1、ITU-T RECM“tT.302 73 4862593 0590703 777 INTERNATIONAL TELECOMMUN CATION UN ION ITU-T TELECOMMUNICATION STAN DARD IZATION SECTOR OF ITU TELEMATIC SERVICES TERMINAL EQUIPMENTS AND PROTOCOLS FOR TELEMATIC SERVICES T.102 (03/93) SYNTAX-BASED VIDEOTEX END-TO-END PROTOCOLS FOR THE CIRCUIT MODE ISDN ITU-T
2、 Recommendation T.102 (P revioucly “CC IT Recommendation“) ITU-T RECMN*T.102 93 = 4862573 0570704 bo3 = FOREWORD The IT Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecom- munication Union. The ITU-T is responsible for studying technical, operating and
3、 tariff questions 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, established the topics for study by the ITU-T Study Groups which, in their turn, pr
4、oduce Recommendations on these topics. ITU-T Recommendation T.102 was prepared by the ITU-T Study Group VI11 (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform process within the International Telecommunication Union (ITU), the CCITT ceased to
5、 exist as of 28 February 1993. In its place, the ITU Telecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector. In order not to delay publication of this Recommendation
6、, no change has been made in the text to references containing the acronyms “CCITT, CCIR or IFRB” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will contain the proper terminology related to the new ITU structure. 2 telecommunication
7、administration and a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1994 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, includ
8、ing photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMN*T*L02 73 m 4862573 0570705 54T m 7 8 9 10 11 12 13 14 15 CONTENTS Scope Normative references . Definitions and abbreviations . 3.1 Definitions 3.2 Abbreviations Overview . Configurations General model 6.1 Referen
9、ce configuration 6.2 Protocol pillars Service definition . Protocol Coding Layer 1 . Use of CCITT Recommendation X.3 parameters 1 1.1 Basic access 1 1.2 Primary rate access . Layer 2 protocols i 2.1 Layer 2 protocol for the D-channel 12.2 Layer 2 protocol for the B-channel . Layer 3 protocol for the
10、 D-channel 13.1.1 Terminal selection . 13.1.3 Service specific use of supplementary services 13.1.4 Call progress signals . 13.2 Layer 3 protocol for the B-channel . Use of the Bearer Independent Service (BIS) Mapping of the BIS to Recommendation Q.93 1 . Layer 3 protocols 13.1.2 Compatibility check
11、ing . 13.1 14.1 Out-band procedure 14.1 . 1 14.1.1 . 1 BIS-N-CONNECT 14.1.1.2 BIS-N-DISCONNECT 14.2 In-band procedure . Coordination between D- and B-channel . Recommendation T.102 (03/93) Page 1 1 2 2 2 3 3 3 3 3 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 5 5 6 1 ITU-T RECMN+T.LOZ 93 W YB62591 0590706 486
12、 Recommendation T.102 SYNTAX-BASED VIDEOTEX END-TO-END PROTOCOLS FOR THE CIRCUIT MODE ISDN (Helsinki, 1993) 1 Scope This Recommendation specifies the usage of all protocols and supplementary services up to and including layer 3 for syntax-based Videotex terminal equipment in the ISDN. The scope of t
13、his Recommendation is limited to circuit switched calls using the 64 kbit/s unrestricted digital information bearer capability and the DTEDTE case of the network layer peer entities in B-channel connection. This standard is applicable to terminal equipment supporting the syntax-based Videotex using
14、either basic access or primary rate access to the ISDN. In this context, a terminal equipment is either a Videotex terminal, a Videotex service centre, a Videotex access point or a Videotex host. This Recommendation is based on other CCITT Recommendations and International Standards and where necess
15、ary, it adds new or other requirements as application rules. 2 Normative references This Recommendation incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter
16、. For dated references subsequent amendments to, or revisions of, any of these publications apply to this Recommendation only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to CCITT Recommendation F.300 (1988), Videotex Service
17、. CCITT Recommendation 1.430 (1 988), Integrated Services Digital Network (ISDN) - Basic user-network interface, Layer I specification. CCITT Recommendation 1.43 1 (1988), Integrated Services Digital Network (ISDN) - Primary rate user- network inteace, Layer I specification. CCIT Recommendation Q.92
18、 I (1 990), Integrated Services Digital Network (ISDN) - User-network interface data-link layer specification. CCITT Recommendation 4.93 1 ( 1990), Integrated Services Digital Network (ISDN) - User-network interface Layer 3, specification for basic call control. CCITT Recommendation 4.932 19881, Gen
