1、INTERNATIONAL TELECOMMUNICATION UNION ITUmT TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU X.350 (1 2/97) SERIES X: DATA NETWORKS AND OPEN SYSTEM COM M U N I CATI ON Interworking between networks - Satellite data transmission systems General interworking requirements to be met for data transmission
2、 in international public mobile satellite systems ITU-T Recommendation X.350 (Previously CCIlT Recommendation) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services_ STD*ITU-T RECMN X.350-ENGL 1997 = L18b2591 Obi3577 TTL1 MESSAGE HANDLING SY
3、STEMS DRECTORY OS1 NETWORKING AND SYSTEM ASPECTS Networking Efficiency Naming, Addressing and Registration Abstract Syntax Notation One (ASN. 1) Systems Management framework and architecture Management Communication Service and Protocol OS1 MANAGEMENT Structure of Management Information I Management
4、 functions SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATION PUBLIC DATA NETWORKS Services and facilities Interfaces Transmission, signalling a
5、nd switching Network aspects Maintenance Administrative arrangements Model and notation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS proformas Protocol Identification Security Protocols Layer Managed Objects Conformance testing OPEN SYS
6、TEM INTERCONNECTION INTERWORKING BETWEEN NETWORKS X.l-X.199 X. I-X. 19 X .20-X.49 X.50-X.89 X.90-X. 149 X. 150-X.179 X.180-X.199 X.200-X.299 X.200-X.209 X.210-X.219 X.220-X.229 X.230-X.239 X.240-X.259 X.260-X.269 X.270-X.279 X.280-X.289 X.290-X.299 X.300-X.399 General X.300-X.349 Satellite data tran
7、smission systems x.350-x.399 X.400-X.499 X.500-X.599 X.600-X.699 X.600-X.629 X.630-X.649 X.650-X.679 X.680-X.699 X.700-X.799 X.700-X.709 X.7 10-X.719 X.720-X.729 X.730-X.799 X. 800-X.849 X.850-X.899 X.850-X.859 X.860-X.879 X.880-X.899 X.900-X.999 For firther details, please refer to ITU-T List of Re
8、commendations. COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesITU-T RECOMMENDATION X.350 GENERAL INTERWORKING REQUIREMENTS TO BE MET FOR DATA TRANSMISSION IN INTERNATIONAL PUBLIC MOBILE SATELLITE SYSTEMS Summary This Recommendation pro
9、vides the general provisions applied for data transmission in international public mobile satellite systems. Source ITU-T Recommendation X.350 was revised by ITU-T Study Group 7 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 12th of December 1997. Recommendation X.350
10、(12/97) 1 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesFOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The Telecommunication Standardization Sector (
11、ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and 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
12、 every four years, establishes the topics for study by the IT-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technol
13、ogy which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTU
14、AL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights,
15、 whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implemento
16、rs 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 rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocop
17、ying and microfilm, without permission in writing from the ITU. ii Recommendation X.350 (12/97) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services1 2 3 4 5 6 7 8 9 10 11 12 STD-ITU-T RECMN X-350-ENGL LS77 PI 48b257L Db43581J 577 I CONTENT
18、S Definitions Choice of interface between a mobile DTE and the MSDSE International data number for a mobile DTE . Data transmission prefixes . Transfer of address signal between the MSDSE and a mobile DTE Calls originating in a PDN Calls originating at a mobile earth station Calls to special termina
19、tions . 5.1 5.2 5.3 5.4 Sub-addressing User services and facilities . Routing . Call progress signals and diagnostic codes Closed user groups Interface to PADS . Transfer of C and I lead information Handling of group calls (broadcast service) . Annex A . Allocation of telephone prefixes. telex acces
20、s codes and data transmission prefixes . Recommendation X.350 (12/97) Page 1 2 3 3 3 3 4 4 4 4 4 4 5 5 5 5 6 . 111 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesRecommendation X.350 GENERAL INTERWORKING REQUIREMENTS TO BE MET FOR DATA
