ITU-T X 39-1996 Procedures for the Exchange of Control Information and User Data between a Facsimile Packet Assembly Disassembly (FPAD) Facility and a Packet Mode Data Terminal EquNet.pdf

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1、INTERNATIONAL TELECOMMUN KATION UN ION ITU=T TELECOMMUN KATION STANDARDIZATION SECTOR OF ITU x.39 (1 0196) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMM UN I CATION Public data networks - Interfaces Procedures for the exchange of control information and user data between a Facsimile Packet AssemblylD

2、isassembly (FPAD) facility and a packet mode Data Terminal Equipment (DTE) or another FPAD ITU-T Recommendation X.39 (Previously “CCITT Recommendation“) ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATION Services and facilities X.1-X. 19 Transmission, signalling and switching

3、 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 General Satellite da

4、ta transmission networks MESSAGE HANDLING SYSTEMS DIRECTORY OS1 NETWORKING AND SYSTEM ASPECTS Networking Efficiency Naming, Addressing and Registration Abstract Syntax Notation One (ASN.l) Systems Management framework and architecture Management Communication Service and Protocol Structure of Manage

5、ment Information Management functions )PEN SYSTEM INTERCONNECTION NTERWORKING BETWEEN NETWORKS OS1 MANAGEMENT SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovexy Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING X.50-X.89 X.90-X. 149 X.150-X.179 X. 180-X. 199 X.200-X.29

6、9 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 X.300-X.349 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.710-X.719 X.720-X.729 X.730-X.799 X.800-X.84

7、9 X.850-X.899 X.850-X.859 X.860-X.879 X.880-X.899 X.900-X.999 For further details, please refer to TU-TList of Recommendations. FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying

8、 technical, operating and tariff questions and issuing Recommen- dations on them with a view to standardizing telecommunications on a worldwide basis, The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Grou

9、ps 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 ResolutionNo. 1 (Helsinki, March 1-12, 1993). ITU-T Recommendation X.39 was revised by ITU-T Study Group 7 (1993-1996) and was a

10、pproved under the WTSC Resolution No. 1 procedure on the 5th of October 1996. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1997 All rights reserved. No part of this pu

11、blication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. Recommendation X.39 (10/96) i CONTENTS Preface . Procedures for the exchange of FPAD control information and user data . 1.

12、2 Address field and destination G3FE telephone number . 1.3 Call user data 1.5 FPAD messages User Data Transfer . Procedure for the use of FPA messages Procedures for reading, setting, and setting and reading of FPAD parameters Procedures for inviting the FPAD to clear Error handling procedures by t

13、he FPAD Procedure for inviting the FPAD to reselect the called DTE 3.5 Facsimile procedure 3.6 Ancillary signals, commands and responses procedures Formats . 4.1 Introduction 4.2 Call user data format . 4.3 User sequence format . 4.4 Control message format 1.4 User sequences . 3.1 3.2 3.3 3.4 Annex

14、A Annex B - Characteristics of virtual calls and Recommendation X.25 as related to the FPAD representation of a G3 facsimile equipment and a packet mode DTE (or remote FPAD) B.l General interface characteristics . B.2 Interface procedures for virtual call control . B.3 Interface procedures for data

15、transfer . B.4 Virtual call characteristics Annex C . Alphabetical list of abbreviations used in this Recommendation Annex D . Access to MHS . D.l Introduction D.2 References D.3 Format of the MHS related FPAD messages D.4 Mapping of the MHS related FPAD messages to the MHS features Page 1 3 3 5 5 5

16、 5 5 6 6 6 6 7 13 15 15 15 15 15 16 17 17 18 18 21 11 Recommendation X.39 (10/96) STD-ITU-T RECMN X.37-ENGL L79b 48b257L UbZLi58b UT8 SUMMARY This Recommendation describes procedures for the exchange of control information and user data between a Facsimile Packet AssemblyDisassembly (FPAD) and a pac

17、ket mode DTE or another FPAD. Recommendation X.39 (10196) . 111 STD-ITU-T RECMN X.39-ENGL L99b 48b2591 Ob24587 T39 W STD-ITU-T RECMN X-37-ENGL 177b m 48b2571 b24588 770 Recommendation X.39 PROCEDURES FOR THE EXCHANGE OF CONTROL INFORMATION AND USER DATA BETWEEN A FACSIMILE PACKET ASSEMBLY/ DISASSEMB

