.rs .\" Troff code generated by TPS Convert from ITU Original Files .\" Not Copyright ( c) 1991 .\" .\" Assumes tbl, eqn, MS macros, and lots of luck. .TA 1c 2c 3c 4c 5c 6c 7c 8c .ds CH .ds CF .EQ delim @@ .EN .nr LL 40.5P .nr ll 40.5P .nr HM 3P .nr FM 6P .nr PO 4P .nr PD 9p .po 4P .rs \v | 5i' .sp 1P .ce 1000 \v'3P' SECTION\ 3 .ce 0 .sp 1P .ce 1000 \fBBEARER\ SERVICES\ SUPPORTED\ BY\ AN\ ISDN\fR .ce 0 .sp 1P .sp 2P .LP \fBRecommendation\ I.230\fR .RT .sp 2P .sp 1P .ce 1000 \fBDEFINITION\ OF\ BEARER\ SERVICE\ CATEGORIES\fR .EF '% Fascicle\ III.7\ \(em\ Rec.\ I.230'' .OF '''Fascicle\ III.7\ \(em\ Rec.\ I.230 %' .ce 0 .sp 1P .ce 1000 \fI(Melbourne, 1988)\fR .sp 9p .RT .ce 0 .sp 1P .LP \fB1\fR \fBGeneral\fR .sp 1P .RT .PP Recommendation\ I.210 describes the principles for defining telecommunication services supported by an ISDN, including the concept of bearer services, bearer capabilities and teleservices. It also provides the tools for the definition and description of such services. .PP The purpose of this Recommendation is to define a recommended set of bearer service categories that may be supported by an ISDN together with their overall provision. These definitions form the basis for detailed descriptions of circuit mode bearer services as given in Recommendation\ I.231 and packet\(hymode bearer services as given in Recommendation\ I.232 and their associated bearer capabilities, which are used to define the network capabilities required. .PP Bearer services are fully described by prose definitions and descriptions, by attributes and by dynamic descriptions, which altogether define the service characteristics as they apply at a given reference point where the customer accesses the service. Recommendation\ I.140 and Recommendation\ I.210, Annex\ B describe the use of attributes for this purpose. .RT .sp 2P .LP \fB2\fR \fBDefinition of bearer services\fR .sp 1P .RT .PP This section identifies several bearer services accessed via the standard network access provided by an ISDN. The identification of possible additional services such as subrate services is left for further study. .PP These possible additional services would not lead to any additional requirements to those already identified for physical characteristics of interfaces to be applied at reference points\ S and/or\ T (see Recommendation\ I.411). .PP The definition of bearer services is based upon the list of attributes as given in Table\ B\(hy1/I.210. The information transfer attributes\ Nos.\ 1\(hy4 are called \*Q dominant attributes \*U. They are used to identify a particular bearer service category. Information transfer attributes\ Nos.\ 5\(hy7 are called \*Qsecondary attributes \*U. They are used to identify individual bearer services within one category. \*QAccess attributes\*U as well as \*Qgeneral attributes\*U are used to further specify an individual bearer service. They are called \*Q qualifying attributes \*U. The principles of categorizing bearer services is presented in Figure\ 1/I.230. .RT .sp 1P .LP 2.1 \fICircuit\(hymode bearer service categories\fR .sp 9p .RT .PP These bearer service categories are typically characterized by the provision of user information over one type of channel and signalling over another type of channel. .PP The use of the channel which conveys signalling information also to provide user\(hyto\(hyuser information transfer is described in the user\(hyto\(hyuser signalling supplementary service as given in Recommendation\ I.257. .bp .RT .LP .rs .sp 25P .ad r \fBFigure 1/I.230 [T1.230], p. (\*`a traiter comme tableau MEP)\fR .sp 1P .RT .ad b .RT .PP .sp 1 The following circuit\(hymode bearer service categories have been identified so far: .RT .LP I.231.1 64\ kbit/s unrestricted, 8\ kHz structured .LP I.231.2 64\ kbit/s, 8\ kHz structured, usable for speech information transfer .LP I.231.3 64\ kbit/s, 8\ kHz structured, usable for\ 3.1\ kHz audio information transfer .LP I.231.4 Alternate speech | | 4\ kbit/s unrestricted, 8\ kHz structured .LP I.231.5 2\ \(mu\ 64\ kbit/s unrestricted, 8\ kHz structured .LP I.231.6 384\ kbit/s unrestricted, 8\ kHz structured .LP I.231.7 1536\ kbit/s unrestricted, 8\ kHz structured .LP I.231.8 1920\ kbit/s unrestricted, 8\ kHz structured .PP The prose descriptions (step\ 1.1) and static descriptions (step\ 1.2) of these services are given in Recommendation\ I.231. A common dynamic description (step\ 1.3) for\ I.231.1, I.231.2, and\ I.231.3 is given in Recommendation\ I.220 for demand services only. .sp 1P .LP 2.2 \fIPacket\(hymode bearer service categories\fR .sp 9p .RT .PP These bearer services involve packet handling functions. .PP The following packet\(hymode bearer service categories have been identified so far and are described in Recommendation\ I.232: .RT .LP I.232.1 Virtual call and permanent virtual circuit .LP I.232.2 Connectionless (Note) .LP I.232.3 User signalling (Note) .PP \fINote\fR \ \(em\ These services require further study and their descriptions are not yet included. .bp .sp 2P .LP \fB3\fR \fBRecommended provision of bearer services\fR .sp 1P .RT .PP In order to facilitate the development of compatible ISDNs and related user equipment, Recommendations\ I.231 and I.232 outline the recommended provision of bearer services defined in this Recommendation. This consists of three parts: .RT .LP a) description of the service category by the dominant attributes,\ i.e., information transfer mode, information transfer rate, type of information transfer capability and structure attributes. The recommended provision of services of the overall bearer service category is described as: .LP E an essential bearer service category to be made available internationally .LP A an additional bearer service category which may be available in some ISDNs and which may also be available internationally .LP FS the recommended provision of this bearer service category is for further study. .LP b) within each bearer service category, a description of the agreed secondary attributes,\ i.e. establishment of communication, symmetry and information transfer configuration attributes. If an ISDN supports the bearer service category, the recommended provision of these secondary attribute combinations within this category are described as: .LP E an essential combination of attributes to be made available internationally (when an ISDN supports the particular overall bearer service category). .LP A an additional combination of attributes which may be available in some ISDNs and which may also be available internationally (when an ISDN supports the particular overall bearer service category). .LP FS the recommended provision of this combination of attributes is for further study. .LP c) within each bearer service category a description of the agreed qualifying attributes, e.g.\ channel/rate and protocol access attributes for user information and for signalling OAM information. If an ISDN supports the bearer service category, the recommended provision of these qualifying attributes within this category are described as: .LP E an essential access arrangement to be made available (when an ISDN supports the particular overall bearer service category) .LP A an additional access arrangement which may be available in some ISDNs (when an ISDN supports the particular overall bearer service category) .LP FS the recommended provision of this access arrangement is for further study. .PP \fINote\ 1\fR \ \(em\ During an evolutionary period, not all items marked \*QE\*U will be provided in all networks. .PP \fINote\ 2\fR \ \(em\ Attributes 10\(hy13 are for further study. .PP The recommended overall provision of bearer service categories, as given in Recommendations\ I.231 and\ I.232, is summarized in Table\ 1/I.230. .RT .sp 2P .LP \fB4\fR \fBProse definitions of bearer service categories\fR .sp 1P .RT .PP In order to give an overview of the bearer service categories identified, their definitions as given in Recommendations\ I.231 and\ I.232 are reproduced in this section. .RT .sp 2P .LP 4.1 \fICircuit\(hymode bearer service categories\fR .sp 1P .RT .sp 1P .LP I.231.1 \fBCircuit\(hymode, 64\ kbit/s unrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .PP This bearer service category provides unrestricted information transfer between S/T reference points. It may, therefore, be used to support various user applications. Examples include: .RT .LP \(em speech; .LP \(em 3.1 kHz audio; .LP \(em multiple subrate information streams multiplexed into 64\ kbit/s by the user; .LP \(em transparent access to an\ X.25 public network [I.462\ case\ a)]. .PP User information is transferred over a B\(hychannel, signalling is provided over a D\(hychannel. .bp .ce \fBH.T. [T2.230]\fR .ce TABLE\ 1/I.230 .ce \fBRecommended overall provision of bearer service categories\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; lw(138p) | lw(30p) . { \fICircuit\(hymode bearer service categories\fR } .T& lw(138p) | cw(30p) . 1) 64 kbit/s unrestricted E .T& lw(138p) | cw(30p) . 2) Speech E .T& lw(138p) | cw(30p) . 3) 3.1 kHz audio E .T& lw(138p) | cw(30p) . { 4) Alternate speech | | 4 kbit/s unrestricted } A .T& lw(138p) | cw(30p) . { 5) 2 \(mu 64 kbit/s unrestricted } A .T& lw(138p) | cw(30p) . 6) 384 kbit/s unrestricted A .T& lw(138p) | cw(30p) . 7) 1536 kbit/s unrestricted A .T& lw(138p) | cw(30p) . 8) 1920 kbit/s unrestricted A .T& lw(138p) | cw(30p) . { \fIPacket\(hymode bearer service categories\fR } .T& lw(138p) | cw(30p) . { 1) Virtual call and permanent virtual circuit } E .T& lw(138p) | cw(30p) . 2) Connectionless FS .T& lw(138p) | cw(30p) . 