1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T V.150.0TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2003) SERIES V: DATA COMMUNICATION OVER THE TELEPHONE NETWORK Interworking with other networks Modem-over-IP networks: Foundation ITU-T Recommendation V.150.0 ITU-T V-SERIES RECOMMENDATIONS DATA C
2、OMMUNICATION OVER THE TELEPHONE NETWORK General V.1V.9 Interfaces and voiceband modems V.10V.34 Wideband modems V.35V.39 Error control V.40V.49 Transmission quality and maintenance V.50V.59 Simultaneous transmission of data and other signals V.60V.99 Interworking with other networks V.100V.199 Inter
3、face layer specifications for data communication V.200V.249 Control procedures V.250V.299 Modems on digital circuits V.300V.399 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. V.150.0 (01/2003) i ITU-T Recommendation V.150.0 Modem-over-IP networks: Foundation Summa
4、ry This Recommendation specifies the road map and high-level details for the V.150 family of modem-over-IP Recommendations. Source ITU-T Recommendation V.150.0 was prepared by ITU-T Study Group 16 (2001-2004) and approved under the WTSA Resolution 1 procedure on 13 January 2003. ii ITU-T Rec. V.150.
5、0 (01/2003) 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 qu
6、estions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendati
7、ons on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA 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
8、, the 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 cla
9、imed 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
10、not 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. ITU 2003 All rights
11、reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. V.150.0 (01/2003) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 4 Abbreviations 1 5 Introduction 2 6 Family members . 2 7 Version management 2 8 Ven
12、dor-defined messages. 2 Appendix I List of Recommendations in the V.150 family 3 ITU-T Rec. V.150.0 (01/2003) 1 ITU-T Recommendation V.150.0 Modem-over-IP networks: Foundation 1 Scope This Recommendation specifies the basic and generic characteristics for devices designed to transport V-series modem
13、 signals across an IP network. The Recommendation defines: a) forward and backward version interoperability; b) the use of Vendor-defined messages and information. This Recommendation includes mandatory requirements, recommendations and options; these are designated by the words “shall,“ “should,“ a
14、nd “may“ respectively. 2 References The following ITU-T Recommendation contains provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the edition indicated was valid. All Recommendations and other references are subject to revisio
15、n; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendation and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Rec
16、ommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T Recommendation T.35 (2000), Procedure for the allocation of ITU-T defined codes for non-standard facilities. 3 Definitions This Recommendation defines the following terms: 3.1 gateway: A gateway converts m
17、edia provided in one type of network to the format required in another type of network. For example, a gateway could terminate bearer channels from a switched circuit network (e.g. DS0s) and media streams from a packet network (e.g. RTP streams in an IP network). 3.2 MoIP gateway: A gateway that is
18、compliant with ITU-T Rec. V.150.1. 3.3 modem relay: The transportation of modem data across a packet network using modem termination at the network access points. 3.4 voice band data: The transport of modem signals over a voice channel of a packet network with the encoding appropriate for modem sign
19、als. 4 Abbreviations This Recommendation uses the following abbreviations: FoIP Fax over Internet Protocol MoIP Modem over Internet Protocol PDU Protocol Data Unit SDP Session Description Protocol 2 ITU-T Rec. V.150.0 (01/2003) ToIP Text over Internet Protocol VoIP Voice over Internet Protocol 5 Int
20、roduction This Recommendation provides a foundation for common procedures that are used by the V.150 family of Recommendations. The V.150 Recommendations are part of the group that consider the inter-working of V-series modems with other networks. In this instance the other network of consideration
21、are Internet Protocol Networks. The Recommendation does not require behaviour that is inconsistent with other V-series Recommendations, or with national regulatory requirements, and shall be interpreted accordingly. Neither does it preclude the use of proprietary or non-standard equipment, however i
22、t does caution that if such devices are used then care should be taken as not to harm the functionality and procedures defined herein. 6 Family members A list of the members of the V.150 family of Recommendations is provided in Appendix I. 7 Version management The V.150 family of Recommendations is
23、expected to contain several functional versions. To ensure both forward and backward compatibility, the version management for these Recommendations is defined here. A functional member of the V.150 family of Recommendations is indicated by a trailing dot-number, e.g. V.150.1 or V.150.2. An integer
24、number within the Recommendation indicates a version or revision of a functional member. Consequently, when used in a PDU or information element a complete version can be indicated for a V.150 member by using an x.y representation. For example, 1.1 would be V.150.1 version 1, 2.3 would be V.150.2 ve
25、rsion 3, etc. 8 Vendor-defined messages Vendor-specific messages are supported within V.150 PDUs. In general, a V.150 member may support up to 255 vendor identifiers (vendor-ID) for a given call. Each vendor-ID may be unique or specific and tied to either a single or a multiple set of attributes. A
26、unique vendor-Tag may also be assigned to each set of attributes associated with a vendor-ID to allow simpler use within the V.150 mechanisms. Usually the vendor-ID is provided during the external signalling used during the call set-up (i.e. H.245, H.248 or SDP, etc.). The format used in signalling
27、schemes may be compliant to either ITU-T Rec. T.35 or the IANA private enterprise number. The choice is up to the vendor. When the vendor-ID format is ITU-T Rec. T.35, the vendor-ID consists of a country code followed by a vendor code. The country code consists of four octets and the vendor-ID consi
28、sts of two octets. If the representation of the vendor-ID is hexadecimal, leading zeros in the country code may be omitted, while leading zeros in the vendor code may not be omitted. When the vendor-ID is the vendors IANA private enterprise number, leading zeros may be omitted. ITU-T Rec. V.150.0 (0
29、1/2003) 3 The vendor-Tag is a decimal integer with a value between 0 and 255. If used, values in the range of 1 to 255 are uniquely mapped to the combination of vendor-ID and vendor-specific information. The choice of this integer made by a gateway is independent of the choice made by its peer gatew
30、ay. Due to the compactness of this index, a gateway or endpoint may use it in a number of places to simplify the messaging. A value of zero for the vendor-Tag is a null value. When present, it is equivalent to omitting the vendor-Tag. A null value of the vendor-Tag is not associated with any vendor-
31、ID. If non-null, the vendor-Tag may serve as a dynamically assigned vendor-specific identifier. The vendor-specific information is an octet string consisting of one or more octets as defined by the vendor. Since it consists of an integer number of octets, it is represented by an even number of hex c
32、haracters. No “0x“ prefix is needed. Limitation on size is context specific. Details where size is limited will be indicated in the appropriate Recommendation. Appendix I List of Recommendations in the V.150 family The following are members of the V.150 family of Recommendations: V.150.0: Modem-over
33、-IP networks: Foundation (2003) V.150.1: Modem-over-IP networks: Procedures for the end-to-end connection of V-series DCEs (2003) Printed in Switzerland Geneva, 2003 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series B Means of expression: definitions, symbols, classif
34、ication Series C General telecommunication statistics Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks
35、Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and othe
36、r elements of outside plant Series M TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment
37、Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communications Series Y Global information infrastructure and Internet protocol aspects Series Z Languages and general software aspects for telecommunication systems
