1、- INTERIM STANDARD DRAFT prl-ETS 300 654 October i995 Source: ETSI TC-TE Reference: DIiTE-04111 ICs: 33.080 Key words: ISDN, videotelephony Integrated Services Digital Network (ISDN); Videotelephony terminals; Interim D-channel signalling aspects ETSI European Telecommunications Standards Institute
2、ETSI Secretariat Postal address: F-O6921 Sophia Antipolis CEDEX - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariatetsi.fr Tel.: +33 92 94 42 O0 - Fax: +33 93 65 47 16 Copyright Notification: No pa
3、rt may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in ali media. O European Telecommunications Standards Institute 1995. Ail rights reserved ETSI PRI-ETSJ300 654 95 3400855 0052299 375 Page 2 Draft prl-ETS 300 654: Octo
4、ber 1995 Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to “ETSI Editing and Committee Support Dept.“ at the address shown on the title page. ET
5、SI PRI-ETSa300 654 95 3400855 0052300 917 Page 3 Draft prl-ETS 300 654: October 1995 Contents Foreword . 5 1 Scope 7 2 Normative References . 7 3 Definitions and abbreviations . 8 3.1 Definitions . 8 3.2 Abbreviations 8 4 Short term D-channel signalling procedures . 8 4.1 General . 8 4.2 Outgoing ca
6、ll . 9 Videotelephony teleservice, outgoing call for the initial connection 9 4.2.1.1 Outgoing call for network type 1 9 4.2.1.2 Outgoing call for network type 2 10 4.2.1.3 4.2.1.4 Outgoing call for interworking with restricted networks 11 4.2.1.5 Procedures for all types of networks Il Videotelepho
7、ny teleservice, outgoing call for the second connection . 12 4.3 Incoming call . 12 Videotelephony teleservice, call request for the initial connection 12 Videotelephony teleservice, call request for the second connection . 13 Call request for the telephony 7 kHz teleservice 13 Incoming call from re
8、stricted networks . 14 4.2.1 Outgoing call for network type 3 10 4.2.2 4.3.1 4.3.2 4.3.3 4.3.4 Annex A (normative): Use of the Bearer Capability and High Layer Compatibility information elements in the outgoing and incoming SETUP message . 15 A.l Call setup by the originating terminal . 15 A.2 Alert
9、ing of the called terminal . 16 A.3 CONNECT message 16 Annex B (informative): Bibliography . 17 History . 18 ETSI PRI-ETS*300 654 95 3400855 0052303 853 Page 4 Draft prl-ETS 300 654: October 1995 Blank page ETSI PRI-ETS*300 654 95 W 3400855 0052302 79T Page 5 Draft prl-ETS 300 654: October 1995 Fore
10、word This draft Interim European Telecommunication Standard (LETS) has been produced by the Terminal Equipment (TE) Technical Committee of the European Telecommunications Standards Institute (ETSI), and is now submitted for the Public Enquiry phase of the ETSI standards approval procedure. An ETSI s
11、tandard may be given LETS status either because it is regarded as a provisional solution ahead of a more advanced standard, or because it is immature and requires a “trial period“. The life of an LETS is limited to three years after which it can be converted into an ETS, have its life extended for a
12、 further two years, be replaced by a new version, or be withdrawn. Proposed announcement date Date of latest announcement of this LETS (doa): 3 months after ETSI publication ETSI PRI-ETSa300 654 95 3400855 0052303 b2b W Page 6 Draft prl-ETS 300 654: October 1995 Blank page ETSI PRI-ETS*300 654 95 34
13、00855 0052304 562 Page 7 Draft prl-ETS 300 654: October 1995 I Scope This I-ETS describes the D-channel signalling procedures for videotelephony terminals connected to a pan-European Integrated Services Digital Network (ISDN) in the case where either the originating network has not yet implemented t
14、he procedures specified in EIS 300267-1 l, or in the case of interworking with a terminal connected to a digital network which does not support fully compatible procedures. The terminal may be connected to the S reference point or coincident S and T reference point. The implementation of the procedu
15、res specified in ETS 300 267-1 l are likely to be introduced at different points in time by the various network providers at the access (D-channel signalling, DSSI) or in the network (Signalling system No. 7, ISDN User Part (ISUP). Some networks (e.g. some non-European networks) may not even impleme
16、nt those procedures at all. The support of this LETS by the terminal will ensure an improved probability of success of videotelephony calls in the near future and avoid the occurrence of unexpected clearing of calls as long as networks have not fully implemented the newly developed standards (which,
17、 however, are mandatory for any new designed terminal). The requirements in this LETS are based on the procedures specified in ETS 300 267-1 l and ETS 300 102-1 2 and the use of the Bearer Capability, Low Layer Compatibility and High Layer Compatibility information elements as specified in ETR 018 3