3) User signalling FS _ .TE .nr PS 9 .RT .ad r \fBTable 1/I.230 [T2.230], p. \fR .sp 1P .RT .ad b .RT .sp 1P .LP .sp 6 I.231.2 \fBCircuit\(hymode 64\ kbit/s, 8\ kHz structured bearer service category usable for speech information transfer\fR .sp 9p .RT .PP This bearer service category is intended to support speech. .PP The digital signal at the S/T reference point shall conform to Recommendation\ G.711 (A\(hylaw\ or\ \(*m\(hylaw). The network may use processing techniques appropriate for speech such as analogue transmission, echo cancellation and low\(hybit rate voice encoding. Hence, bit integrity is not assured. This bearer service category is not intended to support modem derived voice\(hyband data. .PP All Recommendations for the transfer of speech information in the network apply to this bearer service category. .RT .sp 1P .LP I.231.3 \fBCircuit\(hymode 64\ kbit/s, 8\ kHz structured bearer service category usable for\ 3.1\ kHz audio information transfer\fR .sp 9p .RT .PP 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 suh as voice\(hyband data via modems and facsimile group\ 1, 2 and\ 3 information. The digital signal at the S/T reference point shall conform to Recommendation\ G.711 (A\(hylaw or\ \(*m\(hylaw). .bp .PP Connections provided for these services should offer the transfer capability for the information indicated above. (This means that the network may include speech processing techniques provided they are appropriately modified or functionally removed prior to non\(hyspeech information transfer.) The control of echo control devices, speech processing devices,\ etc., is only made by use of disabling tones (see Recommendation\ V.25). Bit integrity is not assured. The network may use analogue transmission. .PP All Recommendations for the transfer of speech information in the network apply to this bearer service category. .RT .sp 1P .LP I.231.4 \fBCircuit\(hymode, alternate speech/64\ kbit/s unrestricted, 8\ kHz\ structured bearer service category\fR .sp 9p .RT .PP This bearer service category provides the alternate transfer of either speech or 64\ kbit/s unrestricted digital information within the same call. .PP The request for this alternate capability and the intial mode desired by the user must be identified at call set\(hyup time. .PP This bearer service category is provided for the support of multiple capability terminals or single capability terminals. .PP 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. .RT .sp 1P .LP I.231.5 \fBCircuit\(hymode 2\ \(mu\ 64\ kbit/s unrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of two 64\ kbit/s user information flows over two B\(hychannels at the user network interface. .RT .sp 1P .LP I.231.6 \fBCircuit\(hymode 384 kbit/s unrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of 384\ kbit/s user information over a H\d0\uchannel at the S/T reference point. The transfer of OAM information for reserved and permanent services may be provided over a D\(hychannel in the same or in another interface structure. .RT .sp 1P .LP I.231.7 \fBCircuit\(hymode 1536 kbit/s unrestricted, 8 kHz structured bearer service category\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of 1536\ kbit/s user information over a H\d1\\d1\uchannel at the \fIS\fR /\fIT\fR reference point. The transfer of OAM information for reserved and permanent services may be provided via a D\(hychannel in another interface structure. .RT .sp 1P .LP I.231.8 \fBCircuit\(hymode 1920\ kbit/s unrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of 1920\ kbit/s user information over a H\d1\\d2\uchannel at the S/T reference point. The transfer of OAM information for reserved and permanent services may be provided over a D\(hychannel. .RT .sp 2P .LP 4.2 \fIPacket mode bearer service categories\fR .sp 1P .RT .sp 1P .LP I.232.1 \fBVirtual call and permanent virtual circuit bearer service category\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of user information in a packetized manner over a virtual circuit within a B\(hy\ or D\(hychannel at the S/T reference point. Signalling information for virtual call and/or possibly OAM information for permanent virtual circuit services are transferred via a D\(hy\ or B\(hychannel as described in Recommendation\ I.462\ (X.31). .RT .sp 1P .LP I.232.2 \fBConnectionless packet\(hybearer service category\fR .sp 9p .RT .PP The defintion of services in this bearer service category is for further study. .RT .sp 1P .LP I.232.3 \fBUser signalling bearer service category\fR .sp 9p .RT .PP The definition of services in this bearer service category is for further study. .bp .RT .sp 2P .LP \fBRecommendation\ I.231\fR .RT .sp 2P .sp 1P .ce 1000 \fBCIRCUIT\(hyMODE\ BEARER\ SERVICE\ CATEGORIES\fR .EF '% Fascicle\ III.7\ \(em\ Rec.\ I.231'' .OF '''Fascicle\ III.7\ \(em\ Rec.\ I.231 %' .ce 0 .sp 1P .ce 1000 \fI(Melbourne, 1988)\fR .sp 9p .RT .ce 0 .sp 1P .PP Recommendation I.210 describes the principles for defining telecommunication services supported by an ISDN including the concept of bearer services, teleservices and supplementary services. It also provides the means for the definition and description of such services. A recommended set of circuit\(hymode bearer services categories is defined in Recommendation I.230. .sp 1P .RT .PP The purpose of this Recommendation is to describe circuit\(hymode bearer service categories, to describe individual circuit\(hymode bearer services, and to recommend their provision in ISDN. The definitions and descriptions form the basis to define the network capabilities required for the support of the services in ISDN. .PP Bearer service categories are described by prose definitions and descriptions, by attributes and their values and by dynamic descriptions following the description method given in Recommendation I.130. The application of the attribute technique and the definitions of these attributes and attribute values is given in Recommendation I.140. .PP The following set of bearer service categories is currently identified and more may be identified in the future. .RT .LP I.231.1 Circuit\(hymode 64 kbit/s unrestricted, 8 kHz structured bearer service category .LP I.231.2 Circuit\(hymode 64 kbit/s, 8 kHz structured bearer service category usable for speech information transfer .LP I.231.3 Circuit\(hymode 64 kbit/s, 8 kHz structured bearer service category usable for 3.1 kHz audio information transfer .LP I.231.4 Circuit\(hymode, alternate speech / 64 kbit/s unrestricted, 8\ kHz structured bearer service category .LP I.231.5 Circuit\(hymode 2 \(mu 64 kbit/s unrestricted, 8 kHz structured bearer service category .LP I.231.6 Circuit\(hymode 384 kbit/s unrestricted, 8 kHz structured bearer service category .LP I.231.7 Circuit\(hymode 1536 kbit/s unrestricted, 8 kHz structured bearer service category .LP I.231.8 Circuit\(hymode 1920 kbit/s unrestricted, 8 kHz structured bearer service category .sp 2P .LP \fB1\fR I.231.1\ \(em \fBCircuit\(hymode 64 kbit/s unrestricted, 8 kHz\fR \fBstructured bearer service category\fR (Note 1) .sp 1P .RT .sp 1P .LP 1.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category provides unrestricted information transfer between SB/FT reference points, it may, therefore, be used to support various user applications. Examples include: .RT .LP \(em speech (Note 2); .LP \(em 3.1 kHz audio (Note 2); .LP \(em multiple subrate information streams multiplexed into 64\ kbit/s by the user; .LP \(em transparent access to an X.25 public network [Recommendation\ I.462 case\ a)]. .PP User information is transferred over a B\(hychannel, signalling is provided over a D\(hychannel. .PP \fINote 1\fR \ \(em\ During an interim period some networks may only support restricted 64\ kbit/s digital information transfer capability, i.e.\ information transfer capability solely restricted by the requirement that the all\(hyzero octet is not allowed. For interworking the rules given in Appendix\ I of Recommendation\ I.520 should apply. The interworking functions have to be provided in the network with restricted 64 kbit/s capability. The ISDN with 64\ kbit/s transfer capabilities will not be affected by this interworking other than by conveying the appropriate signalling message to and from the ISDN terminal. .bp .PP \fINote 2\fR \ \(em\ Whilst speech and 3.1 kHz audio have been given as applications for this bearer service category, it is recognized that it is the responsibility of the customers to ensure that a compatible encoding scheme is in operation. Customers should also recognize that no network provision 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. .RT .sp 2P .LP 1.2\fR \fIDescription\fR .sp 1P .RT .sp 1P .LP 1.2.1 \fIGeneral description\fR .sp 9p .RT .PP This circuit\(hymode bearer service category allows: .RT .LP \(em two users (e.g. terminals, PABXs) in a point\(hyto\(hypoint configuration to communicate via the ISDN using 64 kbit/s digital signals over the B\(hychannel, in both directions continuously and simultaneously for the duration of call; .LP \(em three or more users in a multipoint configuration (refer to Recommendation I.254 for the supplementary service description on Three\(hyParty Service and Conference Calling). .sp 1P .LP 1.2.2 \fISpecific terminology\fR .sp 9p .RT .PP Retention timer : this timer specifies the amount of time that the network retains the call information of the original call upon encountering busy or being released. It is a network provider option. The value for this timer is greater than 15 seconds. .RT .sp 2P .LP 1.3 \fIProcedures\fR .sp 1P .RT .sp 1P .LP 1.3.1 \fIProvision/withdrawal\fR .sp 9p .RT .PP 1.3.1.1 Provision of this service will be by pre\(hyarrangement with the Administration. .sp 9p .RT .PP 1.3.1.2 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 summarized below: .LP .sp 1 \fISubscription option\fR \fIValue\fR Maximum number of information channels available at user B \(em\ \fIm\fR , | where \fIm\fR is not greater than the number of information channels on the interface Maximum number of total calls present at user B \(em \fIn\fR , | where \fIn\fR is not greater than the number of information channels on the interface .PP User B can be an ISDN number or group of ISDN numbers on the interface. .PP \fINote\fR \ \(em\ More than one ISDN number can be associated with the serviceB/Finterface only as a part of a supplementary service such 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 incoming and for outgoing calls for either or both of the limits. .RT .sp 1P .LP 1.3.2 \fINormal procedures\fR .sp 9p .RT .PP All user\(hynetwork signalling is done on the D\(hychannel. .RT .LP a) \fIOriginating the service (call set\(hyup)\fR .LP The call is originated by the user requesting from the network the required bearer service; the request includes a number identifying the called user. Other information, as required, for the bearer service and for use by the network in supplementary services provided to the called user (e.g.