1、CCITT RECMN*X.220 93 = 4862591 0577905 946 H INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU x.220 (03/93) OPEN SYSTEMS INTERCONNECTION - GENERAL CONNECTION MODE PROTOCOL SPECIFICATIONS USE OF X.200-SERIES PROTOCOLS IN CCITT APPLLICATIONS ITU-T Recommendat
2、ion X.220 (Previously “CCITT Recommendation”) CCITT RECMN*X.220 93 m 48b25L 0577906 882 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 tariff question
3、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, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommenda
4、tions on these topics. ITU-T Recommendation X.220 was prepared by the ITU-T Study Group VI1 (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 exist as of 28 F
5、ebruary 1993. In its place, the IT 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 Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector.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, no change has be
6、en made in the text to references containing the acronyms “CCITT, CCIR, or FRB” 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 administration and
7、 a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1993 All rights reserved. No part of this publication niay be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
8、and microfilm, without permission in writing from the ITU. CCITT RECMN*X.220 93 m 4862591 0577907 719 W Recommendation X.220 USE OF X.200-SERIES PROTOCOLS IN CCITT APPLICATIONS (Melbourne, 1988; revised Helsinki, 1993) The CCITT, considering (a) that Administrations in many countries are implementin
9、g a variety of telecommunications services; (b) that these services may be carried on a variety of networks; (cl that users of these services desire a unifying architecture for the applicable protocols; (4 Systems Interconnection for CCITT applications; that such an architecture is provided by Recom
10、mendation X.200 which defines the Reference Model of Open (e that a number of protocols conforming to this architecture are defined in the X.200-Series of Recommendations and in other Recommendations, unanimously declares that for CCITT applications the functional suites of protocols, which involve
11、the use of protocols in the X.200-Series of Recommendations, are summarized in this Recommendation. Details, as well as any conformance requirements, are contained in the relevant Recommendations. A growing number of data terminal equipments are being designed to support more than one CCIT service a
12、nd/or are being designed to be capable of being connected to more than one type of network. In order to facilitate the design of such equipments, the various OS1 protocol suites involving use of the X.200-Series of Recommendations are documented herein. These protocol suites are depicted in Figure 1
13、, which portrays the protocols according to the seven layers defined in Recommendation X.200. The CCITT applications covered are Message Handling Systems (MHS), Directory, Transaction Processing (TP), Systems Management, Teletex and Document Architecture Transfer and Manipulation. The networks cover
14、ed are PSPDN, CSPDN, PSTN and ISDN. The intent is to give a general view of the set of protocol suites in a single figure, while relying on the other Recommendations referenced to provide the necessary additional details. Recommendation X.220 (03/93) 1 CCITT RECNN*X*ZZO 73 4862571 0577708 b55 APPLIC
15、ATION LAYER USER APPLICATION LAYER PRESENTATION LAYER SESSION LAYER TRANSPORT LAYER NETWORK LAYER DATA LINK LAYER PHISICAL LAYER Document architecture, MHS transfer and systems transaction (see x.400) manipulation management Directw processing (see T.400) (see X700 and X701) (see X.500) (see X.860)
16、LLl-I.-l-l-l- Note 17 Document transfer and manipulation (Note 15) 1 Call control phase Data transfer phase Call control Daia transfer we phase I I 3 X.411 -%G-+Jfi/$ X435 x.440 x.420 x.736. (X721) (Note 19 P7 X.419 MHS P1 X.419 P3X.419 MHS 84 P1 X.411 X.711 Il RTS 84 X.410 X.228 1 I (Note 13) 1 I I
17、 Note 14 I 3 X.852 I Vote 20 Teletea ;ee T.61 Note 18) (Note 16) 4-L Teletex and group 4 facsimile mtrol procedures T.62bis I I (Note 12) 1 ACSE - X.227 I Presentation protocd - X226 I I 1 SeSSion Protacol - X.225 I I Tiport protocol - X.224 (Note 11) I X25 call -_-_ X.25 data transfer - - -_ X.25 P