18、. This LETS is applicable to Terminal Equipment (TE) and other equipment (e.g. interworking units, conference bridges). NOTE: The characteristics of the ISDN user-network interface are specified in ETS 300 012, ETS 300 125 and ETS 300 102-1 2. 2 Nonnative References This LETS incorporates by dated a
19、nd undated reference, provisions from other publications. These normative 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 I-ETS only when incor
20、porated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. 141 151 161 ETS 300 267-1 (1 994): “Integrated Services Digital Network (ISDN); Telephony 7 kHz and videotelephony teleservices; Digital Subscriber Signalling System No. one (DSS
21、1); Part 1 : Protocol specification“. ETS 300 102-1 (1990 as amended by A 1 and A 2): “Integrated Services Digital Network (ISDN); User-network interface, Layer 3 aspects“. ETR O1 8 (Edition 3): “Integrated Services Digital Network (ISDN); Application of the Bearer Capability (BC); High Layer Compat
22、ibility (HLC) and Low Layer Compatibility (LLC) information elements by terminals supporting ISDN Services“. ETS 300 143: “Integrated Services Digital Network (ISDN); Audiovisual services; Inband signalling procedures for audiovisual terminals using digital channels up to 2 048 kbis“. ETS 300 145: “
23、Integrated Services Digital Network (ISDN); Audiovisual services; videotelephone systems and terminal equipment operating on one or two 64 kbis channels“. I-ETS 300 281 (1 994): “Integrated Services Digital Network (ISDN); Telephony 7 kHz teleservice, Terminal requirements necessaiy for end-to-end c
24、ompatibility“. ETSI PRI-ETS*300 654 95 W 3400855 0052305 4T7 = Page 8 Draft prl-ETS 300 654: October 1995 3 Definitions and abbreviations 3.1 Definitions For the purposes of this I-ETS, the relevant definitions used in ETSs 300 143 4 and 300 144 and CCITT Recommendations 1.1 12, 1.230 and 1.240 appl
25、y. I-channel: The initial (or only) B-channel allocated to a call where inband signalling according to the principles described in ETS 300 144 is applied. modes of operation: For the videotelephony teleservice in the ISDN, the modes of operation are defined in table 1 of ETS 300 145 5. telephony 3,l
26、 kHz telesenrice: A teleservice providing speech transmission at an audio bandwidth of 3,l kHz. The communication is bi-directional, with both directions active during the speech phase. User information is provided over a B-channel, signalling is provided over the D-channel based on ETS 300 11 1, cl
27、ause 51. telephony 7 kHz telesenrice: A real-time 7 kHz teleservice in which speech (7 kHz or 3,l kHz bandwith) can be interchanged using one circuit-mode 64 kbis connection. The audio bandwith conforms to CCITT Recommendations G.722 and G.711 based on ETS 300 263, clause 51. terminal types: For the
28、 videotelephony teleservice in the ISDN, the terminal types are defined in table 2 of ETS 300 145 (51. videotelephony teleservice: A real-time audiovisual telesewice in which speech and moving pictures are interchanged by means of one or two 64 kbis circuit-mode connections in the ISDN based on ETS
29、300 264, clause 51. 3.2 Abbreviations For the purposes of this I-ETS, the following abbreviations, in addition to those used in CCITT Recommendations 1.112, 1.230 and 1.240, apply. CLI CLIR ISUP MSN TE UD1 UDI-TA Calling Line Identification Calling Line Identification Restriction ISDN User Part Mult
30、iple Subscriber Number supplementary service Termin a I Equipment Unrestricted Digital Information Unrestricted Digital Information with Tones and Announcements 4 Short term D-channel signalling procedures 4.1 General The procedures of ETS 300 267-1 l J, .e. provision of the Bearer Capability with i
31、nformation transfer capability “Unrestricted Digital Information with Tones and Announcements (UDI-TA)“ and the fallback procedure (use of two Bearer Capability and High Layer Compatibility information elements in the SETUP message), may not be implemented in all European and non-European ISDNs for
32、an interim period of time or at all. As a short term solution, terminals supporting the videotelephony teleservice shall meet, along with the procedures specified in ETS 300 267-1 l, the requirements described in the following subclauses. In principle, 3 different types of networks can be distinguis
33、hed for the transition period: Network type 1 : This type of network supports the procedures specified in ETS 300 267-1 l, in particular the use of two Bearer CapabilityIHigh Layer Compatibility information elements, at the access for the D-channel signalling as well as in the network for the signal
34、ling system no. 7 (ISUP). ETSI PRI-ETSs300 654 95 m 3400855 0052306 335 m Page 9 Draft prl-ETS 300 654: October 1995 This type of network supports the procedures specified in ETS 300 267-1 l at the access for the D-channel signalling, but not in the network for the signalling system no. 7 (ISUP). In