\ calling line identity) may also be included. This request may be given to the network either \fIen\ bloc\fR , containing all the required information, or not \fIen\ bloc\fR . .bp .LP b) Indications during call set\(hyup .LP After initiating a call the calling user will receive an acknowledgement that the network is able to process the call. The called user will receive an indication of the arrival of an incoming call of this bearer service. .LP 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 this call. When the call reaches the called user and the connection is established, an indication of this is sent to the calling user. .LP 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 relationship of a connected user with the called user requires further study. .LP Once established, the B\(hychannel 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 network on the content of the digital signals (see Note\ 1 of \(sc\ 1.1). .LP c) \fITerminating the call\fR .LP 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. .sp 1P .LP 1.3.3 \fIExceptional procedures\fR .sp 9p .RT .LP a) \fIFailure situations due to user error\fR .LP i) A user inputting a network\(hyidentifiable, improper service request will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP ii) A user inputting a non\(hyvalid network number will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP b) \fIFailure situations due to called user state\fR .LP i) A calling user attempting to establish a call to a user who is identified by the network to be busy (either network\(hydetermined user busy or user\(hydetermined user busy) will be given an appropriate failure indication by the network. .LP ii) A user attempting to establish a call to a user whose terminal equipment fails to respond will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP 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 answer 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\(hyup will be ceased. .LP c) \fIFailure situations due to network conditions\fR .LP 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. .LP d) \fIFailure situations due to called user state and/or\fR \fInetwork conditions\fR .LP A user attempting to establish a call but meeting call failure situations due to network conditions (e.g.\ congestion) or called user state (e.g.\ busy) can have service data retained for a specified period of time, i.e.\ retention timer. .sp 2P .LP 1.3.4 \fIAlternative procedures\fR .sp 1P .RT .sp 1P .LP 1.3.4.1 \fIReserved service procedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 1.3.4.2 \fIPermanent service procedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 1.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .bp .RT .sp 1P .LP 1.4.1 \fIDemand service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the demand service. .RT .sp 1P .LP 1.4.2 \fIReserved service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the reserved service. .RT .sp 1P .LP 1.4.3 \fIPermanent service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the permanent service. .RT .sp 1P .LP 1.5 \fIInterworking requirements\fR .sp 9p .RT .PP Interworking between the ISDN and networks referred to as \*Qdigital PSTNs\*U, pre\(hyISDNs, pilot ISDNs or extended IDNs as well as between the ISDN and PSTNs may be required for this bearer service category. .PP In advance of the provision of the ISDN, similar services supported by 64 kbit/s connectivity will be available to customers by RPOAs/network operators on what may be described as \*Qdigital PSTNs\*U, pre ISDNs, pilot ISDNs or extended IDNs. Interworking with ISDN customers will therefore be required. To effect this, as a broad guideline, RPOAs/network operators need to ensure these networks have the necessary functionality at the interworking point to provide service connectivity with the ISDN. .PP A V\(hySeries terminal connected to the ISDN via a terminal adaptor and using the 64 kbitB/Fs unrestricted bearer service requires the use of an IWF (including a modem) in the network for calls to PSTN users. To effect the connection, a 64 kbitB/Fs connection would need to be used to the IWF (interworking function) and a 3.1\ kHz audio or equivalent connection would then need to be used to the PSTN user. .RT .sp 1P .LP 1.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP Not applicable. Each supplementary service description identifies the applicability to this bearer service category. .RT .sp 1P .LP 1.7 \fIAttributes and values of attributes of the circuit\(hymode\fR \fI64 kbit/s unrestricted, 8 kHz structured bearer service category\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP 2. Information\ transfer\ rate: 64 kbit/s .LP 3. Information\ transfer\ capability: unrestricted .LP \fR 4. Structure: 8 kHz integrity .LP \fR 5. Establishment\ of\ communication: demand/reserved/permanent .LP \fR 6. Symmetry: bidirectional symmetric/unidirectional .LP \fR 7. Communication\ configuration: point\(hyto\(hypoint/multipoint .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: B for user information, .LP D for signalling (Note) .LP 9. Access\ protocol: I\(hySeries for D\(hychannel .sp 1P .LP \fIGeneral attributes\fR .sp 9p .RT .LP 10. Supplementary services provided \(em\ Refer to Recommendation\ I.250 .LP 11. Quality of Service ?04 12. Interworking possibilities ?05\ for further study 13. Operational and commercial aspects \(rb .PP \fINote\fR \ \(em\ For reservedB/Fpermanent service the operational administrative and maintenance (OAM) messages related to these services may be conveyed over the D\(hychannel. .bp .sp 1P .LP 1.8 \fIProvision of individual circuit\(hymode 64\ kbit/s unrestricted,\fR \fI8\ kHz structured bearer services\fR \v'3p' .sp 9p .RT .LP The definition of E (essential) and A (additional) can be found in Recommendation\ I.230 .FE a) Overall provision : | E .LP b) Variations of secondary attributes: .sp 2P .LP \fIEstablishment\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIconfiguration\fR \fIProvision\fR .sp 1P .RT .sp 1P .LP I.231.1/1 demand pt\(hypt E .sp 9p .RT .LP I.231.1/2 reserved bidirectional pt\(hypt A .LP I.231.1/3 permanent pt\(hypt E .LP I.231.1/4 demand pt\(hypt A .LP I.231.1/5 reserved unidirectional pt\(hypt A .LP I.231.1/6 permanent pt\(hypt A .LP I.231.1/7 demand multipt A .LP I.231.1/8 reserved bidirectional multipt A .LP I.231.1/9 permanent multipt A .LP I.231.1/10 demand multipt A .LP I.231.1/11 reserved unidirectional multipt A .LP I.231.1/12 permanent multipt A .sp 1P .LP c) Access .sp 9p .RT .ce \fBH.T. [T1.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTable [T1.231], p.\fR .sp 1P .RT .ad b .RT .sp 1P .LP .sp 4 1.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service on a demand basis is identical for a number of circuit\(hymode services and is therefore collectively given in Recommentation\ I.220. .RT .LP .sp 1 .bp .sp 2P .LP \fB2\fR I.231.2\ \(em \fBCircuit\(hymode 64 kbit/s, 8 kHz structured bearer\fR \fBservice category usable for speech information transfer\fR .sp 1P .RT .sp 1P .LP \fR 2.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category is intended to support speech. .PP The digital signal at the S/T reference point shall conform to Recommendation G.711 (A\(hylaw or \(*m\(hylaw). The network may use processing techniques appropriate for speech such as analogue transmission, echo cancellation and low bit\(hyrate voice encoding. Hence, bit integrity is not assured. This bearer service is not intended to support modem derived voice\(hyband data. .PP All Recommendations for the transfer of speech information in the network apply to this bearer service category. .RT .sp 2P .LP 2.2 \fIDescription\fR .sp 1P .RT .sp 1P .LP 2.2.1 \fIGeneral description\fR .sp 9p .RT .PP This circuit\(hymode bearer service category allows: .RT .LP \(em two users (e.g.\ terminals, PABXs) in a point\(hyto\(hypoint configuration to communicate via the ISDN using speech encoding into 64 kbitB/Fs digital signals over the B\(hychannel, in both directions continuously and simultaneously for the duration of a call; .LP \(em three or more users in a multipoint configuration (refer to Recommendation I.254 for the supplementary service description for Three\(hyParty Service and Conference Calling). .PP Tones andB/For announcements to indicate the progress or otherwise of a call, are provided by the network. .sp 1P .LP 2.2.2 \fISpecific terminology\fR .sp 9p .RT .PP Retention timer: this timer specifies the amount of time that the network retains the call information of the original call upon encountering busy or being released. It is a network provider option. The value for this timer is greater than 15 seconds. .RT .sp 2P .LP 2.3 \fIProcedures\fR .sp 1P .RT .sp 1P .LP 2.3.1 \fIProvision/withdrawal\fR .sp 9p .RT .PP 2.3.1.1 Provision of this service will be by pre\(hyarrangement with the Administration. .sp 9p .RT .PP 2.3.1.2 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 summarized below: .LP .sp 1 \fISubscription option\fR \fIValue\fR Maximum number of information channels available at user B \(em\ \fIm\fR , | where \fIm\fR is not greater than the number of information channels on the interface Maximum number of total calls present at user B \(em \fIn\fR , | where \fIn\fR is not greater than the number of information channels on the interface .PP User B can be an ISDN number or group of ISDN numbers on the interface. .bp .PP \fINote\fR \ \(em\ More than one ISDN number can be associated with the serviceB/Finterface only as a part of a supplementary service such 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 incoming and for outgoing calls for either or both of the limits. .RT .sp 1P .LP 2.3.2 \fINormal procedures\fR .sp 9p .RT .PP Out\(hyof\(hyband messages shall always be provided to indicate call progress, etc. However, network\(hygenerated in\(hyband tones and announcements shall always be provided for this bearer service category. .RT .LP a) \fIOriginating the service (call set\(hyup)\fR .LP The call is originated by the user requesting the required bearer service; the request includes a number identifying the called user. Other .LP information, as required, for the bearer service and for use by the network in supplementary services provided to the called user (e.g.