1、I_-_-pI_- -II_- _ - - CEPT T/SF*33-02*E 89 2326434 0033013 508 (9 TSF3-02 Page E 1 Recommendation T/SF 31-02 E (Cannes 1983, revised in Odense 1986 and Vienna 1989 (CAC) BEARER SERVICES TO BE PROVIDED BY INTEGRATED SERVICES DIGITAL NETWORK (ISDN) Recommendation proposed by Working Group TIWG 7 “Serv
2、ices and facilities” (SF) Test oj the Recomnientiation adopted by “Telecommurticntioris Commissioii: Content 1. GENERAL 2. LIST OF BEARER SERVICES 3. DESCRIPTIONS OF BEARER SERVICES Annex 1 : Annex 2: Annex 3: Annex 4: Annex 5: Annex 6: Annex 7: Circuit Mode 64 kbit/s unrestricted 8 kHz structured B
3、earer Service Category Circuit Mode 64 kbit/s 8 kHz structured Bearer Service Category usable for Speech Information Transfer Circuit Mode 64 kbit/s 8 kHz structured Bearer Service Category usable for 3.1 kHz Audio Information Transfer Circuit Mode Alternate Speechl64 kbit/s unrestricted 8 kHz struc
4、tured Bearer Service Category Circuit Mode 2 x 64 kbit/s unrestricted 8 kHz structured Bearer Service Category Circuit Mode 384 kbit/s unrestricted 8 kHz structured Bearer Service Category Circuit Mode 1920 kbit/s unrestricted 8 kHz structured Bearer Service Category 1. GENERAL This Recommendation d
5、etails the Bearer Services to be provided by an ISDN. Bearer Services are described by a definition and a set of attribute values which fully describe the service from a users viewpoint. 2. LIST OF BEARER SERVICES A list of Bearer Services that the ISDN should provide, together with an indication of
6、 their priority for introduction is shown below. 1. 1.1. 1.1.1. 1.1.2. 1.2. 1.2.1. 1.2.2. 1.3. 1.3.1. 1.3.2. 1.4. 1.4.1. 1.5. 1.6. 1.6.1. .7. .7.1. .7.2. .8. 3.1. 23.2. Bearer Service Circuit Mode (8 kHz structured) 64 kbit/s unrestricted Demand Permanent 64 kbit/s usable for speech information tran
7、sfer Demand Permanent 64 kbit/s usable for 3.1 kHz audio information transfer Demand Permanent Alternate speecl1/64 kbitjs non-speech Demand 2 x 64 kbit/s unrestricted 8 kHz structured 384 kbitls unrestricted Permanent 1920 kbit/s Demand Permanent 32 kbitls for speech information transfer Demand Per
8、manent Priority E E E A E E A A A A E A A - Edition of September 15. 1989 CEPT T/SF*31-02*E 87 232611311 0011014 41111 81 TIS F 31 -02 E Page 2 3. 3.1. 3.1.1. 3.1.2. 3.1.3. 3.1.4. 3.1.5. 3.1.6. Bearer Service 2. Packe. Mode 2.1. Virtual call and permanent virtual circuit 2.1.1. B-Channel 2.1.2. D-Ch
9、annel 2.2. Connectionless packet Bearer Service on a D-Channel 2.3 Connectionless User Signalling Priority Markings: E= Essential A =Additional Priority E A E A Note. Other Bearer Services than those listed above are for further study. This includes the Reserved Category of Bearer Services. DESCRIPT
10、IONS OF BEARER SERVICES TO BE PROVIDED BY ISDNs Descriptions of the Bearer Services to be provided by an ISDN are contained in Annexes 1 to 7. Definitions are detailed below: Ciruit-Mode Bearer Service Categories Circiiit-Mode 64 kbitls imrestricted striictiired bearer service category 1. speech, 2.