21、 TRANSMISSION IN INTERNATIONAL PUBLIC MOBILE SATELLITE SYSTEMS (Malaga-Torremolinos, 1984; amended at Melbourne, 1988; revised in 1997) The ITU-T, considering 4 (Inmarsat); that a maritime satellite service is being operated by the International Maritime Satellite Organization b) transmission in gen
22、eral; that data transmission services in the Inmarsat system should meet the provisions laid down for data c) that the mobile DTE may be connected to a PDN on a call-by-call basis; d) even though they are located in different countries and interfacing different public data networks, that mobile DTEs
23、 should have the capability of interfacing public data networks through all land earth stations unanimously recommends that the following general provisions should apply for data transmission in international public mobile satellite systems. 1 Definitions The following are definitions of terms used
24、in relation with data transmission in public mobile satellite systems. NOTE - A similar set of definitions for telephone interworking is contained in Recommendation M.1100. 1.1 mobile satellite data transmission system is a means for the establishment of temporary connections between a Data Switchin
25、g Exchange (DSE) in a Fublic Data Network (PDN) and a mobile DE. The maritime satellite data transmission system comprises a mobile satellite circuit, a mobile local circuit, a Mobile Satellite Data Switching Exchange (MSDSE), and a mobile terrestrial circuit. The general maritime mobile satellite c
26、onfiguration is shown in Figure 1. International aeronautical and land mobile satellite data transmission are not defined yet. 1.2 mobile local circuit is a circuit between the mobile earth station and a mobile DTE. 1.3 mobile satellite circuit is a circuit between the mobile earth station and the l
27、and earth station. It comprises all elements required for establishing, maintaining and clearing the mobile satellite circuit including the network coordination station. 1.4 exchange if used. mobile terrestrial circuit is a circuit between the land earth station and the mobile satellite data switchi
28、ng 1.5 mobile earth station is defined in Article 1, Q 4.9, of the Radio Regulations, ITU, Geneva 1982. 1.6 coast earth station is defined in Article 1, Q 4.14, of the Radio Regulations, ITU, Geneva 1982. aeronautical earth station is defined in Article 1, 4.20 of the Radio Regulations, ITU, Geneva
29、1982. land earth station is defined in Article 1, 9 4.10A of the Radio Regulations, as modified by MOB-WARC 1987. Recommendation X.350 (12/97) 1 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesSTD.ITU-T RECMN X.350-ENLL L7 qBb25L llb113
30、5A2 3bL S Mobile local circuit Mobile satellite circuit 4 LA r- Y Mobile terrestrial circuit LA r- b Y TO73091 0-98/dOl MES Mobile Earth Station CES Coast Earth Station MSDSE DSE Date Switching Exchange Mobile Satellite Data Switching Exchange Figure 1K350 - Composition of the maritime satellite dat
31、a transmission system base earth station is defined in Article 1, 8 4.11A of the Radio Regulations, as modified by MOB-WARC 1987. 1.7 satellite data transmission system and a public data network. mobile satellite data switching exchange (MSDSE) is the functional interface between .the public maritim
32、e The MSDSE provides the following functions: - interworking between the signalling systems used in the public mobile satellite data transmission system and the PDN; routing and call control for calls to and from mobile stations; - - charging. 1.8 network coordination station is a station in the pub
33、lic mobile satellite system with the capability to coordinate, supervise and monitor the assignment and utilization of the maritime satellite circuits within a satellite coverage area. The network coordination station is designated and operated by the satellite system operator. NOTE - The rest of th
34、is Recommendation applies to public maritime satellite data transmission systems. Its applicability for public aeronautical and land mobile satellite systems is for further study. 2 Choice of interface between a mobile DTE and the MSDSE 2.1 (Recommendation X. 1): i) For data signalling rates at and
35、above 600 bit/s, two types of terminal mode of operation are defined terminals operating in the synchronous mode for user classes of service 3 through 7 interfacing circuit switched PDNs using the interfaces defined in Recommendations X.2 1, X.2 1 bis and X.22; terminals operating in the packet mode