\ calling line identity) may also be included. This request may be given to the network either \fIen\ bloc\fR , containing all the required information, or not \fIen\ bloc\fR . .LP b) Indications during call set\(hyup .LP All indications entail signalling messages and shall include, where appropriate, in\(hyband tones or announcements. .LP After initiating a call the calling user will receive an acknowledgement that the network is able to process the call. The called user will receive an indication of the arrival of an incoming call of this bearer service. .LP 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 this call. When the call reaches the called user and the connection is established, an indication of this is sent to the calling user. .LP 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 relationship of a connected user with a called user requires further study. .LP Once established, the B\(hychannel is then available for the transmission of speech signals in both directions continuously and simultaneously .LP c) Terminating the call .LP 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. .sp 1P .LP 2.3.3 \fIExceptional procedures\fR .sp 9p .RT .LP a) \fIFailure situations due to user error\fR .LP i) A user inputting a network\(hyidentifiable, improper service request will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP ii) A user inputting a non\(hyvalid network number will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP b) \fIFailure situations due to called user state\fR .LP i) A calling user attempting to establish a call to a user who is identified by the network to be busy (either network\(hydetermined user busy or user\(hydetermined user busy) will be given an appropriate failure indication by the network. .LP ii) A user attempting to establish a call to a user whose terminal equipment fails to respond will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP 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 answer 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\(hyset up will be ceased. .bp .LP c) \fIFailure situations due to network conditions\fR .LP 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. .LP d) \fIFailure situations due to called user state andB/For network\fR \fIconditions\fR .LP A user attempting to establish a call but meeting call failure situations due to network conditions (e.g.\ congestion) or called user state (e.g.\ busy) can have service data retained for a specified period of time, i.e.\ retention timer. .sp 2P .LP 2.3.4 \fIAlternative procedures\fR .sp 1P .RT .sp 1P .LP 2.3.4.1 \fIReserved service procedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 2.3.4.2 \fIPermanent service procedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 2.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .RT .sp 1P .LP 2.4.1 \fIDemand service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the demand service. .RT .sp 1P .LP 2.4.2 \fIReserved service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the reserved service. .RT .sp 1P .LP 2.4.3 \fIPermanent service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the permanent service. .RT .sp 1P .LP 2.5 \fIInterworking requirements\fR .sp 9p .RT .PP Interworking is required between the ISDN and the PSTN for this bearer service category. .RT .sp 1P .LP 2.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP Not applicable. Each supplementary service description indentifies the applicability with this bearer service category. .RT .sp 1P .LP 2.7 \fIAttributes and values of attributes of the circuit\(hymode\fR \fI64 kbit/s, 8\ kHz structured bearer service category usable for speech\fR \fIinformation transfer\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP 2. Information\ transfer\ rate: 64 kbit/s .LP \fR 3. Information\ transfer\ capability: speech (encoded\fR according to Recommendation\ G.711 A\(hylaw, \(*m\(hylaw) (Note 1) .LP \fR 4. Structure: 8 kHz integrity .LP \fR 5. Establishment\ of\ communication: demand/reserved/permanent .LP 6. Symmetry: bidirectional symmetric/unidirectional .LP \fR 7. Communication\ configuration: point\(hyto\(hypoint/multipoint .sp 1P .LP \fR \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: B for user information, .LP D for signalling (Note 2) .LP 9. Access\ protocol: I\(hySeries for D\(hychannel,\fR Rec.\ G.711 for B\(hychannel .bp .LP \fIGeneral attributes\fR .LP 10. Supplementary services provided \(em\ Refer to Recommendation\ I.250 .LP 11. Quality of Service .LP 12. Interworking possibilities .LP 13. Operation and commercial aspects .LP \-v'2P' \-v'1p' \ for further study (may be .LP \ different from I.231.1) \v'5p' .PP \fINote 1\fR \ \(em\ When crossing an international boundary between Administrations which employ different encoding laws, the network shall perform the necessary A\(hy\(*m\ law conversion (see Recommendation\ G.711). .PP \fINote 2\fR \ \(em\ For reservedB/Fpermanent service the operational administrative and maintenance (OAM) messages related to these services may be conveyed over the D\(hychannel. .RT .sp 1P .LP 2.8 \fIProvision of individual circuit\(hymode 64\ kbit/s, 8\ kHz\fR \fIstructured bearer services usable for speech information transfer\fR \v'3p' .sp 9p .RT .LP a) Overall provision : | E .LP \fINote\fR \ \(em\ Some networks will offer this service in a manner identical to the 3.1\ kHz audio service. .LP b) Variations of secondary attributes: .sp 2P .LP \fIEstablishment\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .RT .sp 1P .LP I.231.2/1 demand pt\(hypt E .sp 9p .RT .LP I.231.2/2 reserved bidirectional pt\(hypt A .LP I.231.2/3 permanent pt\(hypt E .LP I.231.2/4 demand pt\(hypt A .LP I.231.2/5 reserved unidirectional pt\(hypt A .LP I.231.2/6 permanent pt\(hypt A .LP I.231.2/7 demand multipt A .LP I.231.2/8 reserved bidirectional multipt A .LP I.231.2/9 permanent multipt A .LP I.231.2/10 demand multipt A .LP I.231.2/11 reserved unidirectional multipt A .LP I.231.2/12 permanent multipt A .sp 1P .LP c) Access .sp 9p .RT .ce \fBH.T. [T2.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTable [T2.231], p.\fR .sp 1P .RT .ad b .RT .LP .bp .sp 1P .LP 2.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service on a demand basis is identical for a number of circuit mode services and is therefore collectively given in Recommentation I.220. .RT .sp 2P .LP \fB3\fR I.231.3\ \(em \fBCircuit\(hymode 64 kbit/s, 8\ kHz structured bearer\fR \fBservice category usable for 3.1\ kHz audio information transfer\fR .sp 1P .RT .sp 1P .LP 3.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category corresponds to the service which is currently offered in the PSTN. It provides for the transfer of speech and of 3.1\ kHz bandwidth audio information such as voice\(hyband data via modems and facsimile group 1, 2 and 3 information (Note). The digital signal at the S/T reference point shall conform to Recommendation G.711 (A\(hylaw or \(*m\(hylaw). .PP Connections provided for these services should offer the transfer capability for the information indicated above. (This means that the network may include speech processing techniques provided they are appropriately modified or functionally removed prior to non\(hyspeech information transfer.) The control of echo control devices, speech processing devices, etc., is only made by use of disabling tones (see Recommendation V.25). Bit integrity is not assured. The network may use analogue transmission. .PP All Recommendations for the transfer of speech information in the network apply to this bearer service category. .PP \fINote\fR \ \(em\ The maximum modem bit rate that can be used by users in applications of this bearer service category depends on the modulation standard employed by the user and on the transmission performance within an Administration or between different Administrations. The extent of support is a matter concerning the network or agreed to bilaterally. .RT .sp 2P .LP 3.2 \fIDescription\fR .sp 1P .RT .sp 1P .LP 3.2.1 \fIGeneral description\fR .sp 9p .RT .PP This circuit\(hymode bearer service category allows: .RT .LP \(em two users (e.g.