19、eric Procedures for the Control of ISDN Supplementary Services. CCITT Recommendation T.90 1991, Characteristics and Protocols for Terminals for Telematic Services in ISDN. CCITT Recommendation T. 105, Syntax-based Videotex Application Layer Protocol. CCITT Recommendation X.3, Packet AssemblyDisassem
20、bly Facility (PAD) in a Public Data Network. CCITT Recommendation X.75 (i 9841, Packet-Switched Signalling System between Public Networks providing Data Transmission Services. ISODEC 8208: 1990, Information Technology - Data Communications - X.25 Packet Layer Protocol for Data Terminal Equipment. IS
21、0 7498, Informarion processing systems - Open Systems Interconnection - Basic Reference Model. Recommendation T.102 (03/93) 1 3 Definitions and abbreviations 3.1 Definitions For the purposes of this Recommendation, the following definitions apply: data terminal equipment: See ISO/IEC 8208 lo. networ
22、k connection: See OS1 Reference Model IS0 7498 113. network layer: See OS1 Reference Model IS0 7498 1 i. packet layer: See ISOAEC 8208 101. videotex access point: See CCIT Recommendation F.300 O. videotex host: This term describes a computer which offers one or more applications andor facilities. It
23、 can be represented through a Videotex Host Computer, an External Videotex Host or a Videotex Service Centre. videotex service centre: See CCIT Recommendation F.300 O. functions, i.e. it may alsi) A LI 3s a Videotex Access Point. videotex terminal: See CCT Recommendation F.300 O NOTE - According to
24、CCITT Recommendation F.30 O, a Videotex Service Centre provides host andor access 3.2 Abbreviations For the purpose of this Recommendation, the following abbreviations apply: BIS Bearer Independent Service CD Call Deflection DTE Data Terminal Equipment ISDN Integrated Services Digital Network HLC Hi
25、gh Layer Compatibility NSAP Network Service Access Point SBV Syntax-based Videotex SUB Sub-addressing UUS User-to-User Signalling 4 Overview Clause 4F.105 7 applies. The following subclauses specify the additional requirements to those as specified in Recommendation T.105 7 to provide the Bearer Ind
26、ependent Service for syntax-based Videotex (SBV BIS). ISDN end-systems conforming to this Recommendation present protocol stacks at the S-or T-reference point as indicated in 6.2. 5 Configurations Various configurations and topologies may be used, examples of which are given in informative Annex Af.
27、105 7. It shall be the responsibility of the Videotex Service providers to opt for the appropriate configuration(s) in the definition of the syntax-based Videotex Service. 6 General model Clause 6m.105 7 applies with the additions given in 6.1 and 6.2. 2 Recommendation T.102 (03/93) 6.1 Reference co
28、nfiguration Figure 1 below illustrates the reference configuration for the DTE/DTE case of connection. The ISDN provides for an end-to-end circuit switched link between the terminai and the Videotex System. ISDN SIT ET Exchange termination SBVT Syntax-based VdeotexTminal Coincident S- and T-referenc
29、e point FIGURE liT.102 Reference cdiguration 6.2 Protocol pillars The protocol pillars are given in Figure 2. I At layer 1, Recommendation 1.430 i is used for ISDN basic access and Recommendation 1.431 2 is used for ISDN primary rate access. At layer 2, Recommendation Q.921 3 provides for the LAPD d
30、ata link procedures on the D-channel and Recommendation X.75 9 provides for the LAPB data link procedures on the B-channel (additional application rules are given in clause 12). At layer 3, CCITT Recommendation 4.93 1 4 signalling procedures are used on the D-channel, and ISO/IEC 8208 101 packet lev
31、el protocol is used in DTEDTE operation on the B-channel (additional application rules are given in clause 13). The provision of the SBV BIS as defined in clause 11fl.105 7 apply with regard to the mappings of the BIS primitives and parameters to and from the elements (additional rules are given in
32、clause 14). 7 Service definition Clause 7m.105 7 applies without any additionai rule. 8 Protocol Clause 8/T. 105 7 applies without any additional rule. 9 Coding Clause 9/T. 105 7 applies without any additional rule. Recommendation T.102 (03/93) 3 -_ - ITU-T RECHN*T.LOZ 93 m 4862591 0590709 195 m 2 C
33、oordination (Note 1) BIS (Note 2) 3 Q.921 3 X.75 9 I ISO 8208 lo I Q.931 4 Il 1 1.431 2 1.430 l B-channel Layer D-channel NOTES 1 The coordination function specifies the relationship between D-channel and B-channel protocol pillars. 2 The syntax-based Videotex Bearer Independent Service (SBV BIS) is
