1、. ETSI ETSI TECHNICAL REPORT ETR u26 January 1992 UDC: 621.395 Key words: Network, Terminals Network Aspects (NA); Terminal selection principles for priority 1 and 2 services of MOU - ISDN applicable in multi-terminal environments at customer premises ETSI European Telecommunications Standards insti
2、tute FTSI Secretariat: B.P.152 . F - 06561 Valbonne Cedex . France TP. + 33 92 94 42 O0 TF. + 33 93 65 47 16 Tx. 47 O0 40 F European Telecommunications Standards Institute 1 992. All rights reserved. No part may be reproduced or used except as authorised by contract or other written permission. The
3、copyright and the foregoing restriction on reproduction and use extend to all media in which the information may be embodied. 3404583 00bb989 156 Page 2 ETR 026:1992 . Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise,
4、 may occur. If you have comments concerning its accuracy, please write to “ETSI Standards Management Dept.“ at the address shown on the title page. 3404583 00bb990 978 Page 3 ETR 026:1992 Contents . I Foreword . Introduction 1 Scope . 2 References 3 List of abbreviations 4 List of services and speci
5、fic user applications covered 4.1 MOU services 4.2 MOU equivalent services for which interworking with MOU services is considered . 4.2.1 Equivalent services offered in PSTN 4.2.2 Equivalent services offered in PSPDN . 4.2.3 Equivalent services offered in pre.ISDNs. pilot ISDNs and extended IDNs 5 G
6、eneral Principles . 5.1 Out-of-band compatibility checking . 5.2 Terminal identification 5.3 Progress indicator . 5.3.1 Purpose of the progress indicator . . . 5.3.2 Possible values of the progress indicator . 5.3.3 Compatibility checking when a progress indicator is present 5.4 Terminal selection m
7、echanism . 5.5 Allocation of MSN numbers to terminals 6 Terminal selection in a pure MOU ISDN environment 6.1 Terminal selection by compatibility checking . 6.2 Terminal selection by identity checking 7 Terminal selection where non-ISDNs are involved 7.1 Calls from PSTN to ISDN where PSTN supports s
8、ervices corresponding to 3. 1 kHz audio 7.1.1 PSTN to ISDN boundary 7.1.2 Situation at the called subscriber premises 7.2 Calls from PSPDN to ISDN . 7.2.1 X.31 Case A: Access to PSPDN services . 7.2.2 X.31 Case 6: Access to the ISDN virtual circuit service . 7.3 Calls from pre.ISDN. pilot ISDN or ex
9、tended IDN to ISDN . Annex A: PSTN to ISDN connections Annex B: PSPDN to ISDN connections 5 5 7 7 8 9 9 10 10 10 11 11 12 12 12 13 13 13 14 14 15 15 15 16 16 16 16 17 17 17 18 19 21 = 3404583 0066993 804 Page 5 ETR 026:1992 Foreword This ETSI Technical Report (ETR) has been prepared by the Network A
10、spects (NA) Technical Committee of the European Telecommunications Standards Institute (ETSI). ETRs are informative documents resulting from ETSI studies which are not appropriate for European Telecommunication Standard (ETS) or Interim European Telecommunication Standard (I-ETS) status. An ETR may
11、be used to publish material which is either of an informative nature, relating to the use or application of ETSs or I-ETSs, or which is immature and not yet suitable for formal adoption as an ETS or an I-ETS. Introduction Terminal selection is a complex mechanism which relies heavily on the basic ca
12、ll setup protocols according to ETS 300 102-1 121 and makes use of complementary elements involved in the call setup process, some of them referring to terminal identity and some others referring to compatibility. The elements referring to terminal identity include any type of number, such as ISDN n
13、umber and subaddress. The elements referring to terminal compatibility include any type of compatibility information, such as bearer capability, low layer compatibility and high layer compatibility. Terminal selection is therefore a combination of terminal identification (based on a number without a
14、ny relationship to compatibility) and compatibility checking up to a prescribed degree, whereby these two mechanisms are used in a complementary manner. For further information see CCITT Recommendation 1.333 i1 21. This report describes in more detail the basic principles of terminal selection and t
15、he combined use of the elements involved. It is meant as a guidance for both terminal manufacturers and the users of a multiple terminal arrangement (e.g. passive-bus, S-bus). 8 Previous page is blank 3404583 0066992 i40 W Page 7 ETR 026:1992 1 Scope The scope of this technical report is to give det
16、ailed guidance on the application of Integrated Services Digital Network (ISDN) terminal selection features to both terminal manufacturers and ISDN customers. In case of multiple terminal arrangements at called subscribers premises, the location of a multiple terminal arrangement (e.g. passive-bus,
17、S-bus) is at either: - 1 an S/T reference point (respectively coincident S, T reference point); or 0- an S reference point. Terminal selection issues for Memorandum of Understanding (MOU) tele-services and bearer services are considered both for pure ISDN (MOU) end-to-end calls, and for calls in sce
