve this transfer stay invisible to the SSCF-
47、CONS user. In particular, the SSCF-CONS service provides for: a) Independence from the underlying transmission media The SSCF-CONS service relieves its users from all concerns of the manner in which the SSCF-CONS service is provided. Except for possible influences of the quality of service, the tran
48、sfer of data over heterogenous underlying networks is, thus, invisible. b) Transparency of the information transferred The SSCF-CONS service provides for the transparent transfer of octet-aligned SSCF-CONS user data and/or control information. It does not restrict the content, format, or coding of t
49、he information nor is there ever a need to interpret its structure or meaning. c) Connection establishment and release The SSCF-CONS service assists the SSCF-CONS user in the connection establishment and release. During connection establishment, the “use” or not use” of the optional Expedited Data andlor Receipt Confirmation service is selected. Simultaneous connection establishment from both sides leads to at most one connection. 4 Recommendation 1.365.2 (11/95) d) Connection reset The SSCF-CONS service provides for a reset mechanism. Its