18、LY (FPAD) FACILITY AND A PACKET MODE DATA TERMINAL EQUIPMENT TE) OR ANOTHER FPAD (Geneva, 1991; revised in 1996) Preface The establishment in various countries of public data networks providing packet switched data transmission services creates a need to produce standards to facilitate international

19、 interworking. The ITU-T, considering (a) and Recommendation X.96 defines call progress signals; that Recommendations X.l and X.2 define the user classes of service and facilities in a public data network, (b) that Recommendation X.5 defines the FPAD in a public data network; (cl accessing the FPAD

20、in a public data network; that Recommendation X.38 defines the G3 facsimile equipment/DCE interface for a G3 facsimile equipment (d) packet mode in public data networks; that Recommendation X.25 defines the interface between the DTE and the DCE for DTEs operating in a (e) a leased line and a packet

21、mode DTE using the virtual call facility of the packet switched transmission service; the need to allow intenvorking between a G3 facsimile equipment in a general switched telephone network or (f) the need to allow intenvorking between FPADs; (g) packet mode DTEs may wish to control specific functio

22、ns of the FPAD, that the packet mode DTE shall not be obliged to use the control procedures for FPAD functions, but that some unanimously declares that (1) the X.39 procedures shall apply to the X.25 interface between the DCE and the packet mode DTE; (2) the X.39 procedures shall be applied for inte

23、rworking between FPADs; (3) the procedures be as specified in clause 1 ; (4) the maker in which user data is transferred be as specified below in clause 2; (5) the procedure for the control of the FPAD via FPAD messages be as specified below in clause 3; (6) the formats of data fields which are tran

24、sferable on a virtual call be as specified below in clause 4. NOTE-For ease of understanding, this Recommendation refers to specific packet types and procedures of Recommendation X.25. When FPAD to FPAD interworking is considered within a national network, these packet types or procedures may have a

25、 different form from those used in Recommendation X.25 but will have the same operational meaning. Recommendation X.39 (10/96) 1 STD-ITU-T RECMN X.37-ENGL 177b m 48b257L Ob24587 807 = 1 Procedures for the exchange of FPAD control information and user data 1.1 FPADs is performed by using data fields

26、defined in Recommendation X.25. The exchange of control information and user data between an FPAD and a packet mode DTE or between 1.2 The telephone number of the destination G3FE is placed in the call request packet either in the address field or in the call user data field. Address field and desti

27、nation G3FE telephone number The originating FPAD shall choose which field to use in placing a call according to prior knowledge of the capabilities of the remote FPAD, the intermediary networks, and/or the remote DTE which receives the call. In cases where the call user data field is used, the addr

28、ess field of the call request packet contains the DTE address of the remote FPAD or the remote DTE. When an FPAD receives a call, it shall check the call user data field in the call request packet according to 1.3.1 to determine which field contains the destination G3FE telephone number. NOTE - Reco

29、mmendation X.39 (1992) defines only the use of the address field to carry the destinaiton G3FE telephone number. If an FPAD conforms to such a version of Recommendation X.39, it will always use the address field of the call request packet to receive the destination G3FE telephone number. Other metho

30、ds, in addition to those specified herein to transfer the telephone number of the destination G3FE, may also be supported. 1.3 Call user data The FPAD will send call request packets and receive incoming call packets including a call user data field. The call user data field is comprised of two field

31、s: a) b) the call data field. the protocol identifier field; and 1.3.1 Protocol identifier field The format of the protocol identifier field is defined in 4.2.1. Incoming calls with an invalid protocol identifier field will be cleared. Bits 2 and 1 of octet 3 of the protocol identifier field are use

32、d as follows: - Bits 2 and 1 = O0 the destination G3FE telephone number is contained in the address field and the call data field shall be discarded if received. the destination G3FE telephone number is contained in the call data field or the call shall terminate in the FPAD. = O1 = 10 reserved. = 1

33、1 reserved. NOTE - A call may be terminated in an FPAD to carry information for billing, management, maintenance, etc. The details of such calls are for further study. 1.3.2 Call data field Call data field is used only when bits 2 and 1 of octet 3 of the protocol identifier field are 01 respectively

34、. If bits 8 to 1 of octet 1 of the call data field are O000 OOlO, the destination G3FE telephone number is contained in octet 6 and subsequent octets, using a maximum of 8 octets, but no more than necessary. The telephone number in the format of E.164 is encoded in BCD, with the first digit in the h