18、narios where also non-Mou ISDNs or dedicated networks are involved. In the latter case interworking is considered between MOU ISDN services and their equivalent in other networks. Service selection for multiple teleservice terminals and multiple terminal installations is covered for incoming calls f
19、or a limited number of combinations. This report does not add any new technical requirements or procedures for terminal selection to the ones described in the referenced ETSI and CCITT documents, however it gives some advice on the applicability of some CCITT Recommendations. 2 References This ETR i
20、ncorporates by dated or undated reference, provisions from other publications. These references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to, or revisions of any of these publications apply to this ETR only
21、when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. 11 i21 i31 I41 i61 i71 ETS 300 125 (1 990): “Integrated Services Digital Network (ISDN); User-network interface data link layer specification Application of CCITT Recom
22、mendations Q.920/1.440 and Q.921/1.441 “. ETS 300 102-1 (1 990): “Integrated Services Digital Network (ISDN); User-network interface layer 3 Specifications for basic call control“. ETR O1 8 (1 990): “Integrated Services Digital Network (ISDN); Application of the BC-, HLC-, LLC- information elements
23、by terminals supporting ISDN services“. Draft prETS 300 007 (March 1990): “Integrated Services Digital Network (ISDNI; Support of packet mode terminal equipment by an ISDN (T/S 46-50)“. Draft prETS 300 050 (July 1990): “Integrated Services Digital Network (ISDN); Multiple Subscriber Number (MSNI sup
24、plementary service Service Description (T/NA1(89)20)“. Draft prETS 300 051 (July 19901: “Integrated Services Digital Network (ISDN); Multiple Subscriber Number (MSN) supplementary service Functional capabilities and information flows (T/S 22-1 5)“. Draft prETS 300 052 (July 1990): “Integrated Servic
25、es Digital Network (ISDN); Multiple Subscriber Number (MSN) supplementary service Digital Subscriber Signalling System No. one (DSSl 1 (T/S 46-33B)“. Previous page is blank M 3404583 O066993 b87 Page 8 ETR 026:1992 i81 91 i101 11 11 11 21 3 AU BC CCITT DDI DSS 1 ETSI IDN ISDN HLC LLC MSN MOU PSPDN P
26、STN SUB TMR Draft prETS 300 059 (July 1990): “integrated Services Digital Network (ISDN); Subaddressing (SUB) supplementary service Service description (T/NA1(89)16)“. Draft prETS 300 060 (July 1990): “Integrated Services Digital Network (ISDN); Subaddressing (SUB) supplementary service Functional c
27、apabilities and information flows (TE 22-26)“. Draft prETS 300 061 (July 1990): “Integrated Services Digitai Network (ISDN); Subaddressing (SUB) supplementary service Digital Subscriber Signalling System No. one (DSS1) protocol (TE 46-331)“. Draft prETS 300 080 (August 1990): “Integrated Services Di
28、gital Network (ISDN); ISDN lower layer protocols for telematic terminals (T/TE 1 2-04)“. CCITT Recommendation 1.333: “Terminal selection in ISDN“ . 0 List of abbreviations Access Unit Bearer Capability the International Telegraph and Telephone Consultative Committee Direct Dialling In Digital Subscr
29、iber Signalling System No. 1 European Telecommunications Standards Institute Integrated Digital Network Integrated Services Digital Network High Layer Compatibility Low Layer Compatibility Multiple Subscriber Number Memorandum of Understanding Packet Switched Public Data Network Public Switched Tele
30、phone Network Subaddressing Transmission Medium Requirement I 3404583 OObb99Y 513 = Page 9 ETR 026:1992 4 List of services and specific user applications covered 4.1 MOU services The following telecommunication services are covered either in this document or by cross-reference to ETR O18 “Applicatio
31、n of the BC-, HLC- and LLC-information elements by terminals supporting ISDN services“ 31. 1 : Circuit-mode bearer services categories 1 .l: Circuit-mode 64 kbit/s 8 kHz structured bearer service category usable for speech information transfer (digital telephony) 1.2: Circuit-mode 64 kbit/s unrestri
32、cted 8 kHz structured bearer service category 1.3: Circuit-mode 64 kbitls 8 kHz structured bearer service category usable for 3,l kHz audio information transfer 2: Packet-mode bearer service categories (case B of X.31) 2.1 : Virtual call bearer service 2.1 .l: Access through the B-channel 2.1.2: Acc
33、ess through the D-channel 3: Teleservices 3.1 : Telephony teleservice (3,l kHz bandwidth) 3.2: Teletex service 3.3: Telefax group 4 service 3.4: ISDN syntax-based videotex service 3.5: 7 kHz Telephony service (for further study) 3.5.1: 3.5.2: ISDN Videotelephony service (for further study) 7 kHz Tel
34、ephony service where fallback to 3,l kHz mode is allowed 7 kHz Telephony service where fallback to 3,l kHz mode is not allowed 3.6: 3.7: Facsimile group 2/3 service 3904583 00bb5 45T Page 10 ETR 026:1992 The following specific user applications of some bearer services are covered either in this docu