34、 defined in clause 11.105 7. It also covers some aspects of the out-band signalling procedures. FIGURE 2/T. 102 Protocol pillars 10 Use of CCITT Recommendation X.3 8 parameters In addition to clause 10fl.105 7, the “X.3 parameter reference number 11” is defined in this Recommendation and shall take
35、the value 18 (64 kbit/s). 11 Layer 1 11.1 Basic access For terminals using the basic access to an ISDN, Recommendation 1.430 1 J is applicable without any additional rule. 11.2 Primary rate access For terminals using the primary rate access to an ISDN, Recommendation 1.43 1 2 is applicable without a
36、ny additional rule. 12 Layer 2 protocols 12.1 Subclause 2.2.2R.90 6 shall apply without any additional rule. Layer 2 protocol for the D-channel 12.2 Subclause 2.2.3.90 6 shall apply without any additional rule. Layer 2 protocol for the B-channel 4 Recommendation T.102 (03/93) ITU-T RECMN*T-L02 93 48
37、62593 0590730 907 = 13 Layer 3 protocols 13.1 Layer 3 protocol for the D-channel 13.1.1 Terminal selection Subclause 2.2.4.90 6 shall apply without any additional rule. 13.1.2 compatibility checking Compatibility checking as part of the access protocol is specified in Annex B/Q.931 and shall apply w
38、ithout any additional rule. 13.1.3 The procedures which are required for the use of supplementary services are specified in Recommendation 4.932 SI and in 1.240-Series and 1.250-Senes Recommendations. Service specific use of supplementary services The use of supplementary services is optional. In or
39、der to realize some of the configurations mentioned in Annex m.105 7, the following services may be necessary: - Sub-addressing (SUB); - - User-to-User Signalling (UUS) Service 1; Call Deflection (CD) in combination with WS Service 1. 13.1.4 Call progress signals Call progress signals may be handled
40、 locally by the terminal. 13.2 Subclause 2.2.5.90 6 shall apply. Clause 4R.90 6 is also relevant, including the restrictions for Videotex. The use of NSAP does not apply. Layer 3 protocol for the B-channel 14 Use of the Bearer Independent Service (BIS) 14.1 Out-band procedure The base Recommendation
41、 for the layer 3 protocol of the D-channel is Recommendation 4.931 4 as already mentioned above. Clause ll/T. 105 7 defines the Bearer Independent Service (BIS) for syntax-based Videotex. General information about the out-band procedure of the BIS are described in subclause 11.3.1.105 7 and the spec
42、ific mapping is given below. 14.1.1 Mapping of the BIS to Recommendation Q.931 14.1.1.1 BIS-N-CONNECT The protocol elements providing the BIS-N-CONNECT service are carried by the D-channel messages as defined in Table 1. Also the mapping of the parameters is given in Table 1. 14.1.1.2 BIS-N-DISCONNE
43、CT The protocol elements providing the BIS-N-DISCONNECT service are carried by the D-channel messages as defined in Table 2. Also the mapping of the parameters is given in Table 2. 14.2 In-band procedure The service that the network layer entity provides to the Videotex application with respect to t
44、he establishment, release and data transfer of network connections, shall be as described in clause 1 l.105 7. Recommendation T.102 (0-3) 5 ITU-T RECMN*T*L02 93 = Lid62591 0590711 843 m BIS TABLE 1n.102 BIS-N-CONNECT mapping Reference Q.93 1 D-channel Service primitives Messages _ BIS-N-CONNECT requ
45、est SETUP BIS-N-CONNECT indication SETUP BIS-N-CONNECT response CONNECT BIS-N-CONNECT confirm CONNECT Parameters Information elements Called Address Calling Address Responding Address BIS-user-data BIS Service primitives Called party number Called party subaddress (Note) Not used Not used User-user
46、D-channel Reference 4.93 1 Messages 3.2.9 3.2.9 3.2.3 3.2.3 _ BIS-N-DISCONNECT request BIS-N-DISCONNECT indication Parameters Originator and Reason Responding Address Bi S-user-data 4.5.8 4.5.9 4.5.29 DISCONNECT 3.2.5 DISCONNECT or 3.2.5 RELEASE or 3.2.1 RELEASE COMPLEfE 3.2.8 Information elements C
47、ause 4.5.12 Not used Not used NOTE -The use of the subaddress is not mandatory and depends on local operation requirements. TABLE 2E. 102 BIS-N-DISCONNECT mapping 15 Clause 6.90 6 shall apply without any additional rule. Annex AIT. 105 7 applies. Annex BE.105 7 applies. Annex C.105 7 applies, with the following addition: Coordination between D- and B-channel - The default value for “X.3 parameter reference 1 1” is 18 &I kbit/s. Annex DE.105 7 applies. Annex E/T. 105 7 applies. 6 Recommendation T.102 (03/93)
