SECTION 2 - BASIC SERVICES Contents of Recommendation Q.71 ISDN 64 kbit/s circuit mode switched bearer service Page 1. Introduction .................................................. 26 1.1 General ....................................................... 26 1.2 Definition of services ........................................ 26 1.3 Service invocation ............................................ 28 2. Call setup and release ........................................ 28 2.1 Functional model .............................................. 28 2.2 Information flows ............................................. 29 2.3 Nodal SDLs .................................................... 40 2.4 Functional Entity Actions (FEAs) .............................. 71 2.5 Allocation of functions to physical entities .................. 76 3. In-call modification procedures for alternate speech/unrestricted information transfer service .............. 79 3.1 Introduction .................................................. 79 3.2 Functional model .............................................. 79 3.3 Information flows for in-call modification .................... 80 3.4 SDL diagrams .................................................. 81 3.5 Functional entity action required for in-call modification procedures ............................... 87 * * * SECTION 2 - BASIC SERVICES FIGURE 2-9/Q.71 (Sheet 16 of 19) CC Functional Entity (r1-r1) cont. FIGURE 2-9/Q.71 (Sheet 17 of 19) CC Functional Entity (r1-r1) cont. FIGURE 2-9/Q.71 (Sheet 18 of 19) CC Functional Entity (r1-r1) cont. FIGURE 2-9/Q.71 (Sheet 19 of 19) CC Functional Entity (r1-r1) cont. Reference Number Action 451 Disconnect - Recognize user DISCONNECT.req - Formulate DISCONNECT req.ind - Disconnect resources 452 Release Resources - Receive and react to RELEASE req.ind - Release resources - both directions - Formulate RELEASE resp.conf 2.5 Additional FEAs required for digit-by-digit call setup cases: Reference Number Action 212 Process Attempt - Interact with user to obtain call address - Formulate messages to send address information to CC - Determine end of dialling and so indicate to CC (if required) 213 Process Attempt - Interact with user to obtain call address - Formulate messages to send address information to CC 226 Perform Originating Screening - Receive and react to SETUP indication - Analyze service request - Identify calling user, terminal characteristics and user priority level - Verify user's authorization, capabilities and availability of appropriate resources - Establish call reference - Formulate ACKNOWLEDGE req.ind 227 Process Attempt - Reserve incoming resources - Analyze information (called number, routing requirements, etc.) - Determine connection elements type, outgoing resource (or virtual circuit), other resources (echo control, pads, etc.), charging treatment, network management controls in effect and any other elements involved in call setup - Select resources - Select path through entity - Reserve outgoing resource and any other required resources - Formulate appropriate SETUP, ADDL ADDR and ADDR END req.inds - Start call control timing, as required 233 Process Attempt - Receive and analyze SETUP, ADDL ADDR and ADDR END req.inds, as required - Establish call reference - Reserve incoming resources - Analyze called number, routing information, network management and/or priority information - Determine connection elements type, outgoing resource, need for other resources - Select and reserve outgoing resource, other resources as required and path through the entity - Formulate SETUP, ADDL ADDR and ADDR END req.inds as required Through Connect - Establish through connection as required (see Note 1 to Figures 2-2/Q.71 to 2-6/Q.71). 2.6 Allocation of functions to physical entities The functional model relates to functions involved in handling a single call or call attempt. The scenarios in Table 2-2/Q.71 identify the roles a physical device (e.g., exchange, NT2, terminal equipment, etc.) may play in handling that call or call attempt. A specific physical device may fulfill different roles in different scenarios, e.g., a local exchange may provide both CCA and CC capabilities. (See scenario D.) TABLE 2-2/Q.71 Physical allocation of functions Legend: Entities connected by dashed line are the same physical entity TE = Terminal Equipment LE = Local Exchange NT2 = Network Termination 2 TR = Transit Exchange Note 1 - In scenario B, the NT2 provides the CC function of the TE and appears to be a CCA to the LE (e.g., when the NT2 is a PABX). 