1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T T.38 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2015) SERIES T: TERMINALS FOR TELEMATIC SERVICES Facsimile Group 3 protocols Procedures for real-time Group 3 facsimile communication over IP networks Recommendation
2、ITU-T T.38 ITU-T T-SERIES RECOMMENDATIONS TERMINALS FOR TELEMATIC SERVICES Facsimile Framework T.0T.19 Still-image compression Test charts T.20T.29 Facsimile Group 3 protocols T.30T.39 Colour representation T.40T.49 Character coding T.50T.59 Facsimile Group 4 protocols T.60T.69 Telematic services Fr
3、amework T.70T.79 Still-image compression JPEG-1, Bi-level and JBIG T.80T.89 Telematic services ISDN Terminals and protocols T.90T.99 Videotext Framework T.100T.109 Data protocols for multimedia conferencing T.120T.149 Telewriting T.150T.159 Multimedia and hypermedia framework T.170T.189 Cooperative
4、document handling T.190T.199 Telematic services Interworking T.300T.399 Open document architecture T.400T.429 Document transfer and manipulation T.430T.449 Document application profile T.500T.509 Communication application profile T.510T.559 Telematic services Equipment characteristics T.560T.649 Sti
5、ll-image compression JPEG 2000 T.800T.829 Still-image compression | JPEG XR T.830T.849 Still-image compression JPEG-1 extensions T.850T.899 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T T.38 (11/2015) i Recommendation ITU-T T.38 Procedures for real-time Group 3 f
6、acsimile communication over IP networks Summary Recommendation ITU-T T.38 defines the procedures to be applied to allow Group 3 facsimile transmission between terminals where, in addition to the public switched telephone network (PSTN) or integrated services digital network (ISDN), a portion of the
7、transmission path used between terminals includes an IP network, e.g., the Internet. This revision of this Recommendation consolidates material from ITU-T T.38 (09/2010) with ITU-T T.38 (2010) Erratum 1 (04/13), ITU-T T.38 (2010) Amd. 1 (10/2014), T.Imp38 (02/2015), and adds new material to Appendix
8、 V related to multiple ITU-T T.38 domains connected in series. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T T.38 1998-06-18 8 11.1002/1000/4393 1.1 ITU-T T.38 (1998) Amd. 1 1999-04-01 8 11.1002/1000/4601 1.2 ITU-T T.38 (1998) Amd. 2 2000-02-10 8 11.1002/1000/4841 1.3 ITU-
9、T T.38 (1998) Cor. 1 2000-03-30 8 11.1002/1000/5144 1.4 ITU-T T.38 (1998) Amd. 3 2000-11-17 16 11.1002/1000/5166 1.5 ITU-T T.38 (1998) Amd. 4 2001-07-29 16 11.1002/1000/5527 2.0 ITU-T T.38 2002-03-29 16 11.1002/1000/5689 2.1 ITU-T T.38 (2002) Cor. 1 2003-07-14 16 11.1002/1000/6479 2.2 ITU-T T.38 (20
10、02) Amd. 1 2003-07-29 16 11.1002/1000/6507 2.3 ITU-T T.38 (2002) Amd. 3 2004-01-30 16 11.1002/1000/7244 2.4 ITU-T T.38 (2002) Amd. 2 2004-04-22 16 11.1002/1000/7239 3.0 ITU-T T.38 2004-04-22 16 11.1002/1000/7313 3.1 ITU-T T.38 (2004) Amd. 1 2005-01-08 16 11.1002/1000/7456 4.0 ITU-T T.38 2005-09-13 1
11、6 11.1002/1000/8559 5.0 ITU-T T.38 2007-04-06 16 11.1002/1000/9044 6.0 ITU-T T.38 2010-09-13 16 11.1002/1000/10995 6.1 ITU-T T.38 (2010) Amd. 1 2014-10-14 16 11.1002/1000/12293 7.0 ITU-T T.38 2015-11-29 16 11.1002/1000/12681 * To access the Recommendation, type the URL http:/handle.itu.int/ in the a
12、ddress field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T T.38 (11/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, inf
13、ormation and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a w
14、orldwide 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 Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down i
15、n 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, the expression “Administration“ is used for conciseness to indicate both a telecommunication adm
16、inistration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory pr
17、ovisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention
18、 to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed 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 out
19、side of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the lates
20、t information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2016 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T T.38 (11/2015) iii Table of