11、 3.1 kHz audio, 3. multiple subrate information streams multiplexed into 64 kbitjs by the user. 4. transparent access to an X.25 public network (1.462 case a). User information is transferred over a B-channel; signalling is provided over a D-channel. Circuit-Mode 64 kbitls, 8 kHz stritiiretl bearer
12、service category iuable for speech information trnnsjer This bearer service category is intended to support speech. The digital signal at the SIT reference point shall conform to Recommendation G.711. The network may use processing techniques appropriate for speech such as analogue transmission. ech
13、o cancellation and low bit rate voice encoding. Hence, bit integrity is not assured. This bearer service category is not intended to support modem derived voice band data. All CCITT Recommendations for the transfer of speech information in the network apply to this bearer service. Circuit-Mode 64 kb
14、itls 8 kHz structured bearer service category idsable for 3.1 kHz airdio iFlformation trcinsfer This bearer service category corresponds to the service which is currently offered in the PSTN. This bearer service category provides for the transfer of speech and of 3.1 kHz bandwidth audio information
15、such as voice band data via modems and facsimile group 1, 2 and 3 information. The digital signal at the S/T reference point shall to conform to Recommendation G.711. Connections provided for these services should offer the transfer capability for the information indicated above. (This means that th
16、e network may include speech processing techniques, provided they are appro- priately modified, or functionally removed prior to non-speech information transfer.) The control of echo control devices, speech processing devices, etc., is only made by use of the 2100 Hz (disabling) in-band tone. Bit in
17、tegrity is not assured. The network may use analogue transmission. All CCITT Recommendations for the transfer of speech information in the network apply to this bearer service category. Circuit-Mode alternate speech/64 kbitls imrestricted 8 kHz structured bearer service category This bearer service
18、category provides the alternate transfer of either speech or 64 kbit Is unrestricted digital information within the same call. The request for this alternate capability and the initial mode desired by the user must be identified at call set up time. This service is provided for the support of multip
19、le capability terminals or single capability terminals. For the speech mode of this bearer service the same applies as for the speech bearer service category. For the unrestricted mode of this bearer service category the same applies as for the unrestricted bearer service category. Circuit-Mode 2 64
20、 kbitls irirestricted 8 kHz structured bearer service category This bearer service category provides the unrestricted transfer of two 64 kbit s user information flows over two B-channels at the user network interface. Circuit-Mode 384 khitls imrestricted 8 kHz striictiired bearer service category Th
21、is bearer service category provides the unrestricted transfer of 384 kbit s user information over a Ho-channel at the SIT reference point. The transfer of OAM information for reserved and permanent services may be provided over a D-channel in the same or in another interfaces structure. e , 15. 1989
22、 Edition of September I - - CEPT T/SF*31-02*E 87 m 232b414 0011015 380 m T/SF 31-02 E Page 3 3.1.7. 3.2. 3.2.1. 3.2.2. 3.2.3. Circiiit-Mode 1920 kbitls iinrestricted 8 kHz striictiired Oerrrer service category This bearer service category provides the unrestricted transfer of 1920 kbitjs user inform
23、ation over a Hl2-channel at the S/T reference point. The transfer of OAM information for reserved and permanent services may be provided over a D-channel. Packet Mode Bearer Service Categories Virtiial call aiid permanent virtiiil circwit hearer service category This bearer service category provides
24、 the unrestricted transfer of user information in a packetized manner over a virtual circuit within a B- or D-channel at the SIT reference point. Signalling information for virtual call and/or possibly OAM information for permanent virtual circuit services are transferred via a D- or B-channel as de
25、scribed in Recommendation. Connectionless packet benrvr servicc category The definition of service in this bearer service category is for further study. User signalling bearer service category The definition of services in this bearer service category is for further study. Edition of Septeinber 15.
26、1989 T/SF 31-02 E Annex 1, Page 1 Annex 1 CIRCUJT-MODE 64 KBIT/S UNRESTRICTED 8 KHZ STRUCTURED BEARER SERVICE CATEGORY (Note I) 1. DEFINITION This Bearer Service Category provides unrestricted information transfer between S/T reference points. It may, therefore, be used to support various user appli
27、cations. Examples include: 1. speech (Note 2); 2. 3.1 kHz audio (Note 2); 3. multiple subrate information streams multiplexed into 64 kbit,k by the user; 4. transparent access to an X.25 public network (1.462 case a). User information is transferred to a B-channel; signalling is provided over a D-ch
28、annel. Note 1. During an interim period some networks may only support restricted 64 kbitjs digital information transfer capability, Le. information transfer capability solely restricted by the requirement that the all-zero octet is not allowed. For interworking the rules given in Appendix 1 of Reco
29、mmendation 1.340 should apply. The interworking functions have to be provided in the network with restricted 64 kbit,ls capability. The ISDN with 64 kbitjs transfer capabilities will not be affected by this interworking, other than by conveying the appropriate signalling message to and from the ISDN
30、 terminal. Note 2. Whilst speech and 3.1 kHz audio have been given as one application for this bearer service category, it is recognised that it is the responsibility of the customers to ensure that a compatible encoding scheme is in operation. Customers should also recognise that no network provisi
31、on can be made for the control of such items as echo and loss, as the network is unaware of the application in use. Furthermore, the quality of service attribute value for information transfer delay will indicate the suitability of a particular version of this bearer service for speech. 2. DESCRIPTI
32、ON 2.1. General Description This circuit mode bearer service category allows : - two users (e.g. terminals, PABXs) in a point-to-point configuration to communicate via the ISDN using 64 kbits digital signals over the B-channel, in both directions continuously and simultaneously for the duration of a
33、 call; - three or more users in a multipoint configuration (refer to Recommendation 1.254 for the supplementary service descriptions of Three Party Service and Conference Calling). 2.2. Specific Terminology Retention Timer: This timer specifies the amount of time that the network retains the call in
34、formation of the original call upon encountering busy or being released. This timer is a network provider option. The value for this timer is greater than 15 seconds. 3. PROCEDURES 3. I. Provision/Withdrawal 3.1.1. Provision of this service will be by arrangement with the Administration/RPOA. 3.1.2.