35、ment or by cross-reference to ETR O1 8 “Application of the BG, HLC- and LLC-information elements by terminals supporting ISDN services“ 31. A) Specific user applications of the circuit-mode 64 kbitls unrestricted 8 kHt structured bearer service: 1: * Support of terminal adaptors V.11 OIX.30 1.1: Syn
36、chronous mode of operation 1.2: Asynchronous mode of operation 2: Support of X.25 terminal equipment allowing access to PSPDN via AU (case A of X.31) 2.1 : Rate adaption using X.31 HDLC flag stuffing 2.2: Rate adaption corresponding to CC1l- Recommendations V.11 OIX.30. B) Specific user applications
37、 of the circuit-mode 64 kbit/s 8 kHz structured 3.1 kHz audio bearer service 1: Voice band data via modem 4.2 MOU equivalent services for which interworking with MOU services is considered 4.2.1 Equivalent services offered in PSTN The following PSTN services for which interworking with equivalent IS
38、DN services is considered are covered in this document: 8 - speech; - facsimile Group 2/3 service. Specific user applications of the PSTN are also covered in this document: - voice band data via modem. 4.2.2 Equivalent services offered in PSPDN The following PSPDN services for which interworking wit
39、h equivalent ISDN packet mode bearer services is considered are covered in this document: - X.25 Virtual Call service (VC); - X.25 Permanent Virtual Circuit service (PVC). Furthermore, examples of applications involved in this interworking are: - teletex; - facsimile Group 4 service; - X.400 (MHS/ED
40、I). = 3404563 OObbib 396 Page 11 ETR 026:1992 4.2.3 Equivalent services offered in pre-ISDNs, pilot ISDNs and extended IDNs For the characteristics of these networks see subclause 7.3. The following circuit-switched services originating in pre-ISDNs, etc., for which intecworking with the equivalent
41、ISDN services is considered, are covered in this document: - speech; 4 * - facsimile Group 2/3 service; - 64 kbit/s unrestricted 8 kHz structured data service: - teletex service; - Facsimile Group 4 service. 5 General Principles Terminal selection primarily relies on end-to-end user capabilities. An
42、y information which: 1) categorises attributes of an incoming call; or 2) refers to a terminal identity; or 3) specifies the call source which could be ISDN or non-ISDN; , may be used for the terminal selection process. The terminal selection process is a combination of out-of-band compatibility che
43、cking and terminal identification which are used in a complementary manner as part of the call setup protocol according to ETS 300 102-1 21. From the networks point of view, in-band compatibility checking is not related to terminal selection, since it starts when a terminal was selected. Intelligent
44、 units at the called subscriber premises which might select a terminal based on the information made available by in-band procedures are out of the scope of this ETR. 3404583 0066997 222 Page 12 ETR 026:1992 5.1 Outof-band compatibility checking With respect to out-of-band compatibility checking the
45、 following elements are relevant. These elements have calling party to called party significance: - Bearer Capability information element (BC); b . - Low Layer Compatibility information element (LLC); High Layer Compatibility information element (HLC). - NOTE: In cases of interworking, e.g. between
46、a MOU ISDN and a non-Mou ISDN, where different speech codings are applied or where a network embedded service interworking is activated, the BC may be changed between calling and called party. 5.2 Terminal identification With respect to terminal identification the following elements are relevant. Th
47、ese elements have calling party to called party significance: - Called Party Number information element; - Called Party Subaddress information element. NOTE 1 : An element such as Terminal Endpoint Identifier (TEU (see ETS 300 125 11 1, subclause 3.3.4) is out of the scope of this report. It is loca
48、lly used and based on mapping from elements with calling party to called party significance which takes place in the terminating local exchange. I NOTE 2: For specific applications the user may use other information elements for notification, such as Calling Party Number or Closed User Group identit
49、y. The use of this kind of information elements is out of the scope of this report. Any type of address such as ISDN number and subaddress, cannot by itself ensure compatibility. The Called Party Number information element, Called Party Subaddress information element and/or techniques as DDI, MSN may provide an alternative for the missing compatibility information. An example of this is the case of a call from a non-ISDN network (e.g. PSTN or PSPDN) to the ISDN. In this case compatibility is not ensured. For details concerning the delivery of the called party number see sp