36、 for user classes of service 8 through 12 interfacing packet switched PDNs using the interface defined in Recommendation X.25. ii) 2.2 i) ii) Operation in the packet mode has several advantages as compared to operation in the synchronous mode: operation in the packet mode permits the interconnection
37、 of DTEs operating in different user classes of service; the interface comprises layers 1, 2 and 3 of the Open System Interconnection (OSI) protocol so that the higher layers may be built directly on top of the interface defined in Recommendation X.25; 2 Recommendation X.350 (12197) COPYRIGHT Intern
38、ational Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Servicesiii) the link level protocol (level 2) provides link-by-link error protection using ARQ techniques. NOTE - This error protection is additional to and independent of any forward error correction applied as
39、 part of level 1. iv) the provision of PADS will also interconnect a mobile packet mode DTE with data subscribers of the public switched telephone network and with subscribers of circuit switched PDNs; the PAD may also be used for interconnection with leased lines; + Inmarsat mobile number (Recommen
40、dations E.215F. 125) v) it would be possible to operate with different data rates in the two directions of transmission over the satellite link. Optional digit identifying a specific mobile DE ship 2.3 systems should be provided for the packet mode of operation. Based on the above considerations, it
41、 is concluded that access to PDNs from the public maritime satellite Interconnection with circuit switched PDNs may be offered on an optional basis. 2.4 transmission system are given in Recommendation X.352. The procedures for interworking between packet switched data networks and the maritime satel
42、lite data 3 International data number for a mobile DTE The format of the international data number for a DTE on the public mobile-satellite system (Inmarsat), is defined in Recommendation X.121, and is composed as follows: NOTE - Global Public Data Networks (including public mobile-satellite systems
43、) may be allocated a Global DNIC as defined in Recommendation X.121 (1996). 4 Data transmission prefixes Prefixes to be used at the mobile DTE for calling a DTE of a PDN or a special termination located at the public maritime Mobile Satellite Data Switching Exchange (MSDSE) or in a PDN are given in
44、Annex A. 5 Transfer of address signal between the MSDSE and a mobile DTE 5.1 Calls originating in a PDN 5.1.1 For an incoming call to a mobile DTE, the part of the called DTE address which includes the DNIC and the Inmarsat mobile number need not be transferred across the DCEDTE interface since the
45、coast earth station identifies the called mobile earth stations by procedures on the radio path. If present, the optional digit identifying a specific mobile DTE must be transferred transparently to the mobile earth station. See also 2.3X.352, item ii). 5.1.2 The calling DTE address transferred acro
46、ss the DCEDTE interface should have the following format: International data number of calling DTE as defined in Recommendation X.121 Prefix O Recommendation X.350 (12/97) 3 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services5.2 5.2.1 foll
47、owing format irrespective of the location of the called DTE: Calls originating at a mobile earth station For a calling mobile DTE, the called DTE address transferred across the DTE/DCE interface must have the I 1 I 1 I International data number of called DTE as defined in Recommendation X.121 Prefix
48、 O 1 I I I 5.2.2 the particular mobile DTE should be tranferred across the DTE/DCE interface see also 2.4m.352, item i). NOTE - As required by Recommendation X.300, the calling DTE address, if present, should be checked by the MSDSE before the call request packet is transmitted into a PDN. The DNIC
49、of the ocean area in which the calling mobile earth station is located should be inserted by the MSDSE. If the calling DTE address is not present, it should be inserted by the MSDSE. The inserted address should consist of the DNIC followed by the mobile earth station number. The calling DTE address consisting of the mobile Inmarsat number optionally followed by the digit identifying 5.3 Cais to special terminations For a mobile DTE calling a special termination defined by one of the prefixes (other than O) given in Annex A, the called DTE