35、 This bearer service is offered with several subscription options which apply separately to each ISDN number or group of ISDN numbers on the interface. For each subscription option, only one value can be selected. Subscription options for the interface are summarised below: Subscription Option Value
36、 Maximum number of information channels available at User B Maximum number of total calls present at User B User B can be an ISDN number or group of ISDN numbers on the interface. Note. More than on ISDN number can be associated with the servicelinterface only as part of a Supplementary Service such
37、 as Multiple Subscriber Number. In the case of one ISDN number, the option given above for the number of calls can only exceed the number of information channels in association with a Supplementary Service (e.g. Call Waiting). As a network provider option, separate values may be specified for incomi
38、ng and for outgoing calls for either or both of the limits. - m, where m is not greater than the number of information clian- nels on interface - n, where n is not greater than the number of information channels on interface Edition of September 15, 1989 - - CEPT T/SF*31-02*E 9 E 2326434 0011037 353
39、 E T/S F 31 -02 E Annex 1, Page 2 CIRCUIT-MODE 64 KBIT/S UNRESTRICTED 8 KHZ STRUCTURED BEARER SERVICE CATEGORY (Note I) 3.2. Normal Procedures All user-network signalling is done over the D-channel. a) Originating the Service (Call Set Up) The call is originated by the user requesting from the netwo
40、rk the required bearer service with this request including a number identifying the called user. Other information, as required, for the bearer service and other information which may be required for use by the network in the supplementary service provided to the called user (e.g. calling line ident
41、ification) may also be included. This request may be given to the network either en-bloc, containing all the required information, or not en-bloc. b) Indications during call set up After initiating a call the calling user will receive an acknowledgement that the network is able to process the call.
42、The called user will receive an indication of the arrival of an incoming call of this bearer service. The calling user shall also be given an indication that the incoming call is being offered to the called user, when an indication is received by the network that the called user is being informed of
43、 this call. When the call reaches the called user and the connection is established, an indication of this is sent to the calling user. The called user may also provide other information, for use by the network in supplementary services provided to other users (e.g. connected line identity). The rel
44、ationship of a connected user with the called user requires fiirther study. Once established, the B-channel is then available for the transmission of 64 kbit,s digital signals in both directions continuously and simultaneously, without alteration by the network. No restriction is placed by the netwo
45、rk on the content of the digital signals (see Note I). c) Terminating the Call The call may be terminated by either or both of the users by indicating this to the network. If one user terminates the call, an appropriate indication is sent to the other user. 3.3. Exceptional Procedures a) Failure Sit
46、uation due to User Error i) A user inputting a network-identifiable, improper service request will be given an appropriate failure indication by the network and the call set up will be ceased. i) A user inputting a non-valid network number will be given an appropriate failure indication by the netwo
47、rk and the call set up will be ceased. A calling user attempting to establish a call to a user who is identified by the network to be busy (either Network Determined User Busy or User Determined User Busy) will be given an appropriate failure indication by the network. i) A user attempting to establ
48、ish a call to a user where terminal equipment fails to respond will be given an appropriate failure indication by the network and the call set up will be ceased. iii) On a call to a user whose terminal equipment has responded that the called user is being informed of the call, but has failed to answ
49、er within a defined period of time, the calling user attempting to establish the call will be given an appropriate failure indication by the network and the call set up will be ceased. b) Failure Situations due to Called User State i) c) Failure Situations due to Network Conditions i) A user attempting to establish a call but meeting call failure situations due to network conditions (e.g. congestion) will be given an appropriate failure indication by the network. A user attempting to establish a call but meeting call failure situations due to network conditi