18、LP or X.25 PLP T.70 (NO& 8.9) (Notes 8,9) - X.25 PLP Q.931 (Note 10) + X.25 call procedures -_ X.25 data transfer PSPDN CSPDN PSTN ISDN ISDN (circuit (packet switched) switched) 2 Recommendation X.220 (03/93) NOTES 1 see 3.2.1lT.70. The modem may also be integrated within the terminal and in such ca
19、ses V.24 need not apply. For Telematic terminals 2 For automatic calling andor answering, V.25 or V.25 bis may be applicable. 3 or X.3 1, the X.25 LAPB procedures are used as set forth in X.32 or X.3 1. For terminals connected to a PSTN, CSPDN or ISDN (circuit switched) and accessing a PSPDN in acco
20、rdance with X.32 4 For DE-to-DTE connections, Telematic terminals employ the X.75 LAPB procedures for single link operation (see 3.2.2.70, 3.3.21T.70 and 2.1.2.2.90). For other terminals, the IS0 7776 LAPB procedures may apply for DTE-to-DTE connections. 5 module (HDTM) as defined in 5.6/X.32 and in
21、 T.71. For half duplex operation over the PSTN, the LAPD procedures are extended to include a haif duplex transmission 6 Terminais obtaining packet access on the D-channel use the LAPD procedures of Q.921 to support both the Q.931 access connection control procedure (if needed) and the X.25 packet l
22、ayer procedures. Terminals obtaining packet access on the B-channel use the LAPD procedures of 4.921 to support the 4.931 access connection control procedure (if needed) and the X.25 LAPB procedures to support the X.25 packet layer procedures. 7 For terminals connected to a PSTN, CSPDN or ISDN (circ
23、uit switched) and accessing a PSPDN in accordance with X.32 or X.31, the network connection is established by two stage selection: the frst stage uses the call control procedures of the attached network (as shown in this figure) and the second stage uses the X.25 call control procedures. 8 For termi
24、nals connected to a PSTN, CSPDN or ISDN (circuit switched) and accessing a PSPDN in accordance with X.32 or X.31, the X.25 packet layer procedures apply during the data transfer phase of the PSTN, CSPDN or ISDN. However, for Telematic terminals connected to a CSPDN and accessing a PSPDN, a minimum n
25、etwork layer functionality is required during the data transfer phase of the CSPDN (see 3.3.3.70). 9 For DE-to-DTE connections, Telematic terminals connected to a CSPDN use the minimum network layer functionality (see 3.3.3.70) during the data transfer phase of the CSPDN and Telematic terminals conn
26、ected to a PSTN use the X.25 packet layer procedures (see 3.2.3lT.70): Telematic terminals connected to an ISDN (circuit switched) use the X.25 packet layer procedures as specified in ISO/IEc 8208 (see 2.2.5lT.90). For other terminals, the ISO/IEc 8208 X.25 packet layer procedures may apply for DTE-
27、to-DTFi connections. 10 The Q.931 access connection control procedures are used if needed. 11 For Telematic terminals, the transport protocol is in accordance with 5.70 plus Annexes Af.70 and B.70: the use of X.224 class O plus application rules is optional but needs further consideration to ensure
28、that there are no discrepancies with T.70. For terminals communicating with network based services such as MHS, CMIP, TP and Directories, the X.224 procedures apply including the mandatory support of class O. 12 T.62 bis, together with the relevant service and protocol elements of X.215 and X.225, a
29、re intended to be equal to T.62. 13 presentation layer. The “normal mode” is used in all other cases. To obtain backward compatibility with X.410 (1984), RTSE uses the “X.410-1984 mode” services of ACSE and the 14 Directory and CMIP use ROSE but not RTSE. 15 The use of ROSE in the T.400-Series is fo
30、r further study. Recommendation X.220 (03/93) 3 CCITT RECMN*X=220 93 4862593 0577930 203 16 bisE.225 environment. T.330 describes Group 4 Facsimile and Teletex access to the MHS Interpersonal Messaging System (IPMS) in the T.62 17 The use of MHS to transfer documents conforming to the T.410-Series i
31、s described in T.411. 18 Character repertoire definition of T.61 only. 19 and X.740. Further study is underway to specify additional systems management functions. Systems management functions, including protocol specifications (by reference to X.721), are prescribed in X.730-X.736 20 X.852, the Commitment, Concurrency and Recovery (CCR) protocol, is currently at the stage of draft Recommendation. FIGURE 1K.220 Protocol suites 4 Recommendation X.220 (03/93) Printed in Switzerland Geneva, 1993