3. In call modification procedures for alternate speech/unrestricted information transfer service 3.1 Introduction This  contains information on in-call modification procedures that are required for alternate speech/unrestricted information transfer service. Call setup and clearing procedures are basically the same as those for speech, 3.1 kHz audio and unrestricted information transfer services. Thus, the call setup and clearing procedures described in  1 and 2 apply to this service also. However, once a connection has been established, the change of use of the bearer service from speech to unrestricted information transfer or vice versa, may require the removal/addition of resources or functions from/to the connection (e.g., echo or loss control). Also, user terminals may be single mode or multiple mode types. Single mode terminals require that the user/network access resource be transferred from one terminal to another during the modification process. Thus, upon receipt of a request from either the calling or called user, the network effects the procedures needed to condition the connection for the alternate use. The procedure for changing terminals, if necessary (as in the case of single mode terminals), can be accomplished by either of two methods: a) the user temporarily suspends service, manually transfers the access resource to another terminal and then resumes use of the service; b) the user requests the network to transfer the access resource to another terminal and the network responds by placing the original connection on "hold" and then initiates a SETUP to another terminal at the same location. After SETUP to the second terminal is confirmed, the connection to the first terminal is released. 3.2 Functional model The functional model for the alternate speech/unrestricted information transfer service is the same as shown in  2.1. However, in the description of in-call modification procedures, CCAs are added, as in Figure 2-7/Q.71. FIGURE 2-7/Q.71 Functional model used to illustrate alternate speech/unrestricted information transfer service modification procedures The Call Control Agents (CCAs) at locations 1, 2, 6 and 7 provide access to/from the user/ISDN access resources for user terminals. They have the capabilities and characteristics required to interact with the network. They may be associated with either the originating or terminating ends of the bearer service call. The Call Control entity (CC) at location 3 is the Call Control entity at which the in-call modification request is received from the user. The CC at location 4 represents other network entities through which the bearer service connection passes. The CC at location 5 is the Call Control entity that interfaces the CCA serving the user terminal at the other end of the call. r1 and r2 are relationships between the functional entities wherein information flows occur in order to process the in-call modification requests. 3.3 Information flows for in-call modification 3.3.1 Information flow diagrams for in-call modification procedures Figure 2-8/Q.71 - Procedures where both terminals have multiple mode capability Figure 2-9/Q.71 - Procedures where single mode terminals are involved and terminal transfer is accomplished manually by the users Figure 2-10/Q.71 - Procedures where the user requesting the alternate use has a single mode terminal and requests the network to connect to an alternate terminal Figure 2-11/Q.71 - Procedures where the user not requesting the alternate use requests the network to connect to an alternate terminal 3.3.2 Definition of information flows needed for in-call modification procedures (in addition to those in  2.2.2) 3.3.2.1 HOLD req.ind is used to request that a user access resource be placed in a "hold" condition (reserved) while other actions are occurring. This is a confirmed information flow and appears within the r1 relationship. The HOLD request itself is the main item of information conveyed in the HOLD req.ind information flow. 3.3.2.2 MODIFY req.ind is used to request the modification of service characteristics by removing/inserting functions as required. This is used in connection with in-call modification for alternate service use of a bearer connection. This is a confirmed information flow within the relationship of r1 and r2. The main item of information conveyed in the MODIFY req.ind is the request for modification of the connection and of terminal(s) as required. 3.3.2.3 RESUME req.ind and resp.conf is an information flow that undoes a "suspend" state of a call. It is a confirmed information flow within the r1 relationship. The main item of information conveyed in the RESUME req.ind/resp.conf is the information that use of the connection by the users may be resumed and the process of modification can proceed. 