\ terminals, PABXs) in a point\(hyto\(hypoint configuration to communicate via the ISDN using 3.1 kHz audio information encoding into 64 kbitB/Fs digital signals over the B\(hychannel, in both directions continuously and simultaneously for the duration of a call; .LP \(em three or more users in a multipoint configuration (refer to Recommendation I.254 for the supplementary service descriptions on Three\(hyparty Service and Conference Calling). .PP Tones andB/For announcements to indicate the progress or otherwise of a call, are provided by the network. .sp 1P .LP 3.2.2 \fISpecific terminology\fR .sp 9p .RT .PP Retention timer: this timer specifies the amount of time that the network retains the call information of the original call upon encountering busy or being released. It is a network provider option. The value for this timer is greater than 15 seconds. .RT .sp 2P .LP 3.3 \fIProcedures\fR .sp 1P .RT .sp 1P .LP 3.3.1 \fIProvisionB/Fwithdrawal\fR .sp 9p .RT .PP 3.3.1.1 Provision of this service will be by pre\(hyarrangement with the Administration. .bp .sp 9p .RT .PP 3.3.1.2 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 summarized below: .LP .sp 1 \fISubscription option\fR \fIValue\fR Maximum number of information channels available at user B \(em\ \fIm\fR , | where \fIm\fR is not greater than the number of information channels on the interface Maximum number of total calls present at user B \(em \fIn\fR , | where \fIn\fR is not greater than the number of information channels on the interface .PP User B can be an ISDN number or group of ISDN numbers on the interface. .PP \fINote\fR \ \(em\ More than one ISDN number can be associated with the serviceB/Finterface only as a part of a supplementary service such 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 incoming and for outgoing calls for either or both of the limits. .RT .sp 1P .LP 3.3.2 \fINormal procedures\fR .sp 9p .RT .PP Out\(hyof\(hyband messages shall always be provided to indicate call progress,\ etc. However, network\(hygenerated in\(hyband tones and announcements shall always be provided for this bearer service. .RT .LP a) \fIOriginating the service (call set\(hyup)\fR .LP The call is originated by the user requesting the required bearer service; the request includes a number identifying the called user. Other information, as required, for the bearer service and for use by the network in supplementary services provided to the called user (e.g.\ calling line identity) may also be included.\fR This request may be given to the network either \fIen\ bloc\fR , containing all the required information, or not \fIen\ bloc\fR . .LP b) \fIIndications during call set\(hyup\fR .LP All indications entail signalling messages and may also include in\(hyband tones or announcements. .LP After initiating a call the calling user will receive an acknowledgement that the network is able to process the call. The called user will receive an indication of the arrival of an incoming call of this bearer service. .LP 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 this call. When the call reaches the called user and the connection is established, an indication of this is sent to the calling user. .LP 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 relationship of a connected user with a called user requires further study. .LP Once established, the B\(hychannel is then available for the transmission of the requested (i.e.\ speech or 3.1\ kHz audio information) signals in both directions continuously and simultaneously. .LP c) \fITerminating the call\fR .LP 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. .bp .sp 1P .LP 3.3.3 \fIExceptional procedures\fR .sp 9p .RT .LP a) \fIFailure situations due to user error\fR .LP i) A user inputting a network\(hyidentifiable, improper service request will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP ii) A user inputting a non\(hyvalid network number will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP b) \fIFailure situations due to called user state\fR .LP i) A calling user attempting to establish a call to a user who is identified by the network to be busy (either network\(hydetermined user busy or user\(hydetermined user busy) will be given an appropriate failure indication by the network. .LP ii) A user attempting to establish a call to a user whose terminal equipment fails to respond will be given an appropriate failure indication by the network and the call set\(hyup will be ceased. .LP 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 answer 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\(hyup will be ceased. .LP c) \fIFailure situations due to network conditions\fR .LP 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. .LP d) \fIFailure situations due to called user state andB/For\fR \fInetwork conditions\fR .LP A user attempting to establish a call but meeting call failure situations due to network conditions (e.g.,\ congestion) or called user state (e.g.\ busy) can have service data retained for a specified period of time, i.e.\ retention timer. .sp 2P .LP 3.3.4 \fIAlternative procedures\fR .sp 1P .RT .sp 1P .LP 3.3.4.1 \fIReserved service procedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 3.3.4.2 \fIPermanent service procedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 3.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .RT .sp 1P .LP 3.4.1 \fIDemand service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the demand service. .RT .sp 1P .LP 3.4.2 \fIReserved service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the reserved service. .RT .sp 1P .LP 3.4.3 \fIPermanent service charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the permanent service. .RT .sp 1P .LP 3.5 \fIInterworking requirements\fR .sp 9p .RT .PP Interworking is required between the ISDN and the PSTN for this bearer service category. .bp .RT .sp 1P .LP 3.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP Not applicable. Each supplementary service description identifies the applicability to this bearer service category. .RT .sp 1P .LP 3.7 \fIAttributes and values of attributes of the circuit\(hymode\fR \fI64\ kbit/s, 8 kHz structured bearer service category usable for 3.1\ kHz audio\fR \fIinformation transfer\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP \fR 2. Information\ transfer\ rate: 64 kbit/s .LP \fR 3. Information\ transfer\ capability: 3.1 kHz audio (Note) .LP 4. Structure: 8 kHz integrity .LP \fR 5. Establishment\ of\ communication: demand/reserved/permanent .LP \fR 6. Symmetry: bidirectional symmetric/unidirectional .LP 7. Communication\ configuration: point\(hyto\(hypointB/Fmultipoint .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: B for user information,\fR \fR D\ for signalling and/or operational, administrative and maintenance (OAM) messages .LP 9. Access\ protocol: Recommendation G.711 for B\(hychannel, I\(hySeries for D\(hychannel .LP \fIGeneral attributes\fR .LP 10. Supplementary services provided \(em\ Refer to Recommendation\ I.250 .LP 11. Quality of Service ?04 12. Interworking possibilities ?05\ for further study 13. Operation and commercial aspects \(rb .PP \fINote\fR \ \(em\ When crossing an international boundary between Administrations which employ different encoding laws the network shall perform the necessary A\(hy\(*m\ law conversion (see Recommendation G.711). .sp 1P .LP 3.8 \fIProvision of individual circuit\(hymode 64\ kbitB/Fs, 8\ kHz structured\fR \fIbearer services usable for 3.1 kHz audio information transfer\fR \v'3p' .sp 9p .RT .LP a) Overall provision : | E .LP b) Variations of secondary attributes: .sp 2P .LP \fIEstablishment\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .RT .sp 1P .LP I.231.3/1 demand pt\(hypt E .sp 9p .RT .LP I.231.3/2 reserved bidirectional pt\(hypt A .LP I.231.3/3 permanent pt\(hypt E .LP I.231.3/4 demand pt\(hypt A .LP I.231.3/5 reserved unidirectional pt\(hypt A .LP I.231.3/6 permanent pt\(hypt A .LP I.231.3/7 demand multipt A .LP I.231.3/8 reserved bidirectional multipt A .LP I.231.3/9 permanent multipt A .LP I.231.3/10 demand multipt A .LP I.231.3/11 reserved unidirectional multipt A .LP I.231.3/12 permanent multipt A .bp .sp 1P .LP c) Access .sp 9p .RT .LP .sp 2 .ce \fBH.T. [T3.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTableau [T3.231], p.\fR .sp 1P .RT .ad b .RT .sp 1P .LP .sp 2 3.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service on a demand basis is identical for a number of circuit mode services and is therefore collectively given in Recommendation\ I.220. .RT .sp 2P .LP \fB4\fR I.231.4\ \(em \fBCircuit\(hymode, alternate speech / 64\ kbit/s\fR \fBunrestricted, 8\ kHz structured bearer service category\fR .sp 1P .RT .sp 1P .LP 4.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category provides the alternate transfer of speech or 64\ kbit/s unrestricted digital information within the same call. .PP The request for this alternate capability and the initial mode desired by the user must be identified at call set\(hyup time. .PP This bearer service category is provided for the support of multiple capability terminals or single capability terminals (Note\ 1). .PP For the speech mode of this bearer service category, 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 (Note\ 2) bearer service category. .PP \fINote 1\fR \ \(em\ Initially, this service will only be applicable to multiple capability terminals. The use of this service by, and the network support of, single capability terminals is for further study, (e.g.\ how does a user change terminals). All references to single capability terminals reflect possible future enhancements and are subject to change and have only been included for information. .PP \fINote 2\fR \ \(em\ During an interim period some networks may only support restricted 64\ kbit/s digital information transfer capability, i.e.