35、 this case, the fallback procedures (use of two Bearer Capability/High Layer Compatibility information elements in the SETUP message) shall not be supported by the network. Network type 2: Network type 3: This type of network does not support the procedures described in ETS 300 267-1 l, neither at t
36、he access for the D-channel signalling, nor in the network for the signalling system no. 7 (ISUP). NOTE 1: The networks type 2 and 3 may support of the Bearer Capability “UDI-TA independent from the fallback procedures. NOTE 2: Videotelephony terminals may be connected outside Europe to another type
37、 of network, providing only restricted transmission capabilities (e.9. 56 kbiffs). For videotelephony terminals complying with this I-ETS, it shall be possible to pre-set the terminal to the type of network where it is intended to be connected to. Procedures for changing the preset-value for the net
38、work type shall be available for the user. NOTE 3: The term “network type“ is used only in the context of this I-ETS. NOTE 4: Conformance test requirements for ETS 300 102-1 2 are given in I-ETS 300 322. NOTE 5: Conformance test requirements for the procedures in ETS 300 267-1 I are not yet publishe
39、d. Conformance test requirements are not included in this I-ETS. 4.2 Outgoing call 4.2.1 Videotelephony teleservice, outgoing call for the initial connection Dependent on the type of network the terminal is connected to, the information elements contained in the SETUP message for the initial connect
40、ion shall be chosen according to tables A.l and A.2 of annex A. 4.2.1.1 Outgoing call for network type 1 For network type 1, the procedures of ETS 300 267-1 i shall apply. When the call setup for the initial connection is rejected by the network with a cause value that indicates that the requested B
41、earer Capability (UDI-TA) is not supported by the destination network or the called terminal, e.g. 31, 47, 65, 88, 127, then the terminal shall automatically repeat the call setup procedures by requesting the “circuit-mode 64 kbit/s unrestricted 8 kHz structured bearer service category“. The coding
42、of the Bearer Capability information element is described in ETR 018 3. NOTE 1: For further possible cause values, see ETS 300 102-1 2. A High Layer Compatibility information element as described in ETR O1 8 3, indicating “videotelephony, CCITT Recommendation F.721“ and possibly “initial channel“, m
43、ay be inserted into the SETUP message. NOTE 2: For an interim period of time it is not guaranteed that all networks will support the transport andlor delivery of the High Layer Compatibility information element to the called terminal. In addition, transport of octet 4 may, in some circumstances be s
44、upported, but the transport of octet 4a will not. ETSI PRI-ETS*300 b54 95 W 3400855 0052307 271 Page 10 Draft prl-ETS 300 654: October 1995 4.2.1.2 Outgoing call for network type 2 For network type 2, the procedures of ETS 300 267-1 l apply with the following exception: The terminal shall always sen
45、d a SETUP message containing only one Bearer Capability information element and one High Layer Compatibility information element according to table A.2 to the network, even in the case where fallback is allowed. When the call setup for the initial connection is rejected by the network with a cause v
46、alue that indicates that the requested Bearer Capability (UDI-TA) is not supported by the destination network or the called terminal, e.g. 31, 47, 65, 88, 127, then the terminal shall automatically repeat the call setup procedures by requesting the “circuit-mode 64 kbis unrestricted 8 kHz structured
47、 bearer service category“. The coding of the Bearer Capability information element is described in ETR O1 8 3. NOTE 1: For further possible cause values, see ETS 300 102-1 2 A High Layer Compatibility information element as described in ETR 018 3, indicating “videotelephony, CCITT Recommendation F.7
48、21“ and possibly “initial channel“, may be inserted into the SETUP message. NOTE 2: For an interim period of time it is not guaranteed that all networks will support the transport and/or delivery of the High Layer Compatibility information element to the called terminal. In addition, transport of oc
49、tet 4 may, in some circumstances be supported, but the transport of octet 4a will not. If this second call attempt is rejected with a cause value 18 (no user responding) and the calling user had allowed fallback, then a third call setup shall automatically be initiated as a request for the telephony 3,l kHz teleservice. The human user shall be informed about the repeated call attempts. NOTE 3: For networks of type 2, the procedures of ETS 300 267-1 l could apply in principle. However, it should be noted that, when a user requests th