21、 Contents Page 1 Scope . 1 2 Normative references 1 3 Definitions 3 4 Abbreviations and acronyms 3 5 Introduction . 5 5.1 Conventions 7 6 Communication between gateways 8 6.1 Internet protocol TCP or UDP . 8 6.2 Gateway facsimile data transfer functions . 8 7 IFT protocol definition and procedures 8
22、 7.1 General . 8 7.2 IFP packet format . 11 7.3 TYPE definitions 12 7.4 The IFP DATA element . 13 7.5 Limitation of ITU-T V.21 frame packet size 16 8 IFP message flow for facsimile modulations up to ITU-T V.17 16 8.1 Data rate management method 1 16 8.2 Data rate management method 2 17 9 IFT over UD
23、P transport 17 9.1 IFT over UDP transport using UDPTL protocol: IFT/UDPTL/UDP . 17 9.2 IFT over UDP transport using RTP protocol: IFT/RTP/UDP 19 10 Message flow for ITU-T V.8 signals and Annex F of ITU-T V.34 facsimile 21 10.1 ITU-T V.8 negotiation 21 10.2 ITU-T V.34 data rate management . 22 10.3 F
24、acsimile mode . 24 10.4 Compatibility with equipment conforming to prior versions of this Recommendation 26 11 Security considerations . 26 Annex A ASN.1 notation 27 A.1 ITU-T T.38 (2002) ASN.1 notation . 27 A.2 ITU-T T.38 (1998) ASN.1 notation . 28 Annex B ITU-T H.323 call establishment procedures
25、31 B.1 Introduction 31 B.2 Communication between facsimile terminal and gateway . 31 B.3 Communication between gateways 31 Annex C The optional forward error correction scheme for UDPTL . 38 C.1 Overview of the optional forward error correction mechanism . 38 iv Rec. ITU-T T.38 (11/2015) Page C.2 Pa
26、rity encode/decode scheme operation and characteristics 38 Annex D SIP/SDP call establishment procedures. 43 D.1 Introduction 43 D.2 Communication between gateways 43 Annex E ITU-T H.248.1 call establishment procedures . 72 E.1 Introduction 72 E.2 Communication between gateways 72 Annex F Interworki
27、ng procedures: ITU-T T.38 and ITU-T V.150.1 in the same gateway 83 F.1 Introduction 83 F.2 SSE reason identifier codes for ITU-T T.38 transition 84 F.3 Mode override from ITU-T V.34 Group 3 facsimile to standard Group 3 facsimile . 85 F.4 External signalling 86 Annex G ITU-T H.245 capability definit
28、ion for ITU-T T.38 over RTP 87 Annex H Signalled and provisioned ITU-T T.38 protocol parameters . 90 H.1 Introduction 90 H.2 Transport conditional ITU-T T.38 parameters . 90 H.3 Guidelines for signalling ITU-T T.38 protocol parameters 96 H.4 Legacy Interpretation of SDP Parameters 96 Appendix I Sess
29、ion examples . 97 I.1 Session examples 97 I.2 IAF device 101 Appendix II Examples of call establishment procedures described in Annex B of ITU-T T.38 . 104 II.1 Sequence examples of call establishment procedures 104 II.2 Protocol data used in call establishment procedures 108 Appendix III ITU-T H.24
30、8 call establishment procedure examples for facsimile-capable media gateways . 114 III.1 Introduction 114 III.2 Examples of call set-up 114 Appendix IV ITU-T V.34 session examples . 143 IV.1 ITU-T V.34 session examples 143 Appendix V ITU-T T.38 implementation guidelines 154 V.1 General issue 154 V.2
31、 IAF issues . 157 V.3 Call set-up issues 158 V.4 Others . 158 Rec. ITU-T T.38 (11/2015) v Page Appendix VI Security considerations from a historical perspective . 160 VI.1 Historical origin and use of Recommendation ITU-T T.38 . 160 VI.2 Application vs network/transport level security . 161 Bibliogr
32、aphy. 163 Rec. ITU-T T.38 (11/2015) 1 Recommendation ITU-T T.38 Procedures for real-time Group 3 facsimile communication over IP networks 1 Scope This Recommendation defines the procedures to be applied to allow Group 3 facsimile transmission between terminals where, in addition to the PSTN or ISDN,
33、 a portion of the transmission path used between terminals includes an IP network, e.g., the Internet. 2 Normative references The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time o
34、f publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users 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 lis
35、t of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T E.180 Recommendation ITU-T E.180/Q.35 (1998), Technical characteristics of tones for the te