\ information transfer capability solely restricted by the requirement that the all\(hyzero octet is not allowed. For interworking, the rules given in the Appendix\ I of Recommendation\ I.520 should apply. The interworking functions have to be provided in the network with restricted capability. The ISDN with 64\ kbit/s transfer capabilities will not be affected by this interworking, other than by conveying the appropriate signalling message to or from the ISDN terminal. .bp .RT .sp 2P .LP 4.2. \fIDescription\fR .sp 1P .RT .sp 1P .LP 4.2.1 \fIGeneral description\fR .sp 9p .RT .PP Once the connection is established, the user may repeatedly request via appropriate signalling messages, to alternate from speech mode to 64\ kbit/s unrestricted digital mode, or vice versa. The in\(hycall modification shall be provided on a per call basis. .RT .sp 1P .LP 4.2.2 \fISpecific terminology\fR .sp 9p .RT .PP None identified. .RT .sp 1P .LP 4.2.3 \fIQualifications on the applicability to telecommunications\fR \fIservices\fR .sp 9p .RT .PP None identified. .RT .sp 2P .LP 4.3 \fIProcedures\fR .sp 1P .RT .sp 1P .LP 4.3.1 \fIProvision/withdrawal\fR .sp 9p .RT .PP This service shall be provided by pre\(hyarrangement with the Administration. .RT .sp 2P .LP 4.3.2 \fINormal procedures\fR .sp 1P .RT .sp 1P .LP 4.3.2.1 \fIActivationB/FdeactivationB/Fregistration\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 4.3.2.2 \fIInvocation and operation\fR .sp 9p .RT .PP At the start of the call the request for an alternate speech/64\ kbit/s unrestricted call and the initial mode of either speech or 64\ kbit/s unrestricted call must be identified. Following call set\(hyup, the calling or called party may choose to modify the characteristics of the call during the conversationB/Fdata phase. During call establishment, the network shall choose a suitable route according to the information included in the set\(hyup message. .PP Depending on the terminal capability type the following procedures will apply: .RT .LP a) For multiple capability terminals the requesting user will send an \fIinvoke in\(hycall modification request\fR to the network. .LP b) For single capability terminals the requesting user will change over the connection from the first terminal to the second terminal before sending an \fIinvoke in\(hycall modification request\fR to the network. .PP The network will, on receipt of the \fIin\(hycall modification\fR \fIrequest\fR from the callingB/Fcalled party, check if that call modification is allowed and if the necessary resources are available. .PP If acceptable, the resources are reserved and an \fIinvoke in\(hycall\fR \fImodification request\fR is sent to the distant end. A timer will be started to supervise that the in\(hycall modification is received successfully. .PP Depending on the terminal configuration at the destination end, the procedures will be the following: .RT .LP a) For multiple capability terminals the distant user, if agreeing with the service changeover, will transmit a \fIreturn result\fR \fIindication\fR while the resources in the network are switched in, if reserved previously and the \fIcall modification indication\fR will be sent to the initiating party. .LP b) For single capability terminals a call changeover will be performed from the first terminal to the second terminal. An \fIin\(hycall\fR \fImodification return result\fR will be sent to the network which will switch in the resources, if reserved previously. .bp .sp 2P .LP 4.3.3 \fIExceptional procedures\fR .sp 1P .RT .sp 1P .LP 4.3.3.1 \fIActivationB/FdeactivationB/Fregistration\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 4.3.3.2 \fIInvocation and operation\fR .sp 9p .RT .PP If the network fails to change resources on receipt of the \fIin\(hycall modification return result\fR , the connection will be cleared with a cause indication \*Qtemporary failure\*U. .PP If on receipt of a \fIcall modification invocation request\fR an exchange determines that in\(hycall modification is not allowed or not possible a \fIcall modification return error indication\fR will be sent. Receipt of the \fIcall modification return error indication\fR will cause the reserved resources to be freed and a \fIcall modification return error indication\fR to be delivered to the initiating party. .PP In case of in\(hycall modification failure, the initiating terminal after having received the \fIin\(hycall modification return error indication\fR , will resume to transmit and receive the bit stream for the previous service. .RT .sp 1P .LP 4.3.4 \fIAlternative procedures\fR .sp 9p .RT .PP None identified. .RT .sp 1P .LP 4.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .PP It shall be possible to charge the subscriber accurately for the service. .RT .sp 1P .LP 4.5 \fIInterworking requirements\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 4.6 \fIInteractions with supplementary services\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 4.7 \fIAttributes and values of attributes of the circuit\(hymode, alternate\fR \fIspeech | | 4\ kbit/s unrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP \fR 2. Information\ transfer\ rate: 64 kbit/s .LP \fR 3. Information\ transfer\ capability: alternately speech (Note 1) or unrestricted digital information .LP 4. Structure: 8 kHz integrity .LP \fR 5. Establishment\ of\ communication: demand/reserved/permanent .LP \fR 6. Symmetry: bidirectional symmetric/unidirectional .LP \fR 7. Communication\ configuration: point\(hyto\(hypoint/multipoint .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: B for user information, .LP D for signalling (Note 2) .LP 9. Access\ protocol: I\(hySeries for D\(hychannel .sp 1P .LP \fIGeneral attributes\fR .sp 9p .RT .LP 10. Supplementary services provided .LP 11. Quality of Service (Note 3) .LP 12. Interworking possibilities \ for further study .LP 13. Operation and commercial aspects .bp .PP \fINote 1\fR \ \(em\ When crossing an international boundary between Administrations which employ different encoding laws, the network shall perform the necessary A\(hy\(*m law conversion (see Recommendation G.711). .PP \fINote 2\fR \ \(em\ For reservedB/Fpermanent service the operational, administrative and maintenance (OAM) messages related to these services may be conveyed over the\fR D\(hychannel. .PP \fINote 3\fR \ \(em\ A short service changeover time (with a high probability of not being exceeded) has been tentatively identified as a requirement. .RT .sp 1P .LP 4.8 \fIProvision of individual circuit\fR \fImode, alternate speech/64\ kbit/s unrestricted, 8\ kHz structured bearer\fR \fIservices\fR .sp 9p .RT .sp 1P .LP a) Overall provision : | A .sp 9p .RT .LP \fINote\fR \ \(em\ Some networks will offer the speech phase of these services in a manner identical to the 3.1\ kHz audio service. .sp 1P .LP b) Variations of secondary attributes: .sp 9p .RT .LP .sp 1 .sp 2P .LP \fIEstablishment\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .RT .sp 1P .LP I.231.4/1 demand pt\(hypt E .sp 9p .RT .LP I.231.4/2 reserved pt\(hypt A .LP I.231.4/3 permanent pt\(hypt E .LP bidirectional .LP I.231.4/4 demand multipt A .LP I.231.4/5 reserved multipt A .LP I.231.4/6 permanent multipt A .sp 1P .LP c) Access .sp 9p .RT .ce \fBH.T. [T4.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTable [T4.231], p.\fR .sp 1P .RT .ad b .RT .LP .sp 2 .bp .sp 1P .LP 4.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service needs further study and is not yet available. .RT .sp 2P .LP \fB5\fR I.231.5\ \(em \fBCircuit\(hymode 2 \(mu 64 kbit/s unrestricted,\fR \fB8\ kHz structured bearer service category\fR .sp 1P .RT .sp 1P .LP 5.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of two 64\ kbitB/Fs user information flows over two B\(hychannels at the user network interface. .RT .sp 1P .LP 5.2 \fIDescription\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 5.3 \fIProcedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 5.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .PP It shall be possible to charge the subscriber accurately for the service. .RT .sp 1P .LP 5.5 \fIInterworking requirements\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 5.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 5.7 \fIAttributes and values of attributes of the circuit mode\fR \fI2\ \(mu\ 64\ kbit/s unrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP 2. Information\ transfer\ rate: 2 \(mu 64 kbit/s .LP 3. Information\ transfer\ capability: unrestricted (Note) .LP 4. Structure: 8 kHz integrity with restricted differential time delay (RDTD) .LP 5. Establishment\ of\ communication: demand/reserved/permanent .LP 6. Symmetry: bidirectional symmetric/bidirectional asymmetric/unidirectional .LP \fR 7. Communication\ configuration: point\(hyto\(hypoint/multipoint .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: two B(64) for user information .LP 9. Access\ protocol: I\(hySeries for D\(hychannel .sp 1P .LP \fIGeneral attributes\fR .sp 9p .RT .LP 10. Supplementary services provided .LP 11. Quality of Service .LP 12. Interworking possibilities \ for further study .LP 13. Operation and commercial aspects .PP \fINote\fR \ \(em\ Digit sequence integrity (DSI) is ensured for each elementary 64\ kbit/s information. .bp .sp 1P .LP 5.8 \fIProvision for individual circuit\(hymode 2 \(mu 64\ kbitB/Fs, unrestricted,\fR \fI8\ kHz structured bearer services\fR .sp 9p .RT .sp 1P .LP a) Overall provision : | A .sp 9p .RT .sp 1P .LP b) Variations of secondary attributes : .sp 9p .RT .LP .sp 1 .LP \fIEtablishment \fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .LP I.231.5/1 demand pt\(hypt E .sp 9p .RT .LP I.231.5/2 reserved pt\(hypt A bidirectional .LP I.231.5/3 permanent pt\(hypt E .LP Other combinations A .sp 1P .LP c) Access .sp 9p .RT .ce \fBH.T. [T5.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTable [T5.231], p.\fR .sp 1P .RT .ad b .RT .sp 1P .LP .sp 1 5.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service needs further study and is not yet available. .RT .sp 2P .LP \fB6\fR I.231.6\ \(em \fBCircuit\(hymode 384 kbit/s unrestricted, 8\ kHz\fR \fBstructured bearer service category\fR .sp 1P .RT .sp 1P .LP 6.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of 384\ kbitB/Fs user information over a H\d0\u\ channel at the S/T reference point. The transfer of OAM information for reserved and permanent services may be provided over a\fR D\(hychannel in the same or in another interface structure. .RT .sp 1P .LP 6.2 \fIDescription\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 6.3 \fIProcedures\fR .sp 9p .RT .PP For further study. .bp .RT .sp 1P .LP 6.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .PP It shall be possible to charge the subscriber accurately for the service. .RT .sp 1P .LP 6.5 \fIInterworking requirements\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 6.