35、igh 4 bits 8,7, 6 and 5 of octet 6, the second digit in the low 4 bits 4, 3, 2 and I of octet 6 and subsequent digits in subsequent octets. If the total number of digits is odd, the low 4 bits of the last octet used is filled with 11 11. Combinations other than 0000 0010 of octet 1 are reserved. The

36、 action by the FPAD upon receiving an incoming call packet with a reserved combination of octet 1 is for further study. 2 Recommendation X.39 (10/96) STD-ITU-T RECMN X-37-ENGL L77b 4b259L ObZq590 529 m 1.4 User sequences 1.4.1 and T.30) between an FPAD and a packet mode DTE or a remote FPAD. User se

37、quences are used to exchange facsimile image data (which is defined in Recommendations T.4 1.4.2 on a virtual call (see Recommendation X.25). User sequences are conveyed in the user data fields of complete packet sequences with Q = O in both directions 1.4.3 1.4.4 There will be only one user sequenc

38、e in a complete packet sequence. The FPAD will transmit all data packets with D-bit set to O. On reception of a data packet with the D-bit set to 1, the FPAD will transmit the corresponding acknowledgement as soon as possible. If the FPAD does not support the D-bit procedure, the FPAD may clear the

39、virtual call. guarantee end-to-end delivery is for further study. NOTE -The possibility of linking the D-bit operation of Recommendation X.25 with the T.30 error correction mode to 1.4.5 One user sequence may be conveyed in one or several complete packet sequences. 1.5 FPAD messages 1.5.1 FPAD: FPAD

40、 messages are used to exchange the following between the FPAD and the packet mode DTE or a remote a) FPAD control information; b) c) signals, commands and responses as defined in Recommendation T.30; and ancillary signals, commands and responses. 1.5.2 directions on a virtual call (see Recommendatio

41、n X.25). FPAD messages are conveyed in the user data fields of complete packet sequences with Q = 1, in both 1.5.3 1.5.4 There will be only one FPAD message in a complete packet sequence. The FPAD will transmit all data packets with the D-bit set to O. On reception of a data packet with both the Q-b

42、it and D-bit set to 1, the FPAD will transmit the corresponding acknowledgement as soon as possible. If the FPAD does not support the D-bit procedure, the FPAD may clear the virtuai call. 2 User Data Transfer 2.1 Data packets will be forwarded by the FPAD in accordance with data forwarding condition

43、s provided in 4.am.3 a. 2.2 The occurrence of a data forwarding condition will not cause the FPAD to transmit empty data packets. 3 Procedure for the use of FPAD messages 3.1 Procedures for reading, setting, and setting and reading of FPAD parameters NOTE - The use of the plural in reference to FPAD

44、 parameters implies the existence of more than one; however, only one FPAD parameter has so far been defined. The use of plural has been continued throughout this and the other Recommendations of the Series as an indication that other FPAD parameters are for further study. 3.1.1 set and read FPAD me

45、ssage. The current values of FPAD parameters may be changed and read by transmitting to the FPAD a set, read, or Recommendation X.39 (10/96) 3 3.1.2 When the FPAD receives a set, read or set and read FPAD message, any data previously received will be delivered to the G3 facsimile equipment before ta

46、king action on the FPAD message. The FPAD will also consider the arrival of such an FPAD message as a data forwarding condition. Action upon FPAD FPAD message received by the FPAD parameters Parameter field 3.1.3 The FPAD will respond to a valid read or set and read FPAD message by transmitting a pa

47、rameter indication FPAD message. This FPAD message will have a parameter field containing a list of parameter references and current values (after any necessary modification) of the FPAD parameters to which the received FPAD message referred. Corresponding parameter indication FPAD message transmitt

48、ed to the packet mode DTE 3.1.4 received. The FPAD will not return a parameter indication FPAD message in response to a valid set FPAD message Set 3.1.5 Table 1 specifies the FPADs response of the FPAD to set, set and read, and read FPAD messages. I None Reset all implemented None X.5 parameters to

49、their initial values corresponding to the initial profile Set the selected Darameters to the List of selected 3.1.6 If the function of a character is duplicated by the selection of parameter values by use of the set or set and read FPAD message, the FPAD will consider these parameter changes as valid, and will respond as described in this Recommendation. parameters with the desired values TABLE 1X.39 given values: a) if no error is encountered a) none FPAD message transmitted by the FPAD in response to set, set and read, and read FPAD message Set and read Read b) if the F