36、lephone service. ITU-T F.185 Recommendation ITU-T F.185 (1998), Internet facsimile: Guidelines for the support of the communication of facsimile documents. ITU-T G.711 Recommendation ITU-T G.711 (1988), Pulse code modulation (PCM) of voice frequencies. ITU-T G.729 Recommendation ITU-T G.729 (2007),
37、Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear prediction (CS-ACELP). ITU-T H.225.0 Recommendation ITU-T H.225.0 (2003), Call signalling protocols and media stream packetization for packet-based multimedia communication systems. ITU-T H.245 Recommendation ITU-T
38、H.245 (2009), Control protocol for multimedia communication. ITU-T H.248.1 Recommendation ITU-T H.248.1 (2013), Gateway control protocol, Version 3. U- H Recommendation ITU-T H.248.2 (2013), Gateway control protocol: Facsimile, text conversation and call discrimination packages. ITU-T H.323 Recommen
39、dation ITU-T H.323 (2003), Packet-based multimedia communications systems. ITU-T Q.850 Recommendation ITU-T Q.850 (1998), Usage of cause and location in the Digital Subscriber Signalling System No. 1 and the Signalling System No. 7 ISDN user part. ITU-T Q.931 Recommendation ITU-T Q.931 (1998), ISDN
40、user-network interface layer 3 specification for basic call control. ITU-T T.4 Recommendation ITU-T T.4 (2003), Standardization of Group 3 facsimile terminals for document transmission. 2 Rec. ITU-T T.38 (11/2015) ITU-T T.6 Recommendation ITU-T T.6 (1988), Facsimile coding schemes and coding control
41、 functions for Group 4 facsimile apparatus. ITU-T T.30 Recommendation ITU-T T.30 (2005), Procedures for document facsimile transmission in the general switched telephone network. ITU-T T.37 Recommendation ITU-T T.37 (1998), Procedures for the transfer of facsimile data via store-and-forward on the I
42、nternet. ITU-T T.66 Recommendation ITU-T T.66 (2002), Facsimile code points for use with Recommendations V.8 and V.8 bis. ITU-T V.8 Recommendation ITU-T V.8 (2000), Procedures for starting sessions of data transmission over the public switched telephone network. ITU-T V.21 Recommendation ITU-T V.21
43、(1988), 300 bits per second duplex modem standardized for use in the general switched telephone network. ITU-T V.33 Recommendation ITU-T V.33 (1988), 14 400 bits per second modem standardized for use on point-to-point 4-wire leased telephone-type circuits. ITU-T V.34 Recommendation ITU-T V.34 (1998)
44、, A modem operating at data signalling rates of up to 33 600 bit/s for use on the general switched telephone network and on leased point-to-point 2-wire telephone-type circuits. ITU-T V.150.1 Recommendation ITU-T V.150.1 (2003), Modem-over-IP networks: Procedures for the end-to-end connection of V-s
45、eries DCEs. ITU-T V.152 Recommendation ITU-T V.152 (2010), Procedures for supporting voice-band data over IP networks. ITU-T V.153 Recommendation ITU-T V.153 (12/2009), Interworking between ITU-T T.38 and ITU-T V.152 using IP peering for real-time facsimile services. ITU-T X.420 Recommendation ITU-T
46、 X.420 (1999) | ISO/IEC 10021-7:2003, Information technology Message Handling Systems (MHS): Interpersonal Messaging System. ITU-T X.680 Recommendation ITU-T X.680 (2002) | ISO/IEC 8824-1:2002, Information technology Abstract Syntax Notation One (ASN.1): Specification of basic notation. ITU-T X.691
47、Recommendation ITU-T X.691 (2002) | ISO/IEC 8825-2:2002, Information technology ASN.1 encoding rules: Specification of Packed Encoding Rules (PER). IETF RFC 768 IETF RFC 768 (1980), User Datagram Protocol. IETF RFC 791 IETF RFC 791 (1981), Internet Protocol DARPA Internet Program Protocol Specificat
48、ion. IETF RFC 793 IETF RFC 793 (1981), Transmission Control Protocol DARPA Internet Program Protocol Specification. IETF RFC 1006 IETF RFC 1006 (1987), ISO transport services on top of the TCP: Version 3. IETF RFC 2198 IEFT RFC 2198 (1997), RTP Payload for Redundant Audio Data. IETF RFC 2327 IETF RF
49、C 2327 (1998), SDP: Session Description Protocol. IETF RFC 3261 IETF RFC 3261 (2002), SIP: Session Initiation Protocol. Rec. ITU-T T.38 (11/2015) 3 IETF RFC 3264 IETF RFC 3264 (2002), An Offer/Answer Model with Session Description Protocol (SDP). IETF RFC 3550 IETF RFC 3550 (2003), RTP: A Transport Protocol for Real-Time Applications. IETF RFC 4733 IETF RFC 4733 (2006), R