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 6.7 \fIAttributes and values of attributes of the circuit\(hymode 384\ kbit/s\fR \fIunrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP 2. Information\ transfer\ rate: 384 kbitB/Fs .LP \fR 3. Information\ transfer\ capability: unrestricted .LP \fR 4. Structure: 8 kHz integrity .LP \fR 5. Establishment\ of\ communication: demand/reserved/permanent .LP 6. Symmetry: bidirectional symmetric/bidirectional asymmetric/unidirectional (Note) .LP \fR 7. Communication\ configuration: point\(hyto\(hypoint/multipoint .LP \fR .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: H\d0\u(384) for user information D(16) or D(64) for OAM information .LP 9. Access\ protocol: I\(hySeries for D\(hychannel .sp 1P .LP \fIGeneral attributes\fR .sp 9p .RT .LP 10. Supplementary services provided .LP 11. Quality of Service .LP 12. Interworking possibilities \ for further study .LP 13. Operation and commercial aspects .PP \fINote\fR \ \(em\ Bidirectional\(hyasymmetric services are for further study. .sp 1P .LP 6.8 \fIProvision of individual circuit\(hymode 384\ kbit/s unrestricted, 8\ kHz\fR \fIstructured bearer services\fR .sp 9p .RT .sp 1P .LP a) Overall provision : | A .sp 9p .RT .sp 1P .LP b) Variations of secondary attributes: .sp 9p .RT .LP .sp 1 \fIEstablishment\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .LP I.231.6/1 demand pt\(hypt A .sp 9p .RT .LP I.231.6/2 reserved bidirectional pt\(hypt E .LP I.231.6/3 permanent pt\(hypt E .LP I.231.6/4 reserved ?04 ?05 unidirectional pt\(hypt A .LP I.231.6/5 permanent \(rb pt\(hypt A I.231.6/6 reserved ?04 ?05 bidirectional multipt A .LP I.231.6/7 permanent \(rb multipt A I.231.6/8 reserved ?04 ?05 unidirectional multipt A .LP I.231.6/9 permanent \(rb multipt A .bp .sp 1P .LP c) Access .sp 9p .RT .LP .sp 4 .ce \fBH.T. [T6.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTable [T6.231], p.\fR .sp 1P .RT .ad b .RT .sp 1P .LP .sp 4 6.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service needs further study and is not yet available. .RT .sp 2P .LP \fB7\fR I.231.7\ \(em \fBCircuit\(hymode 1536 kbit/s unrestricted, 8\ kHz\fR \fBstructured bearer service category\fR .sp 1P .RT .sp 1P .LP 7.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of 1536\ kbitB/Fs user information over a H\d1\\d1\u\ channel at the S/T reference point. Transfer of OAM information for reserved and permanent services may be provided via a D\(hychannel in another interface structure. .RT .sp 1P .LP 7.2 \fIDescription\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 7.3 \fIProcedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 7.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .PP It shall be possible to charge the subscriber accurately for the service. .RT .sp 1P .LP 7.5 \fIInterworking requirements\fR .sp 9p .RT .PP For further study. .bp .RT .sp 1P .LP 7.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 7.7 \fIAttributes and values of attributes of the circuit\(hymode 1536\ kbitB/Fs\fR \fIunrestricted, 8\ kHz structured bearer service category\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP 2. Information\ transfer\ rate: 1536 kbit/s .LP \fR 3. Information\ transfer\ capability: unrestricted .LP \fR 4. Structure: 8 kHz integrity .LP \fR 5. Establishment\ of\ communication: demand/reserved/permanent .LP \fR 6. Symmetry: bidirectional symmetric/bidirectional asymmetric/unidirectional (Note) .LP 7. Communication\ configuration: point\(hyto\(hypoint/multipoint .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: H\d1\\d1\u(1536) for user information D(16) or D(64) for OAM signalling .LP 9. Access\ protocol: I\(hySeries for D\(hychannel .sp 1P .LP \fIGeneral attributes\fR .sp 9p .RT .LP 10. Supplementary services provided .LP 11. Quality of Service .LP 12. Interworking possibilities \ for further study .LP 13. Operation and commercial aspects .PP \fR \fINote\fR \ \(em\ Bidirectional\(hyasymmetric services are for further study. .sp 1P .LP 7.8 \fIProvision of individual circuit\(hymode 1536\ kbit/s unrestricted,\fR \fI8\ kHz structured bearer services\fR .sp 9p .RT .sp 1P .LP a) Overall provision : | A .sp 9p .RT .sp 1P .LP b) Variations of secondary attributes: .sp 9p .RT .LP .sp 1 .LP \fIEstablishment\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .LP I.231.7/1 demand pt\(hypt A .sp 9p .RT .LP I.231.7/2 reserved bidirectional pt\(hypt E .LP I.231.7/3 permanent pt\(hypt E I.231.7/4 reserved ?04 ?05 unidirectional pt\(hypt A .LP I.231.7/5 permanent \(rb pt\(hypt A .LP I.231.7/6 reserved ?04 ?05 bidirectional multipt A .LP I.231.7/7 permanent \(rb multipt A I.231.7/8 reserved ?04 ?05 unidirectional multipt A .LP I.231.7/9 permanent \(rb multipt A .LP .sp 2 .bp .sp 1P .LP c) Access .sp 9p .RT .LP .sp 3 .ce \fBH.T. [T7.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTable [T7.231], p.\fR .sp 1P .RT .ad b .RT .sp 1P .LP .sp 3 7.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service needs further study and is not yet available. .RT .sp 2P .LP \fB8\fR I.231.8\ \(em \fBCircuit\(hymode 1920 kbit/s unrestricted,\fR \fB8\ kHz structured bearer service category\fR .sp 1P .RT .sp 1P .LP 8.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer of 1920\ kbit/s user information over a H\d1\\d2\uchannel at the S/T reference point. The transfer of OAM information for reserved and permanent services may be provided over a D\(hychannel. .RT .sp 1P .LP 8.2 \fIDescription\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 8.3 \fIProcedures\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 8.4 \fINetwork aspects for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .PP It shall be possible to charge the subscriber accurately for the service. .RT .sp 1P .LP 8.5 \fIInterworking requirements\fR .sp 9p .RT .PP For further study. .bp .RT .sp 1P .LP 8.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP For further study. .RT .sp 1P .LP 8.7 \fIAttributes and values of attributes of the circuit\(hymode\fR \fI1920\ kbit/s unrestricted, 8 kHz structured bearer service category\fR .sp 9p .RT .sp 1P .LP \fR \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: circuit .LP \fR 2. Information\ transfer\ rate: 1920 kbit/s .LP \fR 3. Information\ transfer\ capability: unrestricted .LP \fR 4. Structure: 8 kHz integrity .LP \fR 5. Establishment\ of\ communication: demand/reserved/permanent .LP \fR 6. Symmetry: bidirectional symmetric/bidirectional asymmetric/unidirectional .LP (Note) .LP 7. Communication\ configuration: point\(hyto\(hypointB/Fmultipoint .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: H\d1\\d2\u(1920) for user information D(64) for OAM information .LP 9. Access\ protocol: I\(hySeries for D\(hychannel .sp 1P .LP \fIGeneral attributes\fR .sp 9p .RT .LP 10. Supplementary services provided \(em\ Refer to Recommendation I.250 .LP 11. Quality of Service ?04 12. Interworking possibilities ?05\ for further study 13. Operation and commercial aspects \(rb .PP \fINote 1\fR \ \(em\ Bidirectional\(hyasymmetric services are for further study. .sp 1P .LP 8.8 \fIProvision of individual circuit\(hymode 1920\ kbit/s unrestricted,\fR \fI8\ kHz structured bearer services\fR .sp 9p .RT .sp 1P .LP a) Overall provision : | A .sp 9p .RT .sp 1P .LP b) Variations of secondary attributes: .sp 9p .RT .LP .sp 1 \fIEstablishment\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .LP I.231.8/1 demand pt\(hypt A .sp 9p .RT .LP I.231.8/2 reserved bidirectional pt\(hypt E .LP I.231.8/3 permanent pt\(hypt E .LP I.231.8/4 reserved ?04 ?05 unidirectional pt\(hypt A .LP I.231.8/5 permanent \(rb pt\(hypt A I.231.8/6 reserved ?04 ?05 bidirectional multipt A .LP I.231.8/7 permanent \(rb multipt A I.231.8/8 reserved ?04 ?05 unidirectional multipt A .LP I.231.8/9 permanent \(rb multipt A .LP .sp 1 .bp .sp 1P .LP c) Access .sp 9p .RT .ce \fBH.T. [T8.231]\fR .T& lw(42p) | lw(54p) | lw(42p) | lw(48p) | lw(42p) . .TE .nr PS 9 .RT .ad r \fBTable [T8.231], p.\fR .sp 1P .RT .ad b .RT .sp 1P .LP 8.9 \fIDynamic description\fR .sp 9p .RT .PP The dynamic description for this service needs further study and is not yet available. .RT .sp 2P .LP \fBRecommendation\ I.232\fR .RT .sp 2P .sp 1P .ce 1000 \fBPACKET\(hyMODE\ BEARER\ SERVICES\ CATEGORIES\fR .EF '% Fascicle\ III.7\ \(em\ Rec.\ I.232'' .OF '''Fascicle\ III.7\ \(em\ Rec.\ I.232 %' .ce 0 .sp 1P .ce 1000 \fI(Melbourne, 1988)\fR .sp 9p .RT .ce 0 .sp 1P .PP Recommendation I.210 describes the principles for defining telecommunication services supported by an ISDN including the concept of bearer services, teleservices and supplementary services. It also provides the means for the definition and description of such services. .sp 1P .RT .PP The purpose of this Recommendation is to define a recommended set of packet\(hymode bearer services categories, to describe individual packet\(hymode bearer services and to recommend their provision in ISDN. The definitions and descriptions form the basis to define the network capabilities required for the support of the services in ISDN. .PP Bearer service categories are described by prose definitions and descriptions, by attributes and their values and by dynamic descriptions following the description method given in Recommendation\ I.130. The application of the attribute technique and the definitions of these attributes and attribute values is given in Recommendation I.140. .PP The following set of bearer service categories is currently identified and more may be identified in the future: .RT .LP I.232.1 Virtual call and permanent virtual circuit bearer service category, .LP I.232.2 Connectionless bearer service category, .LP I.232.3 User signalling bearer service category. .sp 2P .LP \fB1\fR I.232.1\ \(em \fBVirtual call and permanent virtual circuit\fR \fBbearer service category\fR .sp 1P .RT .sp 1P .LP 1.1 \fIDefinition\fR .sp 9p .RT .PP This bearer service category provides the unrestricted transfer (without alteration) of user information in a packetized manner over a virtual circuit within a B\(hy or D\(hychannel at the SB/FT reference point. Signalling information for virtual call andB/For possibly OAM information for permanent virtual circuit services are transferred via B\(hy or D\(hychannels as described in Recommendation\ I.462 (X.31). .bp .RT .sp 2P .LP 1.2 \fIDescription\fR .sp 1P .RT .sp 1P .LP 1.2.1 \fIGeneral description\fR .sp 9p .RT .PP This packet\(hymode bearer service category allows users (e.g.