3.3.2.4 SUSPEND req.ind and resp.conf is a type of "hold" procedure that allows a user to transfer terminals on his user access without disconnecting the call. It is a confirmed information flow within the r1 relationship. The main item of information conveyed in the SUSPEND req.ind/resp.conf is that use of the connection will be suspended while terminal changes are made. 3.4 SDL diagrams SDLs that describe in-call modification procedures have still to be developed. Notes for Figures 2-8/Q.71 through 2-11/Q.71 Note 1 - Through connection is dependent on the physical location of the functional entity: a) Originating Local Exchange i) for 3.1 kHz audio bearer service, speech and telephony services, backwards only or both directions, depending on the approach adopted by the administration or RPOA; ii) for 64 kbit/s unrestricted information transfer, backwards only, except for own-exchange calls, which may be either backwards only or in both directions at the discretion of the administration or RPOA. b) Transit exchange - both directions. c) Terminating local exchange - no through connection at this stage of call setup, except as a national option for certain classes of users, e.g., PABXs. d) NT2 - may through connect as required. Note 2 - If not already done, complete the through connection in both directions. Note 3 - The method of initiating and stopping charging will depend on the administration's method of charging for service (e.g., pulse metering, recording call detail and billing, etc.). The charging function may be performed at different entities at the discretion of the administration and/or RPOA. Note 4 - Further study is required on the possible inclusion of an entity from/to which information is passed and on the information flows themselves. The "Notify" information may or may not be sent to the user terminal and/or user depending on the terminals involved. Note 5 - The intended use of the service (transfer capability required, e.g., speech, 3.1 kHz audio, unrestricted or alternate speech/unrestricted information transfer) must be indicated as an element of the call SETUP information flow from the CCA to the CC. Note 6 - Tones are used with speech and 3.1 kHz bearer services and telephony. The use of disconnect tone is a national option. Note 7 - This is the CC at which the MODIFY request is received from the CCA (may be either the originating or the terminating local exchange with respect to the direction of the speech/unrestricted information transfer call setup). 3.5 Functional entity actions required for in-call modification procedures Reference Number Action 611 Process Attempt - Receive and react to SETUP req.ind - Send SETUP.ind to user - Formulate alerting REPORT req.ind 621 Process/Reserve - Receive and react to MODIFY req.ind - Verify that call is alternate speech/unrestricted - information transfer - Reserve resources as required - Formulate MODIFY req.ind - Start timer 622 Connect or Disconnect Resources - Receive and react to MODIFY resp.conf - Connect or disconnect resources, as required - Formulate MODIFY resp.conf 623 Suspend - Receive and react to SUSPEND req.ind - Formulate SUSPEND resp.conf and REPORT req.ind 624 Resume - Receive and react to RESUME req.ind - Formulate RESUME resp.conf and REPORT req.ind 625 Hold Resources - Receive and react to MODIFY req.ind - Recognize that a different user terminal is required - Formulate HOLD req.ind and REPORT req.ind 626 SETUP - Receive and react to HOLD resp.conf - Initiate SETUP req.ind and REPORT req.ind 627 Apply Ring Tone (Note 6) - Receive and react to alerting REPORT req.ind - Formulate REPORT req.ind - Apply Ring Tone to circuit toward distant user 628 Process/Reserve - Receive and react to SETUP resp.conf - Reserve resources as required - Formulate MODIFY req.ind Remove Tone - Remove ring tone, if it was applied 629 Connect or Disconnect Resources - Receive and react to MODIFY resp.conf - Connect or disconnect resources, as required - Formulate MODIFY resp.conf - Initiate disconnect procedures for Terminal 1 631 Process/Reserve - Receive and react to MODIFY req.ind - Reserve resources as required - Formulate MODIFY req.ind 632 Connect or Disconnect Resources - Receive and react to MODIFY resp.conf - Connect or disconnect resources, as required - Formulate MODIFY resp.conf 641 Process/Reserve - Receive and react to MODIFY req.ind - Reserve resources as required - Formulate MODIFY req.ind 642 Connect or Disconnect Resources - Receive and react to MODIFY resp.conf - Connect or disconnect resources, as required - Formulate MODIFY resp.conf 643 Suspend - Receive and react to SUSPEND req.ind - Formulate SUSPEND resp.conf and REPORT req.ind 644 Resume - Receive and react to RESUME req.ind - Formulate RESUME resp.conf and REPORT req.ind 645 Hold Resources - Receive and react to MODIFY (w/change) resp.conf - Formulate HOLD req.ind and REPORT req.ind 646 Setup - Receive and react to HOLD resp.conf - Initiate SETUP req.ind 647 Apply Ring Tone (Note 6) - Receive and react to alerting indication - Formulate REPORT req.ind - Apply ring tone to circuit toward distant user 648 Remove Tone - Receive and react to SETUP resp.conf - If applied, remove ring tone Connect or Disconnect Resources - Connect or disconnect resources as required - Formulate MODIFY resp.conf - Initiate disconnect procedures for Terminal Y 651 Process Attempt - Receive and react to SETUP req.ind - Send SETUP.ind to Terminal Z - Formulate alerting REPORT req.ind 컴컴컴컴컴컴컴컴컴컴