\ terminals) in a point\(hyto\(hypoint communication configuration to communicate via the ISDN using X.25 encoding, by means of Recommendation\ I.462 (X.31) procedures over either B\(hy or D\(hychannels, in both directions continuously and simultaneously for the duration of a call. .RT .sp 1P .LP 1.2.2 \fISpecific terminology\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 1.2.3 \fIQualifications\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 1.3 \fIProcedures\fR .sp 9p .RT .PP Detailed procedures for virtual calls appear in Recommendation\ I.462\ (X.31), case B. The description below is a synopsis of those procedures. For actual, complete procedures, refer to Recommendation\ I.462. .RT .sp 1P .LP 1.3.1 \fIProvision/withdrawal\fR .sp 9p .RT .PP For further study. .RT .sp 2P .LP 1.3.2 \fINormal procedures\fR .sp 1P .RT .sp 1P .LP 1.3.2.1 \fIActivation/deactivation/registration\fR .sp 9p .RT .PP Not applicable. .RT .sp 2P .LP 1.3.2.2 \fIInvocation and operation\fR .sp 1P .RT .sp 1P .LP 1.3.2.2.1 \fIVirtual call procedures\fR \v'3p' .sp 9p .RT .LP a) \fICall establishment\fR .LP For virtual calls, X.25 will be used on an active channel (B\ or\ D) to the packet handler. In order to establish that channel and/or to negotiate the type of channel to be used, out\(hyof\(hyband signalling procedures may be used. Once connected to the packet handler, remaining call information, including called user address, are signalled in the X.25 call request. .LP b) \fIData transfer phase\fR .LP Once established, the virtual circuit is then available for unrestricted X.25 data transfer in both directions continuously and simultaneously. During the data transfer phase, information exchange occurs with the following characteristics, among others: .LP \(em packetized; .LP \(em flow control; .LP \(em delivery confirmation (optional); .LP \(em reset/interrupt. .LP c) \fITerminating the call\fR .LP The call may be terminated by either or both of the users by indicating this to the network. In either case, an appropriate indication is sent to the other user. The active channel may be released after the termination of the last virtual call on that channel. .bp .sp 1P .LP 1.3.2.2.2 \fIPermanent virtual circuit procedures\fR .sp 9p .RT .PP For permanent virtual circuits on B\(hy or D\(hychannels, there is no call set\(hyup or clearing. For permanent virtual circuits using B\(hychannel access, a semi\(hypermanent connection of the channel to the packet handler must be in place. The procedures for the control of packets between user terminal equipment and network are covered by X.25 data transfer phase. .RT .sp 1P .LP 1.3.2.3 \fIInterrogationB/Fediting\fR .sp 9p .RT .PP Not applicable. .RT .sp 2P .LP 1.3.3 \fIExceptional procedures\fR .sp 1P .RT .sp 1P .LP 1.3.3.1 \fIActivationB/FdeactivationB/Fregistration\fR .sp 9p .RT .PP Not applicable. .RT .sp 2P .LP 1.3.3.2 \fIInvocation and operation\fR .sp 1P .RT .sp 1P .LP 1.3.3.2.1 \fIVirtual call\fR .sp 9p .RT .PP In case of failure situations due to calling/called user error, user state, or network conditions, appropriate failure indications will be signalled from the network and the call set\(hyup or established call may be terminated. For detailed procedures, see Recommendation\ I.462. .RT .sp 1P .LP 1.3.3.2.2 \fIPermanent virtual circuit\fR .sp 9p .RT .PP In case of failure situations due to user error, user state, or network conditions, appropriate failure indications will be signalled from the network. For detailed procedures, see Recommendation\ I.462. .RT .sp 1P .LP 1.3.3.3 \fIInterrogation/editing\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 1.3.4 \fIAlternative procedures\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 1.3.5 \fIVerification\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 1.4 \fINetwork capabilities for charging\fR .sp 9p .RT .PP This Recommendation does not cover charging principles. Future Recommendations in the D\(hySeries are expected to contain that information. .RT .sp 1P .LP 1.4.1 \fIVirtual call charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the virtual call service. .RT .sp 1P .LP 1.4.2 \fIPermanent virtual circuit charging\fR .sp 9p .RT .PP It shall be possible to charge the subscriber accurately for the permanent virtual circuit service. .bp .RT .sp 1P .LP 1.5 \fIInterworking requirements\fR .sp 9p .RT .PP General interworking arrangements for this bearer service category are defined in Recommendation\ X.300. Specific interworking procedures are in Recommendation\ I.462. .RT .sp 1P .LP 1.6 \fIInteraction with supplementary services\fR .sp 9p .RT .PP Not applicable. .RT .sp 1P .LP 1.7 \fIAttributes and values of attributes \fIof the virtual call\fR \fIand permanent virtual circuit bearer service category\fR .sp 9p .RT .sp 1P .LP \fIInformation transfer attributes\fR .sp 9p .RT .LP 1. Information\ transfer\ mode: packet .LP 2. Information\ transfer\ rate: maximum throughput of a given virtual circuit is less than or equal to the maximum bit rate of the user information access channel and the throughput class of the virtual circuit (Note) .LP 3. Information\ transfer\ capability: unrestricted .LP 4. Structure: service data unit integrity .LP 5. Establishment\ of\ communication: demand (virtual call)/permanent (permanent virtual circuit) .LP 6. Symmetry: bidirectional symmetric .LP 7. Communication\ configuration: point\(hyto\(hypoint .sp 1P .LP \fIAccess attributes\fR .sp 9p .RT .LP 8. Access\ channel: user information over virtual circuit within B\(hy or D\(hychannel. When D\(hychannel is used, maximum packet size and Quality of Service may be restricted. Signalling may be provided via D\(hychannel and/or virtual circuit within B\(hychannel .LP 9. Access\ protocol: as specified in Recommendations I.440, I.450, I.451, I.462 and X.25 (layers 2 and 3) .sp 1P .LP \fIGeneral attributes\fR .sp 9p .RT .LP 10. Supplementary\ services\ provided: as listed in Recommendation X.2. Others are for further study .LP 11. Quality of Service ?04 12. Interworking possibilities ?05\ for further study 13. Operational and commercial aspects \(rb .PP \fINote\fR \ \(em\ The exact values of information transfer rates for the virtual call and permanent virtual circuit are for further study. .sp 1P .LP 1.8 \fIProvision of virtual call and permanent virtual circuit bearer\fR \fIservice\fR \v'3p' .sp 9p .RT .LP a) Overall provision: | E .LP b) Variations of secondary attributes: .sp 2P .LP \fIEstablishment de\fR \fISymmetry\fR \fICommunication\fR \fIProvision\fR \fIof communication\fR \fIof configuration\fR \fIProvision\fR .sp 1P .RT .sp 1P .LP demand ?04 pt\(hypt E ?05 bidirectional symmetric .sp 9p .RT .LP permanent \(rb pt\(hypt E .bp .sp 1P .LP c) \fIAccess\fR .sp 9p .RT .ce \fBH.T. [T1.232]\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(30p) sw(30p) | cw(30p) sw(30p) | cw(30p) sw(30p) | cw(48p) , c | c | c | c | c | c | ^ . { Access channel control Signalling and OAM (Notes 1 and 2) } { Virtual call control Signalling and OAM (Notes 1 and 3) } User information Provision Channel and rate Protocols Channel and rate Protocols Channel and rate Protocols _ .T& cw(30p) | cw(30p) | cw(30p) | lw(30p) | cw(30p) | lw(30p) | cw(48p) . D(16) I.451 I.441 I.430 B(64) X.25, L3 X.25, L2 I.430 B(64) X.25, L3 X.25, L2 I.430 A _ .T& cw(30p) | cw(30p) | cw(30p) | lw(30p) | cw(30p) | lw(30p) | cw(48p) . D(64) I.451 I.441 I.431 B(64) X.25, L3 X.25, L2 I.431 B(64) X.25, L3 X.25, L2 I.431 A _ .T& cw(30p) | cw(30p) | cw(30p) | lw(30p) | cw(30p) | lw(30p) | cw(48p) . D(16) I.451 I.441 I.430 D(16) X.25, L3 I.441 I.430 D(16) X.25, L3 I.441 I.430 A _ .T& cw(30p) | cw(30p) | cw(30p) | lw(30p) | cw(30p) | lw(30p) | cw(48p) . D(64) I.451 I.441 I.431 D(64) X.25, L3 I.441 I.431 D(64) X.25, L3 I.441 I.431 { A L1, L2 and L3 \ Layer 1, layer 2 and layer 3 } .TE \fINote\ 1\fR \ \(em\ The definition of other protocols for OAM is for further study. .LP \fINote\ 2\fR \ \(em\ The protocols listed in this column are for establishing communications with the packet handling function using out\(hyof\(hyband call control signals. This procedure does not apply in certain cases (for example, semi\(hypermanent D\(hychannel connection). .LP \fINote\ 3\fR \ \(em\ The protocols listed in this column are for the establishment of a virtual circuit using X.25\ procedures. These procedures do not apply to permanent virtual circuits. .nr PS 9 .RT .ad r \fBTable [T.1232], p.\fR .sp 1P .RT .ad b .RT .sp 1P .LP 1.9 \fIDynamic description\fR .sp 9p .RT .PP Dynamic descriptions for the Recommendation I.462 procedures in the virtual call and permanent virtual circuit bearer service category are for future study. State transition diagrams for layer\ 3 of Recommendation\ X.25 (Annex\ B) apply for virtual call and permanent virtual circuit. .RT .sp 2P .LP \fB2\fR I.232.2\ \(em \fBConnectionless bearer service category\fR .sp 1P .RT .PP \fINote\fR \ \(em\ This connectionless bearer service category is a different concept from, and should not be confused with, the OSI Connectionless Mode Network Service. Thus, the name of this service may change as the service is better defined. .PP Further aspects of this bearer service category are for further study. .RT .sp 2P .LP \fB3\fR I.232.3\ \(em \fBUser signalling bearer service category\fR .sp 1P .RT .PP \fINote\fR \ \(em\ This service is different from, and should not be confused with, the user\(hyto\(hyuser signalling supplementary service (see Recommendation\ I.257). The user\(hyto\(hyuser signalling supplementary service is used in conjunction with either a bearer service or a teleservice. The user signalling bearer service category stands on its own and is not used in conjunction with a bearer service or a teleservice. .PP Further aspects of this bearer service category are for further study. .RT .LP .bp